linux/fs/proc/base.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/proc/base.c
   4 *
   5 *  Copyright (C) 1991, 1992 Linus Torvalds
   6 *
   7 *  proc base directory handling functions
   8 *
   9 *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
  10 *  Instead of using magical inumbers to determine the kind of object
  11 *  we allocate and fill in-core inodes upon lookup. They don't even
  12 *  go into icache. We cache the reference to task_struct upon lookup too.
  13 *  Eventually it should become a filesystem in its own. We don't use the
  14 *  rest of procfs anymore.
  15 *
  16 *
  17 *  Changelog:
  18 *  17-Jan-2005
  19 *  Allan Bezerra
  20 *  Bruna Moreira <bruna.moreira@indt.org.br>
  21 *  Edjard Mota <edjard.mota@indt.org.br>
  22 *  Ilias Biris <ilias.biris@indt.org.br>
  23 *  Mauricio Lin <mauricio.lin@indt.org.br>
  24 *
  25 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  26 *
  27 *  A new process specific entry (smaps) included in /proc. It shows the
  28 *  size of rss for each memory area. The maps entry lacks information
  29 *  about physical memory size (rss) for each mapped file, i.e.,
  30 *  rss information for executables and library files.
  31 *  This additional information is useful for any tools that need to know
  32 *  about physical memory consumption for a process specific library.
  33 *
  34 *  Changelog:
  35 *  21-Feb-2005
  36 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  37 *  Pud inclusion in the page table walking.
  38 *
  39 *  ChangeLog:
  40 *  10-Mar-2005
  41 *  10LE Instituto Nokia de Tecnologia - INdT:
  42 *  A better way to walks through the page table as suggested by Hugh Dickins.
  43 *
  44 *  Simo Piiroinen <simo.piiroinen@nokia.com>:
  45 *  Smaps information related to shared, private, clean and dirty pages.
  46 *
  47 *  Paul Mundt <paul.mundt@nokia.com>:
  48 *  Overall revision about smaps.
  49 */
  50
  51#include <linux/uaccess.h>
  52
  53#include <linux/errno.h>
  54#include <linux/time.h>
  55#include <linux/proc_fs.h>
  56#include <linux/stat.h>
  57#include <linux/task_io_accounting_ops.h>
  58#include <linux/init.h>
  59#include <linux/capability.h>
  60#include <linux/file.h>
  61#include <linux/fdtable.h>
  62#include <linux/generic-radix-tree.h>
  63#include <linux/string.h>
  64#include <linux/seq_file.h>
  65#include <linux/namei.h>
  66#include <linux/mnt_namespace.h>
  67#include <linux/mm.h>
  68#include <linux/swap.h>
  69#include <linux/rcupdate.h>
  70#include <linux/kallsyms.h>
  71#include <linux/stacktrace.h>
  72#include <linux/resource.h>
  73#include <linux/module.h>
  74#include <linux/mount.h>
  75#include <linux/security.h>
  76#include <linux/ptrace.h>
  77#include <linux/printk.h>
  78#include <linux/cache.h>
  79#include <linux/cgroup.h>
  80#include <linux/cpuset.h>
  81#include <linux/audit.h>
  82#include <linux/poll.h>
  83#include <linux/nsproxy.h>
  84#include <linux/oom.h>
  85#include <linux/elf.h>
  86#include <linux/pid_namespace.h>
  87#include <linux/user_namespace.h>
  88#include <linux/fs_struct.h>
  89#include <linux/slab.h>
  90#include <linux/sched/autogroup.h>
  91#include <linux/sched/mm.h>
  92#include <linux/sched/coredump.h>
  93#include <linux/sched/debug.h>
  94#include <linux/sched/stat.h>
  95#include <linux/posix-timers.h>
  96#include <linux/time_namespace.h>
  97#include <linux/resctrl.h>
  98#include <linux/cn_proc.h>
  99#include <linux/ksm.h>
 100#include <trace/events/oom.h>
 101#include "internal.h"
 102#include "fd.h"
 103
 104#include "../../lib/kstrtox.h"
 105
 106/* NOTE:
 107 *      Implementing inode permission operations in /proc is almost
 108 *      certainly an error.  Permission checks need to happen during
 109 *      each system call not at open time.  The reason is that most of
 110 *      what we wish to check for permissions in /proc varies at runtime.
 111 *
 112 *      The classic example of a problem is opening file descriptors
 113 *      in /proc for a task before it execs a suid executable.
 114 */
 115
 116static u8 nlink_tid __ro_after_init;
 117static u8 nlink_tgid __ro_after_init;
 118
 119struct pid_entry {
 120        const char *name;
 121        unsigned int len;
 122        umode_t mode;
 123        const struct inode_operations *iop;
 124        const struct file_operations *fop;
 125        union proc_op op;
 126};
 127
 128#define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 129        .name = (NAME),                                 \
 130        .len  = sizeof(NAME) - 1,                       \
 131        .mode = MODE,                                   \
 132        .iop  = IOP,                                    \
 133        .fop  = FOP,                                    \
 134        .op   = OP,                                     \
 135}
 136
 137#define DIR(NAME, MODE, iops, fops)     \
 138        NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 139#define LNK(NAME, get_link)                                     \
 140        NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 141                &proc_pid_link_inode_operations, NULL,          \
 142                { .proc_get_link = get_link } )
 143#define REG(NAME, MODE, fops)                           \
 144        NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 145#define ONE(NAME, MODE, show)                           \
 146        NOD(NAME, (S_IFREG|(MODE)),                     \
 147                NULL, &proc_single_file_operations,     \
 148                { .proc_show = show } )
 149#define ATTR(LSM, NAME, MODE)                           \
 150        NOD(NAME, (S_IFREG|(MODE)),                     \
 151                NULL, &proc_pid_attr_operations,        \
 152                { .lsm = LSM })
 153
 154/*
 155 * Count the number of hardlinks for the pid_entry table, excluding the .
 156 * and .. links.
 157 */
 158static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
 159        unsigned int n)
 160{
 161        unsigned int i;
 162        unsigned int count;
 163
 164        count = 2;
 165        for (i = 0; i < n; ++i) {
 166                if (S_ISDIR(entries[i].mode))
 167                        ++count;
 168        }
 169
 170        return count;
 171}
 172
 173static int get_task_root(struct task_struct *task, struct path *root)
 174{
 175        int result = -ENOENT;
 176
 177        task_lock(task);
 178        if (task->fs) {
 179                get_fs_root(task->fs, root);
 180                result = 0;
 181        }
 182        task_unlock(task);
 183        return result;
 184}
 185
 186static int proc_cwd_link(struct dentry *dentry, struct path *path)
 187{
 188        struct task_struct *task = get_proc_task(d_inode(dentry));
 189        int result = -ENOENT;
 190
 191        if (task) {
 192                task_lock(task);
 193                if (task->fs) {
 194                        get_fs_pwd(task->fs, path);
 195                        result = 0;
 196                }
 197                task_unlock(task);
 198                put_task_struct(task);
 199        }
 200        return result;
 201}
 202
 203static int proc_root_link(struct dentry *dentry, struct path *path)
 204{
 205        struct task_struct *task = get_proc_task(d_inode(dentry));
 206        int result = -ENOENT;
 207
 208        if (task) {
 209                result = get_task_root(task, path);
 210                put_task_struct(task);
 211        }
 212        return result;
 213}
 214
 215/*
 216 * If the user used setproctitle(), we just get the string from
 217 * user space at arg_start, and limit it to a maximum of one page.
 218 */
 219static ssize_t get_mm_proctitle(struct mm_struct *mm, char __user *buf,
 220                                size_t count, unsigned long pos,
 221                                unsigned long arg_start)
 222{
 223        char *page;
 224        int ret, got;
 225
 226        if (pos >= PAGE_SIZE)
 227                return 0;
 228
 229        page = (char *)__get_free_page(GFP_KERNEL);
 230        if (!page)
 231                return -ENOMEM;
 232
 233        ret = 0;
 234        got = access_remote_vm(mm, arg_start, page, PAGE_SIZE, FOLL_ANON);
 235        if (got > 0) {
 236                int len = strnlen(page, got);
 237
 238                /* Include the NUL character if it was found */
 239                if (len < got)
 240                        len++;
 241
 242                if (len > pos) {
 243                        len -= pos;
 244                        if (len > count)
 245                                len = count;
 246                        len -= copy_to_user(buf, page+pos, len);
 247                        if (!len)
 248                                len = -EFAULT;
 249                        ret = len;
 250                }
 251        }
 252        free_page((unsigned long)page);
 253        return ret;
 254}
 255
 256static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
 257                              size_t count, loff_t *ppos)
 258{
 259        unsigned long arg_start, arg_end, env_start, env_end;
 260        unsigned long pos, len;
 261        char *page, c;
 262
 263        /* Check if process spawned far enough to have cmdline. */
 264        if (!mm->env_end)
 265                return 0;
 266
 267        spin_lock(&mm->arg_lock);
 268        arg_start = mm->arg_start;
 269        arg_end = mm->arg_end;
 270        env_start = mm->env_start;
 271        env_end = mm->env_end;
 272        spin_unlock(&mm->arg_lock);
 273
 274        if (arg_start >= arg_end)
 275                return 0;
 276
 277        /*
 278         * We allow setproctitle() to overwrite the argument
 279         * strings, and overflow past the original end. But
 280         * only when it overflows into the environment area.
 281         */
 282        if (env_start != arg_end || env_end < env_start)
 283                env_start = env_end = arg_end;
 284        len = env_end - arg_start;
 285
 286        /* We're not going to care if "*ppos" has high bits set */
 287        pos = *ppos;
 288        if (pos >= len)
 289                return 0;
 290        if (count > len - pos)
 291                count = len - pos;
 292        if (!count)
 293                return 0;
 294
 295        /*
 296         * Magical special case: if the argv[] end byte is not
 297         * zero, the user has overwritten it with setproctitle(3).
 298         *
 299         * Possible future enhancement: do this only once when
 300         * pos is 0, and set a flag in the 'struct file'.
 301         */
 302        if (access_remote_vm(mm, arg_end-1, &c, 1, FOLL_ANON) == 1 && c)
 303                return get_mm_proctitle(mm, buf, count, pos, arg_start);
 304
 305        /*
 306         * For the non-setproctitle() case we limit things strictly
 307         * to the [arg_start, arg_end[ range.
 308         */
 309        pos += arg_start;
 310        if (pos < arg_start || pos >= arg_end)
 311                return 0;
 312        if (count > arg_end - pos)
 313                count = arg_end - pos;
 314
 315        page = (char *)__get_free_page(GFP_KERNEL);
 316        if (!page)
 317                return -ENOMEM;
 318
 319        len = 0;
 320        while (count) {
 321                int got;
 322                size_t size = min_t(size_t, PAGE_SIZE, count);
 323
 324                got = access_remote_vm(mm, pos, page, size, FOLL_ANON);
 325                if (got <= 0)
 326                        break;
 327                got -= copy_to_user(buf, page, got);
 328                if (unlikely(!got)) {
 329                        if (!len)
 330                                len = -EFAULT;
 331                        break;
 332                }
 333                pos += got;
 334                buf += got;
 335                len += got;
 336                count -= got;
 337        }
 338
 339        free_page((unsigned long)page);
 340        return len;
 341}
 342
 343static ssize_t get_task_cmdline(struct task_struct *tsk, char __user *buf,
 344                                size_t count, loff_t *pos)
 345{
 346        struct mm_struct *mm;
 347        ssize_t ret;
 348
 349        mm = get_task_mm(tsk);
 350        if (!mm)
 351                return 0;
 352
 353        ret = get_mm_cmdline(mm, buf, count, pos);
 354        mmput(mm);
 355        return ret;
 356}
 357
 358static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 359                                     size_t count, loff_t *pos)
 360{
 361        struct task_struct *tsk;
 362        ssize_t ret;
 363
 364        BUG_ON(*pos < 0);
 365
 366        tsk = get_proc_task(file_inode(file));
 367        if (!tsk)
 368                return -ESRCH;
 369        ret = get_task_cmdline(tsk, buf, count, pos);
 370        put_task_struct(tsk);
 371        if (ret > 0)
 372                *pos += ret;
 373        return ret;
 374}
 375
 376static const struct file_operations proc_pid_cmdline_ops = {
 377        .read   = proc_pid_cmdline_read,
 378        .llseek = generic_file_llseek,
 379};
 380
 381#ifdef CONFIG_KALLSYMS
 382/*
 383 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 384 * Returns the resolved symbol.  If that fails, simply return the address.
 385 */
 386static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 387                          struct pid *pid, struct task_struct *task)
 388{
 389        unsigned long wchan;
 390        char symname[KSYM_NAME_LEN];
 391
 392        if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
 393                goto print0;
 394
 395        wchan = get_wchan(task);
 396        if (wchan && !lookup_symbol_name(wchan, symname)) {
 397                seq_puts(m, symname);
 398                return 0;
 399        }
 400
 401print0:
 402        seq_putc(m, '0');
 403        return 0;
 404}
 405#endif /* CONFIG_KALLSYMS */
 406
 407static int lock_trace(struct task_struct *task)
 408{
 409        int err = down_read_killable(&task->signal->exec_update_lock);
 410        if (err)
 411                return err;
 412        if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 413                up_read(&task->signal->exec_update_lock);
 414                return -EPERM;
 415        }
 416        return 0;
 417}
 418
 419static void unlock_trace(struct task_struct *task)
 420{
 421        up_read(&task->signal->exec_update_lock);
 422}
 423
 424#ifdef CONFIG_STACKTRACE
 425
 426#define MAX_STACK_TRACE_DEPTH   64
 427
 428static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 429                          struct pid *pid, struct task_struct *task)
 430{
 431        unsigned long *entries;
 432        int err;
 433
 434        /*
 435         * The ability to racily run the kernel stack unwinder on a running task
 436         * and then observe the unwinder output is scary; while it is useful for
 437         * debugging kernel issues, it can also allow an attacker to leak kernel
 438         * stack contents.
 439         * Doing this in a manner that is at least safe from races would require
 440         * some work to ensure that the remote task can not be scheduled; and
 441         * even then, this would still expose the unwinder as local attack
 442         * surface.
 443         * Therefore, this interface is restricted to root.
