Pileus Git - ~andy/linux/blob - security/tomoyo/audit.c

   1 /*
   2  * security/tomoyo/audit.c
   3  *
   4  * Pathname restriction functions.
   5  *
   6  * Copyright (C) 2005-2010  NTT DATA CORPORATION
   7  */
   8
   9 #include "common.h"
  10 #include <linux/slab.h>
  11
  12 /**
  13  * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
  14  *
  15  * @bprm: Pointer to "struct linux_binprm".
  16  * @dump: Pointer to "struct tomoyo_page_dump".
  17  *
  18  * Returns the contents of @bprm on success, NULL otherwise.
  19  *
  20  * This function uses kzalloc(), so caller must kfree() if this function
  21  * didn't return NULL.
  22  */
  23 static char *tomoyo_print_bprm(struct linux_binprm *bprm,
  24                                struct tomoyo_page_dump *dump)
  25 {
  26         static const int tomoyo_buffer_len = 4096 * 2;
  27         char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
  28         char *cp;
  29         char *last_start;
  30         int len;
  31         unsigned long pos = bprm->p;
  32         int offset = pos % PAGE_SIZE;
  33         int argv_count = bprm->argc;
  34         int envp_count = bprm->envc;
  35         bool truncated = false;
  36         if (!buffer)
  37                 return NULL;
  38         len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
  39         cp = buffer + len;
  40         if (!argv_count) {
  41                 memmove(cp, "} envp[]={ ", 11);
  42                 cp += 11;
  43         }
  44         last_start = cp;
  45         while (argv_count || envp_count) {
  46                 if (!tomoyo_dump_page(bprm, pos, dump))
  47                         goto out;
  48                 pos += PAGE_SIZE - offset;
  49                 /* Read. */
  50                 while (offset < PAGE_SIZE) {
  51                         const char *kaddr = dump->data;
  52                         const unsigned char c = kaddr[offset++];
  53                         if (cp == last_start)
  54                                 *cp++ = '"';
  55                         if (cp >= buffer + tomoyo_buffer_len - 32) {
  56                                 /* Reserve some room for "..." string. */
  57                                 truncated = true;
  58                         } else if (c == '\\') {
  59                                 *cp++ = '\\';
  60                                 *cp++ = '\\';
  61                         } else if (c > ' ' && c < 127) {
  62                                 *cp++ = c;
  63                         } else if (!c) {
  64                                 *cp++ = '"';
  65                                 *cp++ = ' ';
  66                                 last_start = cp;
  67                         } else {
  68                                 *cp++ = '\\';
  69                                 *cp++ = (c >> 6) + '0';
  70                                 *cp++ = ((c >> 3) & 7) + '0';
  71                                 *cp++ = (c & 7) + '0';
  72                         }
  73                         if (c)
  74                                 continue;
  75                         if (argv_count) {
  76                                 if (--argv_count == 0) {
  77                                         if (truncated) {
  78                                                 cp = last_start;
  79                                                 memmove(cp, "... ", 4);
  80                                                 cp += 4;
  81                                         }
  82                                         memmove(cp, "} envp[]={ ", 11);
  83                                         cp += 11;
  84                                         last_start = cp;
  85                                         truncated = false;
  86                                 }
  87                         } else if (envp_count) {
  88                                 if (--envp_count == 0) {
  89                                         if (truncated) {
  90                                                 cp = last_start;
  91                                                 memmove(cp, "... ", 4);
  92                                                 cp += 4;
  93                                         }
  94                                 }
  95                         }
  96                         if (!argv_count && !envp_count)
  97                                 break;
  98                 }
  99                 offset = 0;
 100         }
 101         *cp++ = '}';
 102         *cp = '\0';
 103         return buffer;
 104 out:
 105         snprintf(buffer, tomoyo_buffer_len - 1,
 106                  "argv[]={ ... } envp[]= { ... }");
 107         return buffer;
 108 }
 109
 110 /**
 111  * tomoyo_filetype - Get string representation of file type.
 112  *
 113  * @mode: Mode value for stat().
