linux-bk/fs/binfmt_elf_fdpic.c
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   1/* binfmt_elf_fdpic.c: FDPIC ELF binary format
   2 *
   3 * Copyright (C) 2003, 2004 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 * Derived from binfmt_elf.c
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * as published by the Free Software Foundation; either version
  10 * 2 of the License, or (at your option) any later version.
  11 */
  12
  13#include <linux/module.h>
  14
  15#include <linux/fs.h>
  16#include <linux/stat.h>
  17#include <linux/sched.h>
  18#include <linux/mm.h>
  19#include <linux/mman.h>
  20#include <linux/errno.h>
  21#include <linux/signal.h>
  22#include <linux/binfmts.h>
  23#include <linux/string.h>
  24#include <linux/file.h>
  25#include <linux/fcntl.h>
  26#include <linux/slab.h>
  27#include <linux/highmem.h>
  28#include <linux/personality.h>
  29#include <linux/ptrace.h>
  30#include <linux/init.h>
  31#include <linux/smp_lock.h>
  32#include <linux/elf.h>
  33#include <linux/elf-fdpic.h>
  34#include <linux/elfcore.h>
  35
  36#include <asm/uaccess.h>
  37#include <asm/param.h>
  38#include <asm/pgalloc.h>
  39
  40typedef char *elf_caddr_t;
  41#ifndef elf_addr_t
  42#define elf_addr_t unsigned long
  43#endif
  44
  45#if 0
  46#define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
  47#else
  48#define kdebug(fmt, ...) do {} while(0)
  49#endif
  50
  51MODULE_LICENSE("GPL");
  52
  53static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs);
  54//static int load_elf_fdpic_library(struct file *);
  55static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file);
  56static int elf_fdpic_map_file(struct elf_fdpic_params *params,
  57                              struct file *file,
  58                              struct mm_struct *mm,
  59                              const char *what);
  60
  61static int create_elf_fdpic_tables(struct linux_binprm *bprm,
  62                                   struct mm_struct *mm,
  63                                   struct elf_fdpic_params *exec_params,
  64                                   struct elf_fdpic_params *interp_params);
  65
  66#ifndef CONFIG_MMU
  67static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp);
  68static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
  69                                                   struct file *file,
  70                                                   struct mm_struct *mm);
  71#endif
  72
  73static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
  74                                             struct file *file,
  75                                             struct mm_struct *mm);
  76
  77static struct linux_binfmt elf_fdpic_format = {
  78        .module         = THIS_MODULE,
  79        .load_binary    = load_elf_fdpic_binary,
  80//      .load_shlib     = load_elf_fdpic_library,
  81//      .core_dump      = elf_fdpic_core_dump,
  82        .min_coredump   = ELF_EXEC_PAGESIZE,
  83};
  84
  85static int __init init_elf_fdpic_binfmt(void)  { return register_binfmt(&elf_fdpic_format); }
  86static void __exit exit_elf_fdpic_binfmt(void) { unregister_binfmt(&elf_fdpic_format); }
  87
  88module_init(init_elf_fdpic_binfmt)
  89module_exit(exit_elf_fdpic_binfmt)
  90
  91static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
  92{
  93        if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
  94                return 0;
  95        if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
  96                return 0;
  97        if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
  98                return 0;
  99        if (!file->f_op || !file->f_op->mmap)
 100                return 0;
 101        return 1;
 102}
 103
 104/*****************************************************************************/
 105/*
 106 * read the program headers table into memory
 107 */
 108static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file)
 109{
 110        struct elf32_phdr *phdr;
 111        unsigned long size;
 112        int retval, loop;
 113
 114        if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
 115                return -ENOMEM;
 116        if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
 117                return -ENOMEM;
 118
 119        size = params->hdr.e_phnum * sizeof(struct elf_phdr);
 120        params->phdrs = kmalloc(size, GFP_KERNEL);
 121        if (!params->phdrs)
 122                return -ENOMEM;
 123
 124        retval = kernel_read(file, params->hdr.e_phoff, (char *) params->phdrs, size);
 125        if (retval < 0)
 126                return retval;
 127
 128        /* determine stack size for this binary */
 129        phdr = params->phdrs;
 130        for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 131                if (phdr->p_type != PT_GNU_STACK)
 132                        continue;
 133
 134                if (phdr->p_flags & PF_X)
 135                        params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
 136                else
 137                        params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
 138
 139                params->stack_size = phdr->p_memsz;
 140                break;
 141        }
 142
 143        return 0;
 144} /* end elf_fdpic_fetch_phdrs() */
 145
