linux/security/tomoyo/audit.c
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   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 */
  21static 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;
 102out:
 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 */
 115static 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 */
 147static 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                       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                if (!obj->stat_valid[i])
 190                        continue;
 191                stat = &obj->stat[i];
 192                dev = stat->dev;
 193                mode = stat->mode;
 194                if (i & 1) {
 195                        pos += snprintf(buffer + pos,
 196                                        tomoyo_buffer_len - 1 - pos,
 197                                        " path%u.parent={ uid=%u gid=%u "
 198                                        "ino=%lu perm=0%o }", (i >> 1) + 1,
 199                                        from_kuid(&init_user_ns, stat->uid),
 200                                        from_kgid(&init_user_ns, stat->gid),
 201                                        (unsigned long)stat->ino,
 202                                        stat->mode & S_IALLUGO);
 203                        continue;
 204                }
 205                pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 206                                " path%u={ uid=%u gid=%u ino=%lu major=%u"
 207                                " minor=%u perm=0%o type=%s", (i >> 1) + 1,
 208                                from_kuid(&init_user_ns, stat->uid),
 209                                from_kgid(&init_user_ns, stat->gid),
 210                                (unsigned long)stat->ino,
 211                                MAJOR(dev), MINOR(dev),
 212                                mode & S_IALLUGO, tomoyo_filetype(mode));
 213                if (S_ISCHR(mode) || S_ISBLK(mode)) {
 214                        dev = stat->rdev;
 215                        pos += snprintf(buffer + pos,
 216                                        tomoyo_buffer_len - 1 - pos,
 217                                        " dev_major=%u dev_minor=%u",
 218                                        MAJOR(dev), MINOR(dev));
 219                }
 220                pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 221                                " }");
 222        }
 223no_obj_info:
 224        if (pos < tomoyo_buffer_len - 1)
 225                return buffer;
 226        kfree(buffer);
 227        return NULL;
 228}
 229
 230/**
 231 * tomoyo_init_log - Allocate buffer for audit logs.
 232 *
 233 * @r:    Pointer to "struct tomoyo_request_info".
 234 * @len:  Buffer size needed for @fmt and @args.
 235 * @fmt:  The printf()'s format string.
 236 * @args: va_list structure for @fmt.
 237 *
 238 * Returns pointer to allocated memory.
 239 *
 240 * This function uses kzalloc(), so caller must kfree() if this function
 241 * didn't return NULL.
 242 */
 243char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
 244                      va_list args)
 245{
 246        char *buf = NULL;
 247        char *bprm_info = NULL;
 248        const char *header = NULL;
 249        char *realpath = NULL;
 250        const char *symlink = NULL;
 251        int pos;
 252        const char *domainname = r->domain->domainname->name;
 253        header = tomoyo_print_header(r);
 254        if (!header)
 255                return NULL;
 256        /* +10 is for '\n' etc. and '\0'. */
 257        len += strlen(domainname) + strlen(header) + 10;
 258        if (r->ee) {
 259                struct file *file = r->ee->bprm->file;
 260                realpath = tomoyo_realpath_from_path(&file->f_path);
 261                bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
 262                if (!realpath || !bprm_info)
 263                        goto out;
 264                /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
 265                len += strlen(realpath) + 80 + strlen(bprm_info);
 266        } else if (r->obj && r->obj->symlink_target) {
 267                symlink = r->obj->symlink_target->name;
 268                /* +18 is for " symlink.target=\"%s\"" */
 269                len += 18 + strlen(symlink);
 270        }
 271        len = tomoyo_round2(len);
 272        buf = kzalloc(len, GFP_NOFS);
 273        if (!buf)
 274                goto out;
 275        len--;
 276        pos = snprintf(buf, len, "%s", header);
 277        if (realpath) {
 278                struct linux_binprm *bprm = r->ee->bprm;
 279                pos += snprintf(buf + pos, len - pos,
 280                                " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
 281                                realpath, bprm->argc, bprm->envc, bprm_info);
 282        } else if (symlink)
 283                pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
 284                                symlink);
 285        pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
 286        vsnprintf(buf + pos, len - pos, fmt, args);
 287out:
 288        kfree(realpath);
 289        kfree(bprm_info);
 290        kfree(header);
 291        return buf;
 292}
 293
 294/* Wait queue for /sys/kernel/security/tomoyo/audit. */
 295static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
 296
 297/* Structure for audit log. */
 298struct tomoyo_log {
 299        struct list_head list;
 300        char *log;
 301        int size;
 302};
 303
 304/* The list for "struct tomoyo_log". */
 305static LIST_HEAD(tomoyo_log);
 306
 307/* Lock for "struct list_head tomoyo_log". */
 308static DEFINE_SPINLOCK(tomoyo_log_lock);
 309
 310/* Length of "stuct list_head tomoyo_log". */
 311static unsigned int tomoyo_log_count;
 312
 313/**
 314 * tomoyo_get_audit - Get audit mode.
 315 *
 316 * @ns:          Pointer to "struct tomoyo_policy_namespace".
