linux/kernel/module.c
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   1/*
   2   Copyright (C) 2002 Richard Henderson
   3   Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18*/
  19#include <linux/export.h>
  20#include <linux/moduleloader.h>
  21#include <linux/ftrace_event.h>
  22#include <linux/init.h>
  23#include <linux/kallsyms.h>
  24#include <linux/file.h>
  25#include <linux/fs.h>
  26#include <linux/sysfs.h>
  27#include <linux/kernel.h>
  28#include <linux/slab.h>
  29#include <linux/vmalloc.h>
  30#include <linux/elf.h>
  31#include <linux/proc_fs.h>
  32#include <linux/security.h>
  33#include <linux/seq_file.h>
  34#include <linux/syscalls.h>
  35#include <linux/fcntl.h>
  36#include <linux/rcupdate.h>
  37#include <linux/capability.h>
  38#include <linux/cpu.h>
  39#include <linux/moduleparam.h>
  40#include <linux/errno.h>
  41#include <linux/err.h>
  42#include <linux/vermagic.h>
  43#include <linux/notifier.h>
  44#include <linux/sched.h>
  45#include <linux/stop_machine.h>
  46#include <linux/device.h>
  47#include <linux/string.h>
  48#include <linux/mutex.h>
  49#include <linux/rculist.h>
  50#include <asm/uaccess.h>
  51#include <asm/cacheflush.h>
  52#include <asm/mmu_context.h>
  53#include <linux/license.h>
  54#include <asm/sections.h>
  55#include <linux/tracepoint.h>
  56#include <linux/ftrace.h>
  57#include <linux/async.h>
  58#include <linux/percpu.h>
  59#include <linux/kmemleak.h>
  60#include <linux/jump_label.h>
  61#include <linux/pfn.h>
  62#include <linux/bsearch.h>
  63#include <linux/fips.h>
  64#include <uapi/linux/module.h>
  65#include "module-internal.h"
  66
  67#define CREATE_TRACE_POINTS
  68#include <trace/events/module.h>
  69
  70#ifndef ARCH_SHF_SMALL
  71#define ARCH_SHF_SMALL 0
  72#endif
  73
  74/*
  75 * Modules' sections will be aligned on page boundaries
  76 * to ensure complete separation of code and data, but
  77 * only when CONFIG_DEBUG_SET_MODULE_RONX=y
  78 */
  79#ifdef CONFIG_DEBUG_SET_MODULE_RONX
  80# define debug_align(X) ALIGN(X, PAGE_SIZE)
  81#else
  82# define debug_align(X) (X)
  83#endif
  84
  85/*
  86 * Given BASE and SIZE this macro calculates the number of pages the
  87 * memory regions occupies
  88 */
  89#define MOD_NUMBER_OF_PAGES(BASE, SIZE) (((SIZE) > 0) ?         \
  90                (PFN_DOWN((unsigned long)(BASE) + (SIZE) - 1) - \
  91                         PFN_DOWN((unsigned long)BASE) + 1)     \
  92                : (0UL))
  93
  94/* If this is set, the section belongs in the init part of the module */
  95#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
  96
  97/*
  98 * Mutex protects:
  99 * 1) List of modules (also safely readable with preempt_disable),
 100 * 2) module_use links,
 101 * 3) module_addr_min/module_addr_max.
 102 * (delete uses stop_machine/add uses RCU list operations). */
 103DEFINE_MUTEX(module_mutex);
 104EXPORT_SYMBOL_GPL(module_mutex);
 105static LIST_HEAD(modules);
 106#ifdef CONFIG_KGDB_KDB
 107struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 108#endif /* CONFIG_KGDB_KDB */
 109
 110#ifdef CONFIG_MODULE_SIG
 111#ifdef CONFIG_MODULE_SIG_FORCE
 112static bool sig_enforce = true;
 113#else
 114static bool sig_enforce = false;
 115
 116static int param_set_bool_enable_only(const char *val,
 117                                      const struct kernel_param *kp)
 118{
 119        int err;
 120        bool test;
 121        struct kernel_param dummy_kp = *kp;
 122
 123        dummy_kp.arg = &test;
 124
 125        err = param_set_bool(val, &dummy_kp);
 126        if (err)
 127                return err;
 128
 129        /* Don't let them unset it once it's set! */
 130        if (!test && sig_enforce)
 131                return -EROFS;
 132
 133        if (test)
 134                sig_enforce = true;
 135        return 0;
 136}
 137
 138static const struct kernel_param_ops param_ops_bool_enable_only = {
 139        .set = param_set_bool_enable_only,
 140        .get = param_get_bool,
 141};
 142#define param_check_bool_enable_only param_check_bool
 143
 144module_param(sig_enforce, bool_enable_only, 0644);
 145#endif /* !CONFIG_MODULE_SIG_FORCE */
 146#endif /* CONFIG_MODULE_SIG */
 147
 148/* Block module loading/unloading? */
 149int modules_disabled = 0;
 150core_param(nomodule, modules_disabled, bint, 0);
 151
 152/* Waiting for a module to finish initializing? */
 153static DECLARE_WAIT_QUEUE_HEAD(module_wq);
 154
 155static BLOCKING_NOTIFIER_HEAD(module_notify_list);
 156
 157/* Bounds of module allocation, for speeding __module_address.
 158 * Protected by module_mutex. */
 159static unsigned long module_addr_min = -1UL, module_addr_max = 0;
 160
 161int register_module_notifier(struct notifier_block * nb)
 162{
 163        return blocking_notifier_chain_register(&module_notify_list, nb);
 164}
 165EXPORT_SYMBOL(register_module_notifier);
 166
 167int unregister_module_notifier(struct notifier_block * nb)
 168{
 169        return blocking_notifier_chain_unregister(&module_notify_list, nb);
 170}
 171EXPORT_SYMBOL(unregister_module_notifier);
 172
 173struct load_info {
 174        Elf_Ehdr *hdr;
 175        unsigned long len;
 176        Elf_Shdr *sechdrs;
 177        char *secstrings, *strtab;
 178        unsigned long symoffs, stroffs;
 179        struct _ddebug *debug;
 180        unsigned int num_debug;
 181        bool sig_ok;
 182        struct {
 183                unsigned int sym, str, mod, vers, info, pcpu;
 184        } index;
 185};
 186
 187/* We require a truly strong try_module_get(): 0 means failure due to
 188   ongoing or failed initialization etc. */
 189static inline int strong_try_module_get(struct module *mod)
 190{
 191        BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
 192        if (mod && mod->state == MODULE_STATE_COMING)
 193                return -EBUSY;
 194        if (try_module_get(mod))
 195                return 0;
 196        else
 197                return -ENOENT;
 198}
 199
 200static inline void add_taint_module(struct module *mod, unsigned flag,
 201                                    enum lockdep_ok lockdep_ok)
 202{
 203        add_taint(flag, lockdep_ok);
 204        mod->taints |= (1U << flag);
 205}
 206
 207/*
 208 * A thread that wants to hold a reference to a module only while it
 209 * is running can call this to safely exit.  nfsd and lockd use this.
 210 */
 211void __module_put_and_exit(struct module *mod, long code)
 212{
 213        module_put(mod);
 214        do_exit(code);
 215}
 216EXPORT_SYMBOL(__module_put_and_exit);
 217
 218/* Find a module section: 0 means not found. */
 219static unsigned int find_sec(const struct load_info *info, const char *name)
 220{
 221        unsigned int i;
 222
 223        for (i = 1; i < info->hdr->e_shnum; i++) {
 224                Elf_Shdr *shdr = &info->sechdrs[i];
 225                /* Alloc bit cleared means "ignore it." */
 226                if ((shdr->sh_flags & SHF_ALLOC)
 227                    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
 228                        return i;
 229        }
 230        return 0;
 231}
 232
 233/* Find a module section, or NULL. */
 234static void *section_addr(const struct load_info *info, const char *name)
 235{
 236        /* Section 0 has sh_addr 0. */
 237        return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
 238}
 239
 240/* Find a module section, or NULL.  Fill in number of "objects" in section. */
 241static void *section_objs(const struct load_info *info,
 242                          const char *name,
 243                          size_t object_size,
 244                          unsigned int *num)
 245{
 246        unsigned int sec = find_sec(info, name);
 247
 248        /* Section 0 has sh_addr 0 and sh_size 0. */
 249        *num = info->sechdrs[sec].sh_size / object_size;
 250        return (void *)info->sechdrs[sec].sh_addr;
 251}
 252
 253/* Provided by the linker */
 254extern const struct kernel_symbol __start___ksymtab[];
 255extern const struct kernel_symbol __stop___ksymtab[];
 256extern const struct kernel_symbol __start___ksymtab_gpl[];
 257extern const struct kernel_symbol __stop___ksymtab_gpl[];
 258extern const struct kernel_symbol __start___ksymtab_gpl_future[];
 259extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
 260extern const unsigned long __start___kcrctab[];
 261extern const unsigned long __start___kcrctab_gpl[];
 262extern const unsigned long __start___kcrctab_gpl_future[];
 263#ifdef CONFIG_UNUSED_SYMBOLS
 264extern const struct kernel_symbol __start___ksymtab_unused[];
 265extern const struct kernel_symbol __stop___ksymtab_unused[];
 266extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
 267extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
 268extern const unsigned long __start___kcrctab_unused[];
 269extern const unsigned long __start___kcrctab_unused_gpl[];
 270#endif
 271
 272#ifndef CONFIG_MODVERSIONS
 273#define symversion(base, idx) NULL
 274#else
 275#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 276#endif
 277
 278static bool each_symbol_in_section(const struct symsearch *arr,
 279                                   unsigned int arrsize,
 280                                   struct module *owner,
 281                                   bool (*fn)(const struct symsearch *syms,
 282                                              struct module *owner,
 283                                              void *data),
 284                                   void *data)
 285{
 286        unsigned int j;
 287
 288        for (j = 0; j < arrsize; j++) {
 289                if (fn(&arr[j], owner, data))
 290                        return true;
 291        }
 292
 293        return false;
 294}
 295
 296/* Returns true as soon as fn returns true, otherwise false. */
 297bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
 298                                    struct module *owner,
 299                                    void *data),
 300                         void *data)
 301{
 302        struct module *mod;
 303        static const struct symsearch arr[] = {
 304                { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
 305                  NOT_GPL_ONLY, false },
 306                { __start___ksymtab_gpl, __stop___ksymtab_gpl,
 307                  __start___kcrctab_gpl,
 308                  GPL_ONLY, false },
 309                { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
 310                  __start___kcrctab_gpl_future,
 311                  WILL_BE_GPL_ONLY, false },
 312#ifdef CONFIG_UNUSED_SYMBOLS
 313                { __start___ksymtab_unused, __stop___ksymtab_unused,
 314                  __start___kcrctab_unused,
 315                  NOT_GPL_ONLY, true },
 316                { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
 317                  __start___kcrctab_unused_gpl,
 318                  GPL_ONLY, true },
 319#endif
 320        };
 321
 322        if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
 323                return true;
 324
 325        list_for_each_entry_rcu(mod, &modules, list) {
 326                struct symsearch arr[] = {
 327                        { mod->syms, mod->syms + mod->num_syms, mod->crcs,
 328                          NOT_GPL_ONLY, false },
 329                        { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
 330                          mod->gpl_crcs,
 331                          GPL_ONLY, false },
 332                        { mod->gpl_future_syms,
 333                          mod->gpl_future_syms + mod->num_gpl_future_syms,
 334                          mod->gpl_future_crcs,
 335                          WILL_BE_GPL_ONLY, false },
 336#ifdef CONFIG_UNUSED_SYMBOLS
 337                        { mod->unused_syms,
 338                          mod->unused_syms + mod->num_unused_syms,
 339                          mod->unused_crcs,
 340                          NOT_GPL_ONLY, true },
 341                        { mod->unused_gpl_syms,
 342                          mod->unused_gpl_syms + mod->num_unused_gpl_syms,
 343                          mod->unused_gpl_crcs,
 344                          GPL_ONLY, true },
 345#endif
 346                };
 347
 348                if (mod->state == MODULE_STATE_UNFORMED)
 349                        continue;
 350
 351                if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
 352                        return true;
 353        }
 354        return false;
 355}
 356EXPORT_SYMBOL_GPL(each_symbol_section);
 357
 358struct find_symbol_arg {
 359        /* Input */
 360        const char *name;
 361        bool gplok;
 362        bool warn;
 363
 364        /* Output */
 365        struct module *owner;
 366        const unsigned long *crc;
 367        const struct kernel_symbol *sym;
 368};
 369
 370static bool check_symbol(const struct symsearch *syms,
 371                                 struct module *owner,
 372                                 unsigned int symnum, void *data)
 373{
 374        struct find_symbol_arg *fsa = data;
 375
 376        if (!fsa->gplok) {
 377                if (syms->licence == GPL_ONLY)
 378                        return false;
 379                if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
 380                        printk(KERN_WARNING "Symbol %s is being used "
 381                               "by a non-GPL module, which will not "
 382                               "be allowed in the future\n", fsa->name);
 383                }
 384        }
 385
 386#ifdef CONFIG_UNUSED_SYMBOLS
 387        if (syms->unused && fsa->warn) {
 388                printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
 389                       "however this module is using it.\n", fsa->name);
 390                printk(KERN_WARNING
 391                       "This symbol will go away in the future.\n");
 392                printk(KERN_WARNING
 393                       "Please evalute if this is the right api to use and if "
 394                       "it really is, submit a report the linux kernel "
 395                       "mailinglist together with submitting your code for "
 396                       "inclusion.\n");
 397        }
 398#endif
 399
 400        fsa->owner = owner;
 401        fsa->crc = symversion(syms->crcs, symnum);
 402        fsa->sym = &syms->start[symnum];
 403        return true;
 404}
 405
 406static int cmp_name(const void *va, const void *vb)
 407{
 408        const char *a;
 409        const struct kernel_symbol *b;
 410        a = va; b = vb;
 411        return strcmp(a, b->name);
 412}
 413
 414static bool find_symbol_in_section(const struct symsearch *syms,
 415                                   struct module *owner,
 416                                   void *data)
 417{
 418        struct find_symbol_arg *fsa = data;
 419        struct kernel_symbol *sym;
 420
 421        sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
 422                        sizeof(struct kernel_symbol), cmp_name);
 423
 424        if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
 425                return true;
 426
 427        return false;
 428}
 429
 430/* Find a symbol and return it, along with, (optional) crc and
 431 * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
 432const struct kernel_symbol *find_symbol(const char *name,
 433                                        struct module **owner,
 434                                        const unsigned long **crc,
 435                                        bool gplok,
 436                                        bool warn)
 437{
 438        struct find_symbol_arg fsa;
 439
 440        fsa.name = name;
 441        fsa.gplok = gplok;
 442        fsa.warn = warn;
 443
 444        if (each_symbol_section(find_symbol_in_section, &fsa)) {
 445                if (owner)
 446                        *owner = fsa.owner;
 447                if (crc)
 448                        *crc = fsa.crc;
 449                return fsa.sym;
 450        }
 451
 452        pr_debug("Failed to find symbol %s\n", name);
 453        return NULL;
 454}
 455EXPORT_SYMBOL_GPL(find_symbol);
 456
 457/* Search for module by name: must hold module_mutex. */
 458static struct module *find_module_all(const char *name,
 459                                      bool even_unformed)
 460{
 461        struct module *mod;
 462
 463        list_for_each_entry(mod, &modules, list) {
 464                if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
 465                        continue;
 466                if (strcmp(mod->name, name) == 0)
 467                        return mod;
 468        }
 469        return NULL;
 470}
 471
 472struct module *find_module(const char *name)
 473{
 474        return find_module_all(name, false);
 475}
 476EXPORT_SYMBOL_GPL(find_module);
 477
 478#ifdef CONFIG_SMP
 479
 480static inline void __percpu *mod_percpu(struct module *mod)
 481{
 482        return mod->percpu;
 483}
 484
 485static int percpu_modalloc(struct module *mod,
 486                           unsigned long size, unsigned long align)
 487{
 488        if (align > PAGE_SIZE) {
 489                printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
 490                       mod->name, align, PAGE_SIZE);
 491                align = PAGE_SIZE;
 492        }
 493
 494        mod->percpu = __alloc_reserved_percpu(size, align);
 495        if (!mod->percpu) {
 496                printk(KERN_WARNING
 497                       "%s: Could not allocate %lu bytes percpu data\n",
 498                       mod->name, size);
 499                return -ENOMEM;
 500        }
 501        mod->percpu_size = size;
 502        return 0;
 503}
 504
 505static void percpu_modfree(struct module *mod)
 506{
 507        free_percpu(mod->percpu);
 508}
 509
 510static unsigned int find_pcpusec(struct load_info *info)
 511{
 512        return find_sec(info, ".data..percpu");
 513}
 514
 515static void percpu_modcopy(struct module *mod,
 516                           const void *from, unsigned long size)
 517{
 518        int cpu;
 519
 520        for_each_possible_cpu(cpu)
 521                memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
 522}
 523
 524/**
 525 * is_module_percpu_address - test whether address is from module static percpu
 526 * @addr: address to test
 527 *
 528 * Test whether @addr belongs to module static percpu area.