 444         */
 445        if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
 446                return -EACCES;
 447
 448        entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
 449                                GFP_KERNEL);
 450        if (!entries)
 451                return -ENOMEM;
 452
 453        err = lock_trace(task);
 454        if (!err) {
 455                unsigned int i, nr_entries;
 456
 457                nr_entries = stack_trace_save_tsk(task, entries,
 458                                                  MAX_STACK_TRACE_DEPTH, 0);
 459
 460                for (i = 0; i < nr_entries; i++) {
 461                        seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
 462                }
 463
 464                unlock_trace(task);
 465        }
 466        kfree(entries);
 467
 468        return err;
 469}
 470#endif
 471
 472#ifdef CONFIG_SCHED_INFO
 473/*
 474 * Provides /proc/PID/schedstat
 475 */
 476static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 477                              struct pid *pid, struct task_struct *task)
 478{
 479        if (unlikely(!sched_info_on()))
 480                seq_puts(m, "0 0 0\n");
 481        else
 482                seq_printf(m, "%llu %llu %lu\n",
 483                   (unsigned long long)task->se.sum_exec_runtime,
 484                   (unsigned long long)task->sched_info.run_delay,
 485                   task->sched_info.pcount);
 486
 487        return 0;
 488}
 489#endif
 490
 491#ifdef CONFIG_LATENCYTOP
 492static int lstats_show_proc(struct seq_file *m, void *v)
 493{
 494        int i;
 495        struct inode *inode = m->private;
 496        struct task_struct *task = get_proc_task(inode);
 497
 498        if (!task)
 499                return -ESRCH;
 500        seq_puts(m, "Latency Top version : v0.1\n");
 501        for (i = 0; i < LT_SAVECOUNT; i++) {
 502                struct latency_record *lr = &task->latency_record[i];
 503                if (lr->backtrace[0]) {
 504                        int q;
 505                        seq_printf(m, "%i %li %li",
 506                                   lr->count, lr->time, lr->max);
 507                        for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 508                                unsigned long bt = lr->backtrace[q];
 509
 510                                if (!bt)
 511                                        break;
 512                                seq_printf(m, " %ps", (void *)bt);
 513                        }
 514                        seq_putc(m, '\n');
 515                }
 516
 517        }
 518        put_task_struct(task);
 519        return 0;
 520}
 521
 522static int lstats_open(struct inode *inode, struct file *file)
 523{
 524        return single_open(file, lstats_show_proc, inode);
 525}
 526
 527static ssize_t lstats_write(struct file *file, const char __user *buf,
 528                            size_t count, loff_t *offs)
 529{
 530        struct task_struct *task = get_proc_task(file_inode(file));
 531
 532        if (!task)
 533                return -ESRCH;
 534        clear_tsk_latency_tracing(task);
 535        put_task_struct(task);
 536
 537        return count;
 538}
 539
 540static const struct file_operations proc_lstats_operations = {
 541        .open           = lstats_open,
 542        .read           = seq_read,
 543        .write          = lstats_write,
 544        .llseek         = seq_lseek,
 545        .release        = single_release,
 546};
 547
 548#endif
 549
 550static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 551                          struct pid *pid, struct task_struct *task)
 552{
 553        unsigned long totalpages = totalram_pages() + total_swap_pages;
 554        unsigned long points = 0;
 555        long badness;
 556
 557        badness = oom_badness(task, totalpages);
 558        /*
 559         * Special case OOM_SCORE_ADJ_MIN for all others scale the
 560         * badness value into [0, 2000] range which we have been
 561         * exporting for a long time so userspace might depend on it.
 562         */
 563        if (badness != LONG_MIN)
 564                points = (1000 + badness * 1000 / (long)totalpages) * 2 / 3;
 565
 566        seq_printf(m, "%lu\n", points);
 567
 568        return 0;
 569}
 570
 571struct limit_names {
 572        const char *name;
 573        const char *unit;
 574};
 575
 576static const struct limit_names lnames[RLIM_NLIMITS] = {
 577        [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 578        [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 579        [RLIMIT_DATA] = {"Max data size", "bytes"},
 580        [RLIMIT_STACK] = {"Max stack size", "bytes"},
 581        [RLIMIT_CORE] = {"Max core file size", "bytes"},
 582        [RLIMIT_RSS] = {"Max resident set", "bytes"},
 583        [RLIMIT_NPROC] = {"Max processes", "processes"},
 584        [RLIMIT_NOFILE] = {"Max open files", "files"},
 585        [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 586        [RLIMIT_AS] = {"Max address space", "bytes"},
 587        [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 588        [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 589        [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 590        [RLIMIT_NICE] = {"Max nice priority", NULL},
 591        [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 592        [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 593};
 594
 595/* Display limits for a process */
 596static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 597                           struct pid *pid, struct task_struct *task)
 598{
 599        unsigned int i;
 600        unsigned long flags;
 601
 602        struct rlimit rlim[RLIM_NLIMITS];
 603
 604        if (!lock_task_sighand(task, &flags))
 605                return 0;
 606        memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 607        unlock_task_sighand(task, &flags);
 608
 609        /*
 610         * print the file header
 611         */
 612        seq_puts(m, "Limit                     "
 613                "Soft Limit           "
 614                "Hard Limit           "
 615                "Units     \n");
 616
 617        for (i = 0; i < RLIM_NLIMITS; i++) {
 618                if (rlim[i].rlim_cur == RLIM_INFINITY)
 619                        seq_printf(m, "%-25s %-20s ",
 620                                   lnames[i].name, "unlimited");
 621                else
 622                        seq_printf(m, "%-25s %-20lu ",
 623                                   lnames[i].name, rlim[i].rlim_cur);
 624
 625                if (rlim[i].rlim_max == RLIM_INFINITY)
 626                        seq_printf(m, "%-20s ", "unlimited");
 627                else
 628                        seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 629
 630                if (lnames[i].unit)
 631                        seq_printf(m, "%-10s\n", lnames[i].unit);
 632                else
 633                        seq_putc(m, '\n');
 634        }
 635
 636        return 0;
 637}
 638
 639#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 640static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 641                            struct pid *pid, struct task_struct *task)
 642{
 643        struct syscall_info info;
 644        u64 *args = &info.data.args[0];
 645        int res;
 646
 647        res = lock_trace(task);
 648        if (res)
 649                return res;
 650
 651        if (task_current_syscall(task, &info))
 652                seq_puts(m, "running\n");
 653        else if (info.data.nr < 0)
 654                seq_printf(m, "%d 0x%llx 0x%llx\n",
 655                           info.data.nr, info.sp, info.data.instruction_pointer);
 656        else
 657                seq_printf(m,
 658                       "%d 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
 659                       info.data.nr,
 660                       args[0], args[1], args[2], args[3], args[4], args[5],
 661                       info.sp, info.data.instruction_pointer);
 662        unlock_trace(task);
 663
 664        return 0;
 665}
 666#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 667
 668/************************************************************************/
 669/*                       Here the fs part begins                        */
 670/************************************************************************/
 671
 672/* permission checks */
 673static bool proc_fd_access_allowed(struct inode *inode)
 674{
 675        struct task_struct *task;
 676        bool allowed = false;
 677        /* Allow access to a task's file descriptors if it is us or we
 678         * may use ptrace attach to the process and find out that
 679         * information.
 680         */
 681        task = get_proc_task(inode);
 682        if (task) {
 683                allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 684                put_task_struct(task);
 685        }
 686        return allowed;
 687}
 688
 689int proc_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 690                 struct iattr *attr)
 691{
 692        int error;
 693        struct inode *inode = d_inode(dentry);
 694
 695        if (attr->ia_valid & ATTR_MODE)
 696                return -EPERM;
 697
 698        error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 699        if (error)
 700                return error;
 701
 702        setattr_copy(&nop_mnt_idmap, inode, attr);
 703        return 0;
 704}
 705
 706/*
 707 * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 708 * or euid/egid (for hide_pid_min=2)?
 709 */
 710static bool has_pid_permissions(struct proc_fs_info *fs_info,
 711                                 struct task_struct *task,
 712                                 enum proc_hidepid hide_pid_min)
 713{
 714        /*
 715         * If 'hidpid' mount option is set force a ptrace check,
 716         * we indicate that we are using a filesystem syscall
 717         * by passing PTRACE_MODE_READ_FSCREDS
 718         */
 719        if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE)
 720                return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 721
 722        if (fs_info->hide_pid < hide_pid_min)
 723                return true;
 724        if (in_group_p(fs_info->pid_gid))
 725                return true;
 726        return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 727}
 728
 729
 730static int proc_pid_permission(struct mnt_idmap *idmap,
 731                               struct inode *inode, int mask)
 732{
 733        struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
 734        struct task_struct *task;
 735        bool has_perms;
 736
 737        task = get_proc_task(inode);
 738        if (!task)
 739                return -ESRCH;
 740        has_perms = has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS);
 741        put_task_struct(task);
 742
 743        if (!has_perms) {
 744                if (fs_info->hide_pid == HIDEPID_INVISIBLE) {
 745                        /*
 746                         * Let's make getdents(), stat(), and open()
 747                         * consistent with each other.  If a process
 748                         * may not stat() a file, it shouldn't be seen
 749                         * in procfs at all.
 750                         */
 751                        return -ENOENT;
 752                }
 753
 754                return -EPERM;
 755        }
 756        return generic_permission(&nop_mnt_idmap, inode, mask);
 757}
 758
 759
 760
 761static const struct inode_operations proc_def_inode_operations = {
 762        .setattr        = proc_setattr,
 763};
 764
 765static int proc_single_show(struct seq_file *m, void *v)
 766{
 767        struct inode *inode = m->private;
 768        struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
 769        struct pid *pid = proc_pid(inode);
 770        struct task_struct *task;
 771        int ret;
 772
 773        task = get_pid_task(pid, PIDTYPE_PID);
 774        if (!task)
 775                return -ESRCH;
 776
 777        ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 778
 779        put_task_struct(task);
 780        return ret;
 781}
 782
 783static int proc_single_open(struct inode *inode, struct file *filp)
 784{
 785        return single_open(filp, proc_single_show, inode);
 786}
 787
 788static const struct file_operations proc_single_file_operations = {
 789        .open           = proc_single_open,
 790        .read           = seq_read,
 791        .llseek         = seq_lseek,
 792        .release        = single_release,
 793};
 794
 795
 796struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 797{
 798        struct task_struct *task = get_proc_task(inode);
 799        struct mm_struct *mm = ERR_PTR(-ESRCH);
 800
 801        if (task) {
 802                mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 803                put_task_struct(task);
 804
 805                if (!IS_ERR_OR_NULL(mm)) {
 806                        /* ensure this mm_struct can't be freed */
 807                        mmgrab(mm);
 808                        /* but do not pin its memory */
 809                        mmput(mm);
 810                }
 811        }
 812
 813        return mm;
 814}
 815
 816static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 817{
 818        struct mm_struct *mm = proc_mem_open(inode, mode);
 819
 820        if (IS_ERR(mm))
 821                return PTR_ERR(mm);
 822
 823        file->private_data = mm;
 824        return 0;
 825}
 826
 827static int mem_open(struct inode *inode, struct file *file)
 828{
 829        int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 830
 831        /* OK to pass negative loff_t, we can catch out-of-range */
 832        file->f_mode |= FMODE_UNSIGNED_OFFSET;
 833
 834        return ret;
 835}
 836
 837static ssize_t mem_rw(struct file *file, char __user *buf,
 838                        size_t count, loff_t *ppos, int write)
 839{
 840        struct mm_struct *mm = file->private_data;
 841        unsigned long addr = *ppos;
 842        ssize_t copied;
 843        char *page;
 844        unsigned int flags;
 845
 846        if (!mm)
 847                return 0;
 848
 849        page = (char *)__get_free_page(GFP_KERNEL);
 850        if (!page)
 851                return -ENOMEM;
 852
 853        copied = 0;
 854        if (!mmget_not_zero(mm))
 855                goto free;
 856
 857        flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
 858
 859        while (count > 0) {
 860                size_t this_len = min_t(size_t, count, PAGE_SIZE);
 861
 862                if (write && copy_from_user(page, buf, this_len)) {
 863                        copied = -EFAULT;
 864                        break;
 865                }
 866
 867                this_len = access_remote_vm(mm, addr, page, this_len, flags);
 868                if (!this_len) {
 869                        if (!copied)
 870                                copied = -EIO;
 871                        break;
 872                }
 873
 874                if (!write && copy_to_user(buf, page, this_len)) {
 875                        copied = -EFAULT;
 876                        break;
 877                }
 878
 879                buf += this_len;
 880                addr += this_len;
 881                copied += this_len;
 882                count -= this_len;
 883        }
 884        *ppos = addr;
 885
 886        mmput(mm);
 887free:
 888        free_page((unsigned long) page);
 889        return copied;
 890}
 891
 892static ssize_t mem_read(struct file *file, char __user *buf,
 893                        size_t count, loff_t *ppos)
 894{
 895        return mem_rw(file, buf, count, ppos, 0);
 896}
 897
 898static ssize_t mem_write(struct file *file, const char __user *buf,
 899                         size_t count, loff_t *ppos)
 900{
 901        return mem_rw(file, (char __user*)buf, count, ppos, 1);
 902}
 903
 904loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 905{
 906        switch (orig) {
 907        case 0:
 908                file->f_pos = offset;
 909                break;
 910        case 1:
 911                file->f_pos += offset;
 912                break;
 913        default:
 914                return -EINVAL;
 915        }
 916        force_successful_syscall_return();
 917        return file->f_pos;
 918}
 919
 920static int mem_release(struct inode *inode, struct file *file)
 921{
 922        struct mm_struct *mm = file->private_data;
 923        if (mm)
 924                mmdrop(mm);
 925        return 0;
 926}
 927
 928static const struct file_operations proc_mem_operations = {
 929        .llseek         = mem_lseek,
 930        .read           = mem_read,
 931        .write          = mem_write,
 932        .open           = mem_open,
 933        .release        = mem_release,
 934};
 935
 936static int environ_open(struct inode *inode, struct file *file)
 937{
 938        return __mem_open(inode, file, PTRACE_MODE_READ);
 939}
 940
 941static ssize_t environ_read(struct file *file, char __user *buf,
 942                        size_t count, loff_t *ppos)
 943{
 944        char *page;
 945        unsigned long src = *ppos;
 946        int ret = 0;
 947        struct mm_struct *mm = file->private_data;
 948        unsigned long env_start, env_end;
 949
 950        /* Ensure the process spawned far enough to have an environment. */
 951        if (!mm || !mm->env_end)
 952                return 0;
 953
 954        page = (char *)__get_free_page(GFP_KERNEL);
 955        if (!page)
 956                return -ENOMEM;
 957
 958        ret = 0;
 959        if (!mmget_not_zero(mm))
 960                goto free;
 961
 962        spin_lock(&mm->arg_lock);
 963        env_start = mm->env_start;
 964        env_end = mm->env_end;
 965        spin_unlock(&mm->arg_lock);
 966
 967        while (count > 0) {
 968                size_t this_len, max_len;
 969                int retval;
 970
 971                if (src >= (env_end - env_start))
 972                        break;
 973
 974                this_len = env_end - (env_start + src);
 975
 976                max_len = min_t(size_t, PAGE_SIZE, count);
 977                this_len = min(max_len, this_len);
 978
 979                retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
 980
 981                if (retval <= 0) {
 982                        ret = retval;
 983                        break;
 984                }
 985
 986                if (copy_to_user(buf, page, retval)) {
 987                        ret = -EFAULT;
 988                        break;
 989                }
 990
 991                ret += retval;
 992                src += retval;
 993                buf += retval;
 994                count -= retval;
 995        }
 996        *ppos = src;
 997        mmput(mm);
 998
 999free:
1000        free_page((unsigned long) page);
1001        return ret;
1002}
1003
1004static const struct file_operations proc_environ_operations = {
1005        .open           = environ_open,
1006        .read           = environ_read,
1007        .llseek         = generic_file_llseek,
1008        .release        = mem_release,
1009};
1010
1011static int auxv_open(struct inode *inode, struct file *file)
1012{
1013        return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
1014}
1015
1016static ssize_t auxv_read(struct file *file, char __user *buf,
1017                        size_t count, loff_t *ppos)
1018{
1019        struct mm_struct *mm = file->private_data;
1020        unsigned int nwords = 0;
1021
1022        if (!mm)
1023                return 0;
1024        do {
1025                nwords += 2;
1026        } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
1027        return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
1028                                       nwords * sizeof(mm->saved_auxv[0]));
1029}
1030
1031static const struct file_operations proc_auxv_operations = {
1032        .open           = auxv_open,
1033        .read           = auxv_read,
1034        .llseek         = generic_file_llseek,
1035        .release        = mem_release,
1036};
1037
1038static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1039                            loff_t *ppos)
1040{
1041        struct task_struct *task = get_proc_task(file_inode(file));
1042        char buffer[PROC_NUMBUF];
1043        int oom_adj = OOM_ADJUST_MIN;
1044        size_t len;
1045
1046        if (!task)
1047                return -ESRCH;
1048        if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1049                oom_adj = OOM_ADJUST_MAX;
1050        else
1051                oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1052                          OOM_SCORE_ADJ_MAX;
1053        put_task_struct(task);
1054        if (oom_adj > OOM_ADJUST_MAX)
1055                oom_adj = OOM_ADJUST_MAX;
1056        len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1057        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1058}
1059
1060static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1061{
1062        struct mm_struct *mm = NULL;
1063        struct task_struct *task;
1064        int err = 0;
1065
1066        task = get_proc_task(file_inode(file));
1067        if (!task)
1068                return -ESRCH;
1069
1070        mutex_lock(&oom_adj_mutex);
1071        if (legacy) {
1072                if (oom_adj < task->signal->oom_score_adj &&
1073                                !capable(CAP_SYS_RESOURCE)) {
1074                        err = -EACCES;
1075                        goto err_unlock;
1076                }
1077                /*
1078                 * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1079                 * /proc/pid/oom_score_adj instead.
