security/tomoyo/audit.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * security/tomoyo/audit.c
   4  *
   5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   6  */
   7
   8 #include "common.h"
   9 #include <linux/slab.h>
  10
  11 /**
  12  * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
  13  *
  14  * @bprm: Pointer to "struct linux_binprm".
  15  * @dump: Pointer to "struct tomoyo_page_dump".
  16  *
  17  * Returns the contents of @bprm on success, NULL otherwise.
  18  *
  19  * This function uses kzalloc(), so caller must kfree() if this function
  20  * didn't return NULL.
  21  */
  22 static char *tomoyo_print_bprm(struct linux_binprm *bprm,
  23                                struct tomoyo_page_dump *dump)
  24 {
  25         static const int tomoyo_buffer_len = 4096 * 2;
  26         char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
  27         char *cp;
  28         char *last_start;
  29         int len;
  30         unsigned long pos = bprm->p;
  31         int offset = pos % PAGE_SIZE;
  32         int argv_count = bprm->argc;
  33         int envp_count = bprm->envc;
  34         bool truncated = false;
  35         if (!buffer)
  36                 return NULL;
  37         len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
  38         cp = buffer + len;
  39         if (!argv_count) {
  40                 memmove(cp, "} envp[]={ ", 11);
  41                 cp += 11;
  42         }
  43         last_start = cp;
  44         while (argv_count || envp_count) {
  45                 if (!tomoyo_dump_page(bprm, pos, dump))
  46                         goto out;
  47                 pos += PAGE_SIZE - offset;
  48                 /* Read. */
  49                 while (offset < PAGE_SIZE) {
  50                         const char *kaddr = dump->data;
  51                         const unsigned char c = kaddr[offset++];
  52                         if (cp == last_start)
  53                                 *cp++ = '"';
  54                         if (cp >= buffer + tomoyo_buffer_len - 32) {
  55                                 /* Reserve some room for "..." string. */
  56                                 truncated = true;
  57                         } else if (c == '\\') {
  58                                 *cp++ = '\\';
  59                                 *cp++ = '\\';
  60                         } else if (c > ' ' && c < 127) {
  61                                 *cp++ = c;
  62                         } else if (!c) {
  63                                 *cp++ = '"';
  64                                 *cp++ = ' ';
  65                                 last_start = cp;
  66                         } else {
  67                                 *cp++ = '\\';
  68                                 *cp++ = (c >> 6) + '0';
  69                                 *cp++ = ((c >> 3) & 7) + '0';
  70                                 *cp++ = (c & 7) + '0';
  71                         }
  72                         if (c)
  73                                 continue;
  74                         if (argv_count) {
  75                                 if (--argv_count == 0) {
  76                                         if (truncated) {
  77                                                 cp = last_start;
  78                                                 memmove(cp, "... ", 4);
  79                                                 cp += 4;
  80                                         }
  81                                         memmove(cp, "} envp[]={ ", 11);
  82                                         cp += 11;
  83                                         last_start = cp;
  84                                         truncated = false;
  85                                 }
  86                         } else if (envp_count) {
  87                                 if (--envp_count == 0) {
  88                                         if (truncated) {
  89                                                 cp = last_start;
  90                                                 memmove(cp, "... ", 4);
  91                                                 cp += 4;
  92                                         }
  93                                 }
  94                         }
  95                         if (!argv_count && !envp_count)
  96                                 break;
  97                 }
  98                 offset = 0;
  99         }
 100         *cp++ = '}';
 101         *cp = '\0';
 102         return buffer;
 103 out:
 104         snprintf(buffer, tomoyo_buffer_len - 1,
 105                  "argv[]={ ... } envp[]= { ... }");
 106         return buffer;
 107 }
 108
 109 /**
 110  * tomoyo_filetype - Get string representation of file type.
 111  *
 112  * @mode: Mode value for stat().
 113  *
 114  * Returns file type string.