 529 *
 530 * RETURNS:
 531 * %true if @addr is from module static percpu area
 532 */
 533bool is_module_percpu_address(unsigned long addr)
 534{
 535        struct module *mod;
 536        unsigned int cpu;
 537
 538        preempt_disable();
 539
 540        list_for_each_entry_rcu(mod, &modules, list) {
 541                if (mod->state == MODULE_STATE_UNFORMED)
 542                        continue;
 543                if (!mod->percpu_size)
 544                        continue;
 545                for_each_possible_cpu(cpu) {
 546                        void *start = per_cpu_ptr(mod->percpu, cpu);
 547
 548                        if ((void *)addr >= start &&
 549                            (void *)addr < start + mod->percpu_size) {
 550                                preempt_enable();
 551                                return true;
 552                        }
 553                }
 554        }
 555
 556        preempt_enable();
 557        return false;
 558}
 559
 560#else /* ... !CONFIG_SMP */
 561
 562static inline void __percpu *mod_percpu(struct module *mod)
 563{
 564        return NULL;
 565}
 566static inline int percpu_modalloc(struct module *mod,
 567                                  unsigned long size, unsigned long align)
 568{
 569        return -ENOMEM;
 570}
 571static inline void percpu_modfree(struct module *mod)
 572{
 573}
 574static unsigned int find_pcpusec(struct load_info *info)
 575{
 576        return 0;
 577}
 578static inline void percpu_modcopy(struct module *mod,
 579                                  const void *from, unsigned long size)
 580{
 581        /* pcpusec should be 0, and size of that section should be 0. */
 582        BUG_ON(size != 0);
 583}
 584bool is_module_percpu_address(unsigned long addr)
 585{
 586        return false;
 587}
 588
 589#endif /* CONFIG_SMP */
 590
 591#define MODINFO_ATTR(field)     \
 592static void setup_modinfo_##field(struct module *mod, const char *s)  \
 593{                                                                     \
 594        mod->field = kstrdup(s, GFP_KERNEL);                          \
 595}                                                                     \
 596static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
 597                        struct module_kobject *mk, char *buffer)      \
 598{                                                                     \
 599        return sprintf(buffer, "%s\n", mk->mod->field);               \
 600}                                                                     \
 601static int modinfo_##field##_exists(struct module *mod)               \
 602{                                                                     \
 603        return mod->field != NULL;                                    \
 604}                                                                     \
 605static void free_modinfo_##field(struct module *mod)                  \
 606{                                                                     \
 607        kfree(mod->field);                                            \
 608        mod->field = NULL;                                            \
 609}                                                                     \
 610static struct module_attribute modinfo_##field = {                    \
 611        .attr = { .name = __stringify(field), .mode = 0444 },         \
 612        .show = show_modinfo_##field,                                 \
 613        .setup = setup_modinfo_##field,                               \
 614        .test = modinfo_##field##_exists,                             \
 615        .free = free_modinfo_##field,                                 \
 616};
 617
 618MODINFO_ATTR(version);
 619MODINFO_ATTR(srcversion);
 620
 621static char last_unloaded_module[MODULE_NAME_LEN+1];
 622
 623#ifdef CONFIG_MODULE_UNLOAD
 624
 625EXPORT_TRACEPOINT_SYMBOL(module_get);
 626
 627/* Init the unload section of the module. */
 628static int module_unload_init(struct module *mod)
 629{
 630        mod->refptr = alloc_percpu(struct module_ref);
 631        if (!mod->refptr)
 632                return -ENOMEM;
 633
 634        INIT_LIST_HEAD(&mod->source_list);
 635        INIT_LIST_HEAD(&mod->target_list);
 636
 637        /* Hold reference count during initialization. */
 638        __this_cpu_write(mod->refptr->incs, 1);
 639        /* Backwards compatibility macros put refcount during init. */
 640        mod->waiter = current;
 641
 642        return 0;
 643}
 644
 645/* Does a already use b? */
 646static int already_uses(struct module *a, struct module *b)
 647{
 648        struct module_use *use;
 649
 650        list_for_each_entry(use, &b->source_list, source_list) {
 651                if (use->source == a) {
 652                        pr_debug("%s uses %s!\n", a->name, b->name);
 653                        return 1;
 654                }
 655        }
 656        pr_debug("%s does not use %s!\n", a->name, b->name);
 657        return 0;
 658}
 659
 660/*
 661 * Module a uses b
 662 *  - we add 'a' as a "source", 'b' as a "target" of module use
 663 *  - the module_use is added to the list of 'b' sources (so
 664 *    'b' can walk the list to see who sourced them), and of 'a'
 665 *    targets (so 'a' can see what modules it targets).
 666 */
 667static int add_module_usage(struct module *a, struct module *b)
 668{
 669        struct module_use *use;
 670
 671        pr_debug("Allocating new usage for %s.\n", a->name);
 672        use = kmalloc(sizeof(*use), GFP_ATOMIC);
 673        if (!use) {
 674                printk(KERN_WARNING "%s: out of memory loading\n", a->name);
 675                return -ENOMEM;
 676        }
 677
 678        use->source = a;
 679        use->target = b;
 680        list_add(&use->source_list, &b->source_list);
 681        list_add(&use->target_list, &a->target_list);
 682        return 0;
 683}
 684
 685/* Module a uses b: caller needs module_mutex() */
 686int ref_module(struct module *a, struct module *b)
 687{
 688        int err;
 689
 690        if (b == NULL || already_uses(a, b))
 691                return 0;
 692
 693        /* If module isn't available, we fail. */
 694        err = strong_try_module_get(b);
 695        if (err)
 696                return err;
 697
 698        err = add_module_usage(a, b);
 699        if (err) {
 700                module_put(b);
 701                return err;
 702        }
 703        return 0;
 704}
 705EXPORT_SYMBOL_GPL(ref_module);
 706
 707/* Clear the unload stuff of the module. */
 708static void module_unload_free(struct module *mod)
 709{
 710        struct module_use *use, *tmp;
 711
 712        mutex_lock(&module_mutex);
 713        list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
 714                struct module *i = use->target;
 715                pr_debug("%s unusing %s\n", mod->name, i->name);
 716                module_put(i);
 717                list_del(&use->source_list);
 718                list_del(&use->target_list);
 719                kfree(use);
 720        }
 721        mutex_unlock(&module_mutex);
 722
 723        free_percpu(mod->refptr);
 724}
 725
 726#ifdef CONFIG_MODULE_FORCE_UNLOAD
 727static inline int try_force_unload(unsigned int flags)
 728{
 729        int ret = (flags & O_TRUNC);
 730        if (ret)
 731                add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
 732        return ret;
 733}
 734#else
 735static inline int try_force_unload(unsigned int flags)
 736{
 737        return 0;
 738}
 739#endif /* CONFIG_MODULE_FORCE_UNLOAD */
 740
 741struct stopref
 742{
 743        struct module *mod;
 744        int flags;
 745        int *forced;
 746};
 747
 748/* Whole machine is stopped with interrupts off when this runs. */
 749static int __try_stop_module(void *_sref)
 750{
 751        struct stopref *sref = _sref;
 752
 753        /* If it's not unused, quit unless we're forcing. */
 754        if (module_refcount(sref->mod) != 0) {
 755                if (!(*sref->forced = try_force_unload(sref->flags)))
 756                        return -EWOULDBLOCK;
 757        }
 758
 759        /* Mark it as dying. */
 760        sref->mod->state = MODULE_STATE_GOING;
 761        return 0;
 762}
 763
 764static int try_stop_module(struct module *mod, int flags, int *forced)
 765{
 766        if (flags & O_NONBLOCK) {
 767                struct stopref sref = { mod, flags, forced };
 768
 769                return stop_machine(__try_stop_module, &sref, NULL);
 770        } else {
 771                /* We don't need to stop the machine for this. */
 772                mod->state = MODULE_STATE_GOING;
 773                synchronize_sched();
 774                return 0;
 775        }
 776}
 777
 778unsigned long module_refcount(struct module *mod)
 779{
 780        unsigned long incs = 0, decs = 0;
 781        int cpu;
 782
 783        for_each_possible_cpu(cpu)
 784                decs += per_cpu_ptr(mod->refptr, cpu)->decs;
 785        /*
 786         * ensure the incs are added up after the decs.
 787         * module_put ensures incs are visible before decs with smp_wmb.
 788         *
 789         * This 2-count scheme avoids the situation where the refcount
 790         * for CPU0 is read, then CPU0 increments the module refcount,
 791         * then CPU1 drops that refcount, then the refcount for CPU1 is
 792         * read. We would record a decrement but not its corresponding
 793         * increment so we would see a low count (disaster).
 794         *
 795         * Rare situation? But module_refcount can be preempted, and we
 796         * might be tallying up 4096+ CPUs. So it is not impossible.
 797         */
 798        smp_rmb();
 799        for_each_possible_cpu(cpu)
 800                incs += per_cpu_ptr(mod->refptr, cpu)->incs;
 801        return incs - decs;
 802}
 803EXPORT_SYMBOL(module_refcount);
 804
 805/* This exists whether we can unload or not */
 806static void free_module(struct module *mod);
 807
 808static void wait_for_zero_refcount(struct module *mod)
 809{
 810        /* Since we might sleep for some time, release the mutex first */
 811        mutex_unlock(&module_mutex);
 812        for (;;) {
 813                pr_debug("Looking at refcount...\n");
 814                set_current_state(TASK_UNINTERRUPTIBLE);
 815                if (module_refcount(mod) == 0)
 816                        break;
 817                schedule();
 818        }
 819        current->state = TASK_RUNNING;
 820        mutex_lock(&module_mutex);
 821}
 822
 823SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
 824                unsigned int, flags)
 825{
 826        struct module *mod;
 827        char name[MODULE_NAME_LEN];
 828        int ret, forced = 0;
 829
 830        if (!capable(CAP_SYS_MODULE) || modules_disabled)
 831                return -EPERM;
 832
 833        if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
 834                return -EFAULT;
 835        name[MODULE_NAME_LEN-1] = '\0';
 836
 837        if (mutex_lock_interruptible(&module_mutex) != 0)
 838                return -EINTR;
 839
 840        mod = find_module(name);
 841        if (!mod) {
 842                ret = -ENOENT;
 843                goto out;
 844        }
 845
 846        if (!list_empty(&mod->source_list)) {
 847                /* Other modules depend on us: get rid of them first. */
 848                ret = -EWOULDBLOCK;
 849                goto out;
 850        }
 851
 852        /* Doing init or already dying? */
 853        if (mod->state != MODULE_STATE_LIVE) {
 854                /* FIXME: if (force), slam module count and wake up
 855                   waiter --RR */
 856                pr_debug("%s already dying\n", mod->name);
 857                ret = -EBUSY;
 858                goto out;
 859        }
 860
 861        /* If it has an init func, it must have an exit func to unload */
 862        if (mod->init && !mod->exit) {
 863                forced = try_force_unload(flags);
 864                if (!forced) {
 865                        /* This module can't be removed */
 866                        ret = -EBUSY;
 867                        goto out;
 868                }
 869        }
 870
 871        /* Set this up before setting mod->state */
 872        mod->waiter = current;
 873
 874        /* Stop the machine so refcounts can't move and disable module. */
 875        ret = try_stop_module(mod, flags, &forced);
 876        if (ret != 0)
 877                goto out;
 878
 879        /* Never wait if forced. */
 880        if (!forced && module_refcount(mod) != 0)
 881                wait_for_zero_refcount(mod);
 882
 883        mutex_unlock(&module_mutex);
 884        /* Final destruction now no one is using it. */
 885        if (mod->exit != NULL)
 886                mod->exit();
 887        blocking_notifier_call_chain(&module_notify_list,
 888                                     MODULE_STATE_GOING, mod);
 889        async_synchronize_full();
 890
 891        /* Store the name of the last unloaded module for diagnostic purposes */
 892        strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
 893
 894        free_module(mod);
 895        return 0;
 896out:
 897        mutex_unlock(&module_mutex);
 898        return ret;
 899}
 900
 901static inline void print_unload_info(struct seq_file *m, struct module *mod)
 902{
 903        struct module_use *use;
 904        int printed_something = 0;
 905
 906        seq_printf(m, " %lu ", module_refcount(mod));
 907
 908        /* Always include a trailing , so userspace can differentiate
 909           between this and the old multi-field proc format. */
 910        list_for_each_entry(use, &mod->source_list, source_list) {
 911                printed_something = 1;
 912                seq_printf(m, "%s,", use->source->name);
 913        }
 914
 915        if (mod->init != NULL && mod->exit == NULL) {
 916                printed_something = 1;
 917                seq_printf(m, "[permanent],");
 918        }
 919
 920        if (!printed_something)
 921                seq_printf(m, "-");
 922}
 923
 924void __symbol_put(const char *symbol)
 925{
 926        struct module *owner;
 927
 928        preempt_disable();
 929        if (!find_symbol(symbol, &owner, NULL, true, false))
 930                BUG();
 931        module_put(owner);
 932        preempt_enable();
 933}
 934EXPORT_SYMBOL(__symbol_put);
 935
 936/* Note this assumes addr is a function, which it currently always is. */
 937void symbol_put_addr(void *addr)
 938{
 939        struct module *modaddr;
 940        unsigned long a = (unsigned long)dereference_function_descriptor(addr);
 941
 942        if (core_kernel_text(a))
 943                return;
 944
 945        /* module_text_address is safe here: we're supposed to have reference
 946         * to module from symbol_get, so it can't go away. */
 947        modaddr = __module_text_address(a);
 948        BUG_ON(!modaddr);
 949        module_put(modaddr);
 950}
 951EXPORT_SYMBOL_GPL(symbol_put_addr);
 952
 953static ssize_t show_refcnt(struct module_attribute *mattr,
 954                           struct module_kobject *mk, char *buffer)
 955{
 956        return sprintf(buffer, "%lu\n", module_refcount(mk->mod));
 957}
 958
 959static struct module_attribute modinfo_refcnt =
 960        __ATTR(refcnt, 0444, show_refcnt, NULL);
 961
 962void __module_get(struct module *module)
 963{
 964        if (module) {
 965                preempt_disable();
 966                __this_cpu_inc(module->refptr->incs);
 967                trace_module_get(module, _RET_IP_);
 968                preempt_enable();
 969        }
 970}
 971EXPORT_SYMBOL(__module_get);
 972
 973bool try_module_get(struct module *module)
 974{
 975        bool ret = true;
 976
 977        if (module) {
 978                preempt_disable();
 979
 980                if (likely(module_is_live(module))) {
 981                        __this_cpu_inc(module->refptr->incs);
 982                        trace_module_get(module, _RET_IP_);
 983                } else
 984                        ret = false;
 985
 986                preempt_enable();
 987        }
 988        return ret;
 989}
 990EXPORT_SYMBOL(try_module_get);
 991
 992void module_put(struct module *module)
 993{
 994        if (module) {
 995                preempt_disable();
 996                smp_wmb(); /* see comment in module_refcount */
 997                __this_cpu_inc(module->refptr->decs);
 998
 999                trace_module_put(module, _RET_IP_);
1000                /* Maybe they're waiting for us to drop reference? */
1001                if (unlikely(!module_is_live(module)))
1002                        wake_up_process(module->waiter);
1003                preempt_enable();
1004        }
1005}
1006EXPORT_SYMBOL(module_put);
1007
1008#else /* !CONFIG_MODULE_UNLOAD */
1009static inline void print_unload_info(struct seq_file *m, struct module *mod)
1010{
1011        /* We don't know the usage count, or what modules are using. */
1012        seq_printf(m, " - -");
1013}
1014
1015static inline void module_unload_free(struct module *mod)
1016{
1017}
1018
1019int ref_module(struct module *a, struct module *b)
1020{
1021        return strong_try_module_get(b);
1022}
1023EXPORT_SYMBOL_GPL(ref_module);
1024
1025static inline int module_unload_init(struct module *mod)
1026{
1027        return 0;
1028}
1029#endif /* CONFIG_MODULE_UNLOAD */
1030
1031static size_t module_flags_taint(struct module *mod, char *buf)
1032{
1033        size_t l = 0;
1034
1035        if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
1036                buf[l++] = 'P';
1037        if (mod->taints & (1 << TAINT_OOT_MODULE))
1038                buf[l++] = 'O';
1039        if (mod->taints & (1 << TAINT_FORCED_MODULE))
1040                buf[l++] = 'F';
1041        if (mod->taints & (1 << TAINT_CRAP))
1042                buf[l++] = 'C';
1043        /*
1044         * TAINT_FORCED_RMMOD: could be added.