1080                 */
1081                pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1082                          current->comm, task_pid_nr(current), task_pid_nr(task),
1083                          task_pid_nr(task));
1084        } else {
1085                if ((short)oom_adj < task->signal->oom_score_adj_min &&
1086                                !capable(CAP_SYS_RESOURCE)) {
1087                        err = -EACCES;
1088                        goto err_unlock;
1089                }
1090        }
1091
1092        /*
1093         * Make sure we will check other processes sharing the mm if this is
1094         * not vfrok which wants its own oom_score_adj.
1095         * pin the mm so it doesn't go away and get reused after task_unlock
1096         */
1097        if (!task->vfork_done) {
1098                struct task_struct *p = find_lock_task_mm(task);
1099
1100                if (p) {
1101                        if (test_bit(MMF_MULTIPROCESS, &p->mm->flags)) {
1102                                mm = p->mm;
1103                                mmgrab(mm);
1104                        }
1105                        task_unlock(p);
1106                }
1107        }
1108
1109        task->signal->oom_score_adj = oom_adj;
1110        if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1111                task->signal->oom_score_adj_min = (short)oom_adj;
1112        trace_oom_score_adj_update(task);
1113
1114        if (mm) {
1115                struct task_struct *p;
1116
1117                rcu_read_lock();
1118                for_each_process(p) {
1119                        if (same_thread_group(task, p))
1120                                continue;
1121
1122                        /* do not touch kernel threads or the global init */
1123                        if (p->flags & PF_KTHREAD || is_global_init(p))
1124                                continue;
1125
1126                        task_lock(p);
1127                        if (!p->vfork_done && process_shares_mm(p, mm)) {
1128                                p->signal->oom_score_adj = oom_adj;
1129                                if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1130                                        p->signal->oom_score_adj_min = (short)oom_adj;
1131                        }
1132                        task_unlock(p);
1133                }
1134                rcu_read_unlock();
1135                mmdrop(mm);
1136        }
1137err_unlock:
1138        mutex_unlock(&oom_adj_mutex);
1139        put_task_struct(task);
1140        return err;
1141}
1142
1143/*
1144 * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1145 * kernels.  The effective policy is defined by oom_score_adj, which has a
1146 * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1147 * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1148 * Processes that become oom disabled via oom_adj will still be oom disabled
1149 * with this implementation.
1150 *
1151 * oom_adj cannot be removed since existing userspace binaries use it.
1152 */
1153static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1154                             size_t count, loff_t *ppos)
1155{
1156        char buffer[PROC_NUMBUF] = {};
1157        int oom_adj;
1158        int err;
1159
1160        if (count > sizeof(buffer) - 1)
1161                count = sizeof(buffer) - 1;
1162        if (copy_from_user(buffer, buf, count)) {
1163                err = -EFAULT;
1164                goto out;
1165        }
1166
1167        err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1168        if (err)
1169                goto out;
1170        if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1171             oom_adj != OOM_DISABLE) {
1172                err = -EINVAL;
1173                goto out;
1174        }
1175
1176        /*
1177         * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1178         * value is always attainable.
1179         */
1180        if (oom_adj == OOM_ADJUST_MAX)
1181                oom_adj = OOM_SCORE_ADJ_MAX;
1182        else
1183                oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1184
1185        err = __set_oom_adj(file, oom_adj, true);
1186out:
1187        return err < 0 ? err : count;
1188}
1189
1190static const struct file_operations proc_oom_adj_operations = {
1191        .read           = oom_adj_read,
1192        .write          = oom_adj_write,
1193        .llseek         = generic_file_llseek,
1194};
1195
1196static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1197                                        size_t count, loff_t *ppos)
1198{
1199        struct task_struct *task = get_proc_task(file_inode(file));
1200        char buffer[PROC_NUMBUF];
1201        short oom_score_adj = OOM_SCORE_ADJ_MIN;
1202        size_t len;
1203
1204        if (!task)
1205                return -ESRCH;
1206        oom_score_adj = task->signal->oom_score_adj;
1207        put_task_struct(task);
1208        len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1209        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1210}
1211
1212static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1213                                        size_t count, loff_t *ppos)
1214{
1215        char buffer[PROC_NUMBUF] = {};
1216        int oom_score_adj;
1217        int err;
1218
1219        if (count > sizeof(buffer) - 1)
1220                count = sizeof(buffer) - 1;
1221        if (copy_from_user(buffer, buf, count)) {
1222                err = -EFAULT;
1223                goto out;
1224        }
1225
1226        err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1227        if (err)
1228                goto out;
1229        if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1230                        oom_score_adj > OOM_SCORE_ADJ_MAX) {
1231                err = -EINVAL;
1232                goto out;
1233        }
1234
1235        err = __set_oom_adj(file, oom_score_adj, false);
1236out:
1237        return err < 0 ? err : count;
1238}
1239
1240static const struct file_operations proc_oom_score_adj_operations = {
1241        .read           = oom_score_adj_read,
1242        .write          = oom_score_adj_write,
1243        .llseek         = default_llseek,
1244};
1245
1246#ifdef CONFIG_AUDIT
1247#define TMPBUFLEN 11
1248static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1249                                  size_t count, loff_t *ppos)
1250{
1251        struct inode * inode = file_inode(file);
1252        struct task_struct *task = get_proc_task(inode);
1253        ssize_t length;
1254        char tmpbuf[TMPBUFLEN];
1255
1256        if (!task)
1257                return -ESRCH;
1258        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1259                           from_kuid(file->f_cred->user_ns,
1260                                     audit_get_loginuid(task)));
1261        put_task_struct(task);
1262        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1263}
1264
1265static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1266                                   size_t count, loff_t *ppos)
1267{
1268        struct inode * inode = file_inode(file);
1269        uid_t loginuid;
1270        kuid_t kloginuid;
1271        int rv;
1272
1273        /* Don't let kthreads write their own loginuid */
1274        if (current->flags & PF_KTHREAD)
1275                return -EPERM;
1276
1277        rcu_read_lock();
1278        if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1279                rcu_read_unlock();
1280                return -EPERM;
1281        }
1282        rcu_read_unlock();
1283
1284        if (*ppos != 0) {
1285                /* No partial writes. */
1286                return -EINVAL;
1287        }
1288
1289        rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1290        if (rv < 0)
1291                return rv;
1292
1293        /* is userspace tring to explicitly UNSET the loginuid? */
1294        if (loginuid == AUDIT_UID_UNSET) {
1295                kloginuid = INVALID_UID;
1296        } else {
1297                kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1298                if (!uid_valid(kloginuid))
1299                        return -EINVAL;
1300        }
1301
1302        rv = audit_set_loginuid(kloginuid);
1303        if (rv < 0)
1304                return rv;
1305        return count;
1306}
1307
1308static const struct file_operations proc_loginuid_operations = {
1309        .read           = proc_loginuid_read,
1310        .write          = proc_loginuid_write,
1311        .llseek         = generic_file_llseek,
1312};
1313
1314static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1315                                  size_t count, loff_t *ppos)
1316{
1317        struct inode * inode = file_inode(file);
1318        struct task_struct *task = get_proc_task(inode);
1319        ssize_t length;
1320        char tmpbuf[TMPBUFLEN];
1321
1322        if (!task)
1323                return -ESRCH;
1324        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1325                                audit_get_sessionid(task));
1326        put_task_struct(task);
1327        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1328}
1329
1330static const struct file_operations proc_sessionid_operations = {
1331        .read           = proc_sessionid_read,
1332        .llseek         = generic_file_llseek,
1333};
1334#endif
1335
1336#ifdef CONFIG_FAULT_INJECTION
1337static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1338                                      size_t count, loff_t *ppos)
1339{
1340        struct task_struct *task = get_proc_task(file_inode(file));
1341        char buffer[PROC_NUMBUF];
1342        size_t len;
1343        int make_it_fail;
1344
1345        if (!task)
1346                return -ESRCH;
1347        make_it_fail = task->make_it_fail;
1348        put_task_struct(task);
1349
1350        len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1351
1352        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1353}
1354
1355static ssize_t proc_fault_inject_write(struct file * file,
1356                        const char __user * buf, size_t count, loff_t *ppos)
1357{
1358        struct task_struct *task;
1359        char buffer[PROC_NUMBUF] = {};
1360        int make_it_fail;
1361        int rv;
1362
1363        if (!capable(CAP_SYS_RESOURCE))
1364                return -EPERM;
1365
1366        if (count > sizeof(buffer) - 1)
1367                count = sizeof(buffer) - 1;
1368        if (copy_from_user(buffer, buf, count))
1369                return -EFAULT;
1370        rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1371        if (rv < 0)
1372                return rv;
1373        if (make_it_fail < 0 || make_it_fail > 1)
1374                return -EINVAL;
1375
1376        task = get_proc_task(file_inode(file));
1377        if (!task)
1378                return -ESRCH;
1379        task->make_it_fail = make_it_fail;
1380        put_task_struct(task);
1381
1382        return count;
1383}
1384
1385static const struct file_operations proc_fault_inject_operations = {
1386        .read           = proc_fault_inject_read,
1387        .write          = proc_fault_inject_write,
1388        .llseek         = generic_file_llseek,
1389};
1390
1391static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
1392                                   size_t count, loff_t *ppos)
1393{
1394        struct task_struct *task;
1395        int err;
1396        unsigned int n;
1397
1398        err = kstrtouint_from_user(buf, count, 0, &n);
1399        if (err)
1400                return err;
1401
1402        task = get_proc_task(file_inode(file));
1403        if (!task)
1404                return -ESRCH;
1405        task->fail_nth = n;
1406        put_task_struct(task);
1407
1408        return count;
1409}
1410
1411static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
1412                                  size_t count, loff_t *ppos)
1413{
1414        struct task_struct *task;
1415        char numbuf[PROC_NUMBUF];
1416        ssize_t len;
1417
1418        task = get_proc_task(file_inode(file));
1419        if (!task)
1420                return -ESRCH;
1421        len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
1422        put_task_struct(task);
1423        return simple_read_from_buffer(buf, count, ppos, numbuf, len);
1424}
1425
1426static const struct file_operations proc_fail_nth_operations = {
1427        .read           = proc_fail_nth_read,
1428        .write          = proc_fail_nth_write,
1429};
1430#endif
1431
1432
1433#ifdef CONFIG_SCHED_DEBUG
1434/*
1435 * Print out various scheduling related per-task fields:
1436 */
1437static int sched_show(struct seq_file *m, void *v)
1438{
1439        struct inode *inode = m->private;
1440        struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
1441        struct task_struct *p;
1442
1443        p = get_proc_task(inode);
1444        if (!p)
1445                return -ESRCH;
1446        proc_sched_show_task(p, ns, m);
1447
1448        put_task_struct(p);
1449
1450        return 0;
1451}
1452
1453static ssize_t
1454sched_write(struct file *file, const char __user *buf,
1455            size_t count, loff_t *offset)
1456{
1457        struct inode *inode = file_inode(file);
1458        struct task_struct *p;
1459
1460        p = get_proc_task(inode);
1461        if (!p)
1462                return -ESRCH;
1463        proc_sched_set_task(p);
1464
1465        put_task_struct(p);
1466
1467        return count;
1468}
1469
1470static int sched_open(struct inode *inode, struct file *filp)
1471{
1472        return single_open(filp, sched_show, inode);
1473}
1474
1475static const struct file_operations proc_pid_sched_operations = {
1476        .open           = sched_open,
1477        .read           = seq_read,
1478        .write          = sched_write,
1479        .llseek         = seq_lseek,
1480        .release        = single_release,
1481};
1482
1483#endif
1484
1485#ifdef CONFIG_SCHED_AUTOGROUP
1486/*
1487 * Print out autogroup related information:
1488 */
1489static int sched_autogroup_show(struct seq_file *m, void *v)
1490{
1491        struct inode *inode = m->private;
1492        struct task_struct *p;
1493
1494        p = get_proc_task(inode);
1495        if (!p)
1496                return -ESRCH;
1497        proc_sched_autogroup_show_task(p, m);
1498
1499        put_task_struct(p);
1500
1501        return 0;
1502}
1503
1504static ssize_t
1505sched_autogroup_write(struct file *file, const char __user *buf,
1506            size_t count, loff_t *offset)
1507{
1508        struct inode *inode = file_inode(file);
1509        struct task_struct *p;
1510        char buffer[PROC_NUMBUF] = {};
1511        int nice;
1512        int err;
1513
1514        if (count > sizeof(buffer) - 1)
1515                count = sizeof(buffer) - 1;
1516        if (copy_from_user(buffer, buf, count))
1517                return -EFAULT;
1518
1519        err = kstrtoint(strstrip(buffer), 0, &nice);
1520        if (err < 0)
1521                return err;
1522
1523        p = get_proc_task(inode);
1524        if (!p)
1525                return -ESRCH;
1526
1527        err = proc_sched_autogroup_set_nice(p, nice);
1528        if (err)
1529                count = err;
1530
1531        put_task_struct(p);
1532
1533        return count;
1534}
1535
1536static int sched_autogroup_open(struct inode *inode, struct file *filp)
1537{
1538        int ret;
1539
1540        ret = single_open(filp, sched_autogroup_show, NULL);
1541        if (!ret) {
1542                struct seq_file *m = filp->private_data;
1543
1544                m->private = inode;
1545        }
1546        return ret;
1547}
1548
1549static const struct file_operations proc_pid_sched_autogroup_operations = {
1550        .open           = sched_autogroup_open,
1551        .read           = seq_read,
1552        .write          = sched_autogroup_write,
