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
  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
  54                         if (cp == last_start)
  55                                 *cp++ = '"';
  56                         if (cp >= buffer + tomoyo_buffer_len - 32) {
  57                                 /* Reserve some room for "..." string. */
  58                                 truncated = true;
  59                         } else if (c == '\\') {
  60                                 *cp++ = '\\';
  61                                 *cp++ = '\\';
  62                         } else if (c > ' ' && c < 127) {
  63                                 *cp++ = c;
  64                         } else if (!c) {
  65                                 *cp++ = '"';
  66                                 *cp++ = ' ';
  67                                 last_start = cp;
  68                         } else {
  69                                 *cp++ = '\\';
  70                                 *cp++ = (c >> 6) + '0';
  71                                 *cp++ = ((c >> 3) & 7) + '0';
  72                                 *cp++ = (c & 7) + '0';
  73                         }
  74                         if (c)
  75                                 continue;
  76                         if (argv_count) {
  77                                 if (--argv_count == 0) {
  78                                         if (truncated) {
  79                                                 cp = last_start;
  80                                                 memmove(cp, "... ", 4);
  81                                                 cp += 4;
  82                                         }
  83                                         memmove(cp, "} envp[]={ ", 11);
  84                                         cp += 11;
  85                                         last_start = cp;
  86                                         truncated = false;
  87                                 }
  88                         } else if (envp_count) {
  89                                 if (--envp_count == 0) {
  90                                         if (truncated) {
  91                                                 cp = last_start;
  92                                                 memmove(cp, "... ", 4);
  93                                                 cp += 4;
  94                                         }
  95                                 }
  96                         }
  97                         if (!argv_count && !envp_count)
  98                                 break;
  99                 }
 100                 offset = 0;
 101         }
 102         *cp++ = '}';
 103         *cp = '\0';
 104         return buffer;
 105 out:
 106         snprintf(buffer, tomoyo_buffer_len - 1,
 107                  "argv[]={ ... } envp[]= { ... }");
 108         return buffer;
 109 }
 110
 111 /**
 112  * tomoyo_filetype - Get string representation of file type.
 113  *
 114  * @mode: Mode value for stat().
 115  *
 116  * Returns file type string.
 117  */
 118 static inline const char *tomoyo_filetype(const umode_t mode)
 119 {
 120         switch (mode & S_IFMT) {
 121         case S_IFREG:
 122         case 0:
 123                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
 124         case S_IFDIR:
 125                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
 126         case S_IFLNK:
 127                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
 128         case S_IFIFO:
 129                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
 130         case S_IFSOCK:
 131                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
 132         case S_IFBLK:
 133                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
 134         case S_IFCHR:
 135                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
 136         }
 137         return "unknown"; /* This should not happen. */
 138 }
 139
 140 /**
 141  * tomoyo_print_header - Get header line of audit log.
 142  *
 143  * @r: Pointer to "struct tomoyo_request_info".
 144  *
 145  * Returns string representation.
 146  *
 147  * This function uses kmalloc(), so caller must kfree() if this function
 148  * didn't return NULL.
 149  */
 150 static char *tomoyo_print_header(struct tomoyo_request_info *r)
 151 {
 152         struct tomoyo_time stamp;
 153         const pid_t gpid = task_pid_nr(current);
 154         struct tomoyo_obj_info *obj = r->obj;
 155         static const int tomoyo_buffer_len = 4096;
 156         char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
 157         int pos;
 158         u8 i;
 159
 160         if (!buffer)
 161                 return NULL;
 162
 163         tomoyo_convert_time(ktime_get_real_seconds(), &stamp);
 164
 165         pos = snprintf(buffer, tomoyo_buffer_len - 1,
 166                        "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s granted=%s (global-pid=%u) task={ pid=%u ppid=%u uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u fsuid=%u fsgid=%u }",
 167                        stamp.year, stamp.month, stamp.day, stamp.hour,
 168                        stamp.min, stamp.sec, r->profile, tomoyo_mode[r->mode],
 169                        str_yes_no(r->granted), gpid, tomoyo_sys_getpid(),
 170                        tomoyo_sys_getppid(),
 171                        from_kuid(&init_user_ns, current_uid()),
 172                        from_kgid(&init_user_ns, current_gid()),
 173                        from_kuid(&init_user_ns, current_euid()),
 174                        from_kgid(&init_user_ns, current_egid()),
 175                        from_kuid(&init_user_ns, current_suid()),
 176                        from_kgid(&init_user_ns, current_sgid()),
 177                        from_kuid(&init_user_ns, current_fsuid()),
 178                        from_kgid(&init_user_ns, current_fsgid()));
 179         if (!obj)
 180                 goto no_obj_info;
 181         if (!obj->validate_done) {