1045         * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
1046         * apply to modules.
1047         */
1048        return l;
1049}
1050
1051static ssize_t show_initstate(struct module_attribute *mattr,
1052                              struct module_kobject *mk, char *buffer)
1053{
1054        const char *state = "unknown";
1055
1056        switch (mk->mod->state) {
1057        case MODULE_STATE_LIVE:
1058                state = "live";
1059                break;
1060        case MODULE_STATE_COMING:
1061                state = "coming";
1062                break;
1063        case MODULE_STATE_GOING:
1064                state = "going";
1065                break;
1066        default:
1067                BUG();
1068        }
1069        return sprintf(buffer, "%s\n", state);
1070}
1071
1072static struct module_attribute modinfo_initstate =
1073        __ATTR(initstate, 0444, show_initstate, NULL);
1074
1075static ssize_t store_uevent(struct module_attribute *mattr,
1076                            struct module_kobject *mk,
1077                            const char *buffer, size_t count)
1078{
1079        enum kobject_action action;
1080
1081        if (kobject_action_type(buffer, count, &action) == 0)
1082                kobject_uevent(&mk->kobj, action);
1083        return count;
1084}
1085
1086struct module_attribute module_uevent =
1087        __ATTR(uevent, 0200, NULL, store_uevent);
1088
1089static ssize_t show_coresize(struct module_attribute *mattr,
1090                             struct module_kobject *mk, char *buffer)
1091{
1092        return sprintf(buffer, "%u\n", mk->mod->core_size);
1093}
1094
1095static struct module_attribute modinfo_coresize =
1096        __ATTR(coresize, 0444, show_coresize, NULL);
1097
1098static ssize_t show_initsize(struct module_attribute *mattr,
1099                             struct module_kobject *mk, char *buffer)
1100{
1101        return sprintf(buffer, "%u\n", mk->mod->init_size);
1102}
1103
1104static struct module_attribute modinfo_initsize =
1105        __ATTR(initsize, 0444, show_initsize, NULL);
1106
1107static ssize_t show_taint(struct module_attribute *mattr,
1108                          struct module_kobject *mk, char *buffer)
1109{
1110        size_t l;
1111
1112        l = module_flags_taint(mk->mod, buffer);
1113        buffer[l++] = '\n';
1114        return l;
1115}
1116
1117static struct module_attribute modinfo_taint =
1118        __ATTR(taint, 0444, show_taint, NULL);
1119
1120static struct module_attribute *modinfo_attrs[] = {
1121        &module_uevent,
1122        &modinfo_version,
1123        &modinfo_srcversion,
1124        &modinfo_initstate,
1125        &modinfo_coresize,
1126        &modinfo_initsize,
1127        &modinfo_taint,
1128#ifdef CONFIG_MODULE_UNLOAD
1129        &modinfo_refcnt,
1130#endif
1131        NULL,
1132};
1133
1134static const char vermagic[] = VERMAGIC_STRING;
1135
1136static int try_to_force_load(struct module *mod, const char *reason)
1137{
1138#ifdef CONFIG_MODULE_FORCE_LOAD
1139        if (!test_taint(TAINT_FORCED_MODULE))
1140                printk(KERN_WARNING "%s: %s: kernel tainted.\n",
1141                       mod->name, reason);
1142        add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
1143        return 0;
1144#else
1145        return -ENOEXEC;
1146#endif
1147}
1148
1149#ifdef CONFIG_MODVERSIONS
1150/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
1151static unsigned long maybe_relocated(unsigned long crc,
1152                                     const struct module *crc_owner)
1153{
1154#ifdef ARCH_RELOCATES_KCRCTAB
1155        if (crc_owner == NULL)
1156                return crc - (unsigned long)reloc_start;
1157#endif
1158        return crc;
1159}
1160
1161static int check_version(Elf_Shdr *sechdrs,
1162                         unsigned int versindex,
1163                         const char *symname,
1164                         struct module *mod, 
1165                         const unsigned long *crc,
1166                         const struct module *crc_owner)
1167{
1168        unsigned int i, num_versions;
1169        struct modversion_info *versions;
1170
1171        /* Exporting module didn't supply crcs?  OK, we're already tainted. */
1172        if (!crc)
1173                return 1;
1174
1175        /* No versions at all?  modprobe --force does this. */
1176        if (versindex == 0)
1177                return try_to_force_load(mod, symname) == 0;
1178
1179        versions = (void *) sechdrs[versindex].sh_addr;
1180        num_versions = sechdrs[versindex].sh_size
1181                / sizeof(struct modversion_info);
1182
1183        for (i = 0; i < num_versions; i++) {
1184                if (strcmp(versions[i].name, symname) != 0)
1185                        continue;
1186
1187                if (versions[i].crc == maybe_relocated(*crc, crc_owner))
1188                        return 1;
1189                pr_debug("Found checksum %lX vs module %lX\n",
1190                       maybe_relocated(*crc, crc_owner), versions[i].crc);
1191                goto bad_version;
1192        }
1193
1194        printk(KERN_WARNING "%s: no symbol version for %s\n",
1195               mod->name, symname);
1196        return 0;
1197
1198bad_version:
1199        printk("%s: disagrees about version of symbol %s\n",
1200               mod->name, symname);
1201        return 0;
1202}
1203
1204static inline int check_modstruct_version(Elf_Shdr *sechdrs,
1205                                          unsigned int versindex,
1206                                          struct module *mod)
1207{
1208        const unsigned long *crc;
1209
1210        /* Since this should be found in kernel (which can't be removed),
1211         * no locking is necessary. */
1212        if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
1213                         &crc, true, false))
1214                BUG();
1215        return check_version(sechdrs, versindex, "module_layout", mod, crc,
1216                             NULL);
1217}
1218
1219/* First part is kernel version, which we ignore if module has crcs. */
1220static inline int same_magic(const char *amagic, const char *bmagic,
1221                             bool has_crcs)
1222{
1223        if (has_crcs) {
1224                amagic += strcspn(amagic, " ");
1225                bmagic += strcspn(bmagic, " ");
1226        }
1227        return strcmp(amagic, bmagic) == 0;
1228}
1229#else
1230static inline int check_version(Elf_Shdr *sechdrs,
1231                                unsigned int versindex,
1232                                const char *symname,
1233                                struct module *mod, 
1234                                const unsigned long *crc,
1235                                const struct module *crc_owner)
1236{
1237        return 1;
1238}
1239
1240static inline int check_modstruct_version(Elf_Shdr *sechdrs,
1241                                          unsigned int versindex,
1242                                          struct module *mod)
1243{
1244        return 1;
1245}
1246
1247static inline int same_magic(const char *amagic, const char *bmagic,
1248                             bool has_crcs)
1249{
1250        return strcmp(amagic, bmagic) == 0;
1251}
1252#endif /* CONFIG_MODVERSIONS */
1253
1254/* Resolve a symbol for this module.  I.e. if we find one, record usage. */
1255static const struct kernel_symbol *resolve_symbol(struct module *mod,
1256                                                  const struct load_info *info,
1257                                                  const char *name,
1258                                                  char ownername[])
1259{
1260        struct module *owner;
1261        const struct kernel_symbol *sym;
1262        const unsigned long *crc;
1263        int err;
1264
1265        mutex_lock(&module_mutex);
1266        sym = find_symbol(name, &owner, &crc,
1267                          !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
1268        if (!sym)
1269                goto unlock;
1270
1271        if (!check_version(info->sechdrs, info->index.vers, name, mod, crc,
1272                           owner)) {
1273                sym = ERR_PTR(-EINVAL);
1274                goto getname;
1275        }
1276
1277        err = ref_module(mod, owner);
1278        if (err) {
1279                sym = ERR_PTR(err);
1280                goto getname;
1281        }
1282
1283getname:
1284        /* We must make copy under the lock if we failed to get ref. */
1285        strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
1286unlock:
1287        mutex_unlock(&module_mutex);
1288        return sym;
1289}
1290
1291static const struct kernel_symbol *
1292resolve_symbol_wait(struct module *mod,
1293                    const struct load_info *info,
1294                    const char *name)
1295{
1296        const struct kernel_symbol *ksym;
1297        char owner[MODULE_NAME_LEN];
1298
1299        if (wait_event_interruptible_timeout(module_wq,
1300                        !IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
1301                        || PTR_ERR(ksym) != -EBUSY,
1302                                             30 * HZ) <= 0) {
1303                printk(KERN_WARNING "%s: gave up waiting for init of module %s.\n",
1304                       mod->name, owner);
1305        }
1306        return ksym;
1307}
1308
1309/*
1310 * /sys/module/foo/sections stuff
1311 * J. Corbet <corbet@lwn.net>
1312 */
1313#ifdef CONFIG_SYSFS
1314
1315#ifdef CONFIG_KALLSYMS
1316static inline bool sect_empty(const Elf_Shdr *sect)
1317{
1318        return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
1319}
1320
1321struct module_sect_attr
1322{
1323        struct module_attribute mattr;
1324        char *name;
1325        unsigned long address;
1326};
1327
1328struct module_sect_attrs
1329{
1330        struct attribute_group grp;
1331        unsigned int nsections;
1332        struct module_sect_attr attrs[0];
1333};
1334
1335static ssize_t module_sect_show(struct module_attribute *mattr,
1336                                struct module_kobject *mk, char *buf)
1337{
1338        struct module_sect_attr *sattr =
1339                container_of(mattr, struct module_sect_attr, mattr);
1340        return sprintf(buf, "0x%pK\n", (void *)sattr->address);
1341}
1342
1343static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
1344{
1345        unsigned int section;
1346
1347        for (section = 0; section < sect_attrs->nsections; section++)
1348                kfree(sect_attrs->attrs[section].name);
1349        kfree(sect_attrs);
1350}
1351
1352static void add_sect_attrs(struct module *mod, const struct load_info *info)
1353{
1354        unsigned int nloaded = 0, i, size[2];
1355        struct module_sect_attrs *sect_attrs;
1356        struct module_sect_attr *sattr;
1357        struct attribute **gattr;
1358
1359        /* Count loaded sections and allocate structures */
1360        for (i = 0; i < info->hdr->e_shnum; i++)
1361                if (!sect_empty(&info->sechdrs[i]))
1362                        nloaded++;
1363        size[0] = ALIGN(sizeof(*sect_attrs)
1364                        + nloaded * sizeof(sect_attrs->attrs[0]),
1365                        sizeof(sect_attrs->grp.attrs[0]));
1366        size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]);
1367        sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
1368        if (sect_attrs == NULL)
1369                return;
1370
1371        /* Setup section attributes. */
1372        sect_attrs->grp.name = "sections";
1373        sect_attrs->grp.attrs = (void *)sect_attrs + size[0];
1374
1375        sect_attrs->nsections = 0;
1376        sattr = &sect_attrs->attrs[0];
1377        gattr = &sect_attrs->grp.attrs[0];
1378        for (i = 0; i < info->hdr->e_shnum; i++) {
1379                Elf_Shdr *sec = &info->sechdrs[i];
1380                if (sect_empty(sec))
1381                        continue;
1382                sattr->address = sec->sh_addr;
1383                sattr->name = kstrdup(info->secstrings + sec->sh_name,
1384                                        GFP_KERNEL);
1385                if (sattr->name == NULL)
1386                        goto out;
1387                sect_attrs->nsections++;
1388                sysfs_attr_init(&sattr->mattr.attr);
1389                sattr->mattr.show = module_sect_show;
1390                sattr->mattr.store = NULL;
1391                sattr->mattr.attr.name = sattr->name;
1392                sattr->mattr.attr.mode = S_IRUGO;
1393                *(gattr++) = &(sattr++)->mattr.attr;
1394        }
1395        *gattr = NULL;
1396
1397        if (sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp))
1398                goto out;
1399
1400        mod->sect_attrs = sect_attrs;
1401        return;
1402  out:
1403        free_sect_attrs(sect_attrs);
1404}
1405
1406static void remove_sect_attrs(struct module *mod)
1407{
1408        if (mod->sect_attrs) {
1409                sysfs_remove_group(&mod->mkobj.kobj,
1410                                   &mod->sect_attrs->grp);
1411                /* We are positive that no one is using any sect attrs
1412                 * at this point.  Deallocate immediately. */
1413                free_sect_attrs(mod->sect_attrs);
1414                mod->sect_attrs = NULL;
1415        }
1416}
1417
1418/*
1419 * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
1420 */
1421
1422struct module_notes_attrs {
1423        struct kobject *dir;
1424        unsigned int notes;
1425        struct bin_attribute attrs[0];
1426};
1427
1428static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
1429                                 struct bin_attribute *bin_attr,
1430                                 char *buf, loff_t pos, size_t count)
1431{
1432        /*
1433         * The caller checked the pos and count against our size.