 114  *
 115  * Returns file type string.
 116  */
 117 static inline const char *tomoyo_filetype(const mode_t mode)
 118 {
 119         switch (mode & S_IFMT) {
 120         case S_IFREG:
 121         case 0:
 122                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
 123         case S_IFDIR:
 124                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
 125         case S_IFLNK:
 126                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
 127         case S_IFIFO:
 128                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
 129         case S_IFSOCK:
 130                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
 131         case S_IFBLK:
 132                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
 133         case S_IFCHR:
 134                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
 135         }
 136         return "unknown"; /* This should not happen. */
 137 }
 138
 139 /**
 140  * tomoyo_print_header - Get header line of audit log.
 141  *
 142  * @r: Pointer to "struct tomoyo_request_info".
 143  *
 144  * Returns string representation.
 145  *
 146  * This function uses kmalloc(), so caller must kfree() if this function
 147  * didn't return NULL.
 148  */
 149 static char *tomoyo_print_header(struct tomoyo_request_info *r)
 150 {
 151         struct tomoyo_time stamp;
 152         const pid_t gpid = task_pid_nr(current);
 153         struct tomoyo_obj_info *obj = r->obj;
 154         static const int tomoyo_buffer_len = 4096;
 155         char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
 156         int pos;
 157         u8 i;
 158         if (!buffer)
 159                 return NULL;
 160         {
 161                 struct timeval tv;
 162                 do_gettimeofday(&tv);
 163                 tomoyo_convert_time(tv.tv_sec, &stamp);
 164         }
 165         pos = snprintf(buffer, tomoyo_buffer_len - 1,
 166                        "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
 167                        "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
 168                        "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
 169                        "fsuid=%u fsgid=%u }", stamp.year, stamp.month,
 170                        stamp.day, stamp.hour, stamp.min, stamp.sec, r->profile,
 171                        tomoyo_mode[r->mode], tomoyo_yesno(r->granted), gpid,
 172                        tomoyo_sys_getpid(), tomoyo_sys_getppid(),
 173                        current_uid(), current_gid(), current_euid(),
 174                        current_egid(), current_suid(), current_sgid(),
 175                        current_fsuid(), current_fsgid());
 176         if (!obj)
 177                 goto no_obj_info;
 178         if (!obj->validate_done) {
 179                 tomoyo_get_attributes(obj);
 180                 obj->validate_done = true;
 181         }
 182         for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
 183                 struct tomoyo_mini_stat *stat;
 184                 unsigned int dev;
 185                 mode_t mode;
 186                 if (!obj->stat_valid[i])
 187                         continue;
 188                 stat = &obj->stat[i];
 189                 dev = stat->dev;
 190                 mode = stat->mode;
 191                 if (i & 1) {
 192                         pos += snprintf(buffer + pos,
 193                                         tomoyo_buffer_len - 1 - pos,
 194                                         " path%u.parent={ uid=%u gid=%u "
 195                                         "ino=%lu perm=0%o }", (i >> 1) + 1,
 196                                         stat->uid, stat->gid, (unsigned long)
 197                                         stat->ino, stat->mode & S_IALLUGO);
 198                         continue;
 199                 }
 200                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 201                                 " path%u={ uid=%u gid=%u ino=%lu major=%u"
 202                                 " minor=%u perm=0%o type=%s", (i >> 1) + 1,
 203                                 stat->uid, stat->gid, (unsigned long)
 204                                 stat->ino, MAJOR(dev), MINOR(dev),
 205                                 mode & S_IALLUGO, tomoyo_filetype(mode));
 206                 if (S_ISCHR(mode) || S_ISBLK(mode)) {
 207                         dev = stat->rdev;
 208                         pos += snprintf(buffer + pos,
 209                                         tomoyo_buffer_len - 1 - pos,
 210                                         " dev_major=%u dev_minor=%u",
 211                                         MAJOR(dev), MINOR(dev));
 212                 }
 213                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 214                                 " }");
 215         }
 216 no_obj_info:
 217         if (pos < tomoyo_buffer_len - 1)
 218                 return buffer;
 219         kfree(buffer);
 220         return NULL;
 221 }
 222
 223 /**
 224  * tomoyo_init_log - Allocate buffer for audit logs.