1553        .llseek         = seq_lseek,
1554        .release        = single_release,
1555};
1556
1557#endif /* CONFIG_SCHED_AUTOGROUP */
1558
1559#ifdef CONFIG_TIME_NS
1560static int timens_offsets_show(struct seq_file *m, void *v)
1561{
1562        struct task_struct *p;
1563
1564        p = get_proc_task(file_inode(m->file));
1565        if (!p)
1566                return -ESRCH;
1567        proc_timens_show_offsets(p, m);
1568
1569        put_task_struct(p);
1570
1571        return 0;
1572}
1573
1574static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
1575                                    size_t count, loff_t *ppos)
1576{
1577        struct inode *inode = file_inode(file);
1578        struct proc_timens_offset offsets[2];
1579        char *kbuf = NULL, *pos, *next_line;
1580        struct task_struct *p;
1581        int ret, noffsets;
1582
1583        /* Only allow < page size writes at the beginning of the file */
1584        if ((*ppos != 0) || (count >= PAGE_SIZE))
1585                return -EINVAL;
1586
1587        /* Slurp in the user data */
1588        kbuf = memdup_user_nul(buf, count);
1589        if (IS_ERR(kbuf))
1590                return PTR_ERR(kbuf);
1591
1592        /* Parse the user data */
1593        ret = -EINVAL;
1594        noffsets = 0;
1595        for (pos = kbuf; pos; pos = next_line) {
1596                struct proc_timens_offset *off = &offsets[noffsets];
1597                char clock[10];
1598                int err;
1599
1600                /* Find the end of line and ensure we don't look past it */
1601                next_line = strchr(pos, '\n');
1602                if (next_line) {
1603                        *next_line = '\0';
1604                        next_line++;
1605                        if (*next_line == '\0')
1606                                next_line = NULL;
1607                }
1608
1609                err = sscanf(pos, "%9s %lld %lu", clock,
1610                                &off->val.tv_sec, &off->val.tv_nsec);
1611                if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC)
1612                        goto out;
1613
1614                clock[sizeof(clock) - 1] = 0;
1615                if (strcmp(clock, "monotonic") == 0 ||
1616                    strcmp(clock, __stringify(CLOCK_MONOTONIC)) == 0)
1617                        off->clockid = CLOCK_MONOTONIC;
1618                else if (strcmp(clock, "boottime") == 0 ||
1619                         strcmp(clock, __stringify(CLOCK_BOOTTIME)) == 0)
1620                        off->clockid = CLOCK_BOOTTIME;
1621                else
1622                        goto out;
1623
1624                noffsets++;
1625                if (noffsets == ARRAY_SIZE(offsets)) {
1626                        if (next_line)
1627                                count = next_line - kbuf;
1628                        break;
1629                }
1630        }
1631
1632        ret = -ESRCH;
1633        p = get_proc_task(inode);
1634        if (!p)
1635                goto out;
1636        ret = proc_timens_set_offset(file, p, offsets, noffsets);
1637        put_task_struct(p);
1638        if (ret)
1639                goto out;
1640
1641        ret = count;
1642out:
1643        kfree(kbuf);
1644        return ret;
1645}
1646
1647static int timens_offsets_open(struct inode *inode, struct file *filp)
1648{
1649        return single_open(filp, timens_offsets_show, inode);
1650}
1651
1652static const struct file_operations proc_timens_offsets_operations = {
1653        .open           = timens_offsets_open,
1654        .read           = seq_read,
1655        .write          = timens_offsets_write,
1656        .llseek         = seq_lseek,
1657        .release        = single_release,
1658};
1659#endif /* CONFIG_TIME_NS */
1660
1661static ssize_t comm_write(struct file *file, const char __user *buf,
1662                                size_t count, loff_t *offset)
1663{
1664        struct inode *inode = file_inode(file);
1665        struct task_struct *p;
1666        char buffer[TASK_COMM_LEN] = {};
1667        const size_t maxlen = sizeof(buffer) - 1;
1668
1669        if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1670                return -EFAULT;
1671
1672        p = get_proc_task(inode);
1673        if (!p)
1674                return -ESRCH;
1675
1676        if (same_thread_group(current, p)) {
1677                set_task_comm(p, buffer);
1678                proc_comm_connector(p);
1679        }
1680        else
1681                count = -EINVAL;
1682
1683        put_task_struct(p);
1684
1685        return count;
1686}
1687
1688static int comm_show(struct seq_file *m, void *v)
1689{
1690        struct inode *inode = m->private;
1691        struct task_struct *p;
1692
1693        p = get_proc_task(inode);
1694        if (!p)
1695                return -ESRCH;
1696
1697        proc_task_name(m, p, false);
1698        seq_putc(m, '\n');
1699
1700        put_task_struct(p);
1701
1702        return 0;
1703}
1704
1705static int comm_open(struct inode *inode, struct file *filp)
1706{
1707        return single_open(filp, comm_show, inode);
1708}
1709
1710static const struct file_operations proc_pid_set_comm_operations = {
1711        .open           = comm_open,
1712        .read           = seq_read,
1713        .write          = comm_write,
1714        .llseek         = seq_lseek,
1715        .release        = single_release,
1716};
1717
1718static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1719{
1720        struct task_struct *task;
1721        struct file *exe_file;
1722
1723        task = get_proc_task(d_inode(dentry));
1724        if (!task)
1725                return -ENOENT;
1726        exe_file = get_task_exe_file(task);
1727        put_task_struct(task);
1728        if (exe_file) {
1729                *exe_path = exe_file->f_path;
1730                path_get(&exe_file->f_path);
1731                fput(exe_file);
1732                return 0;
1733        } else
1734                return -ENOENT;
1735}
1736
1737static const char *proc_pid_get_link(struct dentry *dentry,
1738                                     struct inode *inode,
1739                                     struct delayed_call *done)
1740{
1741        struct path path;
1742        int error = -EACCES;
1743
1744        if (!dentry)
1745                return ERR_PTR(-ECHILD);
1746
1747        /* Are we allowed to snoop on the tasks file descriptors? */
1748        if (!proc_fd_access_allowed(inode))
1749                goto out;
1750
1751        error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1752        if (error)
1753                goto out;
1754
1755        error = nd_jump_link(&path);
1756out:
1757        return ERR_PTR(error);
1758}
1759
1760static int do_proc_readlink(const struct path *path, char __user *buffer, int buflen)
1761{
1762        char *tmp = kmalloc(PATH_MAX, GFP_KERNEL);
1763        char *pathname;
1764        int len;
1765
1766        if (!tmp)
1767                return -ENOMEM;
1768
1769        pathname = d_path(path, tmp, PATH_MAX);
1770        len = PTR_ERR(pathname);
1771        if (IS_ERR(pathname))
1772                goto out;
1773        len = tmp + PATH_MAX - 1 - pathname;
1774
1775        if (len > buflen)
1776                len = buflen;
1777        if (copy_to_user(buffer, pathname, len))
1778                len = -EFAULT;
1779 out:
1780        kfree(tmp);
1781        return len;
1782}
1783
1784static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1785{
1786        int error = -EACCES;
1787        struct inode *inode = d_inode(dentry);
1788        struct path path;
1789
1790        /* Are we allowed to snoop on the tasks file descriptors? */
1791        if (!proc_fd_access_allowed(inode))
1792                goto out;
1793
1794        error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1795        if (error)
1796                goto out;
1797
1798        error = do_proc_readlink(&path, buffer, buflen);
1799        path_put(&path);
1800out:
1801        return error;
1802}
1803
1804const struct inode_operations proc_pid_link_inode_operations = {
1805        .readlink       = proc_pid_readlink,
1806        .get_link       = proc_pid_get_link,
1807        .setattr        = proc_setattr,
1808};
1809
1810
1811/* building an inode */
1812
1813void task_dump_owner(struct task_struct *task, umode_t mode,
1814                     kuid_t *ruid, kgid_t *rgid)
1815{
1816        /* Depending on the state of dumpable compute who should own a
1817         * proc file for a task.
1818         */
1819        const struct cred *cred;
1820        kuid_t uid;
1821        kgid_t gid;
1822
1823        if (unlikely(task->flags & PF_KTHREAD)) {
1824                *ruid = GLOBAL_ROOT_UID;
1825                *rgid = GLOBAL_ROOT_GID;
1826                return;
1827        }
1828
1829        /* Default to the tasks effective ownership */
1830        rcu_read_lock();
1831        cred = __task_cred(task);
1832        uid = cred->euid;
1833        gid = cred->egid;
1834        rcu_read_unlock();
1835
1836        /*
1837         * Before the /proc/pid/status file was created the only way to read
1838         * the effective uid of a /process was to stat /proc/pid.  Reading
1839         * /proc/pid/status is slow enough that procps and other packages
1840         * kept stating /proc/pid.  To keep the rules in /proc simple I have
1841         * made this apply to all per process world readable and executable
1842         * directories.
1843         */
1844        if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1845                struct mm_struct *mm;
1846                task_lock(task);
1847                mm = task->mm;
1848                /* Make non-dumpable tasks owned by some root */
1849                if (mm) {
1850                        if (get_dumpable(mm) != SUID_DUMP_USER) {
1851                                struct user_namespace *user_ns = mm->user_ns;
1852
1853                                uid = make_kuid(user_ns, 0);
1854                                if (!uid_valid(uid))
1855                                        uid = GLOBAL_ROOT_UID;
1856
1857                                gid = make_kgid(user_ns, 0);
1858                                if (!gid_valid(gid))
1859                                        gid = GLOBAL_ROOT_GID;
1860                        }
1861                } else {
1862                        uid = GLOBAL_ROOT_UID;
1863                        gid = GLOBAL_ROOT_GID;
1864                }
1865                task_unlock(task);
1866        }
1867        *ruid = uid;
1868        *rgid = gid;
1869}
1870
1871void proc_pid_evict_inode(struct proc_inode *ei)
1872{
1873        struct pid *pid = ei->pid;
1874
1875        if (S_ISDIR(ei->vfs_inode.i_mode)) {
1876                spin_lock(&pid->lock);
1877                hlist_del_init_rcu(&ei->sibling_inodes);
1878                spin_unlock(&pid->lock);
1879        }
1880
1881        put_pid(pid);
1882}
1883
1884struct inode *proc_pid_make_inode(struct super_block *sb,
1885                                  struct task_struct *task, umode_t mode)
1886{
1887        struct inode * inode;
1888        struct proc_inode *ei;
1889        struct pid *pid;
1890
1891        /* We need a new inode */
1892
1893        inode = new_inode(sb);
1894        if (!inode)
1895                goto out;
1896
1897        /* Common stuff */
1898        ei = PROC_I(inode);
1899        inode->i_mode = mode;
1900        inode->i_ino = get_next_ino();
1901        simple_inode_init_ts(inode);
1902        inode->i_op = &proc_def_inode_operations;
1903
1904        /*
1905         * grab the reference to task.
1906         */
1907        pid = get_task_pid(task, PIDTYPE_PID);
1908        if (!pid)
1909                goto out_unlock;
1910
1911        /* Let the pid remember us for quick removal */
1912        ei->pid = pid;
1913
1914        task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1915        security_task_to_inode(task, inode);
1916
1917out:
1918        return inode;
1919
1920out_unlock:
1921        iput(inode);
1922        return NULL;
1923}
1924
1925/*
1926 * Generating an inode and adding it into @pid->inodes, so that task will
1927 * invalidate inode's dentry before being released.
1928 *
1929 * This helper is used for creating dir-type entries under '/proc' and
1930 * '/proc/<tgid>/task'. Other entries(eg. fd, stat) under '/proc/<tgid>'
1931 * can be released by invalidating '/proc/<tgid>' dentry.
1932 * In theory, dentries under '/proc/<tgid>/task' can also be released by
1933 * invalidating '/proc/<tgid>' dentry, we reserve it to handle single
1934 * thread exiting situation: Any one of threads should invalidate its
1935 * '/proc/<tgid>/task/<pid>' dentry before released.
1936 */
1937static struct inode *proc_pid_make_base_inode(struct super_block *sb,
1938                                struct task_struct *task, umode_t mode)
1939{
1940        struct inode *inode;
1941        struct proc_inode *ei;
1942        struct pid *pid;
1943
1944        inode = proc_pid_make_inode(sb, task, mode);
1945        if (!inode)
1946                return NULL;
1947
1948        /* Let proc_flush_pid find this directory inode */
1949        ei = PROC_I(inode);
1950        pid = ei->pid;
1951        spin_lock(&pid->lock);
1952        hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
1953        spin_unlock(&pid->lock);
1954
1955        return inode;
1956}
1957
1958int pid_getattr(struct mnt_idmap *idmap, const struct path *path,
1959                struct kstat *stat, u32 request_mask, unsigned int query_flags)
1960{
1961        struct inode *inode = d_inode(path->dentry);
1962        struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
1963        struct task_struct *task;
1964
1965        generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1966
1967        stat->uid = GLOBAL_ROOT_UID;
1968        stat->gid = GLOBAL_ROOT_GID;
1969        rcu_read_lock();
1970        task = pid_task(proc_pid(inode), PIDTYPE_PID);
1971        if (task) {
1972                if (!has_pid_permissions(fs_info, task, HIDEPID_INVISIBLE)) {
1973                        rcu_read_unlock();
1974                        /*
1975                         * This doesn't prevent learning whether PID exists,
1976                         * it only makes getattr() consistent with readdir().
1977                         */
1978                        return -ENOENT;
1979                }
1980                task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1981        }
1982        rcu_read_unlock();
1983        return 0;
1984}
1985
1986/* dentry stuff */
1987
1988/*
1989 * Set <pid>/... inode ownership (can change due to setuid(), etc.)
1990 */
1991void pid_update_inode(struct task_struct *task, struct inode *inode)
1992{
1993        task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1994
1995        inode->i_mode &= ~(S_ISUID | S_ISGID);
1996        security_task_to_inode(task, inode);
1997}
1998
1999/*
2000 * Rewrite the inode's ownerships here because the owning task may have
2001 * performed a setuid(), etc.
2002 *
2003 */
2004static int pid_revalidate(struct dentry *dentry, unsigned int flags)
2005{
2006        struct inode *inode;
2007        struct task_struct *task;
2008        int ret = 0;
2009
2010        rcu_read_lock();
2011        inode = d_inode_rcu(dentry);
2012        if (!inode)
2013                goto out;
2014        task = pid_task(proc_pid(inode), PIDTYPE_PID);
2015
2016        if (task) {
2017                pid_update_inode(task, inode);
2018                ret = 1;
2019        }
2020out:
2021        rcu_read_unlock();
2022        return ret;
2023}
2024
2025static inline bool proc_inode_is_dead(struct inode *inode)
2026{
2027        return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
2028}
2029
2030int pid_delete_dentry(const struct dentry *dentry)
2031{
2032        /* Is the task we represent dead?