1434         */
1435        memcpy(buf, bin_attr->private + pos, count);
1436        return count;
1437}
1438
1439static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
1440                             unsigned int i)
1441{
1442        if (notes_attrs->dir) {
1443                while (i-- > 0)
1444                        sysfs_remove_bin_file(notes_attrs->dir,
1445                                              &notes_attrs->attrs[i]);
1446                kobject_put(notes_attrs->dir);
1447        }
1448        kfree(notes_attrs);
1449}
1450
1451static void add_notes_attrs(struct module *mod, const struct load_info *info)
1452{
1453        unsigned int notes, loaded, i;
1454        struct module_notes_attrs *notes_attrs;
1455        struct bin_attribute *nattr;
1456
1457        /* failed to create section attributes, so can't create notes */
1458        if (!mod->sect_attrs)
1459                return;
1460
1461        /* Count notes sections and allocate structures.  */
1462        notes = 0;
1463        for (i = 0; i < info->hdr->e_shnum; i++)
1464                if (!sect_empty(&info->sechdrs[i]) &&
1465                    (info->sechdrs[i].sh_type == SHT_NOTE))
1466                        ++notes;
1467
1468        if (notes == 0)
1469                return;
1470
1471        notes_attrs = kzalloc(sizeof(*notes_attrs)
1472                              + notes * sizeof(notes_attrs->attrs[0]),
1473                              GFP_KERNEL);
1474        if (notes_attrs == NULL)
1475                return;
1476
1477        notes_attrs->notes = notes;
1478        nattr = &notes_attrs->attrs[0];
1479        for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {
1480                if (sect_empty(&info->sechdrs[i]))
1481                        continue;
1482                if (info->sechdrs[i].sh_type == SHT_NOTE) {
1483                        sysfs_bin_attr_init(nattr);
1484                        nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
1485                        nattr->attr.mode = S_IRUGO;
1486                        nattr->size = info->sechdrs[i].sh_size;
1487                        nattr->private = (void *) info->sechdrs[i].sh_addr;
1488                        nattr->read = module_notes_read;
1489                        ++nattr;
1490                }
1491                ++loaded;
1492        }
1493
1494        notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
1495        if (!notes_attrs->dir)
1496                goto out;
1497
1498        for (i = 0; i < notes; ++i)
1499                if (sysfs_create_bin_file(notes_attrs->dir,
1500                                          &notes_attrs->attrs[i]))
1501                        goto out;
1502
1503        mod->notes_attrs = notes_attrs;
1504        return;
1505
1506  out:
1507        free_notes_attrs(notes_attrs, i);
1508}
1509
1510static void remove_notes_attrs(struct module *mod)
1511{
1512        if (mod->notes_attrs)
1513                free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
1514}
1515
1516#else
1517
1518static inline void add_sect_attrs(struct module *mod,
1519                                  const struct load_info *info)
1520{
1521}
1522
1523static inline void remove_sect_attrs(struct module *mod)
1524{
1525}
1526
1527static inline void add_notes_attrs(struct module *mod,
1528                                   const struct load_info *info)
1529{
1530}
1531
1532static inline void remove_notes_attrs(struct module *mod)
1533{
1534}
1535#endif /* CONFIG_KALLSYMS */
1536
1537static void add_usage_links(struct module *mod)
1538{
1539#ifdef CONFIG_MODULE_UNLOAD
1540        struct module_use *use;
1541        int nowarn;
1542
1543        mutex_lock(&module_mutex);
1544        list_for_each_entry(use, &mod->target_list, target_list) {
1545                nowarn = sysfs_create_link(use->target->holders_dir,
1546                                           &mod->mkobj.kobj, mod->name);
1547        }
1548        mutex_unlock(&module_mutex);
1549#endif
1550}
1551
1552static void del_usage_links(struct module *mod)
1553{
1554#ifdef CONFIG_MODULE_UNLOAD
1555        struct module_use *use;
1556
1557        mutex_lock(&module_mutex);
1558        list_for_each_entry(use, &mod->target_list, target_list)
1559                sysfs_remove_link(use->target->holders_dir, mod->name);
1560        mutex_unlock(&module_mutex);
1561#endif
1562}
1563
1564static int module_add_modinfo_attrs(struct module *mod)
1565{
1566        struct module_attribute *attr;
1567        struct module_attribute *temp_attr;
1568        int error = 0;
1569        int i;
1570
1571        mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
1572                                        (ARRAY_SIZE(modinfo_attrs) + 1)),
1573                                        GFP_KERNEL);
1574        if (!mod->modinfo_attrs)
1575                return -ENOMEM;
1576
1577        temp_attr = mod->modinfo_attrs;
1578        for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
1579                if (!attr->test ||
1580                    (attr->test && attr->test(mod))) {
1581                        memcpy(temp_attr, attr, sizeof(*temp_attr));
1582                        sysfs_attr_init(&temp_attr->attr);
1583                        error = sysfs_create_file(&mod->mkobj.kobj,&temp_attr->attr);
1584                        ++temp_attr;
1585                }
1586        }
1587        return error;
1588}
1589
1590static void module_remove_modinfo_attrs(struct module *mod)
1591{
1592        struct module_attribute *attr;
1593        int i;
1594
1595        for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
1596                /* pick a field to test for end of list */
1597                if (!attr->attr.name)
1598                        break;
1599                sysfs_remove_file(&mod->mkobj.kobj,&attr->attr);
1600                if (attr->free)
1601                        attr->free(mod);
1602        }
1603        kfree(mod->modinfo_attrs);
1604}
1605
1606static int mod_sysfs_init(struct module *mod)
1607{
1608        int err;
1609        struct kobject *kobj;
1610
1611        if (!module_sysfs_initialized) {
1612                printk(KERN_ERR "%s: module sysfs not initialized\n",
1613                       mod->name);
1614                err = -EINVAL;
1615                goto out;
1616        }
1617
1618        kobj = kset_find_obj(module_kset, mod->name);
1619        if (kobj) {
1620                printk(KERN_ERR "%s: module is already loaded\n", mod->name);
1621                kobject_put(kobj);
1622                err = -EINVAL;
1623                goto out;
1624        }
1625
1626        mod->mkobj.mod = mod;
1627
1628        memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
1629        mod->mkobj.kobj.kset = module_kset;
1630        err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
1631                                   "%s", mod->name);
1632        if (err)
1633                kobject_put(&mod->mkobj.kobj);
1634
1635        /* delay uevent until full sysfs population */
1636out:
1637        return err;
1638}
1639
1640static int mod_sysfs_setup(struct module *mod,
1641                           const struct load_info *info,
1642                           struct kernel_param *kparam,
1643                           unsigned int num_params)
1644{
1645        int err;
1646
1647        err = mod_sysfs_init(mod);
1648        if (err)
1649                goto out;
1650
1651        mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
1652        if (!mod->holders_dir) {
1653                err = -ENOMEM;
1654                goto out_unreg;
1655        }
1656
1657        err = module_param_sysfs_setup(mod, kparam, num_params);
1658        if (err)
1659                goto out_unreg_holders;
1660
1661        err = module_add_modinfo_attrs(mod);
1662        if (err)
1663                goto out_unreg_param;
1664
1665        add_usage_links(mod);
1666        add_sect_attrs(mod, info);
1667        add_notes_attrs(mod, info);
1668
1669        kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
1670        return 0;
1671
1672out_unreg_param:
1673        module_param_sysfs_remove(mod);
1674out_unreg_holders:
1675        kobject_put(mod->holders_dir);
1676out_unreg:
1677        kobject_put(&mod->mkobj.kobj);
1678out:
1679        return err;
1680}
1681
1682static void mod_sysfs_fini(struct module *mod)
1683{
1684        remove_notes_attrs(mod);
1685        remove_sect_attrs(mod);
1686        kobject_put(&mod->mkobj.kobj);
1687}
1688
1689#else /* !CONFIG_SYSFS */
1690
1691static int mod_sysfs_setup(struct module *mod,
1692                           const struct load_info *info,
1693                           struct kernel_param *kparam,
1694                           unsigned int num_params)
1695{
1696        return 0;
1697}
1698
1699static void mod_sysfs_fini(struct module *mod)
1700{
1701}
1702
1703static void module_remove_modinfo_attrs(struct module *mod)
1704{
1705}
1706
1707static void del_usage_links(struct module *mod)
1708{
1709}
1710
1711#endif /* CONFIG_SYSFS */
1712
1713static void mod_sysfs_teardown(struct module *mod)
1714{
1715        del_usage_links(mod);
1716        module_remove_modinfo_attrs(mod);
1717        module_param_sysfs_remove(mod);
1718        kobject_put(mod->mkobj.drivers_dir);
1719        kobject_put(mod->holders_dir);
1720        mod_sysfs_fini(mod);
1721}
1722
1723/*
1724 * unlink the module with the whole machine is stopped with interrupts off
1725 * - this defends against kallsyms not taking locks
1726 */
1727static int __unlink_module(void *_mod)
1728{
1729        struct module *mod = _mod;
1730        list_del(&mod->list);
1731        module_bug_cleanup(mod);
1732        return 0;
1733}
1734
1735#ifdef CONFIG_DEBUG_SET_MODULE_RONX
1736/*
1737 * LKM RO/NX protection: protect module's text/ro-data
1738 * from modification and any data from execution.
1739 */
1740void set_page_attributes(void *start, void *end, int (*set)(unsigned long start, int num_pages))
1741{
1742        unsigned long begin_pfn = PFN_DOWN((unsigned long)start);
1743        unsigned long end_pfn = PFN_DOWN((unsigned long)end);
1744
1745        if (end_pfn > begin_pfn)
1746                set(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
1747}
1748
1749static void set_section_ro_nx(void *base,
1750                        unsigned long text_size,
1751                        unsigned long ro_size,
1752                        unsigned long total_size)
1753{
1754        /* begin and end PFNs of the current subsection */
1755        unsigned long begin_pfn;
1756        unsigned long end_pfn;
1757
1758        /*
1759         * Set RO for module text and RO-data:
1760         * - Always protect first page.
1761         * - Do not protect last partial page.
1762         */
1763        if (ro_size > 0)
1764                set_page_attributes(base, base + ro_size, set_memory_ro);
1765
1766        /*
1767         * Set NX permissions for module data:
1768         * - Do not protect first partial page.
1769         * - Always protect last page.
1770         */
1771        if (total_size > text_size) {
1772                begin_pfn = PFN_UP((unsigned long)base + text_size);
1773                end_pfn = PFN_UP((unsigned long)base + total_size);
1774                if (end_pfn > begin_pfn)
1775                        set_memory_nx(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
1776        }
1777}
1778
1779static void unset_module_core_ro_nx(struct module *mod)
1780{
1781        set_page_attributes(mod->module_core + mod->core_text_size,
1782                mod->module_core + mod->core_size,
1783                set_memory_x);
1784        set_page_attributes(mod->module_core,
1785                mod->module_core + mod->core_ro_size,
1786                set_memory_rw);
1787}
1788
1789static void unset_module_init_ro_nx(struct module *mod)
1790{
1791        set_page_attributes(mod->module_init + mod->init_text_size,
1792                mod->module_init + mod->init_size,
1793                set_memory_x);
1794        set_page_attributes(mod->module_init,
1795                mod->module_init + mod->init_ro_size,
1796                set_memory_rw);
1797}
1798
1799/* Iterate through all modules and set each module's text as RW */
1800void set_all_modules_text_rw(void)
1801{
1802        struct module *mod;
1803
1804        mutex_lock(&module_mutex);
1805        list_for_each_entry_rcu(mod, &modules, list) {
1806                if (mod->state == MODULE_STATE_UNFORMED)
1807                        continue;
1808                if ((mod->module_core) && (mod->core_text_size)) {
1809                        set_page_attributes(mod->module_core,
1810                                                mod->module_core + mod->core_text_size,
1811                                                set_memory_rw);
1812                }
1813                if ((mod->module_init) && (mod->init_text_size)) {
1814                        set_page_attributes(mod->module_init,
1815                                                mod->module_init + mod->init_text_size,
1816                                                set_memory_rw);
1817                }
1818        }
1819        mutex_unlock(&module_mutex);
1820}
1821
1822/* Iterate through all modules and set each module's text as RO */
1823void set_all_modules_text_ro(void)
1824{
1825        struct module *mod;
1826
1827        mutex_lock(&module_mutex);
1828        list_for_each_entry_rcu(mod, &modules, list) {
1829                if (mod->state == MODULE_STATE_UNFORMED)
1830                        continue;
1831                if ((mod->module_core) && (mod->core_text_size)) {
1832                        set_page_attributes(mod->module_core,
1833                                                mod->module_core + mod->core_text_size,
1834                                                set_memory_ro);
1835                }
1836                if ((mod->module_init) && (mod->init_text_size)) {
1837                        set_page_attributes(mod->module_init,
1838                                                mod->module_init + mod->init_text_size,
1839                                                set_memory_ro);
1840                }
1841        }
1842        mutex_unlock(&module_mutex);
1843}
1844#else
1845static inline void set_section_ro_nx(void *base, unsigned long text_size, unsigned long ro_size, unsigned long total_size) { }
1846static void unset_module_core_ro_nx(struct module *mod) { }
1847static void unset_module_init_ro_nx(struct module *mod) { }
1848#endif
1849
1850void __weak module_free(struct module *mod, void *module_region)
1851{
1852        vfree(module_region);
1853}
1854
1855void __weak module_arch_cleanup(struct module *mod)
1856{
1857}
1858
1859/* Free a module, remove from lists, etc. */
1860static void free_module(struct module *mod)
1861{
1862        trace_module_free(mod);
1863
1864        mod_sysfs_teardown(mod);
1865
1866        /* We leave it in list to prevent duplicate loads, but make sure
1867         * that noone uses it while it's being deconstructed. */
1868        mod->state = MODULE_STATE_UNFORMED;
1869
1870        /* Remove dynamic debug info */
1871        ddebug_remove_module(mod->name);
1872
1873        /* Arch-specific cleanup. */
1874        module_arch_cleanup(mod);
1875
1876        /* Module unload stuff */
1877        module_unload_free(mod);
1878
1879        /* Free any allocated parameters. */
1880        destroy_params(mod->kp, mod->num_kp);
1881
1882        /* Now we can delete it from the lists */
1883        mutex_lock(&module_mutex);
1884        stop_machine(__unlink_module, mod, NULL);
1885        mutex_unlock(&module_mutex);
1886
1887        /* This may be NULL, but that's OK */
1888        unset_module_init_ro_nx(mod);
1889        module_free(mod, mod->module_init);
1890        kfree(mod->args);
1891        percpu_modfree(mod);
1892
1893        /* Free lock-classes: */
1894        lockdep_free_key_range(mod->module_core, mod->core_size);
1895
1896        /* Finally, free the core (containing the module structure) */
1897        unset_module_core_ro_nx(mod);
1898        module_free(mod, mod->module_core);
1899
1900#ifdef CONFIG_MPU
1901        update_protections(current->mm);
1902#endif
1903}
1904
1905void *__symbol_get(const char *symbol)
1906{
1907        struct module *owner;
1908        const struct kernel_symbol *sym;
1909
1910        preempt_disable();
1911        sym = find_symbol(symbol, &owner, NULL, true, true);
1912        if (sym && strong_try_module_get(owner))
1913                sym = NULL;
1914        preempt_enable();
1915
1916        return sym ? (void *)sym->value : NULL;
1917}
1918EXPORT_SYMBOL_GPL(__symbol_get);
1919
1920/*
1921 * Ensure that an exported symbol [global namespace] does not already exist
1922 * in the kernel or in some other module's exported symbol table.
1923 *
1924 * You must hold the module_mutex.