 225  *
 226  * @r:    Pointer to "struct tomoyo_request_info".
 227  * @len:  Buffer size needed for @fmt and @args.
 228  * @fmt:  The printf()'s format string.
 229  * @args: va_list structure for @fmt.
 230  *
 231  * Returns pointer to allocated memory.
 232  *
 233  * This function uses kzalloc(), so caller must kfree() if this function
 234  * didn't return NULL.
 235  */
 236 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
 237                       va_list args)
 238 {
 239         char *buf = NULL;
 240         char *bprm_info = NULL;
 241         const char *header = NULL;
 242         char *realpath = NULL;
 243         const char *symlink = NULL;
 244         int pos;
 245         const char *domainname = r->domain->domainname->name;
 246         header = tomoyo_print_header(r);
 247         if (!header)
 248                 return NULL;
 249         /* +10 is for '\n' etc. and '\0'. */
 250         len += strlen(domainname) + strlen(header) + 10;
 251         if (r->ee) {
 252                 struct file *file = r->ee->bprm->file;
 253                 realpath = tomoyo_realpath_from_path(&file->f_path);
 254                 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
 255                 if (!realpath || !bprm_info)
 256                         goto out;
 257                 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
 258                 len += strlen(realpath) + 80 + strlen(bprm_info);
 259         } else if (r->obj && r->obj->symlink_target) {
 260                 symlink = r->obj->symlink_target->name;
 261                 /* +18 is for " symlink.target=\"%s\"" */
 262                 len += 18 + strlen(symlink);
 263         }
 264         len = tomoyo_round2(len);
 265         buf = kzalloc(len, GFP_NOFS);
 266         if (!buf)
 267                 goto out;
 268         len--;
 269         pos = snprintf(buf, len, "%s", header);
 270         if (realpath) {
 271                 struct linux_binprm *bprm = r->ee->bprm;
 272                 pos += snprintf(buf + pos, len - pos,
 273                                 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
 274                                 realpath, bprm->argc, bprm->envc, bprm_info);
 275         } else if (symlink)
 276                 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
 277                                 symlink);
 278         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
 279         vsnprintf(buf + pos, len - pos, fmt, args);
 280 out:
 281         kfree(realpath);
 282         kfree(bprm_info);
 283         kfree(header);
 284         return buf;
 285 }
 286
 287 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
 288 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
 289
 290 /* Structure for audit log. */
 291 struct tomoyo_log {
 292         struct list_head list;
 293         char *log;
 294         int size;
 295 };
 296
 297 /* The list for "struct tomoyo_log". */
 298 static LIST_HEAD(tomoyo_log);
 299
 300 /* Lock for "struct list_head tomoyo_log". */
 301 static DEFINE_SPINLOCK(tomoyo_log_lock);
 302
 303 /* Length of "stuct list_head tomoyo_log". */
 304 static unsigned int tomoyo_log_count;
 305
 306 /**
 307  * tomoyo_get_audit - Get audit mode.
 308  *
 309  * @ns:          Pointer to "struct tomoyo_policy_namespace".
 310  * @profile:     Profile number.
 311  * @index:       Index number of functionality.
 312  * @is_granted:  True if granted log, false otherwise.
 313  *
 314  * Returns true if this request should be audited, false otherwise.
 315  */
 316 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
 317                              const u8 profile, const u8 index,
 318                              const bool is_granted)
 319 {
 320         u8 mode;
 321         const u8 category = tomoyo_index2category[index] +
 322                 TOMOYO_MAX_MAC_INDEX;
 323         struct tomoyo_profile *p;
 324         if (!tomoyo_policy_loaded)
 325                 return false;
 326         p = tomoyo_profile(ns, profile);
 327         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
 328                 return false;
 329         mode = p->config[index];
 330         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 331                 mode = p->config[category];
 332         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 333                 mode = p->default_config;
 334         if (is_granted)
 335                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
 336         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
 337 }
 338
 339 /**
 340  * tomoyo_write_log2 - Write an audit log.