 146/*****************************************************************************/
 147/*
 148 * load an fdpic binary into various bits of memory
 149 */
 150static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 151{
 152        struct elf_fdpic_params exec_params, interp_params;
 153        struct elf_phdr *phdr;
 154        unsigned long stack_size;
 155        struct file *interpreter = NULL; /* to shut gcc up */
 156        char *interpreter_name = NULL;
 157        int executable_stack;
 158        int retval, i;
 159
 160        memset(&exec_params, 0, sizeof(exec_params));
 161        memset(&interp_params, 0, sizeof(interp_params));
 162
 163        exec_params.hdr = *(struct elfhdr *) bprm->buf;
 164        exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
 165
 166        /* check that this is a binary we know how to deal with */
 167        retval = -ENOEXEC;
 168        if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
 169                goto error;
 170
 171        /* read the program header table */
 172        retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
 173        if (retval < 0)
 174                goto error;
 175
 176        /* scan for a program header that specifies an interpreter */
 177        phdr = exec_params.phdrs;
 178
 179        for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
 180                switch (phdr->p_type) {
 181                case PT_INTERP:
 182                        retval = -ENOMEM;
 183                        if (phdr->p_filesz > PATH_MAX)
 184                                goto error;
 185                        retval = -ENOENT;
 186                        if (phdr->p_filesz < 2)
 187                                goto error;
 188
 189                        /* read the name of the interpreter into memory */
 190                        interpreter_name = (char *) kmalloc(phdr->p_filesz, GFP_KERNEL);
 191                        if (!interpreter_name)
 192                                goto error;
 193
 194                        retval = kernel_read(bprm->file,
 195                                             phdr->p_offset,
 196                                             interpreter_name,
 197                                             phdr->p_filesz);
 198                        if (retval < 0)
 199                                goto error;
 200
 201                        retval = -ENOENT;
 202                        if (interpreter_name[phdr->p_filesz - 1] != '\0')
 203                                goto error;
 204
 205                        kdebug("Using ELF interpreter %s", interpreter_name);
 206
 207                        /* replace the program with the interpreter */
 208                        interpreter = open_exec(interpreter_name);
 209                        retval = PTR_ERR(interpreter);
 210                        if (IS_ERR(interpreter)) {
 211                                interpreter = NULL;
 212                                goto error;
 213                        }
 214
 215                        retval = kernel_read(interpreter, 0, bprm->buf, BINPRM_BUF_SIZE);
 216                        if (retval < 0)
 217                                goto error;
 218
 219                        interp_params.hdr = *((struct elfhdr *) bprm->buf);
 220                        break;
 221
 222                case PT_LOAD:
 223#ifdef CONFIG_MMU
 224                        if (exec_params.load_addr == 0)
 225                                exec_params.load_addr = phdr->p_vaddr;
 226#endif
 227                        break;
 228                }
 229
 230        }
 231
 232        if (elf_check_const_displacement(&exec_params.hdr))
 233                exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 234
 235        /* perform insanity checks on the interpreter */
 236        if (interpreter_name) {
 237                retval = -ELIBBAD;
 238                if (!is_elf_fdpic(&interp_params.hdr, interpreter))
 239                        goto error;
 240
 241                interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
 242
 243                /* read the interpreter's program header table */
 244                retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
 245                if (retval < 0)
 246                        goto error;
 247        }
 248
 249        stack_size = exec_params.stack_size;
 250        if (stack_size < interp_params.stack_size)
 251                stack_size = interp_params.stack_size;
 252
 253        if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 254                executable_stack = EXSTACK_ENABLE_X;
 255        else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 256                executable_stack = EXSTACK_DISABLE_X;
 257        else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 258                executable_stack = EXSTACK_ENABLE_X;
 259        else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 260                executable_stack = EXSTACK_DISABLE_X;
 261        else
 262                executable_stack = EXSTACK_DEFAULT;
 263
 264        retval = -ENOEXEC;
 265        if (stack_size == 0)
 266                goto error;
 267
 268        if (elf_check_const_displacement(&interp_params.hdr))
 269                interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 270