1925 */
1926static int verify_export_symbols(struct module *mod)
1927{
1928        unsigned int i;
1929        struct module *owner;
1930        const struct kernel_symbol *s;
1931        struct {
1932                const struct kernel_symbol *sym;
1933                unsigned int num;
1934        } arr[] = {
1935                { mod->syms, mod->num_syms },
1936                { mod->gpl_syms, mod->num_gpl_syms },
1937                { mod->gpl_future_syms, mod->num_gpl_future_syms },
1938#ifdef CONFIG_UNUSED_SYMBOLS
1939                { mod->unused_syms, mod->num_unused_syms },
1940                { mod->unused_gpl_syms, mod->num_unused_gpl_syms },
1941#endif
1942        };
1943
1944        for (i = 0; i < ARRAY_SIZE(arr); i++) {
1945                for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
1946                        if (find_symbol(s->name, &owner, NULL, true, false)) {
1947                                printk(KERN_ERR
1948                                       "%s: exports duplicate symbol %s"
1949                                       " (owned by %s)\n",
1950                                       mod->name, s->name, module_name(owner));
1951                                return -ENOEXEC;
1952                        }
1953                }
1954        }
1955        return 0;
1956}
1957
1958/* Change all symbols so that st_value encodes the pointer directly. */
1959static int simplify_symbols(struct module *mod, const struct load_info *info)
1960{
1961        Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
1962        Elf_Sym *sym = (void *)symsec->sh_addr;
1963        unsigned long secbase;
1964        unsigned int i;
1965        int ret = 0;
1966        const struct kernel_symbol *ksym;
1967
1968        for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
1969                const char *name = info->strtab + sym[i].st_name;
1970
1971                switch (sym[i].st_shndx) {
1972                case SHN_COMMON:
1973                        /* We compiled with -fno-common.  These are not
1974                           supposed to happen.  */
1975                        pr_debug("Common symbol: %s\n", name);
1976                        printk("%s: please compile with -fno-common\n",
1977                               mod->name);
1978                        ret = -ENOEXEC;
1979                        break;
1980
1981                case SHN_ABS:
1982                        /* Don't need to do anything */
1983                        pr_debug("Absolute symbol: 0x%08lx\n",
1984                               (long)sym[i].st_value);
1985                        break;
1986
1987                case SHN_UNDEF:
1988                        ksym = resolve_symbol_wait(mod, info, name);
1989                        /* Ok if resolved.  */
1990                        if (ksym && !IS_ERR(ksym)) {
1991                                sym[i].st_value = ksym->value;
1992                                break;
1993                        }
1994
1995                        /* Ok if weak.  */
1996                        if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
1997                                break;
1998
1999                        printk(KERN_WARNING "%s: Unknown symbol %s (err %li)\n",
2000                               mod->name, name, PTR_ERR(ksym));
2001                        ret = PTR_ERR(ksym) ?: -ENOENT;
2002                        break;
2003
2004                default:
2005                        /* Divert to percpu allocation if a percpu var. */
2006                        if (sym[i].st_shndx == info->index.pcpu)
2007                                secbase = (unsigned long)mod_percpu(mod);
2008                        else
2009                                secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
2010                        sym[i].st_value += secbase;
2011                        break;
2012                }
2013        }
2014
2015        return ret;
2016}
2017
2018static int apply_relocations(struct module *mod, const struct load_info *info)
2019{
2020        unsigned int i;
2021        int err = 0;
2022
2023        /* Now do relocations. */
2024        for (i = 1; i < info->hdr->e_shnum; i++) {
2025                unsigned int infosec = info->sechdrs[i].sh_info;
2026
2027                /* Not a valid relocation section? */
2028                if (infosec >= info->hdr->e_shnum)
2029                        continue;
2030
2031                /* Don't bother with non-allocated sections */
2032                if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
2033                        continue;
2034
2035                if (info->sechdrs[i].sh_type == SHT_REL)
2036                        err = apply_relocate(info->sechdrs, info->strtab,
2037                                             info->index.sym, i, mod);
2038                else if (info->sechdrs[i].sh_type == SHT_RELA)
2039                        err = apply_relocate_add(info->sechdrs, info->strtab,
2040                                                 info->index.sym, i, mod);
2041                if (err < 0)
2042                        break;
2043        }
2044        return err;
2045}
2046
2047/* Additional bytes needed by arch in front of individual sections */
2048unsigned int __weak arch_mod_section_prepend(struct module *mod,
2049                                             unsigned int section)
2050{
2051        /* default implementation just returns zero */
2052        return 0;
2053}
2054
2055/* Update size with this section: return offset. */
2056static long get_offset(struct module *mod, unsigned int *size,
2057                       Elf_Shdr *sechdr, unsigned int section)
2058{
2059        long ret;
2060
2061        *size += arch_mod_section_prepend(mod, section);
2062        ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
2063        *size = ret + sechdr->sh_size;
2064        return ret;
2065}
2066
2067/* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
2068   might -- code, read-only data, read-write data, small data.  Tally
2069   sizes, and place the offsets into sh_entsize fields: high bit means it
2070   belongs in init. */
2071static void layout_sections(struct module *mod, struct load_info *info)
2072{
2073        static unsigned long const masks[][2] = {
2074                /* NOTE: all executable code must be the first section
2075                 * in this array; otherwise modify the text_size
2076                 * finder in the two loops below */
2077                { SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
2078                { SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
2079                { SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
2080                { ARCH_SHF_SMALL | SHF_ALLOC, 0 }
2081        };
2082        unsigned int m, i;
2083
2084        for (i = 0; i < info->hdr->e_shnum; i++)
2085                info->sechdrs[i].sh_entsize = ~0UL;
2086
2087        pr_debug("Core section allocation order:\n");
2088        for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2089                for (i = 0; i < info->hdr->e_shnum; ++i) {
2090                        Elf_Shdr *s = &info->sechdrs[i];
2091                        const char *sname = info->secstrings + s->sh_name;
2092
2093                        if ((s->sh_flags & masks[m][0]) != masks[m][0]
2094                            || (s->sh_flags & masks[m][1])
2095                            || s->sh_entsize != ~0UL
2096                            || strstarts(sname, ".init"))
2097                                continue;
2098                        s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
2099                        pr_debug("\t%s\n", sname);
2100                }
2101                switch (m) {
2102                case 0: /* executable */
2103                        mod->core_size = debug_align(mod->core_size);
2104                        mod->core_text_size = mod->core_size;
2105                        break;
2106                case 1: /* RO: text and ro-data */
2107                        mod->core_size = debug_align(mod->core_size);
2108                        mod->core_ro_size = mod->core_size;
2109                        break;
2110                case 3: /* whole core */
2111                        mod->core_size = debug_align(mod->core_size);
2112                        break;
2113                }
2114        }
2115
2116        pr_debug("Init section allocation order:\n");
2117        for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2118                for (i = 0; i < info->hdr->e_shnum; ++i) {
2119                        Elf_Shdr *s = &info->sechdrs[i];
2120                        const char *sname = info->secstrings + s->sh_name;
2121
2122                        if ((s->sh_flags & masks[m][0]) != masks[m][0]
2123                            || (s->sh_flags & masks[m][1])
2124                            || s->sh_entsize != ~0UL
2125                            || !strstarts(sname, ".init"))
2126                                continue;
2127                        s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
2128                                         | INIT_OFFSET_MASK);
2129                        pr_debug("\t%s\n", sname);
2130                }
2131                switch (m) {
2132                case 0: /* executable */
2133                        mod->init_size = debug_align(mod->init_size);
2134                        mod->init_text_size = mod->init_size;
2135                        break;
2136                case 1: /* RO: text and ro-data */
2137                        mod->init_size = debug_align(mod->init_size);
2138                        mod->init_ro_size = mod->init_size;
2139                        break;
2140                case 3: /* whole init */
2141                        mod->init_size = debug_align(mod->init_size);
2142                        break;
2143                }
2144        }
2145}
2146
2147static void set_license(struct module *mod, const char *license)
2148{
2149        if (!license)
2150                license = "unspecified";
2151
2152        if (!license_is_gpl_compatible(license)) {
2153                if (!test_taint(TAINT_PROPRIETARY_MODULE))
2154                        printk(KERN_WARNING "%s: module license '%s' taints "
2155                                "kernel.\n", mod->name, license);
2156                add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2157                                 LOCKDEP_NOW_UNRELIABLE);
2158        }
2159}
2160
2161/* Parse tag=value strings from .modinfo section */
2162static char *next_string(char *string, unsigned long *secsize)
2163{
2164        /* Skip non-zero chars */
2165        while (string[0]) {
2166                string++;
2167                if ((*secsize)-- <= 1)
2168                        return NULL;
2169        }
2170
2171        /* Skip any zero padding. */
2172        while (!string[0]) {
2173                string++;
2174                if ((*secsize)-- <= 1)
2175                        return NULL;
2176        }
2177        return string;
2178}
2179
2180static char *get_modinfo(struct load_info *info, const char *tag)
2181{
2182        char *p;
2183        unsigned int taglen = strlen(tag);
2184        Elf_Shdr *infosec = &info->sechdrs[info->index.info];
2185        unsigned long size = infosec->sh_size;
2186
2187        for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) {
2188                if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
2189                        return p + taglen + 1;
2190        }
2191        return NULL;
2192}
2193
2194static void setup_modinfo(struct module *mod, struct load_info *info)
2195{
2196        struct module_attribute *attr;
2197        int i;
2198
2199        for (i = 0; (attr = modinfo_attrs[i]); i++) {
2200                if (attr->setup)
2201                        attr->setup(mod, get_modinfo(info, attr->attr.name));
2202        }
2203}
2204
2205static void free_modinfo(struct module *mod)
2206{
2207        struct module_attribute *attr;
2208        int i;
2209
2210        for (i = 0; (attr = modinfo_attrs[i]); i++) {
2211                if (attr->free)
2212                        attr->free(mod);
2213        }
2214}
2215
2216#ifdef CONFIG_KALLSYMS
2217
2218/* lookup symbol in given range of kernel_symbols */
2219static const struct kernel_symbol *lookup_symbol(const char *name,
2220        const struct kernel_symbol *start,
2221        const struct kernel_symbol *stop)
2222{
2223        return bsearch(name, start, stop - start,
2224                        sizeof(struct kernel_symbol), cmp_name);
2225}
2226
2227static int is_exported(const char *name, unsigned long value,
2228                       const struct module *mod)
2229{
2230        const struct kernel_symbol *ks;
2231        if (!mod)
2232                ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
2233        else
2234                ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
2235        return ks != NULL && ks->value == value;
2236}
2237
2238/* As per nm */
2239static char elf_type(const Elf_Sym *sym, const struct load_info *info)
2240{
2241        const Elf_Shdr *sechdrs = info->sechdrs;
2242
2243        if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
2244                if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
2245                        return 'v';
2246                else
2247                        return 'w';
2248        }
2249        if (sym->st_shndx == SHN_UNDEF)
2250                return 'U';
2251        if (sym->st_shndx == SHN_ABS)
2252                return 'a';
2253        if (sym->st_shndx >= SHN_LORESERVE)
2254                return '?';
2255        if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
2256                return 't';
2257        if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
2258            && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
2259                if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
2260                        return 'r';
2261                else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2262                        return 'g';
2263                else
2264                        return 'd';
2265        }
2266        if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
2267                if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2268                        return 's';
2269                else
2270                        return 'b';
2271        }
2272        if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name,
2273                      ".debug")) {
2274                return 'n';
2275        }
2276        return '?';
2277}
2278
2279static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
2280                           unsigned int shnum)
2281{
2282        const Elf_Shdr *sec;
2283
2284        if (src->st_shndx == SHN_UNDEF
2285            || src->st_shndx >= shnum
2286            || !src->st_name)
2287                return false;
2288
2289        sec = sechdrs + src->st_shndx;
2290        if (!(sec->sh_flags & SHF_ALLOC)
2291#ifndef CONFIG_KALLSYMS_ALL
2292            || !(sec->sh_flags & SHF_EXECINSTR)
2293#endif
2294            || (sec->sh_entsize & INIT_OFFSET_MASK))
2295                return false;
2296
2297        return true;
2298}
2299
2300/*
2301 * We only allocate and copy the strings needed by the parts of symtab
2302 * we keep.  This is simple, but has the effect of making multiple
2303 * copies of duplicates.  We could be more sophisticated, see
2304 * linux-kernel thread starting with
2305 * <73defb5e4bca04a6431392cc341112b1@localhost>.