 115  */
 116 static inline const char *tomoyo_filetype(const umode_t mode)
 117 {
 118         switch (mode & S_IFMT) {
 119         case S_IFREG:
 120         case 0:
 121                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
 122         case S_IFDIR:
 123                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
 124         case S_IFLNK:
 125                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
 126         case S_IFIFO:
 127                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
 128         case S_IFSOCK:
 129                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
 130         case S_IFBLK:
 131                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
 132         case S_IFCHR:
 133                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
 134         }
 135         return "unknown"; /* This should not happen. */
 136 }
 137
 138 /**
 139  * tomoyo_print_header - Get header line of audit log.
 140  *
 141  * @r: Pointer to "struct tomoyo_request_info".
 142  *
 143  * Returns string representation.
 144  *
 145  * This function uses kmalloc(), so caller must kfree() if this function
 146  * didn't return NULL.
 147  */
 148 static char *tomoyo_print_header(struct tomoyo_request_info *r)
 149 {
 150         struct tomoyo_time stamp;
 151         const pid_t gpid = task_pid_nr(current);
 152         struct tomoyo_obj_info *obj = r->obj;
 153         static const int tomoyo_buffer_len = 4096;
 154         char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
 155         int pos;
 156         u8 i;
 157         if (!buffer)
 158                 return NULL;
 159
 160         tomoyo_convert_time(ktime_get_real_seconds(), &stamp);
 161
 162         pos = snprintf(buffer, tomoyo_buffer_len - 1,
 163                        "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
 164                        "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
 165                        "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
 166                        "fsuid=%u fsgid=%u }", stamp.year, stamp.month,
 167                        stamp.day, stamp.hour, stamp.min, stamp.sec, r->profile,
 168                        tomoyo_mode[r->mode], tomoyo_yesno(r->granted), gpid,
 169                        tomoyo_sys_getpid(), tomoyo_sys_getppid(),
 170                        from_kuid(&init_user_ns, current_uid()),
 171                        from_kgid(&init_user_ns, current_gid()),
 172                        from_kuid(&init_user_ns, current_euid()),
 173                        from_kgid(&init_user_ns, current_egid()),
 174                        from_kuid(&init_user_ns, current_suid()),
 175                        from_kgid(&init_user_ns, current_sgid()),
 176                        from_kuid(&init_user_ns, current_fsuid()),
 177                        from_kgid(&init_user_ns, current_fsgid()));
 178         if (!obj)
 179                 goto no_obj_info;
 180         if (!obj->validate_done) {
 181                 tomoyo_get_attributes(obj);
 182                 obj->validate_done = true;
 183         }
 184         for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
 185                 struct tomoyo_mini_stat *stat;
 186                 unsigned int dev;
 187                 umode_t mode;
 188                 if (!obj->stat_valid[i])
 189                         continue;
 190                 stat = &obj->stat[i];
 191                 dev = stat->dev;
 192                 mode = stat->mode;
 193                 if (i & 1) {
 194                         pos += snprintf(buffer + pos,
 195                                         tomoyo_buffer_len - 1 - pos,
 196                                         " path%u.parent={ uid=%u gid=%u "
 197                                         "ino=%lu perm=0%o }", (i >> 1) + 1,
 198                                         from_kuid(&init_user_ns, stat->uid),
 199                                         from_kgid(&init_user_ns, stat->gid),
 200                                         (unsigned long)stat->ino,
 201                                         stat->mode & S_IALLUGO);
 202                         continue;
 203                 }
 204                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 205                                 " path%u={ uid=%u gid=%u ino=%lu major=%u"
 206                                 " minor=%u perm=0%o type=%s", (i >> 1) + 1,
 207                                 from_kuid(&init_user_ns, stat->uid),
 208                                 from_kgid(&init_user_ns, stat->gid),
 209                                 (unsigned long)stat->ino,
 210                                 MAJOR(dev), MINOR(dev),
 211                                 mode & S_IALLUGO, tomoyo_filetype(mode));
 212                 if (S_ISCHR(mode) || S_ISBLK(mode)) {
 213                         dev = stat->rdev;
 214                         pos += snprintf(buffer + pos,
 215                                         tomoyo_buffer_len - 1 - pos,
 216                                         " dev_major=%u dev_minor=%u",
 217                                         MAJOR(dev), MINOR(dev));
 218                 }
 219                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 220                                 " }");
 221         }
 222 no_obj_info:
 223         if (pos < tomoyo_buffer_len - 1)
 224                 return buffer;
 225         kfree(buffer);
 226         return NULL;
 227 }
 228
 229 /**
 230  * tomoyo_init_log - Allocate buffer for audit logs.