 271        /* flush all traces of the currently running executable */
 272        retval = flush_old_exec(bprm);
 273        if (retval)
 274                goto error;
 275
 276        /* there's now no turning back... the old userspace image is dead,
 277         * defunct, deceased, etc. after this point we have to exit via
 278         * error_kill */
 279        set_personality(PER_LINUX_FDPIC);
 280        set_binfmt(&elf_fdpic_format);
 281
 282        current->mm->start_code = 0;
 283        current->mm->end_code = 0;
 284        current->mm->start_stack = 0;
 285        current->mm->start_data = 0;
 286        current->mm->end_data = 0;
 287        current->mm->context.exec_fdpic_loadmap = 0;
 288        current->mm->context.interp_fdpic_loadmap = 0;
 289
 290        current->flags &= ~PF_FORKNOEXEC;
 291
 292#ifdef CONFIG_MMU
 293        elf_fdpic_arch_lay_out_mm(&exec_params,
 294                                  &interp_params,
 295                                  &current->mm->start_stack,
 296                                  &current->mm->start_brk);
 297#endif
 298
 299        /* do this so that we can load the interpreter, if need be
 300         * - we will change some of these later
 301         */
 302        current->mm->rss = 0;
 303
 304#ifdef CONFIG_MMU
 305        retval = setup_arg_pages(bprm, current->mm->start_stack, executable_stack);
 306        if (retval < 0) {
 307                send_sig(SIGKILL, current, 0);
 308                goto error_kill;
 309        }
 310#endif
 311
 312        /* load the executable and interpreter into memory */
 313        retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm, "executable");
 314        if (retval < 0)
 315                goto error_kill;
 316
 317        if (interpreter_name) {
 318                retval = elf_fdpic_map_file(&interp_params, interpreter,
 319                                            current->mm, "interpreter");
 320                if (retval < 0) {
 321                        printk(KERN_ERR "Unable to load interpreter\n");
 322                        goto error_kill;
 323                }
 324
 325                allow_write_access(interpreter);
 326                fput(interpreter);
 327                interpreter = NULL;
 328        }
 329
 330#ifdef CONFIG_MMU
 331        if (!current->mm->start_brk)
 332                current->mm->start_brk = current->mm->end_data;
 333
 334        current->mm->brk = current->mm->start_brk = PAGE_ALIGN(current->mm->start_brk);
 335
 336#else
 337        /* create a stack and brk area big enough for everyone
 338         * - the brk heap starts at the bottom and works up
 339         * - the stack starts at the top and works down
 340         */
 341        stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
 342        if (stack_size < PAGE_SIZE * 2)
 343                stack_size = PAGE_SIZE * 2;
 344
 345        down_write(&current->mm->mmap_sem);
 346        current->mm->start_brk = do_mmap(NULL,
 347                                         0,
 348                                         stack_size,
 349                                         PROT_READ | PROT_WRITE | PROT_EXEC,
 350                                         MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN,
 351                                         0);
 352
 353        if (IS_ERR((void *) current->mm->start_brk)) {
 354                up_write(&current->mm->mmap_sem);
 355                retval = current->mm->start_brk;
 356                current->mm->start_brk = 0;
 357                goto error_kill;
 358        }
 359
 360        if (do_mremap(current->mm->start_brk,
 361                      stack_size,
 362                      ksize((char *) current->mm->start_brk),
 363                      0, 0
 364                      ) == current->mm->start_brk
 365            )
 366                stack_size = ksize((char *) current->mm->start_brk);
 367        up_write(&current->mm->mmap_sem);
 368
 369        current->mm->brk = current->mm->start_brk;
 370        current->mm->context.end_brk = current->mm->start_brk;
 371        current->mm->context.end_brk += (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
 372        current->mm->start_stack = current->mm->start_brk + stack_size;
 373#endif
 374
 375        compute_creds(bprm);
 376        current->flags &= ~PF_FORKNOEXEC;
 377        if (create_elf_fdpic_tables(bprm, current->mm, &exec_params, &interp_params) < 0)
 378                goto error_kill;
 379
 380        kdebug("- start_code  %lx",     (long) current->mm->start_code);
 381        kdebug("- end_code    %lx",     (long) current->mm->end_code);
 382        kdebug("- start_data  %lx",     (long) current->mm->start_data);
 383        kdebug("- end_data    %lx",     (long) current->mm->end_data);
 384        kdebug("- start_brk   %lx",     (long) current->mm->start_brk);
 385        kdebug("- brk         %lx",     (long) current->mm->brk);
 386        kdebug("- start_stack %lx",     (long) current->mm->start_stack);
 387
 388#ifdef ELF_FDPIC_PLAT_INIT
 389        /*
 390         * The ABI may specify that certain registers be set up in special
 391         * ways (on i386 %edx is the address of a DT_FINI function, for
 392         * example.  This macro performs whatever initialization to
 393         * the regs structure is required.
