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 mode_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                 struct timeval tv;
 160                 do_gettimeofday(&tv);
 161                 tomoyo_convert_time(tv.tv_sec, &stamp);
 162         }
 163         pos = snprintf(buffer, tomoyo_buffer_len - 1,
 164                        "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
 165                        "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
 166                        "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
 167                        "fsuid=%u fsgid=%u }", stamp.year, stamp.month,
 168                        stamp.day, stamp.hour, stamp.min, stamp.sec, r->profile,
 169                        tomoyo_mode[r->mode], tomoyo_yesno(r->granted), gpid,
 170                        tomoyo_sys_getpid(), tomoyo_sys_getppid(),
 171                        current_uid(), current_gid(), current_euid(),
 172                        current_egid(), current_suid(), current_sgid(),
 173                        current_fsuid(), current_fsgid());
 174         if (!obj)
 175                 goto no_obj_info;
 176         if (!obj->validate_done) {
 177                 tomoyo_get_attributes(obj);
 178                 obj->validate_done = true;
 179         }
 180         for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
 181                 struct tomoyo_mini_stat *stat;
 182                 unsigned int dev;
 183                 mode_t mode;
 184                 if (!obj->stat_valid[i])
 185                         continue;
 186                 stat = &obj->stat[i];
 187                 dev = stat->dev;
 188                 mode = stat->mode;
 189                 if (i & 1) {
 190                         pos += snprintf(buffer + pos,
 191                                         tomoyo_buffer_len - 1 - pos,
 192                                         " path%u.parent={ uid=%u gid=%u "
 193                                         "ino=%lu perm=0%o }", (i >> 1) + 1,
 194                                         stat->uid, stat->gid, (unsigned long)
 195                                         stat->ino, stat->mode & S_IALLUGO);
 196                         continue;
 197                 }
 198                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 199                                 " path%u={ uid=%u gid=%u ino=%lu major=%u"
 200                                 " minor=%u perm=0%o type=%s", (i >> 1) + 1,
 201                                 stat->uid, stat->gid, (unsigned long)
 202                                 stat->ino, MAJOR(dev), MINOR(dev),
 203                                 mode & S_IALLUGO, tomoyo_filetype(mode));
 204                 if (S_ISCHR(mode) || S_ISBLK(mode)) {
 205                         dev = stat->rdev;
 206                         pos += snprintf(buffer + pos,
 207                                         tomoyo_buffer_len - 1 - pos,
 208                                         " dev_major=%u dev_minor=%u",
 209                                         MAJOR(dev), MINOR(dev));
 210                 }
 211                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 212                                 " }");
 213         }
 214 no_obj_info:
 215         if (pos < tomoyo_buffer_len - 1)
 216                 return buffer;
 217         kfree(buffer);
 218         return NULL;
 219 }
 220
 221 /**
 222  * tomoyo_init_log - Allocate buffer for audit logs.
 223  *
 224  * @r:    Pointer to "struct tomoyo_request_info".
 225  * @len:  Buffer size needed for @fmt and @args.
 226  * @fmt:  The printf()'s format string.
 227  * @args: va_list structure for @fmt.
 228  *
 229  * Returns pointer to allocated memory.
 230  *
 231  * This function uses kzalloc(), so caller must kfree() if this function
 232  * didn't return NULL.
 233  */
 234 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
 235                       va_list args)
 236 {
 237         char *buf = NULL;
 238         char *bprm_info = NULL;
 239         const char *header = NULL;
 240         char *realpath = NULL;
 241         const char *symlink = NULL;
 242         int pos;
 243         const char *domainname = r->domain->domainname->name;
 244         header = tomoyo_print_header(r);
 245         if (!header)
 246                 return NULL;
 247         /* +10 is for '\n' etc. and '\0'. */
 248         len += strlen(domainname) + strlen(header) + 10;
 249         if (r->ee) {
 250                 struct file *file = r->ee->bprm->file;
 251                 realpath = tomoyo_realpath_from_path(&file->f_path);
 252                 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
 253                 if (!realpath || !bprm_info)
 254                         goto out;
 255                 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
 256                 len += strlen(realpath) + 80 + strlen(bprm_info);
 257         } else if (r->obj && r->obj->symlink_target) {
 258                 symlink = r->obj->symlink_target->name;
 259                 /* +18 is for " symlink.target=\"%s\"" */
 260                 len += 18 + strlen(symlink);
 261         }
 262         len = tomoyo_round2(len);
 263         buf = kzalloc(len, GFP_NOFS);
 264         if (!buf)
 265                 goto out;
 266         len--;
 267         pos = snprintf(buf, len, "%s", header);
 268         if (realpath) {
 269                 struct linux_binprm *bprm = r->ee->bprm;
 270                 pos += snprintf(buf + pos, len - pos,
 271                                 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
 272                                 realpath, bprm->argc, bprm->envc, bprm_info);
 273         } else if (symlink)
 274                 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
 275                                 symlink);
 276         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
 277         vsnprintf(buf + pos, len - pos, fmt, args);
 278 out:
 279         kfree(realpath);
 280         kfree(bprm_info);
 281         kfree(header);
 282         return buf;
 283 }
 284
 285 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
 286 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
 287
 288 /* Structure for audit log. */
 289 struct tomoyo_log {
 290         struct list_head list;
 291         char *log;
 292         int size;
 293 };
 294
 295 /* The list for "struct tomoyo_log". */
 296 static LIST_HEAD(tomoyo_log);
 297
 298 /* Lock for "struct list_head tomoyo_log". */
 299 static DEFINE_SPINLOCK(tomoyo_log_lock);
 300
 301 /* Length of "stuct list_head tomoyo_log". */
 302 static unsigned int tomoyo_log_count;
 303
 304 /**
 305  * tomoyo_get_audit - Get audit mode.