 317 * @profile:     Profile number.
 318 * @index:       Index number of functionality.
 319 * @is_granted:  True if granted log, false otherwise.
 320 *
 321 * Returns true if this request should be audited, false otherwise.
 322 */
 323static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
 324                             const u8 profile, const u8 index,
 325                             const struct tomoyo_acl_info *matched_acl,
 326                             const bool is_granted)
 327{
 328        u8 mode;
 329        const u8 category = tomoyo_index2category[index] +
 330                TOMOYO_MAX_MAC_INDEX;
 331        struct tomoyo_profile *p;
 332        if (!tomoyo_policy_loaded)
 333                return false;
 334        p = tomoyo_profile(ns, profile);
 335        if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
 336                return false;
 337        if (is_granted && matched_acl && matched_acl->cond &&
 338            matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
 339                return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
 340        mode = p->config[index];
 341        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 342                mode = p->config[category];
 343        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 344                mode = p->default_config;
 345        if (is_granted)
 346                return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
 347        return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
 348}
 349
 350/**
 351 * tomoyo_write_log2 - Write an audit log.
 352 *
 353 * @r:    Pointer to "struct tomoyo_request_info".
 354 * @len:  Buffer size needed for @fmt and @args.
 355 * @fmt:  The printf()'s format string.
 356 * @args: va_list structure for @fmt.
 357 *
 358 * Returns nothing.
 359 */
 360void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
 361                       va_list args)
 362{
 363        char *buf;
 364        struct tomoyo_log *entry;
 365        bool quota_exceeded = false;
 366        if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
 367                              r->matched_acl, r->granted))
 368                goto out;
 369        buf = tomoyo_init_log(r, len, fmt, args);
 370        if (!buf)
 371                goto out;
 372        entry = kzalloc(sizeof(*entry), GFP_NOFS);
 373        if (!entry) {
 374                kfree(buf);
 375                goto out;
 376        }
 377        entry->log = buf;
 378        len = tomoyo_round2(strlen(buf) + 1);
 379        /*
 380         * The entry->size is used for memory quota checks.
 381         * Don't go beyond strlen(entry->log).
 382         */
 383        entry->size = len + tomoyo_round2(sizeof(*entry));
 384        spin_lock(&tomoyo_log_lock);
 385        if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
 386            tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
 387            tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
 388                quota_exceeded = true;
 389        } else {
 390                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
 391                list_add_tail(&entry->list, &tomoyo_log);
 392                tomoyo_log_count++;
 393        }
 394        spin_unlock(&tomoyo_log_lock);
 395        if (quota_exceeded) {
 396                kfree(buf);
 397                kfree(entry);
 398                goto out;
 399        }
 400        wake_up(&tomoyo_log_wait);
 401out:
 402        return;
 403}
 404
 405/**
 406 * tomoyo_write_log - Write an audit log.
 407 *
 408 * @r:   Pointer to "struct tomoyo_request_info".
 409 * @fmt: The printf()'s format string, followed by parameters.
 410 *
 411 * Returns nothing.
 412 */
 413void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 414{
 415        va_list args;
 416        int len;
 417        va_start(args, fmt);
 418        len = vsnprintf((char *) &len, 1, fmt, args) + 1;
 419        va_end(args);
 420        va_start(args, fmt);
 421        tomoyo_write_log2(r, len, fmt, args);
 422        va_end(args);
 423}
 424
 425/**
 426 * tomoyo_read_log - Read an audit log.
 427 *
 428 * @head: Pointer to "struct tomoyo_io_buffer".
 429 *
 430 * Returns nothing.
 431 */
 432void tomoyo_read_log(struct tomoyo_io_buffer *head)
 433{
 434        struct tomoyo_log *ptr = NULL;
 435        if (head->r.w_pos)
 436                return;
 437        kfree(head->read_buf);
 438        head->read_buf = NULL;
 439        spin_lock(&tomoyo_log_lock);
 440        if (!list_empty(&tomoyo_log)) {
 441                ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
 442                list_del(&ptr->list);
 443                tomoyo_log_count--;
 444                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
 445        }
 446        spin_unlock(&tomoyo_log_lock);
 447        if (ptr) {
 448                head->read_buf = ptr->log;
 449                head->r.w[head->r.w_pos++] = head->read_buf;
 450                kfree(ptr);
 451        }
 452}
 453
 454/**
 455 * tomoyo_poll_log - Wait for an audit log.
 456 *
 457 * @file: Pointer to "struct file".
 458 * @wait: Pointer to "poll_table". Maybe NULL.
 459 *
 460 * Returns POLLIN | POLLRDNORM when ready to read an audit log.
 461 */
 462unsigned int tomoyo_poll_log(struct file *file, poll_table *wait)
 463{
 464        if (tomoyo_log_count)
 465                return POLLIN | POLLRDNORM;
 466        poll_wait(file, &tomoyo_log_wait, wait);
 467        if (tomoyo_log_count)
 468                return POLLIN | POLLRDNORM;
 469        return 0;
 470}
 471
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