 394         */
 395        ELF_FDPIC_PLAT_INIT(regs,
 396                            exec_params.map_addr,
 397                            interp_params.map_addr,
 398                            interp_params.dynamic_addr ?: exec_params.dynamic_addr
 399                            );
 400#endif
 401
 402        /* everything is now ready... get the userspace context ready to roll */
 403        start_thread(regs,
 404                     interp_params.entry_addr ?: exec_params.entry_addr,
 405                     current->mm->start_stack);
 406
 407        if (unlikely(current->ptrace & PT_PTRACED)) {
 408                if (current->ptrace & PT_TRACE_EXEC)
 409                        ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 410                else
 411                        send_sig(SIGTRAP, current, 0);
 412        }
 413
 414        retval = 0;
 415
 416error:
 417        if (interpreter) {
 418                allow_write_access(interpreter);
 419                fput(interpreter);
 420        }
 421        if (interpreter_name)
 422                kfree(interpreter_name);
 423        if (exec_params.phdrs)
 424                kfree(exec_params.phdrs);
 425        if (exec_params.loadmap)
 426                kfree(exec_params.loadmap);
 427        if (interp_params.phdrs)
 428                kfree(interp_params.phdrs);
 429        if (interp_params.loadmap)
 430                kfree(interp_params.loadmap);
 431        return retval;
 432
 433        /* unrecoverable error - kill the process */
 434 error_kill:
 435        send_sig(SIGSEGV, current, 0);
 436        goto error;
 437
 438} /* end load_elf_fdpic_binary() */
 439
 440/*****************************************************************************/
 441/*
 442 * present useful information to the program
 443 */
 444static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 445                                   struct mm_struct *mm,
 446                                   struct elf_fdpic_params *exec_params,
 447                                   struct elf_fdpic_params *interp_params)
 448{
 449        unsigned long sp, csp, nitems;
 450        elf_caddr_t *argv, *envp;
 451        size_t platform_len = 0, len;
 452        char *k_platform, *u_platform, *p;
 453        long hwcap;
 454        int loop;
 455
 456        /* we're going to shovel a whole load of stuff onto the stack */
 457#ifdef CONFIG_MMU
 458        sp = bprm->p;
 459#else
 460        sp = mm->start_stack;
 461
 462        /* stack the program arguments and environment */
 463        if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
 464                return -EFAULT;
 465#endif
 466
 467        /* get hold of platform and hardware capabilities masks for the machine
 468         * we are running on.  In some cases (Sparc), this info is impossible
 469         * to get, in others (i386) it is merely difficult.
 470         */
 471        hwcap = ELF_HWCAP;
 472        k_platform = ELF_PLATFORM;
 473
 474        if (k_platform) {
 475                platform_len = strlen(k_platform) + 1;
 476                sp -= platform_len;
 477                if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
 478                        return -EFAULT;
 479        }
 480
 481        u_platform = (char *) sp;
 482
 483#if defined(__i386__) && defined(CONFIG_SMP)
 484        /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 485         * by the processes running on the same package. One thing we can do
 486         * is to shuffle the initial stack for them.
 487         *
 488         * the conditionals here are unneeded, but kept in to make the
 489         * code behaviour the same as pre change unless we have hyperthreaded
 490         * processors. This keeps Mr Marcelo Person happier but should be
 491         * removed for 2.5
 492         */
 493        if (smp_num_siblings > 1)
 494                sp = sp - ((current->pid % 64) << 7);
 495#endif
 496
 497        sp &= ~7UL;
 498
 499        /* stack the load map(s) */
 500        len = sizeof(struct elf32_fdpic_loadmap);
 501        len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 502        sp = (sp - len) & ~7UL;
 503        exec_params->map_addr = sp;
 504
 505        if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0)
 506                return -EFAULT;
 507
 508        current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 509
 510        if (interp_params->loadmap) {
 511                len = sizeof(struct elf32_fdpic_loadmap);
 512                len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs;
 513                sp = (sp - len) & ~7UL;
 514                interp_params->map_addr = sp;
 515
 516                if (copy_to_user((void *) sp, interp_params->loadmap, len) != 0)
 517                        return -EFAULT;
 518
 519                current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
 520        }
 521
 522        /* force 16 byte _final_ alignment here for generality */
 523#define DLINFO_ITEMS 13
 524
 525        nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
 526#ifdef DLINFO_ARCH_ITEMS
 527        nitems += DLINFO_ARCH_ITEMS;
 528#endif
 529
 530        csp = sp;
 531        sp -= nitems * 2 * sizeof(unsigned long);
 532        sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
 533        sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
 534        sp -= 1 * sizeof(unsigned long);                /* argc */
 535
 536        csp -= sp & 15UL;
 537        sp -= sp & 15UL;
 538
 539        /* put the ELF interpreter info on the stack */
 540#define NEW_AUX_ENT(nr, id, val)                                                \
 541        do {                                                                    \
 542                struct { unsigned long _id, _val; } *ent = (void *) csp;        \
 543                __put_user((id), &ent[nr]._id);                                 \