 182                 tomoyo_get_attributes(obj);
 183                 obj->validate_done = true;
 184         }
 185         for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
 186                 struct tomoyo_mini_stat *stat;
 187                 unsigned int dev;
 188                 umode_t mode;
 189
 190                 if (!obj->stat_valid[i])
 191                         continue;
 192                 stat = &obj->stat[i];
 193                 dev = stat->dev;
 194                 mode = stat->mode;
 195                 if (i & 1) {
 196                         pos += snprintf(buffer + pos,
 197                                         tomoyo_buffer_len - 1 - pos,
 198                                         " path%u.parent={ uid=%u gid=%u ino=%lu perm=0%o }",
 199                                         (i >> 1) + 1,
 200                                         from_kuid(&init_user_ns, stat->uid),
 201                                         from_kgid(&init_user_ns, stat->gid),
 202                                         (unsigned long)stat->ino,
 203                                         stat->mode & S_IALLUGO);
 204                         continue;
 205                 }
 206                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 207                                 " path%u={ uid=%u gid=%u ino=%lu major=%u minor=%u perm=0%o type=%s",
 208                                 (i >> 1) + 1,
 209                                 from_kuid(&init_user_ns, stat->uid),
 210                                 from_kgid(&init_user_ns, stat->gid),
 211                                 (unsigned long)stat->ino,
 212                                 MAJOR(dev), MINOR(dev),
 213                                 mode & S_IALLUGO, tomoyo_filetype(mode));
 214                 if (S_ISCHR(mode) || S_ISBLK(mode)) {
 215                         dev = stat->rdev;
 216                         pos += snprintf(buffer + pos,
 217                                         tomoyo_buffer_len - 1 - pos,
 218                                         " dev_major=%u dev_minor=%u",
 219                                         MAJOR(dev), MINOR(dev));
 220                 }
 221                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 222                                 " }");
 223         }
 224 no_obj_info:
 225         if (pos < tomoyo_buffer_len - 1)
 226                 return buffer;
 227         kfree(buffer);
 228         return NULL;
 229 }
 230
 231 /**
 232  * tomoyo_init_log - Allocate buffer for audit logs.
 233  *
 234  * @r:    Pointer to "struct tomoyo_request_info".
 235  * @len:  Buffer size needed for @fmt and @args.
 236  * @fmt:  The printf()'s format string.
 237  * @args: va_list structure for @fmt.
 238  *
 239  * Returns pointer to allocated memory.
 240  *
 241  * This function uses kzalloc(), so caller must kfree() if this function
 242  * didn't return NULL.
 243  */
 244 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
 245                       va_list args)
 246 {
 247         char *buf = NULL;
 248         char *bprm_info = NULL;
 249         const char *header = NULL;
 250         char *realpath = NULL;
 251         const char *symlink = NULL;
 252         int pos;
 253         const char *domainname = r->domain->domainname->name;
 254
 255         header = tomoyo_print_header(r);
 256         if (!header)
 257                 return NULL;
 258         /* +10 is for '\n' etc. and '\0'. */
 259         len += strlen(domainname) + strlen(header) + 10;
 260         if (r->ee) {
 261                 struct file *file = r->ee->bprm->file;
 262
 263                 realpath = tomoyo_realpath_from_path(&file->f_path);
 264                 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
 265                 if (!realpath || !bprm_info)
 266                         goto out;
 267                 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
 268                 len += strlen(realpath) + 80 + strlen(bprm_info);
 269         } else if (r->obj && r->obj->symlink_target) {
 270                 symlink = r->obj->symlink_target->name;
 271                 /* +18 is for " symlink.target=\"%s\"" */
 272                 len += 18 + strlen(symlink);
 273         }
 274         len = kmalloc_size_roundup(len);
 275         buf = kzalloc(len, GFP_NOFS);
 276         if (!buf)
 277                 goto out;
 278         len--;
 279         pos = snprintf(buf, len, "%s", header);
 280         if (realpath) {
 281                 struct linux_binprm *bprm = r->ee->bprm;
 282
 283                 pos += snprintf(buf + pos, len - pos,
 284                                 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
 285                                 realpath, bprm->argc, bprm->envc, bprm_info);
 286         } else if (symlink)
 287                 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
 288                                 symlink);
 289         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
 290         vsnprintf(buf + pos, len - pos, fmt, args);
 291 out:
 292         kfree(realpath);
 293         kfree(bprm_info);
 294         kfree(header);
 295         return buf;
 296 }
 297
 298 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
 299 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
 300
 301 /* Structure for audit log. */
 302 struct tomoyo_log {
 303         struct list_head list;
 304         char *log;
 305         int size;
 306 };
 307
 308 /* The list for "struct tomoyo_log". */
 309 static LIST_HEAD(tomoyo_log);
 310
 311 /* Lock for "struct list_head tomoyo_log". */
 312 static DEFINE_SPINLOCK(tomoyo_log_lock);
 313
 314 /* Length of "struct list_head tomoyo_log". */
 315 static unsigned int tomoyo_log_count;
 316
 317 /**
 318  * tomoyo_get_audit - Get audit mode.
 319  *
 320  * @ns:          Pointer to "struct tomoyo_policy_namespace".
 321  * @profile:     Profile number.
 322  * @index:       Index number of functionality.
 323  * @matched_acl: Pointer to "struct tomoyo_acl_info".