2033         * If so, then don't put the dentry on the lru list,
2034         * kill it immediately.
2035         */
2036        return proc_inode_is_dead(d_inode(dentry));
2037}
2038
2039const struct dentry_operations pid_dentry_operations =
2040{
2041        .d_revalidate   = pid_revalidate,
2042        .d_delete       = pid_delete_dentry,
2043};
2044
2045/* Lookups */
2046
2047/*
2048 * Fill a directory entry.
2049 *
2050 * If possible create the dcache entry and derive our inode number and
2051 * file type from dcache entry.
2052 *
2053 * Since all of the proc inode numbers are dynamically generated, the inode
2054 * numbers do not exist until the inode is cache.  This means creating
2055 * the dcache entry in readdir is necessary to keep the inode numbers
2056 * reported by readdir in sync with the inode numbers reported
2057 * by stat.
2058 */
2059bool proc_fill_cache(struct file *file, struct dir_context *ctx,
2060        const char *name, unsigned int len,
2061        instantiate_t instantiate, struct task_struct *task, const void *ptr)
2062{
2063        struct dentry *child, *dir = file->f_path.dentry;
2064        struct qstr qname = QSTR_INIT(name, len);
2065        struct inode *inode;
2066        unsigned type = DT_UNKNOWN;
2067        ino_t ino = 1;
2068
2069        child = d_hash_and_lookup(dir, &qname);
2070        if (!child) {
2071                DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
2072                child = d_alloc_parallel(dir, &qname, &wq);
2073                if (IS_ERR(child))
2074                        goto end_instantiate;
2075                if (d_in_lookup(child)) {
2076                        struct dentry *res;
2077                        res = instantiate(child, task, ptr);
2078                        d_lookup_done(child);
2079                        if (unlikely(res)) {
2080                                dput(child);
2081                                child = res;
2082                                if (IS_ERR(child))
2083                                        goto end_instantiate;
2084                        }
2085                }
2086        }
2087        inode = d_inode(child);
2088        ino = inode->i_ino;
2089        type = inode->i_mode >> 12;
2090        dput(child);
2091end_instantiate:
2092        return dir_emit(ctx, name, len, ino, type);
2093}
2094
2095/*
2096 * dname_to_vma_addr - maps a dentry name into two unsigned longs
2097 * which represent vma start and end addresses.
2098 */
2099static int dname_to_vma_addr(struct dentry *dentry,
2100                             unsigned long *start, unsigned long *end)
2101{
2102        const char *str = dentry->d_name.name;
2103        unsigned long long sval, eval;
2104        unsigned int len;
2105
2106        if (str[0] == '0' && str[1] != '-')
2107                return -EINVAL;
2108        len = _parse_integer(str, 16, &sval);
2109        if (len & KSTRTOX_OVERFLOW)
2110                return -EINVAL;
2111        if (sval != (unsigned long)sval)
2112                return -EINVAL;
2113        str += len;
2114
2115        if (*str != '-')
2116                return -EINVAL;
2117        str++;
2118
2119        if (str[0] == '0' && str[1])
2120                return -EINVAL;
2121        len = _parse_integer(str, 16, &eval);
2122        if (len & KSTRTOX_OVERFLOW)
2123                return -EINVAL;
2124        if (eval != (unsigned long)eval)
2125                return -EINVAL;
2126        str += len;
2127
2128        if (*str != '\0')
2129                return -EINVAL;
2130
2131        *start = sval;
2132        *end = eval;
2133
2134        return 0;
2135}
2136
2137static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
2138{
2139        unsigned long vm_start, vm_end;
2140        bool exact_vma_exists = false;
2141        struct mm_struct *mm = NULL;
2142        struct task_struct *task;
2143        struct inode *inode;
2144        int status = 0;
2145
2146        if (flags & LOOKUP_RCU)
2147                return -ECHILD;
2148
2149        inode = d_inode(dentry);
2150        task = get_proc_task(inode);
2151        if (!task)
2152                goto out_notask;
2153
2154        mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
2155        if (IS_ERR_OR_NULL(mm))
2156                goto out;
2157
2158        if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
2159                status = mmap_read_lock_killable(mm);
2160                if (!status) {
2161                        exact_vma_exists = !!find_exact_vma(mm, vm_start,
2162                                                            vm_end);
2163                        mmap_read_unlock(mm);
2164                }
2165        }
2166
2167        mmput(mm);
2168
2169        if (exact_vma_exists) {
2170                task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
2171
2172                security_task_to_inode(task, inode);
2173                status = 1;
2174        }
2175
2176out:
2177        put_task_struct(task);
2178
2179out_notask:
2180        return status;
2181}
2182
2183static const struct dentry_operations tid_map_files_dentry_operations = {
2184        .d_revalidate   = map_files_d_revalidate,
2185        .d_delete       = pid_delete_dentry,
2186};
2187
2188static int map_files_get_link(struct dentry *dentry, struct path *path)
2189{
2190        unsigned long vm_start, vm_end;
2191        struct vm_area_struct *vma;
2192        struct task_struct *task;
2193        struct mm_struct *mm;
2194        int rc;
2195
2196        rc = -ENOENT;
2197        task = get_proc_task(d_inode(dentry));
2198        if (!task)
2199                goto out;
2200
2201        mm = get_task_mm(task);
2202        put_task_struct(task);
2203        if (!mm)
2204                goto out;
2205
2206        rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2207        if (rc)
2208                goto out_mmput;
2209
2210        rc = mmap_read_lock_killable(mm);
2211        if (rc)
2212                goto out_mmput;
2213
2214        rc = -ENOENT;
2215        vma = find_exact_vma(mm, vm_start, vm_end);
2216        if (vma && vma->vm_file) {
2217                *path = *file_user_path(vma->vm_file);
2218                path_get(path);
2219                rc = 0;
2220        }
2221        mmap_read_unlock(mm);
2222
2223out_mmput:
2224        mmput(mm);
2225out:
2226        return rc;
2227}
2228
2229struct map_files_info {
2230        unsigned long   start;
2231        unsigned long   end;
2232        fmode_t         mode;
2233};
2234
2235/*
2236 * Only allow CAP_SYS_ADMIN and CAP_CHECKPOINT_RESTORE to follow the links, due
2237 * to concerns about how the symlinks may be used to bypass permissions on
2238 * ancestor directories in the path to the file in question.
2239 */
2240static const char *
2241proc_map_files_get_link(struct dentry *dentry,
2242                        struct inode *inode,
2243                        struct delayed_call *done)
2244{
2245        if (!checkpoint_restore_ns_capable(&init_user_ns))
2246                return ERR_PTR(-EPERM);
2247
2248        return proc_pid_get_link(dentry, inode, done);
2249}
2250
2251/*
2252 * Identical to proc_pid_link_inode_operations except for get_link()
2253 */
2254static const struct inode_operations proc_map_files_link_inode_operations = {
2255        .readlink       = proc_pid_readlink,
2256        .get_link       = proc_map_files_get_link,
2257        .setattr        = proc_setattr,
2258};
2259
2260static struct dentry *
2261proc_map_files_instantiate(struct dentry *dentry,
2262                           struct task_struct *task, const void *ptr)
2263{
2264        fmode_t mode = (fmode_t)(unsigned long)ptr;
2265        struct proc_inode *ei;
2266        struct inode *inode;
2267
2268        inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
2269                                    ((mode & FMODE_READ ) ? S_IRUSR : 0) |
2270                                    ((mode & FMODE_WRITE) ? S_IWUSR : 0));
2271        if (!inode)
2272                return ERR_PTR(-ENOENT);
2273
2274        ei = PROC_I(inode);
2275        ei->op.proc_get_link = map_files_get_link;
2276
2277        inode->i_op = &proc_map_files_link_inode_operations;
2278        inode->i_size = 64;
2279
2280        d_set_d_op(dentry, &tid_map_files_dentry_operations);
2281        return d_splice_alias(inode, dentry);
2282}
2283
2284static struct dentry *proc_map_files_lookup(struct inode *dir,
2285                struct dentry *dentry, unsigned int flags)
2286{
2287        unsigned long vm_start, vm_end;
2288        struct vm_area_struct *vma;
2289        struct task_struct *task;
2290        struct dentry *result;
2291        struct mm_struct *mm;
2292
2293        result = ERR_PTR(-ENOENT);
2294        task = get_proc_task(dir);
2295        if (!task)
2296                goto out;
2297
2298        result = ERR_PTR(-EACCES);
2299        if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2300                goto out_put_task;
2301
2302        result = ERR_PTR(-ENOENT);
2303        if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2304                goto out_put_task;
2305
2306        mm = get_task_mm(task);
2307        if (!mm)
2308                goto out_put_task;
2309
2310        result = ERR_PTR(-EINTR);
2311        if (mmap_read_lock_killable(mm))
2312                goto out_put_mm;
2313
2314        result = ERR_PTR(-ENOENT);
2315        vma = find_exact_vma(mm, vm_start, vm_end);
2316        if (!vma)
2317                goto out_no_vma;
2318
2319        if (vma->vm_file)
2320                result = proc_map_files_instantiate(dentry, task,
2321                                (void *)(unsigned long)vma->vm_file->f_mode);
2322
2323out_no_vma:
2324        mmap_read_unlock(mm);
2325out_put_mm:
2326        mmput(mm);
2327out_put_task:
2328        put_task_struct(task);
2329out:
2330        return result;
2331}
2332
2333static const struct inode_operations proc_map_files_inode_operations = {
2334        .lookup         = proc_map_files_lookup,
2335        .permission     = proc_fd_permission,
2336        .setattr        = proc_setattr,
2337};
2338
2339static int
2340proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2341{
2342        struct vm_area_struct *vma;
2343        struct task_struct *task;
2344        struct mm_struct *mm;
2345        unsigned long nr_files, pos, i;
2346        GENRADIX(struct map_files_info) fa;
2347        struct map_files_info *p;
2348        int ret;
2349        struct vma_iterator vmi;
2350
2351        genradix_init(&fa);
2352
2353        ret = -ENOENT;
2354        task = get_proc_task(file_inode(file));
2355        if (!task)
2356                goto out;
2357
2358        ret = -EACCES;
2359        if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2360                goto out_put_task;
2361
2362        ret = 0;
2363        if (!dir_emit_dots(file, ctx))
2364                goto out_put_task;
2365
2366        mm = get_task_mm(task);
2367        if (!mm)
2368                goto out_put_task;
2369
2370        ret = mmap_read_lock_killable(mm);
2371        if (ret) {
2372                mmput(mm);
2373                goto out_put_task;
2374        }
2375
2376        nr_files = 0;
2377
2378        /*
2379         * We need two passes here:
2380         *
2381         *  1) Collect vmas of mapped files with mmap_lock taken
2382         *  2) Release mmap_lock and instantiate entries
2383         *
2384         * otherwise we get lockdep complained, since filldir()
2385         * routine might require mmap_lock taken in might_fault().