 544                __put_user((val), &ent[nr]._val);                               \
 545        } while (0)
 546
 547        csp -= 2 * sizeof(unsigned long);
 548        NEW_AUX_ENT(0, AT_NULL, 0);
 549        if (k_platform) {
 550                csp -= 2 * sizeof(unsigned long);
 551                NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
 552        }
 553
 554        csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 555        NEW_AUX_ENT( 0, AT_HWCAP,               hwcap);
 556        NEW_AUX_ENT( 1, AT_PAGESZ,              PAGE_SIZE);
 557        NEW_AUX_ENT( 2, AT_CLKTCK,              CLOCKS_PER_SEC);
 558        NEW_AUX_ENT( 3, AT_PHDR,                exec_params->ph_addr);
 559        NEW_AUX_ENT( 4, AT_PHENT,               sizeof(struct elf_phdr));
 560        NEW_AUX_ENT( 5, AT_PHNUM,               exec_params->hdr.e_phnum);
 561        NEW_AUX_ENT( 6, AT_BASE,                interp_params->elfhdr_addr);
 562        NEW_AUX_ENT( 7, AT_FLAGS,               0);
 563        NEW_AUX_ENT( 8, AT_ENTRY,               exec_params->entry_addr);
 564        NEW_AUX_ENT( 9, AT_UID,                 (elf_addr_t) current->uid);
 565        NEW_AUX_ENT(10, AT_EUID,                (elf_addr_t) current->euid);
 566        NEW_AUX_ENT(11, AT_GID,                 (elf_addr_t) current->gid);
 567        NEW_AUX_ENT(12, AT_EGID,                (elf_addr_t) current->egid);
 568
 569#ifdef ARCH_DLINFO
 570        /* ARCH_DLINFO must come last so platform specific code can enforce
 571         * special alignment requirements on the AUXV if necessary (eg. PPC).
 572         */
 573        ARCH_DLINFO;
 574#endif
 575#undef NEW_AUX_ENT
 576
 577        /* allocate room for argv[] and envv[] */
 578        csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 579        envp = (elf_caddr_t *) csp;
 580        csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 581        argv = (elf_caddr_t *) csp;
 582
 583        /* stack argc */
 584        csp -= sizeof(unsigned long);
 585        __put_user(bprm->argc, (unsigned long *) csp);
 586
 587        if (csp != sp)
 588                BUG();
 589
 590        /* fill in the argv[] array */
 591#ifdef CONFIG_MMU
 592        current->mm->arg_start = bprm->p;
 593#else
 594        current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 595#endif
 596
 597        p = (char *) current->mm->arg_start;
 598        for (loop = bprm->argc; loop > 0; loop--) {
 599                __put_user((elf_caddr_t) p, argv++);
 600                len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 601                if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 602                        return -EINVAL;
 603                p += len;
 604        }
 605        __put_user(NULL, argv);
 606        current->mm->arg_end = (unsigned long) p;
 607
 608        /* fill in the envv[] array */
 609        current->mm->env_start = (unsigned long) p;
 610        for (loop = bprm->envc; loop > 0; loop--) {
 611                __put_user((elf_caddr_t)(unsigned long) p, envp++);
 612                len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 613                if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 614                        return -EINVAL;
 615                p += len;
 616        }
 617        __put_user(NULL, envp);
 618        current->mm->env_end = (unsigned long) p;
 619
 620        mm->start_stack = (unsigned long) sp;
 621        return 0;
 622} /* end create_elf_fdpic_tables() */
 623
 624/*****************************************************************************/
 625/*
 626 * transfer the program arguments and environment from the holding pages onto
 627 * the stack
 628 */
 629#ifndef CONFIG_MMU
 630static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp)
 631{
 632        unsigned long index, stop, sp;
 633        char *src;
 634        int ret = 0;
 635
 636        stop = bprm->p >> PAGE_SHIFT;
 637        sp = *_sp;
 638
 639        for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
 640                src = kmap(bprm->page[index]);
 641                sp -= PAGE_SIZE;
 642                if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
 643                        ret = -EFAULT;
 644                kunmap(bprm->page[index]);
 645                if (ret < 0)
 646                        goto out;
 647        }
 648
 649        *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
 650
 651 out:
 652        return ret;
 653} /* end elf_fdpic_transfer_args_to_stack() */
 654#endif
 655
 656/*****************************************************************************/
 657/*
 658 * load the appropriate binary image (executable or interpreter) into memory
 659 * - we assume no MMU is available
 660 * - if no other PIC bits are set in params->hdr->e_flags
 661 *   - we assume that the LOADable segments in the binary are independently relocatable
 662 *   - we assume R/O executable segments are shareable
 663 * - else
 664 *   - we assume the loadable parts of the image to require fixed displacement
 665 *   - the image is not shareable
 666 */
 667static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 668                              struct file *file,
 669                              struct mm_struct *mm,
 670                              const char *what)
 671{
 672        struct elf32_fdpic_loadmap *loadmap;
 673#ifdef CONFIG_MMU
 674        struct elf32_fdpic_loadseg *mseg;
 675#endif
 676        struct elf32_fdpic_loadseg *seg;
 677        struct elf32_phdr *phdr;
 678        unsigned long load_addr, stop;
 679        unsigned nloads, tmp;
 680        size_t size;
 681        int loop, ret;
 682
 683        /* allocate a load map table */
 684        nloads = 0;
 685        for (loop = 0; loop < params->hdr.e_phnum; loop++)
 686                if (params->phdrs[loop].p_type == PT_LOAD)