 306  *
 307  * @ns:          Pointer to "struct tomoyo_policy_namespace".
 308  * @profile:     Profile number.
 309  * @index:       Index number of functionality.
 310  * @is_granted:  True if granted log, false otherwise.
 311  *
 312  * Returns true if this request should be audited, false otherwise.
 313  */
 314 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
 315                              const u8 profile, const u8 index,
 316                              const struct tomoyo_acl_info *matched_acl,
 317                              const bool is_granted)
 318 {
 319         u8 mode;
 320         const u8 category = tomoyo_index2category[index] +
 321                 TOMOYO_MAX_MAC_INDEX;
 322         struct tomoyo_profile *p;
 323         if (!tomoyo_policy_loaded)
 324                 return false;
 325         p = tomoyo_profile(ns, profile);
 326         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
 327                 return false;
 328         if (is_granted && matched_acl && matched_acl->cond &&
 329             matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
 330                 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
 331         mode = p->config[index];
 332         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 333                 mode = p->config[category];
 334         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 335                 mode = p->default_config;
 336         if (is_granted)
 337                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
 338         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
 339 }
 340
 341 /**
 342  * tomoyo_write_log2 - Write an audit log.
 343  *
 344  * @r:    Pointer to "struct tomoyo_request_info".
 345  * @len:  Buffer size needed for @fmt and @args.
 346  * @fmt:  The printf()'s format string.
 347  * @args: va_list structure for @fmt.
 348  *
 349  * Returns nothing.
 350  */
 351 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
 352                        va_list args)
 353 {
 354         char *buf;
 355         struct tomoyo_log *entry;
 356         bool quota_exceeded = false;
 357         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
 358                               r->matched_acl, r->granted))
 359                 goto out;
 360         buf = tomoyo_init_log(r, len, fmt, args);
 361         if (!buf)
 362                 goto out;
 363         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 364         if (!entry) {
 365                 kfree(buf);
 366                 goto out;
 367         }
 368         entry->log = buf;
 369         len = tomoyo_round2(strlen(buf) + 1);
 370         /*
 371          * The entry->size is used for memory quota checks.
 372          * Don't go beyond strlen(entry->log).
 373          */
 374         entry->size = len + tomoyo_round2(sizeof(*entry));
 375         spin_lock(&tomoyo_log_lock);
 376         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
 377             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
 378             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
 379                 quota_exceeded = true;
 380         } else {
 381                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
 382                 list_add_tail(&entry->list, &tomoyo_log);
 383                 tomoyo_log_count++;
 384         }
 385         spin_unlock(&tomoyo_log_lock);
 386         if (quota_exceeded) {
 387                 kfree(buf);
 388                 kfree(entry);
 389                 goto out;
 390         }
 391         wake_up(&tomoyo_log_wait);
 392 out:
 393         return;
 394 }
 395
 396 /**
 397  * tomoyo_write_log - Write an audit log.
 398  *
 399  * @r:   Pointer to "struct tomoyo_request_info".
 400  * @fmt: The printf()'s format string, followed by parameters.
 401  *
 402  * Returns nothing.
 403  */
 404 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 405 {
 406         va_list args;
 407         int len;
 408         va_start(args, fmt);
 409         len = vsnprintf((char *) &len, 1, fmt, args) + 1;
 410         va_end(args);
 411         va_start(args, fmt);
 412         tomoyo_write_log2(r, len, fmt, args);
 413         va_end(args);
 414 }
 415
 416 /**
 417  * tomoyo_read_log - Read an audit log.
 418  *
 419  * @head: Pointer to "struct tomoyo_io_buffer".
 420  *
 421  * Returns nothing.
 422  */
 423 void tomoyo_read_log(struct tomoyo_io_buffer *head)
 424 {
 425         struct tomoyo_log *ptr = NULL;
 426         if (head->r.w_pos)
 427                 return;
 428         kfree(head->read_buf);
 429         head->read_buf = NULL;
 430         spin_lock(&tomoyo_log_lock);
 431         if (!list_empty(&tomoyo_log)) {
 432                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
 433                 list_del(&ptr->list);
 434                 tomoyo_log_count--;
 435                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
 436         }
 437         spin_unlock(&tomoyo_log_lock);
 438         if (ptr) {
 439                 head->read_buf = ptr->log;
 440                 head->r.w[head->r.w_pos++] = head->read_buf;
 441                 kfree(ptr);
 442         }
 443 }
 444
 445 /**
 446  * tomoyo_poll_log - Wait for an audit log.
 447  *
 448  * @file: Pointer to "struct file".
 449  * @wait: Pointer to "poll_table".
 450  *
 451  * Returns POLLIN | POLLRDNORM when ready to read an audit log.
 452  */
 453 int tomoyo_poll_log(struct file *file, poll_table *wait)
 454 {
 455         if (tomoyo_log_count)
 456                 return POLLIN | POLLRDNORM;
 457         poll_wait(file, &tomoyo_log_wait, wait);
 458         if (tomoyo_log_count)
 459                 return POLLIN | POLLRDNORM;
 460         return 0;
 461 }