2306 */
2307static void layout_symtab(struct module *mod, struct load_info *info)
2308{
2309        Elf_Shdr *symsect = info->sechdrs + info->index.sym;
2310        Elf_Shdr *strsect = info->sechdrs + info->index.str;
2311        const Elf_Sym *src;
2312        unsigned int i, nsrc, ndst, strtab_size = 0;
2313
2314        /* Put symbol section at end of init part of module. */
2315        symsect->sh_flags |= SHF_ALLOC;
2316        symsect->sh_entsize = get_offset(mod, &mod->init_size, symsect,
2317                                         info->index.sym) | INIT_OFFSET_MASK;
2318        pr_debug("\t%s\n", info->secstrings + symsect->sh_name);
2319
2320        src = (void *)info->hdr + symsect->sh_offset;
2321        nsrc = symsect->sh_size / sizeof(*src);
2322
2323        /* Compute total space required for the core symbols' strtab. */
2324        for (ndst = i = 0; i < nsrc; i++) {
2325                if (i == 0 ||
2326                    is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
2327                        strtab_size += strlen(&info->strtab[src[i].st_name])+1;
2328                        ndst++;
2329                }
2330        }
2331
2332        /* Append room for core symbols at end of core part. */
2333        info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
2334        info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
2335        mod->core_size += strtab_size;
2336
2337        /* Put string table section at end of init part of module. */
2338        strsect->sh_flags |= SHF_ALLOC;
2339        strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
2340                                         info->index.str) | INIT_OFFSET_MASK;
2341        pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
2342}
2343
2344static void add_kallsyms(struct module *mod, const struct load_info *info)
2345{
2346        unsigned int i, ndst;
2347        const Elf_Sym *src;
2348        Elf_Sym *dst;
2349        char *s;
2350        Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
2351
2352        mod->symtab = (void *)symsec->sh_addr;
2353        mod->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
2354        /* Make sure we get permanent strtab: don't use info->strtab. */
2355        mod->strtab = (void *)info->sechdrs[info->index.str].sh_addr;
2356
2357        /* Set types up while we still have access to sections. */
2358        for (i = 0; i < mod->num_symtab; i++)
2359                mod->symtab[i].st_info = elf_type(&mod->symtab[i], info);
2360
2361        mod->core_symtab = dst = mod->module_core + info->symoffs;
2362        mod->core_strtab = s = mod->module_core + info->stroffs;
2363        src = mod->symtab;
2364        for (ndst = i = 0; i < mod->num_symtab; i++) {
2365                if (i == 0 ||
2366                    is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
2367                        dst[ndst] = src[i];
2368                        dst[ndst++].st_name = s - mod->core_strtab;
2369                        s += strlcpy(s, &mod->strtab[src[i].st_name],
2370                                     KSYM_NAME_LEN) + 1;
2371                }
2372        }
2373        mod->core_num_syms = ndst;
2374}
2375#else
2376static inline void layout_symtab(struct module *mod, struct load_info *info)
2377{
2378}
2379
2380static void add_kallsyms(struct module *mod, const struct load_info *info)
2381{
2382}
2383#endif /* CONFIG_KALLSYMS */
2384
2385static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
2386{
2387        if (!debug)
2388                return;
2389#ifdef CONFIG_DYNAMIC_DEBUG
2390        if (ddebug_add_module(debug, num, debug->modname))
2391                printk(KERN_ERR "dynamic debug error adding module: %s\n",
2392                                        debug->modname);
2393#endif
2394}
2395
2396static void dynamic_debug_remove(struct _ddebug *debug)
2397{
2398        if (debug)
2399                ddebug_remove_module(debug->modname);
2400}
2401
2402void * __weak module_alloc(unsigned long size)
2403{
2404        return vmalloc_exec(size);
2405}
2406
2407static void *module_alloc_update_bounds(unsigned long size)
2408{
2409        void *ret = module_alloc(size);
2410
2411        if (ret) {
2412                mutex_lock(&module_mutex);
2413                /* Update module bounds. */
2414                if ((unsigned long)ret < module_addr_min)
2415                        module_addr_min = (unsigned long)ret;
2416                if ((unsigned long)ret + size > module_addr_max)
2417                        module_addr_max = (unsigned long)ret + size;
2418                mutex_unlock(&module_mutex);
2419        }
2420        return ret;
2421}
2422
2423#ifdef CONFIG_DEBUG_KMEMLEAK
2424static void kmemleak_load_module(const struct module *mod,
2425                                 const struct load_info *info)
2426{
2427        unsigned int i;
2428
2429        /* only scan the sections containing data */
2430        kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
2431
2432        for (i = 1; i < info->hdr->e_shnum; i++) {
2433                const char *name = info->secstrings + info->sechdrs[i].sh_name;
2434                if (!(info->sechdrs[i].sh_flags & SHF_ALLOC))
2435                        continue;
2436                if (!strstarts(name, ".data") && !strstarts(name, ".bss"))
2437                        continue;
2438
2439                kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
2440                                   info->sechdrs[i].sh_size, GFP_KERNEL);
2441        }
2442}
2443#else
2444static inline void kmemleak_load_module(const struct module *mod,
2445                                        const struct load_info *info)
2446{
2447}
2448#endif
2449
2450#ifdef CONFIG_MODULE_SIG
2451static int module_sig_check(struct load_info *info)
2452{
2453        int err = -ENOKEY;
2454        const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
2455        const void *mod = info->hdr;
2456
2457        if (info->len > markerlen &&
2458            memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
2459                /* We truncate the module to discard the signature */
2460                info->len -= markerlen;
2461                err = mod_verify_sig(mod, &info->len);
2462        }
2463
2464        if (!err) {
2465                info->sig_ok = true;
2466                return 0;
2467        }
2468
2469        /* Not having a signature is only an error if we're strict. */
2470        if (err < 0 && fips_enabled)
2471                panic("Module verification failed with error %d in FIPS mode\n",
2472                      err);
2473        if (err == -ENOKEY && !sig_enforce)
2474                err = 0;
2475
2476        return err;
2477}
2478#else /* !CONFIG_MODULE_SIG */
2479static int module_sig_check(struct load_info *info)
2480{
2481        return 0;
2482}
2483#endif /* !CONFIG_MODULE_SIG */
2484
2485/* Sanity checks against invalid binaries, wrong arch, weird elf version. */
2486static int elf_header_check(struct load_info *info)
2487{
2488        if (info->len < sizeof(*(info->hdr)))
2489                return -ENOEXEC;
2490
2491        if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0
2492            || info->hdr->e_type != ET_REL
2493            || !elf_check_arch(info->hdr)
2494            || info->hdr->e_shentsize != sizeof(Elf_Shdr))
2495                return -ENOEXEC;
2496
2497        if (info->hdr->e_shoff >= info->len
2498            || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
2499                info->len - info->hdr->e_shoff))
2500                return -ENOEXEC;
2501
2502        return 0;
2503}
2504
2505/* Sets info->hdr and info->len. */
2506static int copy_module_from_user(const void __user *umod, unsigned long len,
2507                                  struct load_info *info)
2508{
2509        int err;
2510
2511        info->len = len;
2512        if (info->len < sizeof(*(info->hdr)))
2513                return -ENOEXEC;
2514
2515        err = security_kernel_module_from_file(NULL);
2516        if (err)
2517                return err;
2518
2519        /* Suck in entire file: we'll want most of it. */
2520        info->hdr = vmalloc(info->len);
2521        if (!info->hdr)
2522                return -ENOMEM;
2523
2524        if (copy_from_user(info->hdr, umod, info->len) != 0) {
2525                vfree(info->hdr);
2526                return -EFAULT;
2527        }
2528
2529        return 0;
2530}
2531
2532/* Sets info->hdr and info->len. */
2533static int copy_module_from_fd(int fd, struct load_info *info)
2534{
2535        struct file *file;
2536        int err;
2537        struct kstat stat;
2538        loff_t pos;
2539        ssize_t bytes = 0;
2540
2541        file = fget(fd);
2542        if (!file)
2543                return -ENOEXEC;
2544
2545        err = security_kernel_module_from_file(file);
2546        if (err)
2547                goto out;
2548
2549        err = vfs_getattr(&file->f_path, &stat);
2550        if (err)
2551                goto out;
2552
2553        if (stat.size > INT_MAX) {
2554                err = -EFBIG;
2555                goto out;
2556        }
2557
2558        /* Don't hand 0 to vmalloc, it whines. */
2559        if (stat.size == 0) {
2560                err = -EINVAL;
2561                goto out;
2562        }
2563
2564        info->hdr = vmalloc(stat.size);
2565        if (!info->hdr) {
2566                err = -ENOMEM;
2567                goto out;
2568        }
2569
2570        pos = 0;
2571        while (pos < stat.size) {
2572                bytes = kernel_read(file, pos, (char *)(info->hdr) + pos,
2573                                    stat.size - pos);
2574                if (bytes < 0) {
2575                        vfree(info->hdr);
2576                        err = bytes;
2577                        goto out;
2578                }
2579                if (bytes == 0)
2580                        break;
2581                pos += bytes;
2582        }
2583        info->len = pos;
2584
2585out:
2586        fput(file);
2587        return err;
2588}
2589
2590static void free_copy(struct load_info *info)
2591{
2592        vfree(info->hdr);
2593}
2594
2595static int rewrite_section_headers(struct load_info *info, int flags)
2596{
2597        unsigned int i;
2598
2599        /* This should always be true, but let's be sure. */
2600        info->sechdrs[0].sh_addr = 0;
2601
2602        for (i = 1; i < info->hdr->e_shnum; i++) {
2603                Elf_Shdr *shdr = &info->sechdrs[i];
2604                if (shdr->sh_type != SHT_NOBITS
2605                    && info->len < shdr->sh_offset + shdr->sh_size) {
2606                        printk(KERN_ERR "Module len %lu truncated\n",
2607                               info->len);
2608                        return -ENOEXEC;
2609                }
2610
2611                /* Mark all sections sh_addr with their address in the
2612                   temporary image. */
2613                shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
2614
2615#ifndef CONFIG_MODULE_UNLOAD
2616                /* Don't load .exit sections */
2617                if (strstarts(info->secstrings+shdr->sh_name, ".exit"))
2618                        shdr->sh_flags &= ~(unsigned long)SHF_ALLOC;
2619#endif
2620        }
2621
2622        /* Track but don't keep modinfo and version sections. */
2623        if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
2624                info->index.vers = 0; /* Pretend no __versions section! */
2625        else
2626                info->index.vers = find_sec(info, "__versions");
2627        info->index.info = find_sec(info, ".modinfo");
2628        info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
2629        info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
2630        return 0;
2631}
2632
2633/*
2634 * Set up our basic convenience variables (pointers to section headers,
2635 * search for module section index etc), and do some basic section
2636 * verification.
2637 *
2638 * Return the temporary module pointer (we'll replace it with the final
2639 * one when we move the module sections around).
2640 */
2641static struct module *setup_load_info(struct load_info *info, int flags)
2642{
2643        unsigned int i;
2644        int err;
2645        struct module *mod;
2646
2647        /* Set up the convenience variables */
2648        info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
2649        info->secstrings = (void *)info->hdr
2650                + info->sechdrs[info->hdr->e_shstrndx].sh_offset;
2651
2652        err = rewrite_section_headers(info, flags);
2653        if (err)
2654                return ERR_PTR(err);
2655
2656        /* Find internal symbols and strings. */
2657        for (i = 1; i < info->hdr->e_shnum; i++) {
2658                if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
2659                        info->index.sym = i;
2660                        info->index.str = info->sechdrs[i].sh_link;
2661                        info->strtab = (char *)info->hdr
2662                                + info->sechdrs[info->index.str].sh_offset;
2663                        break;
2664                }
2665        }
2666
2667        info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
2668        if (!info->index.mod) {
2669                printk(KERN_WARNING "No module found in object\n");
2670                return ERR_PTR(-ENOEXEC);
2671        }
2672        /* This is temporary: point mod into copy of data. */
2673        mod = (void *)info->sechdrs[info->index.mod].sh_addr;
2674
2675        if (info->index.sym == 0) {
2676                printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
2677                       mod->name);
2678                return ERR_PTR(-ENOEXEC);
2679        }
2680
2681        info->index.pcpu = find_pcpusec(info);
2682
2683        /* Check module struct version now, before we try to use module. */
2684        if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
2685                return ERR_PTR(-ENOEXEC);
2686
2687        return mod;
2688}
2689
2690static int check_modinfo(struct module *mod, struct load_info *info, int flags)
2691{
2692        const char *modmagic = get_modinfo(info, "vermagic");
2693        int err;
2694
2695        if (flags & MODULE_INIT_IGNORE_VERMAGIC)
2696                modmagic = NULL;
2697
2698        /* This is allowed: modprobe --force will invalidate it. */
2699        if (!modmagic) {
2700                err = try_to_force_load(mod, "bad vermagic");
2701                if (err)
2702                        return err;
2703        } else if (!same_magic(modmagic, vermagic, info->index.vers)) {
2704                printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
2705                       mod->name, modmagic, vermagic);
2706                return -ENOEXEC;
2707        }
2708
2709        if (!get_modinfo(info, "intree"))
2710                add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
2711
2712        if (get_modinfo(info, "staging")) {
2713                add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
2714                printk(KERN_WARNING "%s: module is from the staging directory,"
2715                       " the quality is unknown, you have been warned.\n",
2716                       mod->name);
2717        }
2718
2719        /* Set up license info based on the info section */
2720        set_license(mod, get_modinfo(info, "license"));
2721
2722        return 0;
2723}
2724
2725static void find_module_sections(struct module *mod, struct load_info *info)
2726{
2727        mod->kp = section_objs(info, "__param",
2728                               sizeof(*mod->kp), &mod->num_kp);
2729        mod->syms = section_objs(info, "__ksymtab",
2730                                 sizeof(*mod->syms), &mod->num_syms);
2731        mod->crcs = section_addr(info, "__kcrctab");
2732        mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
2733                                     sizeof(*mod->gpl_syms),
2734                                     &mod->num_gpl_syms);
2735        mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
2736        mod->gpl_future_syms = section_objs(info,
2737                                            "__ksymtab_gpl_future",
2738                                            sizeof(*mod->gpl_future_syms),
2739                                            &mod->num_gpl_future_syms);
2740        mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
2741
2742#ifdef CONFIG_UNUSED_SYMBOLS
2743        mod->unused_syms = section_objs(info, "__ksymtab_unused",
2744                                        sizeof(*mod->unused_syms),
2745                                        &mod->num_unused_syms);
2746        mod->unused_crcs = section_addr(info, "__kcrctab_unused");
2747        mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
2748                                            sizeof(*mod->unused_gpl_syms),
2749                                            &mod->num_unused_gpl_syms);
2750        mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
2751#endif
2752#ifdef CONFIG_CONSTRUCTORS
2753        mod->ctors = section_objs(info, ".ctors",
2754                                  sizeof(*mod->ctors), &mod->num_ctors);
2755#endif
2756
2757#ifdef CONFIG_TRACEPOINTS
2758        mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
2759                                             sizeof(*mod->tracepoints_ptrs),
2760                                             &mod->num_tracepoints);
2761#endif
2762#ifdef HAVE_JUMP_LABEL
2763        mod->jump_entries = section_objs(info, "__jump_table",
2764                                        sizeof(*mod->jump_entries),
2765                                        &mod->num_jump_entries);
2766#endif
2767#ifdef CONFIG_EVENT_TRACING
2768        mod->trace_events = section_objs(info, "_ftrace_events",
2769                                         sizeof(*mod->trace_events),
2770                                         &mod->num_trace_events);
2771        /*
2772         * This section contains pointers to allocated objects in the trace
2773         * code and not scanning it leads to false positives.
2774         */
2775        kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
2776                           mod->num_trace_events, GFP_KERNEL);
2777#endif
2778#ifdef CONFIG_TRACING
2779        mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
2780                                         sizeof(*mod->trace_bprintk_fmt_start),
2781                                         &mod->num_trace_bprintk_fmt);
2782        /*
2783         * This section contains pointers to allocated objects in the trace
2784         * code and not scanning it leads to false positives.
2785         */
2786        kmemleak_scan_area(mod->trace_bprintk_fmt_start,
2787                           sizeof(*mod->trace_bprintk_fmt_start) *
2788                           mod->num_trace_bprintk_fmt, GFP_KERNEL);
2789#endif
2790#ifdef CONFIG_FTRACE_MCOUNT_RECORD
2791        /* sechdrs[0].sh_size is always zero */
2792        mod->ftrace_callsites = section_objs(info, "__mcount_loc",
2793                                             sizeof(*mod->ftrace_callsites),
2794                                             &mod->num_ftrace_callsites);
2795#endif
2796
2797        mod->extable = section_objs(info, "__ex_table",
2798                                    sizeof(*mod->extable), &mod->num_exentries);
2799
2800        if (section_addr(info, "__obsparm"))
2801                printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
2802                       mod->name);
2803
2804        info->debug = section_objs(info, "__verbose",
2805                                   sizeof(*info->debug), &info->num_debug);
2806}
2807
2808static int move_module(struct module *mod, struct load_info *info)
2809{
2810        int i;
2811        void *ptr;
2812
2813        /* Do the allocs. */
2814        ptr = module_alloc_update_bounds(mod->core_size);
2815        /*
2816         * The pointer to this block is stored in the module structure
2817         * which is inside the block. Just mark it as not being a
2818         * leak.
2819         */
2820        kmemleak_not_leak(ptr);
2821        if (!ptr)
2822                return -ENOMEM;
2823
2824        memset(ptr, 0, mod->core_size);
2825        mod->module_core = ptr;
2826
2827        if (mod->init_size) {
2828                ptr = module_alloc_update_bounds(mod->init_size);
2829                /*
2830                 * The pointer to this block is stored in the module structure
2831                 * which is inside the block. This block doesn't need to be
2832                 * scanned as it contains data and code that will be freed
2833                 * after the module is initialized.
2834                 */
2835                kmemleak_ignore(ptr);
2836                if (!ptr) {
2837                        module_free(mod, mod->module_core);
2838                        return -ENOMEM;
2839                }
2840                memset(ptr, 0, mod->init_size);
2841                mod->module_init = ptr;
2842        } else
2843                mod->module_init = NULL;
2844
2845        /* Transfer each section which specifies SHF_ALLOC */
2846        pr_debug("final section addresses:\n");
2847        for (i = 0; i < info->hdr->e_shnum; i++) {
2848                void *dest;
2849                Elf_Shdr *shdr = &info->sechdrs[i];
2850
2851                if (!(shdr->sh_flags & SHF_ALLOC))
2852                        continue;
2853
2854                if (shdr->sh_entsize & INIT_OFFSET_MASK)
2855                        dest = mod->module_init
2856                                + (shdr->sh_entsize & ~INIT_OFFSET_MASK);
2857                else
2858                        dest = mod->module_core + shdr->sh_entsize;
2859
2860                if (shdr->sh_type != SHT_NOBITS)
2861                        memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
2862                /* Update sh_addr to point to copy in image. */
2863                shdr->sh_addr = (unsigned long)dest;
2864                pr_debug("\t0x%lx %s\n",
2865                         (long)shdr->sh_addr, info->secstrings + shdr->sh_name);
2866        }
2867
2868        return 0;
2869}
2870
2871static int check_module_license_and_versions(struct module *mod)
2872{
2873        /*
2874         * ndiswrapper is under GPL by itself, but loads proprietary modules.
2875         * Don't use add_taint_module(), as it would prevent ndiswrapper from
2876         * using GPL-only symbols it needs.