 687                        nloads++;
 688
 689        if (nloads == 0)
 690                return -ELIBBAD;
 691
 692        size = sizeof(*loadmap) + nloads * sizeof(*seg);
 693        loadmap = kmalloc(size, GFP_KERNEL);
 694        if (!loadmap)
 695                return -ENOMEM;
 696
 697        params->loadmap = loadmap;
 698        memset(loadmap, 0, size);
 699
 700        loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 701        loadmap->nsegs = nloads;
 702
 703        load_addr = params->load_addr;
 704        seg = loadmap->segs;
 705
 706        /* map the requested LOADs into the memory space */
 707        switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 708        case ELF_FDPIC_FLAG_CONSTDISP:
 709        case ELF_FDPIC_FLAG_CONTIGUOUS:
 710#ifndef CONFIG_MMU
 711                ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 712                if (ret < 0)
 713                        return ret;
 714                break;
 715#endif
 716        default:
 717                ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 718                if (ret < 0)
 719                        return ret;
 720                break;
 721        }
 722
 723        /* map the entry point */
 724        if (params->hdr.e_entry) {
 725                seg = loadmap->segs;
 726                for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 727                        if (params->hdr.e_entry >= seg->p_vaddr &&
 728                            params->hdr.e_entry < seg->p_vaddr + seg->p_memsz
 729                            ) {
 730                                params->entry_addr =
 731                                        (params->hdr.e_entry - seg->p_vaddr) + seg->addr;
 732                                break;
 733                        }
 734                }
 735        }
 736
 737        /* determine where the program header table has wound up if mapped */
 738        stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr);
 739        phdr = params->phdrs;
 740
 741        for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 742                if (phdr->p_type != PT_LOAD)
 743                        continue;
 744
 745                if (phdr->p_offset > params->hdr.e_phoff ||
 746                    phdr->p_offset + phdr->p_filesz < stop)
 747                        continue;
 748
 749                seg = loadmap->segs;
 750                for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 751                        if (phdr->p_vaddr >= seg->p_vaddr &&
 752                            phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz
 753                            ) {
 754                                params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr +
 755                                        params->hdr.e_phoff - phdr->p_offset;
 756                                break;
 757                        }
 758                }
 759                break;
 760        }
 761
 762        /* determine where the dynamic section has wound up if there is one */
 763        phdr = params->phdrs;
 764        for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 765                if (phdr->p_type != PT_DYNAMIC)
 766                        continue;
 767
 768                seg = loadmap->segs;
 769                for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 770                        if (phdr->p_vaddr >= seg->p_vaddr &&
 771                            phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz
 772                            ) {
 773                                params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr;
 774
 775                                /* check the dynamic section contains at least one item, and that
 776                                 * the last item is a NULL entry */
 777                                if (phdr->p_memsz == 0 ||
 778                                    phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 779                                        goto dynamic_error;
 780
 781                                tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 782                                if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0)
 783                                        goto dynamic_error;
 784                                break;
 785                        }
 786                }
 787                break;
 788        }
 789
 790        /* now elide adjacent segments in the load map on MMU linux
 791         * - on uClinux the holes between may actually be filled with system stuff or stuff from
 792         *   other processes
 793         */
 794#ifdef CONFIG_MMU
 795        nloads = loadmap->nsegs;
 796        mseg = loadmap->segs;
 797        seg = mseg + 1;
 798        for (loop = 1; loop < nloads; loop++) {
 799                /* see if we have a candidate for merging */
 800                if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 801                        load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 802                        if (load_addr == (seg->addr & PAGE_MASK)) {
 803                                mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz);
 804                                mseg->p_memsz += seg->addr & ~PAGE_MASK;
 805                                mseg->p_memsz += seg->p_memsz;
 806                                loadmap->nsegs--;
 807                                continue;
 808                        }
 809                }
 810
 811                mseg++;
 812                if (mseg != seg)
 813                        *mseg = *seg;
 814        }
 815#endif
 816
 817        kdebug("Mapped Object [%s]:", what);
 818        kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 819        kdebug("- entry    : %lx", params->entry_addr);
 820        kdebug("- PHDR[]   : %lx", params->ph_addr);