 231  *
 232  * @r:    Pointer to "struct tomoyo_request_info".
 233  * @len:  Buffer size needed for @fmt and @args.
 234  * @fmt:  The printf()'s format string.
 235  * @args: va_list structure for @fmt.
 236  *
 237  * Returns pointer to allocated memory.
 238  *
 239  * This function uses kzalloc(), so caller must kfree() if this function
 240  * didn't return NULL.
 241  */
 242 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
 243                       va_list args)
 244 {
 245         char *buf = NULL;
 246         char *bprm_info = NULL;
 247         const char *header = NULL;
 248         char *realpath = NULL;
 249         const char *symlink = NULL;
 250         int pos;
 251         const char *domainname = r->domain->domainname->name;
 252         header = tomoyo_print_header(r);
 253         if (!header)
 254                 return NULL;
 255         /* +10 is for '\n' etc. and '\0'. */
 256         len += strlen(domainname) + strlen(header) + 10;
 257         if (r->ee) {
 258                 struct file *file = r->ee->bprm->file;
 259                 realpath = tomoyo_realpath_from_path(&file->f_path);
 260                 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
 261                 if (!realpath || !bprm_info)
 262                         goto out;
 263                 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
 264                 len += strlen(realpath) + 80 + strlen(bprm_info);
 265         } else if (r->obj && r->obj->symlink_target) {
 266                 symlink = r->obj->symlink_target->name;
 267                 /* +18 is for " symlink.target=\"%s\"" */
 268                 len += 18 + strlen(symlink);
 269         }
 270         len = tomoyo_round2(len);
 271         buf = kzalloc(len, GFP_NOFS);
 272         if (!buf)
 273                 goto out;
 274         len--;
 275         pos = snprintf(buf, len, "%s", header);
 276         if (realpath) {
 277                 struct linux_binprm *bprm = r->ee->bprm;
 278                 pos += snprintf(buf + pos, len - pos,
 279                                 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
 280                                 realpath, bprm->argc, bprm->envc, bprm_info);
 281         } else if (symlink)
 282                 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
 283                                 symlink);
 284         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
 285         vsnprintf(buf + pos, len - pos, fmt, args);
 286 out:
 287         kfree(realpath);
 288         kfree(bprm_info);
 289         kfree(header);
 290         return buf;
 291 }
 292
 293 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
 294 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
 295
 296 /* Structure for audit log. */
 297 struct tomoyo_log {
 298         struct list_head list;
 299         char *log;
 300         int size;
 301 };
 302
 303 /* The list for "struct tomoyo_log". */
 304 static LIST_HEAD(tomoyo_log);
 305
 306 /* Lock for "struct list_head tomoyo_log". */
 307 static DEFINE_SPINLOCK(tomoyo_log_lock);
 308
 309 /* Length of "stuct list_head tomoyo_log". */
 310 static unsigned int tomoyo_log_count;
 311
 312 /**
 313  * tomoyo_get_audit - Get audit mode.
 314  *
 315  * @ns:          Pointer to "struct tomoyo_policy_namespace".
 316  * @profile:     Profile number.
 317  * @index:       Index number of functionality.
 318  * @is_granted:  True if granted log, false otherwise.
 319  *
 320  * Returns true if this request should be audited, false otherwise.
 321  */
 322 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
 323                              const u8 profile, const u8 index,
 324                              const struct tomoyo_acl_info *matched_acl,
 325                              const bool is_granted)
 326 {
 327         u8 mode;
 328         const u8 category = tomoyo_index2category[index] +
 329                 TOMOYO_MAX_MAC_INDEX;
 330         struct tomoyo_profile *p;
 331         if (!tomoyo_policy_loaded)
 332                 return false;
 333         p = tomoyo_profile(ns, profile);
 334         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
 335                 return false;
 336         if (is_granted && matched_acl && matched_acl->cond &&
 337             matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
 338                 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
 339         mode = p->config[index];
 340         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 341                 mode = p->config[category];
 342         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 343                 mode = p->default_config;
 344         if (is_granted)
 345                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
 346         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
 347 }
 348
 349 /**
 350  * tomoyo_write_log2 - Write an audit log.