 324  * @is_granted:  True if granted log, false otherwise.
 325  *
 326  * Returns true if this request should be audited, false otherwise.
 327  */
 328 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
 329                              const u8 profile, const u8 index,
 330                              const struct tomoyo_acl_info *matched_acl,
 331                              const bool is_granted)
 332 {
 333         u8 mode;
 334         const u8 category = tomoyo_index2category[index] +
 335                 TOMOYO_MAX_MAC_INDEX;
 336         struct tomoyo_profile *p;
 337
 338         if (!tomoyo_policy_loaded)
 339                 return false;
 340         p = tomoyo_profile(ns, profile);
 341         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
 342                 return false;
 343         if (is_granted && matched_acl && matched_acl->cond &&
 344             matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
 345                 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
 346         mode = p->config[index];
 347         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 348                 mode = p->config[category];
 349         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 350                 mode = p->default_config;
 351         if (is_granted)
 352                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
 353         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
 354 }
 355
 356 /**
 357  * tomoyo_write_log2 - Write an audit log.
 358  *
 359  * @r:    Pointer to "struct tomoyo_request_info".
 360  * @len:  Buffer size needed for @fmt and @args.
 361  * @fmt:  The printf()'s format string.
 362  * @args: va_list structure for @fmt.
 363  *
 364  * Returns nothing.
 365  */
 366 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
 367                        va_list args)
 368 {
 369         char *buf;
 370         struct tomoyo_log *entry;
 371         bool quota_exceeded = false;
 372
 373         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
 374                               r->matched_acl, r->granted))
 375                 goto out;
 376         buf = tomoyo_init_log(r, len, fmt, args);
 377         if (!buf)
 378                 goto out;
 379         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 380         if (!entry) {
 381                 kfree(buf);
 382                 goto out;
 383         }
 384         entry->log = buf;
 385         len = kmalloc_size_roundup(strlen(buf) + 1);
 386         /*
 387          * The entry->size is used for memory quota checks.
 388          * Don't go beyond strlen(entry->log).
 389          */
 390         entry->size = len + kmalloc_size_roundup(sizeof(*entry));
 391         spin_lock(&tomoyo_log_lock);
 392         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
 393             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
 394             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
 395                 quota_exceeded = true;
 396         } else {
 397                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
 398                 list_add_tail(&entry->list, &tomoyo_log);
 399                 tomoyo_log_count++;
 400         }
 401         spin_unlock(&tomoyo_log_lock);
 402         if (quota_exceeded) {
 403                 kfree(buf);
 404                 kfree(entry);
 405                 goto out;
 406         }
 407         wake_up(&tomoyo_log_wait);
 408 out:
 409         return;
 410 }
 411
 412 /**
 413  * tomoyo_write_log - Write an audit log.
 414  *
 415  * @r:   Pointer to "struct tomoyo_request_info".
 416  * @fmt: The printf()'s format string, followed by parameters.
 417  *
 418  * Returns nothing.
 419  */
 420 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 421 {
 422         va_list args;
 423         int len;
 424
 425         va_start(args, fmt);
 426         len = vsnprintf(NULL, 0, fmt, args) + 1;
 427         va_end(args);
 428         va_start(args, fmt);
 429         tomoyo_write_log2(r, len, fmt, args);
 430         va_end(args);
 431 }
 432
 433 /**
 434  * tomoyo_read_log - Read an audit log.
 435  *
 436  * @head: Pointer to "struct tomoyo_io_buffer".
 437  *
 438  * Returns nothing.
 439  */
 440 void tomoyo_read_log(struct tomoyo_io_buffer *head)
 441 {
 442         struct tomoyo_log *ptr = NULL;
 443
 444         if (head->r.w_pos)
 445                 return;
 446         kfree(head->read_buf);
 447         head->read_buf = NULL;
 448         spin_lock(&tomoyo_log_lock);
 449         if (!list_empty(&tomoyo_log)) {
 450                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
 451                 list_del(&ptr->list);
 452                 tomoyo_log_count--;
 453                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
 454         }
 455         spin_unlock(&tomoyo_log_lock);
 456         if (ptr) {
 457                 head->read_buf = ptr->log;
 458                 head->r.w[head->r.w_pos++] = head->read_buf;
 459                 kfree(ptr);
 460         }
 461 }
 462
 463 /**
 464  * tomoyo_poll_log - Wait for an audit log.
 465  *
 466  * @file: Pointer to "struct file".
 467  * @wait: Pointer to "poll_table". Maybe NULL.
 468  *
 469  * Returns EPOLLIN | EPOLLRDNORM when ready to read an audit log.
 470  */
 471 __poll_t tomoyo_poll_log(struct file *file, poll_table *wait)
 472 {
 473         if (tomoyo_log_count)
 474                 return EPOLLIN | EPOLLRDNORM;
 475         poll_wait(file, &tomoyo_log_wait, wait);
 476         if (tomoyo_log_count)
 477                 return EPOLLIN | EPOLLRDNORM;
 478         return 0;
 479 }