2877         */
2878        if (strcmp(mod->name, "ndiswrapper") == 0)
2879                add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
2880
2881        /* driverloader was caught wrongly pretending to be under GPL */
2882        if (strcmp(mod->name, "driverloader") == 0)
2883                add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2884                                 LOCKDEP_NOW_UNRELIABLE);
2885
2886        /* lve claims to be GPL but upstream won't provide source */
2887        if (strcmp(mod->name, "lve") == 0)
2888                add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2889                                 LOCKDEP_NOW_UNRELIABLE);
2890
2891#ifdef CONFIG_MODVERSIONS
2892        if ((mod->num_syms && !mod->crcs)
2893            || (mod->num_gpl_syms && !mod->gpl_crcs)
2894            || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
2895#ifdef CONFIG_UNUSED_SYMBOLS
2896            || (mod->num_unused_syms && !mod->unused_crcs)
2897            || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
2898#endif
2899                ) {
2900                return try_to_force_load(mod,
2901                                         "no versions for exported symbols");
2902        }
2903#endif
2904        return 0;
2905}
2906
2907static void flush_module_icache(const struct module *mod)
2908{
2909        mm_segment_t old_fs;
2910
2911        /* flush the icache in correct context */
2912        old_fs = get_fs();
2913        set_fs(KERNEL_DS);
2914
2915        /*
2916         * Flush the instruction cache, since we've played with text.
2917         * Do it before processing of module parameters, so the module
2918         * can provide parameter accessor functions of its own.
2919         */
2920        if (mod->module_init)
2921                flush_icache_range((unsigned long)mod->module_init,
2922                                   (unsigned long)mod->module_init
2923                                   + mod->init_size);
2924        flush_icache_range((unsigned long)mod->module_core,
2925                           (unsigned long)mod->module_core + mod->core_size);
2926
2927        set_fs(old_fs);
2928}
2929
2930int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
2931                                     Elf_Shdr *sechdrs,
2932                                     char *secstrings,
2933                                     struct module *mod)
2934{
2935        return 0;
2936}
2937
2938static struct module *layout_and_allocate(struct load_info *info, int flags)
2939{
2940        /* Module within temporary copy. */
2941        struct module *mod;
2942        Elf_Shdr *pcpusec;
2943        int err;
2944
2945        mod = setup_load_info(info, flags);
2946        if (IS_ERR(mod))
2947                return mod;
2948
2949        err = check_modinfo(mod, info, flags);
2950        if (err)
2951                return ERR_PTR(err);
2952
2953        /* Allow arches to frob section contents and sizes.  */
2954        err = module_frob_arch_sections(info->hdr, info->sechdrs,
2955                                        info->secstrings, mod);
2956        if (err < 0)
2957                goto out;
2958
2959        pcpusec = &info->sechdrs[info->index.pcpu];
2960        if (pcpusec->sh_size) {
2961                /* We have a special allocation for this section. */
2962                err = percpu_modalloc(mod,
2963                                      pcpusec->sh_size, pcpusec->sh_addralign);
2964                if (err)
2965                        goto out;
2966                pcpusec->sh_flags &= ~(unsigned long)SHF_ALLOC;
2967        }
2968
2969        /* Determine total sizes, and put offsets in sh_entsize.  For now
2970           this is done generically; there doesn't appear to be any
2971           special cases for the architectures. */
2972        layout_sections(mod, info);
2973        layout_symtab(mod, info);
2974
2975        /* Allocate and move to the final place */
2976        err = move_module(mod, info);
2977        if (err)
2978                goto free_percpu;
2979
2980        /* Module has been copied to its final place now: return it. */
2981        mod = (void *)info->sechdrs[info->index.mod].sh_addr;
2982        kmemleak_load_module(mod, info);
2983        return mod;
2984
2985free_percpu:
2986        percpu_modfree(mod);
2987out:
2988        return ERR_PTR(err);
2989}
2990
2991/* mod is no longer valid after this! */
2992static void module_deallocate(struct module *mod, struct load_info *info)
2993{
2994        percpu_modfree(mod);
2995        module_free(mod, mod->module_init);
2996        module_free(mod, mod->module_core);
2997}
2998
2999int __weak module_finalize(const Elf_Ehdr *hdr,
3000                           const Elf_Shdr *sechdrs,
3001                           struct module *me)
3002{
3003        return 0;
3004}
3005
3006static int post_relocation(struct module *mod, const struct load_info *info)
3007{
3008        /* Sort exception table now relocations are done. */
3009        sort_extable(mod->extable, mod->extable + mod->num_exentries);
3010
3011        /* Copy relocated percpu area over. */
3012        percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
3013                       info->sechdrs[info->index.pcpu].sh_size);
3014
3015        /* Setup kallsyms-specific fields. */
3016        add_kallsyms(mod, info);
3017
3018        /* Arch-specific module finalizing. */
3019        return module_finalize(info->hdr, info->sechdrs, mod);
3020}
3021
3022/* Is this module of this name done loading?  No locks held. */
3023static bool finished_loading(const char *name)
3024{
3025        struct module *mod;
3026        bool ret;
3027
3028        mutex_lock(&module_mutex);
3029        mod = find_module_all(name, true);
3030        ret = !mod || mod->state == MODULE_STATE_LIVE
3031                || mod->state == MODULE_STATE_GOING;
3032        mutex_unlock(&module_mutex);
3033
3034        return ret;
3035}
3036
3037/* Call module constructors. */
3038static void do_mod_ctors(struct module *mod)
3039{
3040#ifdef CONFIG_CONSTRUCTORS
3041        unsigned long i;
3042
3043        for (i = 0; i < mod->num_ctors; i++)
3044                mod->ctors[i]();
3045#endif
3046}
3047
3048/* This is where the real work happens */
3049static int do_init_module(struct module *mod)
3050{
3051        int ret = 0;
3052
3053        /*
3054         * We want to find out whether @mod uses async during init.  Clear
3055         * PF_USED_ASYNC.  async_schedule*() will set it.
3056         */
3057        current->flags &= ~PF_USED_ASYNC;
3058
3059        blocking_notifier_call_chain(&module_notify_list,
3060                        MODULE_STATE_COMING, mod);
3061
3062        /* Set RO and NX regions for core */
3063        set_section_ro_nx(mod->module_core,
3064                                mod->core_text_size,
3065                                mod->core_ro_size,
3066                                mod->core_size);
3067
3068        /* Set RO and NX regions for init */
3069        set_section_ro_nx(mod->module_init,
3070                                mod->init_text_size,
3071                                mod->init_ro_size,
3072                                mod->init_size);
3073
3074        do_mod_ctors(mod);
3075        /* Start the module */
3076        if (mod->init != NULL)
3077                ret = do_one_initcall(mod->init);
3078        if (ret < 0) {
3079                /* Init routine failed: abort.  Try to protect us from
3080                   buggy refcounters. */
3081                mod->state = MODULE_STATE_GOING;
3082                synchronize_sched();
3083                module_put(mod);
3084                blocking_notifier_call_chain(&module_notify_list,
3085                                             MODULE_STATE_GOING, mod);
3086                free_module(mod);
3087                wake_up_all(&module_wq);
3088                return ret;
3089        }
3090        if (ret > 0) {
3091                printk(KERN_WARNING
3092"%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n"
3093"%s: loading module anyway...\n",
3094                       __func__, mod->name, ret,
3095                       __func__);
3096                dump_stack();
3097        }
3098
3099        /* Now it's a first class citizen! */
3100        mod->state = MODULE_STATE_LIVE;
3101        blocking_notifier_call_chain(&module_notify_list,
3102                                     MODULE_STATE_LIVE, mod);
3103
3104        /*
3105         * We need to finish all async code before the module init sequence
3106         * is done.  This has potential to deadlock.  For example, a newly
3107         * detected block device can trigger request_module() of the
3108         * default iosched from async probing task.  Once userland helper
3109         * reaches here, async_synchronize_full() will wait on the async
3110         * task waiting on request_module() and deadlock.
3111         *
3112         * This deadlock is avoided by perfomring async_synchronize_full()
3113         * iff module init queued any async jobs.  This isn't a full
3114         * solution as it will deadlock the same if module loading from
3115         * async jobs nests more than once; however, due to the various
3116         * constraints, this hack seems to be the best option for now.
3117         * Please refer to the following thread for details.
3118         *
3119         * http://thread.gmane.org/gmane.linux.kernel/1420814
3120         */
3121        if (current->flags & PF_USED_ASYNC)
3122                async_synchronize_full();
3123
3124        mutex_lock(&module_mutex);
3125        /* Drop initial reference. */
3126        module_put(mod);
3127        trim_init_extable(mod);
3128#ifdef CONFIG_KALLSYMS
3129        mod->num_symtab = mod->core_num_syms;
3130        mod->symtab = mod->core_symtab;
3131        mod->strtab = mod->core_strtab;
3132#endif
3133        unset_module_init_ro_nx(mod);
3134        module_free(mod, mod->module_init);
3135        mod->module_init = NULL;
3136        mod->init_size = 0;
3137        mod->init_ro_size = 0;
3138        mod->init_text_size = 0;
3139        mutex_unlock(&module_mutex);
3140        wake_up_all(&module_wq);
3141
3142        return 0;
3143}
3144
3145static int may_init_module(void)
3146{
3147        if (!capable(CAP_SYS_MODULE) || modules_disabled)
3148                return -EPERM;
3149
3150        return 0;
3151}
3152
3153/*
3154 * We try to place it in the list now to make sure it's unique before
3155 * we dedicate too many resources.  In particular, temporary percpu
3156 * memory exhaustion.
3157 */
3158static int add_unformed_module(struct module *mod)
3159{
3160        int err;
3161        struct module *old;
3162
3163        mod->state = MODULE_STATE_UNFORMED;
3164
3165again:
3166        mutex_lock(&module_mutex);
3167        if ((old = find_module_all(mod->name, true)) != NULL) {
3168                if (old->state == MODULE_STATE_COMING
3169                    || old->state == MODULE_STATE_UNFORMED) {
3170                        /* Wait in case it fails to load. */
3171                        mutex_unlock(&module_mutex);
3172                        err = wait_event_interruptible(module_wq,
3173                                               finished_loading(mod->name));
3174                        if (err)
3175                                goto out_unlocked;
3176                        goto again;
3177                }
3178                err = -EEXIST;
3179                goto out;
3180        }
3181        list_add_rcu(&mod->list, &modules);
3182        err = 0;
3183
3184out:
3185        mutex_unlock(&module_mutex);
3186out_unlocked:
3187        return err;
3188}
3189
3190static int complete_formation(struct module *mod, struct load_info *info)
3191{
3192        int err;
3193
3194        mutex_lock(&module_mutex);
3195
3196        /* Find duplicate symbols (must be called under lock). */
3197        err = verify_export_symbols(mod);
3198        if (err < 0)
3199                goto out;
3200
3201        /* This relies on module_mutex for list integrity. */
3202        module_bug_finalize(info->hdr, info->sechdrs, mod);
3203
3204        /* Mark state as coming so strong_try_module_get() ignores us,
3205         * but kallsyms etc. can see us. */
3206        mod->state = MODULE_STATE_COMING;
3207
3208out:
3209        mutex_unlock(&module_mutex);
3210        return err;
3211}
3212
3213/* Allocate and load the module: note that size of section 0 is always
3214   zero, and we rely on this for optional sections. */
3215static int load_module(struct load_info *info, const char __user *uargs,
3216                       int flags)
3217{
3218        struct module *mod;
3219        long err;
3220
3221        err = module_sig_check(info);
3222        if (err)
3223                goto free_copy;
3224
3225        err = elf_header_check(info);
3226        if (err)
3227                goto free_copy;
3228
3229        /* Figure out module layout, and allocate all the memory. */
3230        mod = layout_and_allocate(info, flags);
3231        if (IS_ERR(mod)) {
3232                err = PTR_ERR(mod);
3233                goto free_copy;
3234        }
3235
3236        /* Reserve our place in the list. */
3237        err = add_unformed_module(mod);
3238        if (err)
3239                goto free_module;
3240
3241#ifdef CONFIG_MODULE_SIG
3242        mod->sig_ok = info->sig_ok;
3243        if (!mod->sig_ok) {
3244                printk_once(KERN_NOTICE
3245                            "%s: module verification failed: signature and/or"
3246                            " required key missing - tainting kernel\n",
3247                            mod->name);
3248                add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_STILL_OK);
3249        }
3250#endif
3251
3252        /* Now module is in final location, initialize linked lists, etc. */
3253        err = module_unload_init(mod);
3254        if (err)
3255                goto unlink_mod;
3256
3257        /* Now we've got everything in the final locations, we can
3258         * find optional sections. */
3259        find_module_sections(mod, info);
3260
3261        err = check_module_license_and_versions(mod);
3262        if (err)
3263                goto free_unload;
3264
3265        /* Set up MODINFO_ATTR fields */
3266        setup_modinfo(mod, info);
3267
3268        /* Fix up syms, so that st_value is a pointer to location. */
3269        err = simplify_symbols(mod, info);
3270        if (err < 0)
3271                goto free_modinfo;
3272
3273        err = apply_relocations(mod, info);
3274        if (err < 0)
3275                goto free_modinfo;
3276
3277        err = post_relocation(mod, info);
3278        if (err < 0)
3279                goto free_modinfo;
3280
3281        flush_module_icache(mod);
3282
3283        /* Now copy in args */
3284        mod->args = strndup_user(uargs, ~0UL >> 1);
3285        if (IS_ERR(mod->args)) {
3286                err = PTR_ERR(mod->args);
3287                goto free_arch_cleanup;
3288        }
3289
3290        dynamic_debug_setup(info->debug, info->num_debug);
3291
3292        /* Finally it's fully formed, ready to start executing. */
3293        err = complete_formation(mod, info);
3294        if (err)
3295                goto ddebug_cleanup;
3296
3297        /* Module is ready to execute: parsing args may do that. */
3298        err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
3299                         -32768, 32767, &ddebug_dyndbg_module_param_cb);
3300        if (err < 0)
3301                goto bug_cleanup;
3302
3303        /* Link in to syfs. */
3304        err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
3305        if (err < 0)
3306                goto bug_cleanup;
3307
3308        /* Get rid of temporary copy. */
3309        free_copy(info);
3310
3311        /* Done! */
3312        trace_module_load(mod);
3313
3314        return do_init_module(mod);
3315
3316 bug_cleanup:
3317        /* module_bug_cleanup needs module_mutex protection */
3318        mutex_lock(&module_mutex);
3319        module_bug_cleanup(mod);
3320        mutex_unlock(&module_mutex);
3321 ddebug_cleanup:
3322        dynamic_debug_remove(info->debug);
3323        synchronize_sched();
3324        kfree(mod->args);
3325 free_arch_cleanup:
3326        module_arch_cleanup(mod);
3327 free_modinfo:
3328        free_modinfo(mod);
3329 free_unload:
3330        module_unload_free(mod);
3331 unlink_mod:
3332        mutex_lock(&module_mutex);
3333        /* Unlink carefully: kallsyms could be walking list. */
3334        list_del_rcu(&mod->list);
3335        wake_up_all(&module_wq);
3336        mutex_unlock(&module_mutex);
3337 free_module:
3338        module_deallocate(mod, info);
3339 free_copy:
3340        free_copy(info);
3341        return err;
3342}
3343
3344SYSCALL_DEFINE3(init_module, void __user *, umod,
3345                unsigned long, len, const char __user *, uargs)
3346{
3347        int err;
3348        struct load_info info = { };
3349
3350        err = may_init_module();
3351        if (err)
3352                return err;
3353
3354        pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
3355               umod, len, uargs);
3356
3357        err = copy_module_from_user(umod, len, &info);
3358        if (err)
3359                return err;
3360
3361        return load_module(&info, uargs, 0);
3362}
3363
3364SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
3365{
3366        int err;
3367        struct load_info info = { };
3368
3369        err = may_init_module();
3370        if (err)
3371                return err;
3372
3373        pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
3374
3375        if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
3376                      |MODULE_INIT_IGNORE_VERMAGIC))
3377                return -EINVAL;
3378
3379        err = copy_module_from_fd(fd, &info);
3380        if (err)
3381                return err;
3382
3383        return load_module(&info, uargs, flags);
3384}
3385
3386static inline int within(unsigned long addr, void *start, unsigned long size)
3387{
3388        return ((void *)addr >= start && (void *)addr < start + size);
3389}
3390
3391#ifdef CONFIG_KALLSYMS
3392/*
3393 * This ignores the intensely annoying "mapping symbols" found
3394 * in ARM ELF files: $a, $t and $d.
