kernel/security/tomoyo/audit.c

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