2386         */
2387
2388        pos = 2;
2389        vma_iter_init(&vmi, mm, 0);
2390        for_each_vma(vmi, vma) {
2391                if (!vma->vm_file)
2392                        continue;
2393                if (++pos <= ctx->pos)
2394                        continue;
2395
2396                p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
2397                if (!p) {
2398                        ret = -ENOMEM;
2399                        mmap_read_unlock(mm);
2400                        mmput(mm);
2401                        goto out_put_task;
2402                }
2403
2404                p->start = vma->vm_start;
2405                p->end = vma->vm_end;
2406                p->mode = vma->vm_file->f_mode;
2407        }
2408        mmap_read_unlock(mm);
2409        mmput(mm);
2410
2411        for (i = 0; i < nr_files; i++) {
2412                char buf[4 * sizeof(long) + 2]; /* max: %lx-%lx\0 */
2413                unsigned int len;
2414
2415                p = genradix_ptr(&fa, i);
2416                len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
2417                if (!proc_fill_cache(file, ctx,
2418                                      buf, len,
2419                                      proc_map_files_instantiate,
2420                                      task,
2421                                      (void *)(unsigned long)p->mode))
2422                        break;
2423                ctx->pos++;
2424        }
2425
2426out_put_task:
2427        put_task_struct(task);
2428out:
2429        genradix_free(&fa);
2430        return ret;
2431}
2432
2433static const struct file_operations proc_map_files_operations = {
2434        .read           = generic_read_dir,
2435        .iterate_shared = proc_map_files_readdir,
2436        .llseek         = generic_file_llseek,
2437};
2438
2439#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2440struct timers_private {
2441        struct pid *pid;
2442        struct task_struct *task;
2443        struct sighand_struct *sighand;
2444        struct pid_namespace *ns;
2445        unsigned long flags;
2446};
2447
2448static void *timers_start(struct seq_file *m, loff_t *pos)
2449{
2450        struct timers_private *tp = m->private;
2451
2452        tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2453        if (!tp->task)
2454                return ERR_PTR(-ESRCH);
2455
2456        tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2457        if (!tp->sighand)
2458                return ERR_PTR(-ESRCH);
2459
2460        return seq_list_start(&tp->task->signal->posix_timers, *pos);
2461}
2462
2463static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2464{
2465        struct timers_private *tp = m->private;
2466        return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2467}
2468
2469static void timers_stop(struct seq_file *m, void *v)
2470{
2471        struct timers_private *tp = m->private;
2472
2473        if (tp->sighand) {
2474                unlock_task_sighand(tp->task, &tp->flags);
2475                tp->sighand = NULL;
2476        }
2477
2478        if (tp->task) {
2479                put_task_struct(tp->task);
2480                tp->task = NULL;
2481        }
2482}
2483
2484static int show_timer(struct seq_file *m, void *v)
2485{
2486        struct k_itimer *timer;
2487        struct timers_private *tp = m->private;
2488        int notify;
2489        static const char * const nstr[] = {
2490                [SIGEV_SIGNAL] = "signal",
2491                [SIGEV_NONE] = "none",
2492                [SIGEV_THREAD] = "thread",
2493        };
2494
2495        timer = list_entry((struct list_head *)v, struct k_itimer, list);
2496        notify = timer->it_sigev_notify;
2497
2498        seq_printf(m, "ID: %d\n", timer->it_id);
2499        seq_printf(m, "signal: %d/%px\n",
2500                   timer->sigq->info.si_signo,
2501                   timer->sigq->info.si_value.sival_ptr);
2502        seq_printf(m, "notify: %s/%s.%d\n",
2503                   nstr[notify & ~SIGEV_THREAD_ID],
2504                   (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2505                   pid_nr_ns(timer->it_pid, tp->ns));
2506        seq_printf(m, "ClockID: %d\n", timer->it_clock);
2507
2508        return 0;
2509}
2510
2511static const struct seq_operations proc_timers_seq_ops = {
2512        .start  = timers_start,
2513        .next   = timers_next,
2514        .stop   = timers_stop,
2515        .show   = show_timer,
2516};
2517
2518static int proc_timers_open(struct inode *inode, struct file *file)
2519{
2520        struct timers_private *tp;
2521
2522        tp = __seq_open_private(file, &proc_timers_seq_ops,
2523                        sizeof(struct timers_private));
2524        if (!tp)
2525                return -ENOMEM;
2526
2527        tp->pid = proc_pid(inode);
2528        tp->ns = proc_pid_ns(inode->i_sb);
2529        return 0;
2530}
2531
2532static const struct file_operations proc_timers_operations = {
2533        .open           = proc_timers_open,
2534        .read           = seq_read,
2535        .llseek         = seq_lseek,
2536        .release        = seq_release_private,
2537};
2538#endif
2539
2540static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2541                                        size_t count, loff_t *offset)
2542{
2543        struct inode *inode = file_inode(file);
2544        struct task_struct *p;
2545        u64 slack_ns;
2546        int err;
2547
2548        err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2549        if (err < 0)
2550                return err;
2551
2552        p = get_proc_task(inode);
2553        if (!p)
2554                return -ESRCH;
2555
2556        if (p != current) {
2557                rcu_read_lock();
2558                if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2559                        rcu_read_unlock();
2560                        count = -EPERM;
2561                        goto out;
2562                }
2563                rcu_read_unlock();
2564
2565                err = security_task_setscheduler(p);
2566                if (err) {
2567                        count = err;
2568                        goto out;
2569                }
2570        }
2571
2572        task_lock(p);
2573        if (slack_ns == 0)
2574                p->timer_slack_ns = p->default_timer_slack_ns;
2575        else
2576                p->timer_slack_ns = slack_ns;
2577        task_unlock(p);
2578
2579out:
2580        put_task_struct(p);
2581
2582        return count;
2583}
2584
2585static int timerslack_ns_show(struct seq_file *m, void *v)
2586{
2587        struct inode *inode = m->private;
2588        struct task_struct *p;
2589        int err = 0;
2590
2591        p = get_proc_task(inode);
2592        if (!p)
2593                return -ESRCH;
2594
2595        if (p != current) {
2596                rcu_read_lock();
2597                if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2598                        rcu_read_unlock();
2599                        err = -EPERM;
2600                        goto out;
2601                }
2602                rcu_read_unlock();
2603
2604                err = security_task_getscheduler(p);
2605                if (err)
2606                        goto out;
2607        }
2608
2609        task_lock(p);
2610        seq_printf(m, "%llu\n", p->timer_slack_ns);
2611        task_unlock(p);
2612
2613out:
2614        put_task_struct(p);
2615
2616        return err;
2617}
2618
2619static int timerslack_ns_open(struct inode *inode, struct file *filp)
2620{
2621        return single_open(filp, timerslack_ns_show, inode);
2622}
2623
2624static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2625        .open           = timerslack_ns_open,
2626        .read           = seq_read,
2627        .write          = timerslack_ns_write,
2628        .llseek         = seq_lseek,
2629        .release        = single_release,
2630};
2631
2632static struct dentry *proc_pident_instantiate(struct dentry *dentry,
2633        struct task_struct *task, const void *ptr)
2634{
2635        const struct pid_entry *p = ptr;
2636        struct inode *inode;
2637        struct proc_inode *ei;
2638
2639        inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
2640        if (!inode)
2641                return ERR_PTR(-ENOENT);
2642
2643        ei = PROC_I(inode);
2644        if (S_ISDIR(inode->i_mode))
2645                set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2646        if (p->iop)
2647                inode->i_op = p->iop;
2648        if (p->fop)
2649                inode->i_fop = p->fop;
2650        ei->op = p->op;
2651        pid_update_inode(task, inode);
2652        d_set_d_op(dentry, &pid_dentry_operations);
2653        return d_splice_alias(inode, dentry);
2654}
2655
2656static struct dentry *proc_pident_lookup(struct inode *dir, 
2657                                         struct dentry *dentry,
2658                                         const struct pid_entry *p,
2659                                         const struct pid_entry *end)
2660{
2661        struct task_struct *task = get_proc_task(dir);
2662        struct dentry *res = ERR_PTR(-ENOENT);
2663
2664        if (!task)
2665                goto out_no_task;
2666
2667        /*
2668         * Yes, it does not scale. And it should not. Don't add
2669         * new entries into /proc/<tgid>/ without very good reasons.
2670         */
2671        for (; p < end; p++) {
2672                if (p->len != dentry->d_name.len)
2673                        continue;
2674                if (!memcmp(dentry->d_name.name, p->name, p->len)) {
2675                        res = proc_pident_instantiate(dentry, task, p);
2676                        break;
2677                }
2678        }
2679        put_task_struct(task);
2680out_no_task:
2681        return res;
2682}
2683
2684static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2685                const struct pid_entry *ents, unsigned int nents)
2686{
2687        struct task_struct *task = get_proc_task(file_inode(file));
2688        const struct pid_entry *p;
2689
2690        if (!task)
2691                return -ENOENT;
2692
2693        if (!dir_emit_dots(file, ctx))
2694                goto out;
2695
2696        if (ctx->pos >= nents + 2)
2697                goto out;
2698
2699        for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2700                if (!proc_fill_cache(file, ctx, p->name, p->len,
2701                                proc_pident_instantiate, task, p))
2702                        break;
2703                ctx->pos++;
2704        }
2705out:
2706        put_task_struct(task);
2707        return 0;
2708}
2709
2710#ifdef CONFIG_SECURITY
2711static int proc_pid_attr_open(struct inode *inode, struct file *file)
2712{
2713        file->private_data = NULL;
2714        __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
2715        return 0;
2716}
2717
2718static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2719                                  size_t count, loff_t *ppos)
2720{
2721        struct inode * inode = file_inode(file);
2722        char *p = NULL;
2723        ssize_t length;
2724        struct task_struct *task = get_proc_task(inode);
2725
2726        if (!task)
2727                return -ESRCH;
2728
2729        length = security_getprocattr(task, PROC_I(inode)->op.lsm,
2730                                      file->f_path.dentry->d_name.name,
2731                                      &p);
2732        put_task_struct(task);
2733        if (length > 0)
2734                length = simple_read_from_buffer(buf, count, ppos, p, length);
2735        kfree(p);
2736        return length;
2737}
2738
2739static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2740                                   size_t count, loff_t *ppos)
2741{
2742        struct inode * inode = file_inode(file);
2743        struct task_struct *task;
2744        void *page;
2745        int rv;
2746
2747        /* A task may only write when it was the opener. */
2748        if (file->private_data != current->mm)
2749                return -EPERM;
2750
2751        rcu_read_lock();
2752        task = pid_task(proc_pid(inode), PIDTYPE_PID);
2753        if (!task) {
2754                rcu_read_unlock();
2755                return -ESRCH;
2756        }
2757        /* A task may only write its own attributes. */
2758        if (current != task) {
2759                rcu_read_unlock();
2760                return -EACCES;
2761        }
2762        /* Prevent changes to overridden credentials. */
2763        if (current_cred() != current_real_cred()) {
2764                rcu_read_unlock();
2765                return -EBUSY;
2766        }
2767        rcu_read_unlock();
2768
2769        if (count > PAGE_SIZE)
2770                count = PAGE_SIZE;
2771
2772        /* No partial writes. */
2773        if (*ppos != 0)
2774                return -EINVAL;
2775
2776        page = memdup_user(buf, count);
2777        if (IS_ERR(page)) {
2778                rv = PTR_ERR(page);
2779                goto out;
2780        }
2781
2782        /* Guard against adverse ptrace interaction */
2783        rv = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2784        if (rv < 0)
2785                goto out_free;
2786
2787        rv = security_setprocattr(PROC_I(inode)->op.lsm,
2788                                  file->f_path.dentry->d_name.name, page,
2789                                  count);
2790        mutex_unlock(&current->signal->cred_guard_mutex);
2791out_free:
2792        kfree(page);
2793out:
2794        return rv;
2795}
2796
2797static const struct file_operations proc_pid_attr_operations = {
2798        .open           = proc_pid_attr_open,
2799        .read           = proc_pid_attr_read,
2800        .write          = proc_pid_attr_write,
2801        .llseek         = generic_file_llseek,
2802        .release        = mem_release,
2803};
2804
2805#define LSM_DIR_OPS(LSM) \
2806static int proc_##LSM##_attr_dir_iterate(struct file *filp, \
2807                             struct dir_context *ctx) \
2808{ \
2809        return proc_pident_readdir(filp, ctx, \
2810                                   LSM##_attr_dir_stuff, \
2811                                   ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2812} \
2813\
2814static const struct file_operations proc_##LSM##_attr_dir_ops = { \
2815        .read           = generic_read_dir, \
2816        .iterate_shared = proc_##LSM##_attr_dir_iterate, \
2817        .llseek         = default_llseek, \
2818}; \
2819\
2820static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \
2821                                struct dentry *dentry, unsigned int flags) \
2822{ \
2823        return proc_pident_lookup(dir, dentry, \
2824                                  LSM##_attr_dir_stuff, \
2825                                  LSM##_attr_dir_stuff + ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2826} \
2827\
2828static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
2829        .lookup         = proc_##LSM##_attr_dir_lookup, \
2830        .getattr        = pid_getattr, \
2831        .setattr        = proc_setattr, \
2832}
2833
2834#ifdef CONFIG_SECURITY_SMACK
2835static const struct pid_entry smack_attr_dir_stuff[] = {
2836        ATTR("smack", "current",        0666),
2837};
2838LSM_DIR_OPS(smack);
2839#endif
2840
2841#ifdef CONFIG_SECURITY_APPARMOR
2842static const struct pid_entry apparmor_attr_dir_stuff[] = {
2843        ATTR("apparmor", "current",     0666),
2844        ATTR("apparmor", "prev",        0444),
2845        ATTR("apparmor", "exec",        0666),
2846};
2847LSM_DIR_OPS(apparmor);
2848#endif
2849
2850static const struct pid_entry attr_dir_stuff[] = {
2851        ATTR(NULL, "current",           0666),
2852        ATTR(NULL, "prev",              0444),
2853        ATTR(NULL, "exec",              0666),
2854        ATTR(NULL, "fscreate",          0666),
2855        ATTR(NULL, "keycreate",         0666),
2856        ATTR(NULL, "sockcreate",        0666),
2857#ifdef CONFIG_SECURITY_SMACK
2858        DIR("smack",                    0555,
2859            proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
2860#endif
2861#ifdef CONFIG_SECURITY_APPARMOR
2862        DIR("apparmor",                 0555,
2863            proc_apparmor_attr_dir_inode_ops, proc_apparmor_attr_dir_ops),
2864#endif
2865};
2866
2867static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2868{
2869        return proc_pident_readdir(file, ctx, 
2870                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2871}
2872
2873static const struct file_operations proc_attr_dir_operations = {
2874        .read           = generic_read_dir,
2875        .iterate_shared = proc_attr_dir_readdir,
2876        .llseek         = generic_file_llseek,
2877};
2878
2879static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2880                                struct dentry *dentry, unsigned int flags)
2881{
2882        return proc_pident_lookup(dir, dentry,
2883                                  attr_dir_stuff,
2884                                  attr_dir_stuff + ARRAY_SIZE(attr_dir_stuff));
2885}
2886
2887static const struct inode_operations proc_attr_dir_inode_operations = {
2888        .lookup         = proc_attr_dir_lookup,
2889        .getattr        = pid_getattr,
2890        .setattr        = proc_setattr,
2891};
2892
2893#endif
2894
2895#ifdef CONFIG_ELF_CORE
2896static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2897                                         size_t count, loff_t *ppos)
2898{
2899        struct task_struct *task = get_proc_task(file_inode(file));
2900        struct mm_struct *mm;
2901        char buffer[PROC_NUMBUF];
2902        size_t len;
2903        int ret;
2904
2905        if (!task)
2906                return -ESRCH;
2907
2908        ret = 0;
2909        mm = get_task_mm(task);
2910        if (mm) {
2911                len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2912                               ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2913                                MMF_DUMP_FILTER_SHIFT));
2914                mmput(mm);
2915                ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2916        }
2917
2918        put_task_struct(task);
2919