3395 */
3396static inline int is_arm_mapping_symbol(const char *str)
3397{
3398        return str[0] == '$' && strchr("atd", str[1])
3399               && (str[2] == '\0' || str[2] == '.');
3400}
3401
3402static const char *get_ksymbol(struct module *mod,
3403                               unsigned long addr,
3404                               unsigned long *size,
3405                               unsigned long *offset)
3406{
3407        unsigned int i, best = 0;
3408        unsigned long nextval;
3409
3410        /* At worse, next value is at end of module */
3411        if (within_module_init(addr, mod))
3412                nextval = (unsigned long)mod->module_init+mod->init_text_size;
3413        else
3414                nextval = (unsigned long)mod->module_core+mod->core_text_size;
3415
3416        /* Scan for closest preceding symbol, and next symbol. (ELF
3417           starts real symbols at 1). */
3418        for (i = 1; i < mod->num_symtab; i++) {
3419                if (mod->symtab[i].st_shndx == SHN_UNDEF)
3420                        continue;
3421
3422                /* We ignore unnamed symbols: they're uninformative
3423                 * and inserted at a whim. */
3424                if (mod->symtab[i].st_value <= addr
3425                    && mod->symtab[i].st_value > mod->symtab[best].st_value
3426                    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
3427                    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
3428                        best = i;
3429                if (mod->symtab[i].st_value > addr
3430                    && mod->symtab[i].st_value < nextval
3431                    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
3432                    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
3433                        nextval = mod->symtab[i].st_value;
3434        }
3435
3436        if (!best)
3437                return NULL;
3438
3439        if (size)
3440                *size = nextval - mod->symtab[best].st_value;
3441        if (offset)
3442                *offset = addr - mod->symtab[best].st_value;
3443        return mod->strtab + mod->symtab[best].st_name;
3444}
3445
3446/* For kallsyms to ask for address resolution.  NULL means not found.  Careful
3447 * not to lock to avoid deadlock on oopses, simply disable preemption. */
3448const char *module_address_lookup(unsigned long addr,
3449                            unsigned long *size,
3450                            unsigned long *offset,
3451                            char **modname,
3452                            char *namebuf)
3453{
3454        struct module *mod;
3455        const char *ret = NULL;
3456
3457        preempt_disable();
3458        list_for_each_entry_rcu(mod, &modules, list) {
3459                if (mod->state == MODULE_STATE_UNFORMED)
3460                        continue;
3461                if (within_module_init(addr, mod) ||
3462                    within_module_core(addr, mod)) {
3463                        if (modname)
3464                                *modname = mod->name;
3465                        ret = get_ksymbol(mod, addr, size, offset);
3466                        break;
3467                }
3468        }
3469        /* Make a copy in here where it's safe */
3470        if (ret) {
3471                strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
3472                ret = namebuf;
3473        }
3474        preempt_enable();
3475        return ret;
3476}
3477
3478int lookup_module_symbol_name(unsigned long addr, char *symname)
3479{
3480        struct module *mod;
3481
3482        preempt_disable();
3483        list_for_each_entry_rcu(mod, &modules, list) {
3484                if (mod->state == MODULE_STATE_UNFORMED)
3485                        continue;
3486                if (within_module_init(addr, mod) ||
3487                    within_module_core(addr, mod)) {
3488                        const char *sym;
3489
3490                        sym = get_ksymbol(mod, addr, NULL, NULL);
3491                        if (!sym)
3492                                goto out;
3493                        strlcpy(symname, sym, KSYM_NAME_LEN);
3494                        preempt_enable();
3495                        return 0;
3496                }
3497        }
3498out:
3499        preempt_enable();
3500        return -ERANGE;
3501}
3502
3503int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
3504                        unsigned long *offset, char *modname, char *name)
3505{
3506        struct module *mod;
3507
3508        preempt_disable();
3509        list_for_each_entry_rcu(mod, &modules, list) {
3510                if (mod->state == MODULE_STATE_UNFORMED)
3511                        continue;
3512                if (within_module_init(addr, mod) ||
3513                    within_module_core(addr, mod)) {
3514                        const char *sym;
3515
3516                        sym = get_ksymbol(mod, addr, size, offset);
3517                        if (!sym)
3518                                goto out;
3519                        if (modname)
3520                                strlcpy(modname, mod->name, MODULE_NAME_LEN);
3521                        if (name)
3522                                strlcpy(name, sym, KSYM_NAME_LEN);
3523                        preempt_enable();
3524                        return 0;
3525                }
3526        }
3527out:
3528        preempt_enable();
3529        return -ERANGE;
3530}
3531
3532int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
3533                        char *name, char *module_name, int *exported)
3534{
3535        struct module *mod;
3536
3537        preempt_disable();
3538        list_for_each_entry_rcu(mod, &modules, list) {
3539                if (mod->state == MODULE_STATE_UNFORMED)
3540                        continue;
3541                if (symnum < mod->num_symtab) {
3542                        *value = mod->symtab[symnum].st_value;
3543                        *type = mod->symtab[symnum].st_info;
3544                        strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
3545                                KSYM_NAME_LEN);
3546                        strlcpy(module_name, mod->name, MODULE_NAME_LEN);
3547                        *exported = is_exported(name, *value, mod);
3548                        preempt_enable();
3549                        return 0;
3550                }
3551                symnum -= mod->num_symtab;
3552        }
3553        preempt_enable();
3554        return -ERANGE;
3555}
3556
3557static unsigned long mod_find_symname(struct module *mod, const char *name)
3558{
3559        unsigned int i;
3560
3561        for (i = 0; i < mod->num_symtab; i++)
3562                if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
3563                    mod->symtab[i].st_info != 'U')
3564                        return mod->symtab[i].st_value;
3565        return 0;
3566}
3567
3568/* Look for this name: can be of form module:name. */
3569unsigned long module_kallsyms_lookup_name(const char *name)
3570{
3571        struct module *mod;
3572        char *colon;
3573        unsigned long ret = 0;
3574
3575        /* Don't lock: we're in enough trouble already. */
3576        preempt_disable();
3577        if ((colon = strchr(name, ':')) != NULL) {
3578                *colon = '\0';
3579                if ((mod = find_module(name)) != NULL)
3580                        ret = mod_find_symname(mod, colon+1);
3581                *colon = ':';
3582        } else {
3583                list_for_each_entry_rcu(mod, &modules, list) {
3584                        if (mod->state == MODULE_STATE_UNFORMED)
3585                                continue;
3586                        if ((ret = mod_find_symname(mod, name)) != 0)
3587                                break;
3588                }
3589        }
3590        preempt_enable();
3591        return ret;
3592}
3593
3594int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
3595                                             struct module *, unsigned long),
3596                                   void *data)
3597{
3598        struct module *mod;
3599        unsigned int i;
3600        int ret;
3601
3602        list_for_each_entry(mod, &modules, list) {
3603                if (mod->state == MODULE_STATE_UNFORMED)
3604                        continue;
3605                for (i = 0; i < mod->num_symtab; i++) {
3606                        ret = fn(data, mod->strtab + mod->symtab[i].st_name,
3607                                 mod, mod->symtab[i].st_value);
3608                        if (ret != 0)
3609                                return ret;
3610                }
3611        }
3612        return 0;
3613}
3614#endif /* CONFIG_KALLSYMS */
3615
3616static char *module_flags(struct module *mod, char *buf)
3617{
3618        int bx = 0;
3619
3620        BUG_ON(mod->state == MODULE_STATE_UNFORMED);
3621        if (mod->taints ||
3622            mod->state == MODULE_STATE_GOING ||
3623            mod->state == MODULE_STATE_COMING) {
3624                buf[bx++] = '(';
3625                bx += module_flags_taint(mod, buf + bx);
3626                /* Show a - for module-is-being-unloaded */
3627                if (mod->state == MODULE_STATE_GOING)
3628                        buf[bx++] = '-';
3629                /* Show a + for module-is-being-loaded */
3630                if (mod->state == MODULE_STATE_COMING)
3631                        buf[bx++] = '+';
3632                buf[bx++] = ')';
3633        }
3634        buf[bx] = '\0';
3635
3636        return buf;
3637}
3638
3639#ifdef CONFIG_PROC_FS
3640/* Called by the /proc file system to return a list of modules. */
3641static void *m_start(struct seq_file *m, loff_t *pos)
3642{
3643        mutex_lock(&module_mutex);
3644        return seq_list_start(&modules, *pos);
3645}
3646
3647static void *m_next(struct seq_file *m, void *p, loff_t *pos)
3648{
3649        return seq_list_next(p, &modules, pos);
3650}
3651
3652static void m_stop(struct seq_file *m, void *p)
3653{
3654        mutex_unlock(&module_mutex);
3655}
3656
3657static int m_show(struct seq_file *m, void *p)
3658{
3659        struct module *mod = list_entry(p, struct module, list);
3660        char buf[8];
3661
3662        /* We always ignore unformed modules. */
3663        if (mod->state == MODULE_STATE_UNFORMED)
3664                return 0;
3665
3666        seq_printf(m, "%s %u",
3667                   mod->name, mod->init_size + mod->core_size);
3668        print_unload_info(m, mod);
3669
3670        /* Informative for users. */
3671        seq_printf(m, " %s",
3672                   mod->state == MODULE_STATE_GOING ? "Unloading":
3673                   mod->state == MODULE_STATE_COMING ? "Loading":
3674                   "Live");
3675        /* Used by oprofile and other similar tools. */
3676        seq_printf(m, " 0x%pK", mod->module_core);
3677
3678        /* Taints info */
3679        if (mod->taints)
3680                seq_printf(m, " %s", module_flags(mod, buf));
3681
3682        seq_printf(m, "\n");
3683        return 0;
3684}
3685
3686/* Format: modulename size refcount deps address
3687
3688   Where refcount is a number or -, and deps is a comma-separated list
3689   of depends or -.
3690*/
3691static const struct seq_operations modules_op = {
3692        .start  = m_start,
3693        .next   = m_next,
3694        .stop   = m_stop,
3695        .show   = m_show
3696};
3697
3698static int modules_open(struct inode *inode, struct file *file)
3699{
3700        return seq_open(file, &modules_op);
3701}
3702
3703static const struct file_operations proc_modules_operations = {
3704        .open           = modules_open,
3705        .read           = seq_read,
3706        .llseek         = seq_lseek,
3707        .release        = seq_release,
3708};
3709
3710static int __init proc_modules_init(void)
3711{
3712        proc_create("modules", 0, NULL, &proc_modules_operations);
3713        return 0;
3714}
3715module_init(proc_modules_init);
3716#endif
3717
3718/* Given an address, look for it in the module exception tables. */
3719const struct exception_table_entry *search_module_extables(unsigned long addr)
3720{
3721        const struct exception_table_entry *e = NULL;
3722        struct module *mod;
3723
3724        preempt_disable();
3725        list_for_each_entry_rcu(mod, &modules, list) {
3726                if (mod->state == MODULE_STATE_UNFORMED)
3727                        continue;
3728                if (mod->num_exentries == 0)
3729                        continue;
3730
3731                e = search_extable(mod->extable,
3732                                   mod->extable + mod->num_exentries - 1,
3733                                   addr);
3734                if (e)
3735                        break;
3736        }
3737        preempt_enable();
3738
3739        /* Now, if we found one, we are running inside it now, hence
3740           we cannot unload the module, hence no refcnt needed. */
3741        return e;
3742}
3743
3744/*
3745 * is_module_address - is this address inside a module?
3746 * @addr: the address to check.
3747 *
3748 * See is_module_text_address() if you simply want to see if the address
3749 * is code (not data).
3750 */
3751bool is_module_address(unsigned long addr)
3752{
3753        bool ret;
3754
3755        preempt_disable();
3756        ret = __module_address(addr) != NULL;
3757        preempt_enable();
3758
3759        return ret;
3760}
3761
3762/*
3763 * __module_address - get the module which contains an address.
3764 * @addr: the address.
3765 *
3766 * Must be called with preempt disabled or module mutex held so that
3767 * module doesn't get freed during this.
3768 */
3769struct module *__module_address(unsigned long addr)
3770{
3771        struct module *mod;
3772
3773        if (addr < module_addr_min || addr > module_addr_max)
3774                return NULL;
3775
3776        list_for_each_entry_rcu(mod, &modules, list) {
3777                if (mod->state == MODULE_STATE_UNFORMED)
3778                        continue;
3779                if (within_module_core(addr, mod)
3780                    || within_module_init(addr, mod))
3781                        return mod;
3782        }
3783        return NULL;
3784}
3785EXPORT_SYMBOL_GPL(__module_address);
3786
3787/*
3788 * is_module_text_address - is this address inside module code?
3789 * @addr: the address to check.
3790 *
3791 * See is_module_address() if you simply want to see if the address is
3792 * anywhere in a module.  See kernel_text_address() for testing if an
3793 * address corresponds to kernel or module code.
3794 */
3795bool is_module_text_address(unsigned long addr)
3796{
3797        bool ret;
3798
3799        preempt_disable();
3800        ret = __module_text_address(addr) != NULL;
3801        preempt_enable();
3802
3803        return ret;
3804}
3805
3806/*
3807 * __module_text_address - get the module whose code contains an address.
3808 * @addr: the address.
3809 *
3810 * Must be called with preempt disabled or module mutex held so that
3811 * module doesn't get freed during this.
3812 */
3813struct module *__module_text_address(unsigned long addr)
3814{
3815        struct module *mod = __module_address(addr);
3816        if (mod) {
3817                /* Make sure it's within the text section. */
3818                if (!within(addr, mod->module_init, mod->init_text_size)
3819                    && !within(addr, mod->module_core, mod->core_text_size))
3820                        mod = NULL;
3821        }
3822        return mod;
3823}
3824EXPORT_SYMBOL_GPL(__module_text_address);
3825
3826/* Don't grab lock, we're oopsing. */
3827void print_modules(void)
3828{
3829        struct module *mod;
3830        char buf[8];
3831
3832        printk(KERN_DEFAULT "Modules linked in:");
3833        /* Most callers should already have preempt disabled, but make sure */
3834        preempt_disable();
3835        list_for_each_entry_rcu(mod, &modules, list) {
3836                if (mod->state == MODULE_STATE_UNFORMED)
3837                        continue;
3838                printk(" %s%s", mod->name, module_flags(mod, buf));
3839        }
3840        preempt_enable();
3841        if (last_unloaded_module[0])
3842                printk(" [last unloaded: %s]", last_unloaded_module);
3843        printk("\n");
3844}
3845
3846#ifdef CONFIG_MODVERSIONS
3847/* Generate the signature for all relevant module structures here.
3848 * If these change, we don't want to try to parse the module. */
3849void module_layout(struct module *mod,
3850                   struct modversion_info *ver,
3851                   struct kernel_param *kp,
3852                   struct kernel_symbol *ks,
3853                   struct tracepoint * const *tp)
3854{
3855}
3856EXPORT_SYMBOL(module_layout);
3857#endif
3858
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