 821        kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 822        seg = loadmap->segs;
 823        for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 824                kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 825                       loop,
 826                       seg->addr, seg->addr + seg->p_memsz - 1,
 827                       seg->p_vaddr, seg->p_memsz);
 828
 829        return 0;
 830
 831 dynamic_error:
 832        printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 833               what, file->f_dentry->d_inode->i_ino);
 834        return -ELIBBAD;
 835} /* end elf_fdpic_map_file() */
 836
 837/*****************************************************************************/
 838/*
 839 * map a file with constant displacement under uClinux
 840 */
 841#ifndef CONFIG_MMU
 842static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
 843                                                   struct file *file,
 844                                                   struct mm_struct *mm)
 845{
 846        struct elf32_fdpic_loadseg *seg;
 847        struct elf32_phdr *phdr;
 848        unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 849        loff_t fpos;
 850        int loop, ret;
 851
 852        load_addr = params->load_addr;
 853        seg = params->loadmap->segs;
 854
 855        /* determine the bounds of the contiguous overall allocation we must make */
 856        phdr = params->phdrs;
 857        for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 858                if (params->phdrs[loop].p_type != PT_LOAD)
 859                        continue;
 860
 861                if (base > phdr->p_vaddr)
 862                        base = phdr->p_vaddr;
 863                if (top < phdr->p_vaddr + phdr->p_memsz)
 864                        top = phdr->p_vaddr + phdr->p_memsz;
 865        }
 866
 867        /* allocate one big anon block for everything */
 868        mflags = MAP_PRIVATE;
 869        if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 870                mflags |= MAP_EXECUTABLE;
 871
 872        down_write(&mm->mmap_sem);
 873        maddr = do_mmap(NULL, load_addr, top - base,
 874                        PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 875        up_write(&mm->mmap_sem);
 876        if (IS_ERR((void *) maddr))
 877                return (int) maddr;
 878
 879        if (load_addr != 0)
 880                load_addr += PAGE_ALIGN(top - base);
 881
 882        /* and then load the file segments into it */
 883        phdr = params->phdrs;
 884        for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 885                if (params->phdrs[loop].p_type != PT_LOAD)
 886                        continue;
 887
 888                fpos = phdr->p_offset;
 889
 890                seg->addr = maddr + (phdr->p_vaddr - base);
 891                seg->p_vaddr = phdr->p_vaddr;
 892                seg->p_memsz = phdr->p_memsz;
 893
 894                ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos);
 895                if (ret < 0)
 896                        return ret;
 897
 898                /* map the ELF header address if in this segment */
 899                if (phdr->p_offset == 0)
 900                        params->elfhdr_addr = seg->addr;
 901
 902                /* clear any space allocated but not loaded */
 903                if (phdr->p_filesz < phdr->p_memsz)
 904                        clear_user((void *) (seg->addr + phdr->p_filesz),
 905                                   phdr->p_memsz - phdr->p_filesz);
 906
 907                if (mm) {
 908                        if (phdr->p_flags & PF_X) {
 909                                mm->start_code = seg->addr;
 910                                mm->end_code = seg->addr + phdr->p_memsz;
 911                        }
 912                        else if (!mm->start_data) {
 913                                mm->start_data = seg->addr;
 914#ifndef CONFIG_MMU
 915                                mm->end_data = seg->addr + phdr->p_memsz;
 916#endif
 917                        }
 918
 919#ifdef CONFIG_MMU
 920                        if (seg->addr + phdr->p_memsz > mm->end_data)
 921                                mm->end_data = seg->addr + phdr->p_memsz;
 922#endif
 923                }
 924
 925                seg++;
 926        }
 927
 928        return 0;
 929} /* end elf_fdpic_map_file_constdisp_on_uclinux() */
 930#endif
 931
 932/*****************************************************************************/
 933/*
 934 * map a binary by direct mmap() of the individual PT_LOAD segments
 935 */
 936static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 937                                             struct file *file,
 938                                             struct mm_struct *mm)
 939{
 940        struct elf32_fdpic_loadseg *seg;
 941        struct elf32_phdr *phdr;
 942        unsigned long load_addr, delta_vaddr;
 943        int loop, dvset;
 944
 945        load_addr = params->load_addr;
 946        delta_vaddr = 0;
 947        dvset = 0;
 948
 949        seg = params->loadmap->segs;
 950
 951        /* deal with each load segment separately */
 952        phdr = params->phdrs;
 953        for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 954                unsigned long maddr, disp, excess, excess1;
 955                int prot = 0, flags;
 956
 957                if (phdr->p_type != PT_LOAD)
 958                        continue;
 959
 960                kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
 961                       (unsigned long) phdr->p_vaddr,
 962                       (unsigned long) phdr->p_offset,
 963                       (unsigned long) phdr->p_filesz,
 964                       (unsigned long) phdr->p_memsz);
 965
 966                /* determine the mapping parameters */
 967                if (phdr->p_flags & PF_R) prot |= PROT_READ;