2920        return ret;
2921}
2922
2923static ssize_t proc_coredump_filter_write(struct file *file,
2924                                          const char __user *buf,
2925                                          size_t count,
2926                                          loff_t *ppos)
2927{
2928        struct task_struct *task;
2929        struct mm_struct *mm;
2930        unsigned int val;
2931        int ret;
2932        int i;
2933        unsigned long mask;
2934
2935        ret = kstrtouint_from_user(buf, count, 0, &val);
2936        if (ret < 0)
2937                return ret;
2938
2939        ret = -ESRCH;
2940        task = get_proc_task(file_inode(file));
2941        if (!task)
2942                goto out_no_task;
2943
2944        mm = get_task_mm(task);
2945        if (!mm)
2946                goto out_no_mm;
2947        ret = 0;
2948
2949        for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2950                if (val & mask)
2951                        set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2952                else
2953                        clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2954        }
2955
2956        mmput(mm);
2957 out_no_mm:
2958        put_task_struct(task);
2959 out_no_task:
2960        if (ret < 0)
2961                return ret;
2962        return count;
2963}
2964
2965static const struct file_operations proc_coredump_filter_operations = {
2966        .read           = proc_coredump_filter_read,
2967        .write          = proc_coredump_filter_write,
2968        .llseek         = generic_file_llseek,
2969};
2970#endif
2971
2972#ifdef CONFIG_TASK_IO_ACCOUNTING
2973static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2974{
2975        struct task_io_accounting acct;
2976        int result;
2977
2978        result = down_read_killable(&task->signal->exec_update_lock);
2979        if (result)
2980                return result;
2981
2982        if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2983                result = -EACCES;
2984                goto out_unlock;
2985        }
2986
2987        if (whole) {
2988                struct signal_struct *sig = task->signal;
2989                struct task_struct *t;
2990                unsigned int seq = 1;
2991                unsigned long flags;
2992
2993                rcu_read_lock();
2994                do {
2995                        seq++; /* 2 on the 1st/lockless path, otherwise odd */
2996                        flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
2997
2998                        acct = sig->ioac;
2999                        __for_each_thread(sig, t)
3000                                task_io_accounting_add(&acct, &t->ioac);
3001
3002                } while (need_seqretry(&sig->stats_lock, seq));
3003                done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
3004                rcu_read_unlock();
3005        } else {
3006                acct = task->ioac;
3007        }
3008
3009        seq_printf(m,
3010                   "rchar: %llu\n"
3011                   "wchar: %llu\n"
3012                   "syscr: %llu\n"
3013                   "syscw: %llu\n"
3014                   "read_bytes: %llu\n"
3015                   "write_bytes: %llu\n"
3016                   "cancelled_write_bytes: %llu\n",
3017                   (unsigned long long)acct.rchar,
3018                   (unsigned long long)acct.wchar,
3019                   (unsigned long long)acct.syscr,
3020                   (unsigned long long)acct.syscw,
3021                   (unsigned long long)acct.read_bytes,
3022                   (unsigned long long)acct.write_bytes,
3023                   (unsigned long long)acct.cancelled_write_bytes);
3024        result = 0;
3025
3026out_unlock:
3027        up_read(&task->signal->exec_update_lock);
3028        return result;
3029}
3030
3031static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
3032                                  struct pid *pid, struct task_struct *task)
3033{
3034        return do_io_accounting(task, m, 0);
3035}
3036
3037static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
3038                                   struct pid *pid, struct task_struct *task)
3039{
3040        return do_io_accounting(task, m, 1);
3041}
3042#endif /* CONFIG_TASK_IO_ACCOUNTING */
3043
3044#ifdef CONFIG_USER_NS
3045static int proc_id_map_open(struct inode *inode, struct file *file,
3046        const struct seq_operations *seq_ops)
3047{
3048        struct user_namespace *ns = NULL;
3049        struct task_struct *task;
3050        struct seq_file *seq;
3051        int ret = -EINVAL;
3052
3053        task = get_proc_task(inode);
3054        if (task) {
3055                rcu_read_lock();
3056                ns = get_user_ns(task_cred_xxx(task, user_ns));
3057                rcu_read_unlock();
3058                put_task_struct(task);
3059        }
3060        if (!ns)
3061                goto err;
3062
3063        ret = seq_open(file, seq_ops);
3064        if (ret)
3065                goto err_put_ns;
3066
3067        seq = file->private_data;
3068        seq->private = ns;
3069
3070        return 0;
3071err_put_ns:
3072        put_user_ns(ns);
3073err:
3074        return ret;
3075}
3076
3077static int proc_id_map_release(struct inode *inode, struct file *file)
3078{
3079        struct seq_file *seq = file->private_data;
3080        struct user_namespace *ns = seq->private;
3081        put_user_ns(ns);
3082        return seq_release(inode, file);
3083}
3084
3085static int proc_uid_map_open(struct inode *inode, struct file *file)
3086{
3087        return proc_id_map_open(inode, file, &proc_uid_seq_operations);
3088}
3089
3090static int proc_gid_map_open(struct inode *inode, struct file *file)
3091{
3092        return proc_id_map_open(inode, file, &proc_gid_seq_operations);
3093}
3094
3095static int proc_projid_map_open(struct inode *inode, struct file *file)
3096{
3097        return proc_id_map_open(inode, file, &proc_projid_seq_operations);
3098}
3099
3100static const struct file_operations proc_uid_map_operations = {
3101        .open           = proc_uid_map_open,
3102        .write          = proc_uid_map_write,
3103        .read           = seq_read,
3104        .llseek         = seq_lseek,
3105        .release        = proc_id_map_release,
3106};
3107
3108static const struct file_operations proc_gid_map_operations = {
3109        .open           = proc_gid_map_open,
3110        .write          = proc_gid_map_write,
3111        .read           = seq_read,
3112        .llseek         = seq_lseek,
3113        .release        = proc_id_map_release,
3114};
3115
3116static const struct file_operations proc_projid_map_operations = {
3117        .open           = proc_projid_map_open,
3118        .write          = proc_projid_map_write,
3119        .read           = seq_read,
3120        .llseek         = seq_lseek,
3121        .release        = proc_id_map_release,
3122};
3123
3124static int proc_setgroups_open(struct inode *inode, struct file *file)
3125{
3126        struct user_namespace *ns = NULL;
3127        struct task_struct *task;
3128        int ret;
3129
3130        ret = -ESRCH;
3131        task = get_proc_task(inode);
3132        if (task) {
3133                rcu_read_lock();
3134                ns = get_user_ns(task_cred_xxx(task, user_ns));
3135                rcu_read_unlock();
3136                put_task_struct(task);
3137        }
3138        if (!ns)
3139                goto err;
3140
3141        if (file->f_mode & FMODE_WRITE) {
3142                ret = -EACCES;
3143                if (!ns_capable(ns, CAP_SYS_ADMIN))
3144                        goto err_put_ns;
3145        }
3146
3147        ret = single_open(file, &proc_setgroups_show, ns);
3148        if (ret)
3149                goto err_put_ns;
3150
3151        return 0;
3152err_put_ns:
3153        put_user_ns(ns);
3154err:
3155        return ret;
3156}
3157
3158static int proc_setgroups_release(struct inode *inode, struct file *file)
3159{
3160        struct seq_file *seq = file->private_data;
3161        struct user_namespace *ns = seq->private;
3162        int ret = single_release(inode, file);
3163        put_user_ns(ns);
3164        return ret;
3165}
3166
3167static const struct file_operations proc_setgroups_operations = {
3168        .open           = proc_setgroups_open,
3169        .write          = proc_setgroups_write,
3170        .read           = seq_read,
3171        .llseek         = seq_lseek,
3172        .release        = proc_setgroups_release,
3173};
3174#endif /* CONFIG_USER_NS */
3175
3176static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
3177                                struct pid *pid, struct task_struct *task)
3178{
3179        int err = lock_trace(task);
3180        if (!err) {
3181                seq_printf(m, "%08x\n", task->personality);
3182                unlock_trace(task);
3183        }
3184        return err;
3185}
3186
3187#ifdef CONFIG_LIVEPATCH
3188static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
3189                                struct pid *pid, struct task_struct *task)
3190{
3191        seq_printf(m, "%d\n", task->patch_state);
3192        return 0;
3193}
3194#endif /* CONFIG_LIVEPATCH */
3195
3196#ifdef CONFIG_KSM
3197static int proc_pid_ksm_merging_pages(struct seq_file *m, struct pid_namespace *ns,
3198                                struct pid *pid, struct task_struct *task)
3199{
3200        struct mm_struct *mm;
3201
3202        mm = get_task_mm(task);
3203        if (mm) {
3204                seq_printf(m, "%lu\n", mm->ksm_merging_pages);
3205                mmput(mm);
3206        }
3207
3208        return 0;
3209}
3210static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns,
3211                                struct pid *pid, struct task_struct *task)
3212{
3213        struct mm_struct *mm;
3214
3215        mm = get_task_mm(task);
3216        if (mm) {
3217                seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items);
3218                seq_printf(m, "ksm_zero_pages %lu\n", mm->ksm_zero_pages);
3219                seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages);
3220                seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm));
3221                mmput(mm);
3222        }
3223
3224        return 0;
3225}
3226#endif /* CONFIG_KSM */
3227
3228#ifdef CONFIG_STACKLEAK_METRICS
3229static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
3230                                struct pid *pid, struct task_struct *task)
3231{
3232        unsigned long prev_depth = THREAD_SIZE -
3233                                (task->prev_lowest_stack & (THREAD_SIZE - 1));
3234        unsigned long depth = THREAD_SIZE -
3235                                (task->lowest_stack & (THREAD_SIZE - 1));
3236
3237        seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n",
3238                                                        prev_depth, depth);
3239        return 0;
3240}
3241#endif /* CONFIG_STACKLEAK_METRICS */
3242
3243/*
3244 * Thread groups
3245 */
3246static const struct file_operations proc_task_operations;
3247static const struct inode_operations proc_task_inode_operations;
3248
3249static const struct pid_entry tgid_base_stuff[] = {
3250        DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
3251        DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3252        DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
3253        DIR("fdinfo",     S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3254        DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3255#ifdef CONFIG_NET
3256        DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3257#endif
3258        REG("environ",    S_IRUSR, proc_environ_operations),
3259        REG("auxv",       S_IRUSR, proc_auxv_operations),
3260        ONE("status",     S_IRUGO, proc_pid_status),
3261        ONE("personality", S_IRUSR, proc_pid_personality),
3262        ONE("limits",     S_IRUGO, proc_pid_limits),
3263#ifdef CONFIG_SCHED_DEBUG
3264        REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3265#endif
3266#ifdef CONFIG_SCHED_AUTOGROUP
3267        REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
3268#endif
3269#ifdef CONFIG_TIME_NS
3270        REG("timens_offsets",  S_IRUGO|S_IWUSR, proc_timens_offsets_operations),
3271#endif
3272        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3273#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3274        ONE("syscall",    S_IRUSR, proc_pid_syscall),
3275#endif
3276        REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
3277        ONE("stat",       S_IRUGO, proc_tgid_stat),
3278        ONE("statm",      S_IRUGO, proc_pid_statm),
3279        REG("maps",       S_IRUGO, proc_pid_maps_operations),
3280#ifdef CONFIG_NUMA
3281        REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
3282#endif
3283        REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
3284        LNK("cwd",        proc_cwd_link),
3285        LNK("root",       proc_root_link),
3286        LNK("exe",        proc_exe_link),
3287        REG("mounts",     S_IRUGO, proc_mounts_operations),
3288        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3289        REG("mountstats", S_IRUSR, proc_mountstats_operations),
3290#ifdef CONFIG_PROC_PAGE_MONITOR
3291        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3292        REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
3293        REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3294        REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3295#endif
3296#ifdef CONFIG_SECURITY
3297        DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3298#endif
3299#ifdef CONFIG_KALLSYMS
3300        ONE("wchan",      S_IRUGO, proc_pid_wchan),
3301#endif
3302#ifdef CONFIG_STACKTRACE
3303        ONE("stack",      S_IRUSR, proc_pid_stack),
3304#endif
3305#ifdef CONFIG_SCHED_INFO
3306        ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
3307#endif
3308#ifdef CONFIG_LATENCYTOP
3309        REG("latency",  S_IRUGO, proc_lstats_operations),
3310#endif
3311#ifdef CONFIG_PROC_PID_CPUSET
3312        ONE("cpuset",     S_IRUGO, proc_cpuset_show),
3313#endif
3314#ifdef CONFIG_CGROUPS
3315        ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3316#endif
3317#ifdef CONFIG_PROC_CPU_RESCTRL
3318        ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3319#endif
3320        ONE("oom_score",  S_IRUGO, proc_oom_score),
3321        REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3322        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3323#ifdef CONFIG_AUDIT
3324        REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
3325        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3326#endif
3327#ifdef CONFIG_FAULT_INJECTION
3328        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3329        REG("fail-nth", 0644, proc_fail_nth_operations),
3330#endif
3331#ifdef CONFIG_ELF_CORE
3332        REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
3333#endif
3334#ifdef CONFIG_TASK_IO_ACCOUNTING
3335        ONE("io",       S_IRUSR, proc_tgid_io_accounting),
3336#endif
3337#ifdef CONFIG_USER_NS
3338        REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3339        REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3340        REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3341        REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3342#endif
3343#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
3344        REG("timers",     S_IRUGO, proc_timers_operations),
3345#endif
3346        REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
3347#ifdef CONFIG_LIVEPATCH
3348        ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3349#endif
3350#ifdef CONFIG_STACKLEAK_METRICS
3351        ONE("stack_depth", S_IRUGO, proc_stack_depth),
3352#endif
3353#ifdef CONFIG_PROC_PID_ARCH_STATUS
3354        ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3355#endif
3356#ifdef CONFIG_SECCOMP_CACHE_DEBUG
3357        ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3358#endif
3359#ifdef CONFIG_KSM
3360        ONE("ksm_merging_pages",  S_IRUSR, proc_pid_ksm_merging_pages),
3361        ONE("ksm_stat",  S_IRUSR, proc_pid_ksm_stat),
3362#endif
3363};
3364
3365static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
3366{
3367        return proc_pident_readdir(file, ctx,
3368                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3369}
3370
3371static const struct file_operations proc_tgid_base_operations = {
3372        .read           = generic_read_dir,
3373        .iterate_shared = proc_tgid_base_readdir,
3374        .llseek         = generic_file_llseek,
3375};
3376
3377struct pid *tgid_pidfd_to_pid(const struct file *file)
3378{
3379        if (file->f_op != &proc_tgid_base_operations)
3380                return ERR_PTR(-EBADF);
3381
3382        return proc_pid(file_inode(file));
3383}
3384
3385static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3386{
3387        return proc_pident_lookup(dir, dentry,
3388                                  tgid_base_stuff,
3389                                  tgid_base_stuff + ARRAY_SIZE(tgid_base_stuff));
3390}
3391
3392static const struct inode_operations proc_tgid_base_inode_operations = {
3393        .lookup         = proc_tgid_base_lookup,
3394        .getattr        = pid_getattr,
3395        .setattr        = proc_setattr,
3396        .permission     = proc_pid_permission,
3397};
3398
3399/**
3400 * proc_flush_pid -  Remove dcache entries for @pid from the /proc dcache.
3401 * @pid: pid that should be flushed.
3402 *
3403 * This function walks a list of inodes (that belong to any proc
3404 * filesystem) that are attached to the pid and flushes them from
3405 * the dentry cache.
3406 *
3407 * It is safe and reasonable to cache /proc entries for a task until
3408 * that task exits.  After that they just clog up the dcache with
3409 * useless entries, possibly causing useful dcache entries to be
3410 * flushed instead.  This routine is provided to flush those useless
3411 * dcache entries when a process is reaped.
3412 *
3413 * NOTE: This routine is just an optimization so it does not guarantee
3414 *       that no dcache entries will exist after a process is reaped
3415 *       it just makes it very unlikely that any will persist.