 351  *
 352  * @r:    Pointer to "struct tomoyo_request_info".
 353  * @len:  Buffer size needed for @fmt and @args.
 354  * @fmt:  The printf()'s format string.
 355  * @args: va_list structure for @fmt.
 356  *
 357  * Returns nothing.
 358  */
 359 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
 360                        va_list args)
 361 {
 362         char *buf;
 363         struct tomoyo_log *entry;
 364         bool quota_exceeded = false;
 365         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
 366                               r->matched_acl, r->granted))
 367                 goto out;
 368         buf = tomoyo_init_log(r, len, fmt, args);
 369         if (!buf)
 370                 goto out;
 371         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 372         if (!entry) {
 373                 kfree(buf);
 374                 goto out;
 375         }
 376         entry->log = buf;
 377         len = tomoyo_round2(strlen(buf) + 1);
 378         /*
 379          * The entry->size is used for memory quota checks.
 380          * Don't go beyond strlen(entry->log).
 381          */
 382         entry->size = len + tomoyo_round2(sizeof(*entry));
 383         spin_lock(&tomoyo_log_lock);
 384         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
 385             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
 386             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
 387                 quota_exceeded = true;
 388         } else {
 389                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
 390                 list_add_tail(&entry->list, &tomoyo_log);
 391                 tomoyo_log_count++;
 392         }
 393         spin_unlock(&tomoyo_log_lock);
 394         if (quota_exceeded) {
 395                 kfree(buf);
 396                 kfree(entry);
 397                 goto out;
 398         }
 399         wake_up(&tomoyo_log_wait);
 400 out:
 401         return;
 402 }
 403
 404 /**
 405  * tomoyo_write_log - Write an audit log.
 406  *
 407  * @r:   Pointer to "struct tomoyo_request_info".
 408  * @fmt: The printf()'s format string, followed by parameters.
 409  *
 410  * Returns nothing.
 411  */
 412 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 413 {
 414         va_list args;
 415         int len;
 416         va_start(args, fmt);
 417         len = vsnprintf((char *) &len, 1, fmt, args) + 1;
 418         va_end(args);
 419         va_start(args, fmt);
 420         tomoyo_write_log2(r, len, fmt, args);
 421         va_end(args);
 422 }
 423
 424 /**
 425  * tomoyo_read_log - Read an audit log.
 426  *
 427  * @head: Pointer to "struct tomoyo_io_buffer".
 428  *
 429  * Returns nothing.
 430  */
 431 void tomoyo_read_log(struct tomoyo_io_buffer *head)
 432 {
 433         struct tomoyo_log *ptr = NULL;
 434         if (head->r.w_pos)
 435                 return;
 436         kfree(head->read_buf);
 437         head->read_buf = NULL;
 438         spin_lock(&tomoyo_log_lock);
 439         if (!list_empty(&tomoyo_log)) {
 440                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
 441                 list_del(&ptr->list);
 442                 tomoyo_log_count--;
 443                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
 444         }
 445         spin_unlock(&tomoyo_log_lock);
 446         if (ptr) {
 447                 head->read_buf = ptr->log;
 448                 head->r.w[head->r.w_pos++] = head->read_buf;
 449                 kfree(ptr);
 450         }
 451 }
 452
 453 /**
 454  * tomoyo_poll_log - Wait for an audit log.
 455  *
 456  * @file: Pointer to "struct file".
 457  * @wait: Pointer to "poll_table". Maybe NULL.
 458  *
 459  * Returns EPOLLIN | EPOLLRDNORM when ready to read an audit log.
 460  */
 461 __poll_t tomoyo_poll_log(struct file *file, poll_table *wait)
 462 {
 463         if (tomoyo_log_count)
 464                 return EPOLLIN | EPOLLRDNORM;
 465         poll_wait(file, &tomoyo_log_wait, wait);
 466         if (tomoyo_log_count)
 467                 return EPOLLIN | EPOLLRDNORM;
 468         return 0;
 469 }