 968                if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
 969                if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
 970
 971                flags = MAP_PRIVATE | MAP_DENYWRITE;
 972                if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 973                        flags |= MAP_EXECUTABLE;
 974
 975                maddr = 0;
 976
 977                switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 978                case ELF_FDPIC_FLAG_INDEPENDENT:
 979                        /* PT_LOADs are independently locatable */
 980                        break;
 981
 982                case ELF_FDPIC_FLAG_HONOURVADDR:
 983                        /* the specified virtual address must be honoured */
 984                        maddr = phdr->p_vaddr;
 985                        flags |= MAP_FIXED;
 986                        break;
 987
 988                case ELF_FDPIC_FLAG_CONSTDISP:
 989                        /* constant displacement
 990                         * - can be mapped anywhere, but must be mapped as a unit
 991                         */
 992                        if (!dvset) {
 993                                maddr = load_addr;
 994                                delta_vaddr = phdr->p_vaddr;
 995                                dvset = 1;
 996                        }
 997                        else {
 998                                maddr = load_addr + phdr->p_vaddr - delta_vaddr;
 999                                flags |= MAP_FIXED;
1000                        }
1001                        break;
1002
1003                case ELF_FDPIC_FLAG_CONTIGUOUS:
1004                        /* contiguity handled later */
1005                        break;
1006
1007                default:
1008                        BUG();
1009                }
1010
1011                maddr &= PAGE_MASK;
1012
1013                /* create the mapping */
1014                disp = phdr->p_vaddr & ~PAGE_MASK;
1015                down_write(&mm->mmap_sem);
1016                maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1017                                phdr->p_offset - disp);
1018                up_write(&mm->mmap_sem);
1019
1020                kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1021                       loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
1022                       maddr);
1023
1024                if (IS_ERR((void *) maddr))
1025                        return (int) maddr;
1026
1027                if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS)
1028                        load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1029
1030                seg->addr = maddr + disp;
1031                seg->p_vaddr = phdr->p_vaddr;
1032                seg->p_memsz = phdr->p_memsz;
1033
1034                /* map the ELF header address if in this segment */
1035                if (phdr->p_offset == 0)
1036                        params->elfhdr_addr = seg->addr;
1037
1038                /* clear the bit between beginning of mapping and beginning of PT_LOAD */
1039                if (prot & PROT_WRITE && disp > 0) {
1040                        kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1041                        clear_user((void *) maddr, disp);
1042                        maddr += disp;
1043                }
1044
1045                /* clear any space allocated but not loaded
1046                 * - on uClinux we can just clear the lot
1047                 * - on MMU linux we'll get a SIGBUS beyond the last page
1048                 *   extant in the file
1049                 */
1050                excess = phdr->p_memsz - phdr->p_filesz;
1051                excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1052
1053#ifdef CONFIG_MMU
1054
1055                if (excess > excess1) {
1056                        unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1057                        unsigned long xmaddr;
1058
1059                        flags |= MAP_FIXED | MAP_ANONYMOUS;
1060                        down_write(&mm->mmap_sem);
1061                        xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
1062                        up_write(&mm->mmap_sem);
1063
1064                        kdebug("mmap[%d] <anon>"
1065                               " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1066                               loop, xaddr, excess - excess1, prot, flags, xmaddr);
1067
1068                        if (xmaddr != xaddr)
1069                                return -ENOMEM;
1070                }
1071
1072                if (prot & PROT_WRITE && excess1 > 0) {
1073                        kdebug("clear[%d] ad=%lx sz=%lx",
1074                               loop, maddr + phdr->p_filesz, excess1);
1075                        clear_user((void *) maddr + phdr->p_filesz, excess1);
1076                }
1077
1078#else
1079                if (excess > 0) {
1080                        kdebug("clear[%d] ad=%lx sz=%lx",
1081                               loop, maddr + phdr->p_filesz, excess);
1082                        clear_user((void *) maddr + phdr->p_filesz, excess);
1083                }
1084#endif
1085
1086                if (mm) {
1087                        if (phdr->p_flags & PF_X) {
1088                                mm->start_code = maddr;
1089                                mm->end_code = maddr + phdr->p_memsz;
1090                        }
1091                        else if (!mm->start_data) {
1092                                mm->start_data = maddr;
1093                                mm->end_data = maddr + phdr->p_memsz;
1094                        }
1095                }
1096
1097                seg++;
1098        }
1099
1100        return 0;
1101} /* end elf_fdpic_map_file_by_direct_mmap() */
1102
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