3416 */
3417
3418void proc_flush_pid(struct pid *pid)
3419{
3420        proc_invalidate_siblings_dcache(&pid->inodes, &pid->lock);
3421}
3422
3423static struct dentry *proc_pid_instantiate(struct dentry * dentry,
3424                                   struct task_struct *task, const void *ptr)
3425{
3426        struct inode *inode;
3427
3428        inode = proc_pid_make_base_inode(dentry->d_sb, task,
3429                                         S_IFDIR | S_IRUGO | S_IXUGO);
3430        if (!inode)
3431                return ERR_PTR(-ENOENT);
3432
3433        inode->i_op = &proc_tgid_base_inode_operations;
3434        inode->i_fop = &proc_tgid_base_operations;
3435        inode->i_flags|=S_IMMUTABLE;
3436
3437        set_nlink(inode, nlink_tgid);
3438        pid_update_inode(task, inode);
3439
3440        d_set_d_op(dentry, &pid_dentry_operations);
3441        return d_splice_alias(inode, dentry);
3442}
3443
3444struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags)
3445{
3446        struct task_struct *task;
3447        unsigned tgid;
3448        struct proc_fs_info *fs_info;
3449        struct pid_namespace *ns;
3450        struct dentry *result = ERR_PTR(-ENOENT);
3451
3452        tgid = name_to_int(&dentry->d_name);
3453        if (tgid == ~0U)
3454                goto out;
3455
3456        fs_info = proc_sb_info(dentry->d_sb);
3457        ns = fs_info->pid_ns;
3458        rcu_read_lock();
3459        task = find_task_by_pid_ns(tgid, ns);
3460        if (task)
3461                get_task_struct(task);
3462        rcu_read_unlock();
3463        if (!task)
3464                goto out;
3465
3466        /* Limit procfs to only ptraceable tasks */
3467        if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE) {
3468                if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS))
3469                        goto out_put_task;
3470        }
3471
3472        result = proc_pid_instantiate(dentry, task, NULL);
3473out_put_task:
3474        put_task_struct(task);
3475out:
3476        return result;
3477}
3478
3479/*
3480 * Find the first task with tgid >= tgid
3481 *
3482 */
3483struct tgid_iter {
3484        unsigned int tgid;
3485        struct task_struct *task;
3486};
3487static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3488{
3489        struct pid *pid;
3490
3491        if (iter.task)
3492                put_task_struct(iter.task);
3493        rcu_read_lock();
3494retry:
3495        iter.task = NULL;
3496        pid = find_ge_pid(iter.tgid, ns);
3497        if (pid) {
3498                iter.tgid = pid_nr_ns(pid, ns);
3499                iter.task = pid_task(pid, PIDTYPE_TGID);
3500                if (!iter.task) {
3501                        iter.tgid += 1;
3502                        goto retry;
3503                }
3504                get_task_struct(iter.task);
3505        }
3506        rcu_read_unlock();
3507        return iter;
3508}
3509
3510#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3511
3512/* for the /proc/ directory itself, after non-process stuff has been done */
3513int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3514{
3515        struct tgid_iter iter;
3516        struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb);
3517        struct pid_namespace *ns = proc_pid_ns(file_inode(file)->i_sb);
3518        loff_t pos = ctx->pos;
3519
3520        if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3521                return 0;
3522
3523        if (pos == TGID_OFFSET - 2) {
3524                struct inode *inode = d_inode(fs_info->proc_self);
3525                if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3526                        return 0;
3527                ctx->pos = pos = pos + 1;
3528        }
3529        if (pos == TGID_OFFSET - 1) {
3530                struct inode *inode = d_inode(fs_info->proc_thread_self);
3531                if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3532                        return 0;
3533                ctx->pos = pos = pos + 1;
3534        }
3535        iter.tgid = pos - TGID_OFFSET;
3536        iter.task = NULL;
3537        for (iter = next_tgid(ns, iter);
3538             iter.task;
3539             iter.tgid += 1, iter = next_tgid(ns, iter)) {
3540                char name[10 + 1];
3541                unsigned int len;
3542
3543                cond_resched();
3544                if (!has_pid_permissions(fs_info, iter.task, HIDEPID_INVISIBLE))
3545                        continue;
3546
3547                len = snprintf(name, sizeof(name), "%u", iter.tgid);
3548                ctx->pos = iter.tgid + TGID_OFFSET;
3549                if (!proc_fill_cache(file, ctx, name, len,
3550                                     proc_pid_instantiate, iter.task, NULL)) {
3551                        put_task_struct(iter.task);
3552                        return 0;
3553                }
3554        }
3555        ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3556        return 0;
3557}
3558
3559/*
3560 * proc_tid_comm_permission is a special permission function exclusively
3561 * used for the node /proc/<pid>/task/<tid>/comm.
3562 * It bypasses generic permission checks in the case where a task of the same
3563 * task group attempts to access the node.
3564 * The rationale behind this is that glibc and bionic access this node for
3565 * cross thread naming (pthread_set/getname_np(!self)). However, if
3566 * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3567 * which locks out the cross thread naming implementation.
3568 * This function makes sure that the node is always accessible for members of
3569 * same thread group.
3570 */
3571static int proc_tid_comm_permission(struct mnt_idmap *idmap,
3572                                    struct inode *inode, int mask)
3573{
3574        bool is_same_tgroup;
3575        struct task_struct *task;
3576
3577        task = get_proc_task(inode);
3578        if (!task)
3579                return -ESRCH;
3580        is_same_tgroup = same_thread_group(current, task);
3581        put_task_struct(task);
3582
3583        if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3584                /* This file (/proc/<pid>/task/<tid>/comm) can always be
3585                 * read or written by the members of the corresponding
3586                 * thread group.
3587                 */
3588                return 0;
3589        }
3590
3591        return generic_permission(&nop_mnt_idmap, inode, mask);
3592}
3593
3594static const struct inode_operations proc_tid_comm_inode_operations = {
3595                .setattr        = proc_setattr,
3596                .permission     = proc_tid_comm_permission,
3597};
3598
3599/*
3600 * Tasks
3601 */
3602static const struct pid_entry tid_base_stuff[] = {
3603        DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3604        DIR("fdinfo",    S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3605        DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3606#ifdef CONFIG_NET
3607        DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3608#endif
3609        REG("environ",   S_IRUSR, proc_environ_operations),
3610        REG("auxv",      S_IRUSR, proc_auxv_operations),
3611        ONE("status",    S_IRUGO, proc_pid_status),
3612        ONE("personality", S_IRUSR, proc_pid_personality),
3613        ONE("limits",    S_IRUGO, proc_pid_limits),
3614#ifdef CONFIG_SCHED_DEBUG
3615        REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3616#endif
3617        NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3618                         &proc_tid_comm_inode_operations,
3619                         &proc_pid_set_comm_operations, {}),
3620#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3621        ONE("syscall",   S_IRUSR, proc_pid_syscall),
3622#endif
3623        REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3624        ONE("stat",      S_IRUGO, proc_tid_stat),
3625        ONE("statm",     S_IRUGO, proc_pid_statm),
3626        REG("maps",      S_IRUGO, proc_pid_maps_operations),
3627#ifdef CONFIG_PROC_CHILDREN
3628        REG("children",  S_IRUGO, proc_tid_children_operations),
3629#endif
3630#ifdef CONFIG_NUMA
3631        REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations),
3632#endif
3633        REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3634        LNK("cwd",       proc_cwd_link),
3635        LNK("root",      proc_root_link),
3636        LNK("exe",       proc_exe_link),
3637        REG("mounts",    S_IRUGO, proc_mounts_operations),
3638        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3639#ifdef CONFIG_PROC_PAGE_MONITOR
3640        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3641        REG("smaps",     S_IRUGO, proc_pid_smaps_operations),
3642        REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3643        REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3644#endif
3645#ifdef CONFIG_SECURITY
3646        DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3647#endif
3648#ifdef CONFIG_KALLSYMS
3649        ONE("wchan",     S_IRUGO, proc_pid_wchan),
3650#endif
3651#ifdef CONFIG_STACKTRACE
3652        ONE("stack",      S_IRUSR, proc_pid_stack),
3653#endif
3654#ifdef CONFIG_SCHED_INFO
3655        ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3656#endif
3657#ifdef CONFIG_LATENCYTOP
3658        REG("latency",  S_IRUGO, proc_lstats_operations),
3659#endif
3660#ifdef CONFIG_PROC_PID_CPUSET
3661        ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3662#endif
3663#ifdef CONFIG_CGROUPS
3664        ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3665#endif
3666#ifdef CONFIG_PROC_CPU_RESCTRL
3667        ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3668#endif
3669        ONE("oom_score", S_IRUGO, proc_oom_score),
3670        REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3671        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3672#ifdef CONFIG_AUDIT
3673        REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3674        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3675#endif
3676#ifdef CONFIG_FAULT_INJECTION
3677        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3678        REG("fail-nth", 0644, proc_fail_nth_operations),
3679#endif
3680#ifdef CONFIG_TASK_IO_ACCOUNTING
3681        ONE("io",       S_IRUSR, proc_tid_io_accounting),
3682#endif
3683#ifdef CONFIG_USER_NS
3684        REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3685        REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3686        REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3687        REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3688#endif
3689#ifdef CONFIG_LIVEPATCH
3690        ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3691#endif
3692#ifdef CONFIG_PROC_PID_ARCH_STATUS
3693        ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3694#endif
3695#ifdef CONFIG_SECCOMP_CACHE_DEBUG
3696        ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
3697#endif
3698#ifdef CONFIG_KSM
3699        ONE("ksm_merging_pages",  S_IRUSR, proc_pid_ksm_merging_pages),
3700        ONE("ksm_stat",  S_IRUSR, proc_pid_ksm_stat),
3701#endif
3702};
3703
3704static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3705{
3706        return proc_pident_readdir(file, ctx,
3707                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3708}
3709
3710static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3711{
3712        return proc_pident_lookup(dir, dentry,
3713                                  tid_base_stuff,
3714                                  tid_base_stuff + ARRAY_SIZE(tid_base_stuff));
3715}
3716
3717static const struct file_operations proc_tid_base_operations = {
3718        .read           = generic_read_dir,
3719        .iterate_shared = proc_tid_base_readdir,
3720        .llseek         = generic_file_llseek,
3721};
3722
3723static const struct inode_operations proc_tid_base_inode_operations = {
3724        .lookup         = proc_tid_base_lookup,
3725        .getattr        = pid_getattr,
3726        .setattr        = proc_setattr,
3727};
3728
3729static struct dentry *proc_task_instantiate(struct dentry *dentry,
3730        struct task_struct *task, const void *ptr)
3731{
3732        struct inode *inode;
3733        inode = proc_pid_make_base_inode(dentry->d_sb, task,
3734                                         S_IFDIR | S_IRUGO | S_IXUGO);
3735        if (!inode)
3736                return ERR_PTR(-ENOENT);
3737
3738        inode->i_op = &proc_tid_base_inode_operations;
3739        inode->i_fop = &proc_tid_base_operations;
3740        inode->i_flags |= S_IMMUTABLE;
3741
3742        set_nlink(inode, nlink_tid);
3743        pid_update_inode(task, inode);
3744
3745        d_set_d_op(dentry, &pid_dentry_operations);
3746        return d_splice_alias(inode, dentry);
3747}
3748
3749static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3750{
3751        struct task_struct *task;
3752        struct task_struct *leader = get_proc_task(dir);
3753        unsigned tid;
3754        struct proc_fs_info *fs_info;
3755        struct pid_namespace *ns;
3756        struct dentry *result = ERR_PTR(-ENOENT);
3757
3758        if (!leader)
3759                goto out_no_task;
3760
3761        tid = name_to_int(&dentry->d_name);
3762        if (tid == ~0U)
3763                goto out;
3764
3765        fs_info = proc_sb_info(dentry->d_sb);
3766        ns = fs_info->pid_ns;
3767        rcu_read_lock();
3768        task = find_task_by_pid_ns(tid, ns);
3769        if (task)
3770                get_task_struct(task);
3771        rcu_read_unlock();
3772        if (!task)
3773                goto out;
3774        if (!same_thread_group(leader, task))
3775                goto out_drop_task;
3776
3777        result = proc_task_instantiate(dentry, task, NULL);
3778out_drop_task:
3779        put_task_struct(task);
3780out:
3781        put_task_struct(leader);
3782out_no_task:
3783        return result;
3784}
3785
3786/*
3787 * Find the first tid of a thread group to return to user space.
3788 *
3789 * Usually this is just the thread group leader, but if the users
3790 * buffer was too small or there was a seek into the middle of the
3791 * directory we have more work todo.
3792 *
3793 * In the case of a short read we start with find_task_by_pid.
3794 *
3795 * In the case of a seek we start with the leader and walk nr
3796 * threads past it.
3797 */
3798static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3799                                        struct pid_namespace *ns)
3800{
3801        struct task_struct *pos, *task;
3802        unsigned long nr = f_pos;
3803
3804        if (nr != f_pos)        /* 32bit overflow? */
3805                return NULL;
3806
3807        rcu_read_lock();
3808        task = pid_task(pid, PIDTYPE_PID);
3809        if (!task)
3810                goto fail;
3811
3812        /* Attempt to start with the tid of a thread */
3813        if (tid && nr) {
3814                pos = find_task_by_pid_ns(tid, ns);
3815                if (pos && same_thread_group(pos, task))
3816                        goto found;
3817        }
3818
3819        /* If nr exceeds the number of threads there is nothing todo */
3820        if (nr >= get_nr_threads(task))
3821                goto fail;
3822
3823        /* If we haven't found our starting place yet start
3824         * with the leader and walk nr threads forward.
3825         */
3826        for_each_thread(task, pos) {
3827                if (!nr--)
3828                        goto found;
3829        }
3830fail:
3831        pos = NULL;
3832        goto out;
3833found:
3834        get_task_struct(pos);
3835out:
3836        rcu_read_unlock();
3837        return pos;
3838}
3839
3840/*
3841 * Find the next thread in the thread list.
3842 * Return NULL if there is an error or no next thread.
3843 *
3844 * The reference to the input task_struct is released.
3845 */
3846static struct task_struct *next_tid(struct task_struct *start)
3847{
3848        struct task_struct *pos = NULL;
3849        rcu_read_lock();
3850        if (pid_alive(start)) {
3851                pos = __next_thread(start);
3852                if (pos)
3853                        get_task_struct(pos);
3854        }
3855        rcu_read_unlock();
3856        put_task_struct(start);
3857        return pos;
3858}
3859
3860/* for the /proc/TGID/task/ directories */
3861static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3862{
3863        struct inode *inode = file_inode(file);
3864        struct task_struct *task;
3865        struct pid_namespace *ns;
3866        int tid;
3867
3868        if (proc_inode_is_dead(inode))
3869                return -ENOENT;
3870
3871        if (!dir_emit_dots(file, ctx))
3872                return 0;
3873
3874        /* f_version caches the tgid value that the last readdir call couldn't
3875         * return. lseek aka telldir automagically resets f_version to 0.
3876         */
3877        ns = proc_pid_ns(inode->i_sb);
3878        tid = (int)file->f_version;
3879        file->f_version = 0;
3880        for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3881             task;
3882             task = next_tid(task), ctx->pos++) {
3883                char name[10 + 1];
3884                unsigned int len;
3885
3886                tid = task_pid_nr_ns(task, ns);
3887                if (!tid)
3888                        continue;       /* The task has just exited. */
3889                len = snprintf(name, sizeof(name), "%u", tid);
3890                if (!proc_fill_cache(file, ctx, name, len,
3891                                proc_task_instantiate, task, NULL)) {
3892                        /* returning this tgid failed, save it as the first
3893                         * pid for the next readir call */
3894                        file->f_version = (u64)tid;
3895                        put_task_struct(task);
3896                        break;
3897                }
3898        }
3899
3900        return 0;
3901}
3902
3903static int proc_task_getattr(struct mnt_idmap *idmap,
3904                             const struct path *path, struct kstat *stat,
3905                             u32 request_mask, unsigned int query_flags)
3906{
3907        struct inode *inode = d_inode(path->dentry);
3908        struct task_struct *p = get_proc_task(inode);
3909        generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
3910
3911        if (p) {
3912                stat->nlink += get_nr_threads(p);
3913                put_task_struct(p);
3914        }
3915
3916        return 0;
3917}
3918
3919static const struct inode_operations proc_task_inode_operations = {
3920        .lookup         = proc_task_lookup,
3921        .getattr        = proc_task_getattr,
3922        .setattr        = proc_setattr,
3923        .permission     = proc_pid_permission,
3924};
3925
3926static const struct file_operations proc_task_operations = {
3927        .read           = generic_read_dir,
3928        .iterate_shared = proc_task_readdir,
3929        .llseek         = generic_file_llseek,
3930};
3931
3932void __init set_proc_pid_nlink(void)
3933{
3934        nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3935        nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3936}
3937