 341  *
 342  * @r:    Pointer to "struct tomoyo_request_info".
 343  * @len:  Buffer size needed for @fmt and @args.
 344  * @fmt:  The printf()'s format string.
 345  * @args: va_list structure for @fmt.
 346  *
 347  * Returns nothing.
 348  */
 349 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
 350                        va_list args)
 351 {
 352         char *buf;
 353         struct tomoyo_log *entry;
 354         bool quota_exceeded = false;
 355         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type, r->granted))
 356                 goto out;
 357         buf = tomoyo_init_log(r, len, fmt, args);
 358         if (!buf)
 359                 goto out;
 360         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 361         if (!entry) {
 362                 kfree(buf);
 363                 goto out;
 364         }
 365         entry->log = buf;
 366         len = tomoyo_round2(strlen(buf) + 1);
 367         /*
 368          * The entry->size is used for memory quota checks.
 369          * Don't go beyond strlen(entry->log).
 370          */
 371         entry->size = len + tomoyo_round2(sizeof(*entry));
 372         spin_lock(&tomoyo_log_lock);
 373         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
 374             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
 375             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
 376                 quota_exceeded = true;
 377         } else {
 378                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
 379                 list_add_tail(&entry->list, &tomoyo_log);
 380                 tomoyo_log_count++;
 381         }
 382         spin_unlock(&tomoyo_log_lock);
 383         if (quota_exceeded) {
 384                 kfree(buf);
 385                 kfree(entry);
 386                 goto out;
 387         }
 388         wake_up(&tomoyo_log_wait);
 389 out:
 390         return;
 391 }
 392
 393 /**
 394  * tomoyo_write_log - Write an audit log.
 395  *
 396  * @r:   Pointer to "struct tomoyo_request_info".
 397  * @fmt: The printf()'s format string, followed by parameters.
 398  *
 399  * Returns nothing.
 400  */
 401 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 402 {
 403         va_list args;
 404         int len;
 405         va_start(args, fmt);
 406         len = vsnprintf((char *) &len, 1, fmt, args) + 1;
 407         va_end(args);
 408         va_start(args, fmt);
 409         tomoyo_write_log2(r, len, fmt, args);
 410         va_end(args);
 411 }
 412
 413 /**
 414  * tomoyo_read_log - Read an audit log.
 415  *
 416  * @head: Pointer to "struct tomoyo_io_buffer".
 417  *
 418  * Returns nothing.
 419  */
 420 void tomoyo_read_log(struct tomoyo_io_buffer *head)
 421 {
 422         struct tomoyo_log *ptr = NULL;
 423         if (head->r.w_pos)
 424                 return;
 425         kfree(head->read_buf);
 426         head->read_buf = NULL;
 427         spin_lock(&tomoyo_log_lock);
 428         if (!list_empty(&tomoyo_log)) {
 429                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
 430                 list_del(&ptr->list);
 431                 tomoyo_log_count--;
 432                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
 433         }
 434         spin_unlock(&tomoyo_log_lock);
 435         if (ptr) {
 436                 head->read_buf = ptr->log;
 437                 head->r.w[head->r.w_pos++] = head->read_buf;
 438                 kfree(ptr);
 439         }
 440 }
 441
 442 /**
 443  * tomoyo_poll_log - Wait for an audit log.
 444  *
 445  * @file: Pointer to "struct file".
 446  * @wait: Pointer to "poll_table".
 447  *
 448  * Returns POLLIN | POLLRDNORM when ready to read an audit log.
 449  */
 450 int tomoyo_poll_log(struct file *file, poll_table *wait)
 451 {
 452         if (tomoyo_log_count)
 453                 return POLLIN | POLLRDNORM;
 454         poll_wait(file, &tomoyo_log_wait, wait);
 455         if (tomoyo_log_count)
 456                 return POLLIN | POLLRDNORM;
 457         return 0;
 458 }