linux/security/tomoyo/audit.c
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   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 */
  22static 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;
 105out:
 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 */
 118static 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 */
 150static 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                       tomoyo_yesno(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        }
 224no_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 */
 244char *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 = tomoyo_round2(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);
 291out:
 292        kfree(realpath);
 293        kfree(bprm_info);
 294        kfree(header);
 295        return buf;
 296}
 297
 298/* Wait queue for /sys/kernel/security/tomoyo/audit. */
 299static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
 300
 301/* Structure for audit log. */
 302struct tomoyo_log {
 303        struct list_head list;
 304        char *log;
 305        int size;
 306};
 307
 308/* The list for "struct tomoyo_log". */
 309static LIST_HEAD(tomoyo_log);
 310
 311/* Lock for "struct list_head tomoyo_log". */
 312static DEFINE_SPINLOCK(tomoyo_log_lock);
 313
 314/* Length of "struct list_head tomoyo_log". */
 315static 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 * @is_granted:  True if granted log, false otherwise.
 324 *
 325 * Returns true if this request should be audited, false otherwise.
 326 */
 327static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
 328                             const u8 profile, const u8 index,
 329                             const struct tomoyo_acl_info *matched_acl,
 330                             const bool is_granted)
 331{
 332        u8 mode;
 333        const u8 category = tomoyo_index2category[index] +
 334                TOMOYO_MAX_MAC_INDEX;
 335        struct tomoyo_profile *p;
 336
 337        if (!tomoyo_policy_loaded)
 338                return false;
 339        p = tomoyo_profile(ns, profile);
 340        if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
 341                return false;
 342        if (is_granted && matched_acl && matched_acl->cond &&
 343            matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
 344                return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
 345        mode = p->config[index];
 346        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 347                mode = p->config[category];
 348        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 349                mode = p->default_config;
 350        if (is_granted)
 351                return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
 352        return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
 353}
 354
 355/**
 356 * tomoyo_write_log2 - Write an audit log.
 357 *
 358 * @r:    Pointer to "struct tomoyo_request_info".
 359 * @len:  Buffer size needed for @fmt and @args.
 360 * @fmt:  The printf()'s format string.
 361 * @args: va_list structure for @fmt.
 362 *
 363 * Returns nothing.
 364 */
 365void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
 366                       va_list args)
 367{
 368        char *buf;
 369        struct tomoyo_log *entry;
 370        bool quota_exceeded = false;
 371
 372        if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
 373                              r->matched_acl, r->granted))
 374                goto out;
 375        buf = tomoyo_init_log(r, len, fmt, args);
 376        if (!buf)
 377                goto out;
 378        entry = kzalloc(sizeof(*entry), GFP_NOFS);
 379        if (!entry) {
 380                kfree(buf);
 381                goto out;
 382        }
 383        entry->log = buf;
 384        len = tomoyo_round2(strlen(buf) + 1);
 385        /*
 386         * The entry->size is used for memory quota checks.
 387         * Don't go beyond strlen(entry->log).
 388         */
 389        entry->size = len + tomoyo_round2(sizeof(*entry));
 390        spin_lock(&tomoyo_log_lock);
 391        if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
 392            tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
 393            tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
 394                quota_exceeded = true;
 395        } else {
 396                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
 397                list_add_tail(&entry->list, &tomoyo_log);
 398                tomoyo_log_count++;
 399        }
 400        spin_unlock(&tomoyo_log_lock);
 401        if (quota_exceeded) {
 402                kfree(buf);
 403                kfree(entry);
 404                goto out;
 405        }
 406        wake_up(&tomoyo_log_wait);
 407out:
 408        return;
 409}
 410
 411/**
 412 * tomoyo_write_log - Write an audit log.
 413 *
 414 * @r:   Pointer to "struct tomoyo_request_info".
 415 * @fmt: The printf()'s format string, followed by parameters.
 416 *
 417 * Returns nothing.
 418 */
 419void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 420{
 421        va_list args;
 422        int len;
 423
 424        va_start(args, fmt);
 425        len = vsnprintf((char *) &len, 1, fmt, args) + 1;
 426        va_end(args);
 427        va_start(args, fmt);
 428        tomoyo_write_log2(r, len, fmt, args);
 429        va_end(args);
 430}
 431
 432/**
 433 * tomoyo_read_log - Read an audit log.
 434 *
 435 * @head: Pointer to "struct tomoyo_io_buffer".
 436 *
 437 * Returns nothing.
 438 */
 439void tomoyo_read_log(struct tomoyo_io_buffer *head)
 440{
 441        struct tomoyo_log *ptr = NULL;
 442
 443        if (head->r.w_pos)
 444                return;
 445        kfree(head->read_buf);
 446        head->read_buf = NULL;
 447        spin_lock(&tomoyo_log_lock);
 448        if (!list_empty(&tomoyo_log)) {
 449                ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
 450                list_del(&ptr->list);
 451                tomoyo_log_count--;
 452                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
 453        }
 454        spin_unlock(&tomoyo_log_lock);
 455        if (ptr) {
 456                head->read_buf = ptr->log;
 457                head->r.w[head->r.w_pos++] = head->read_buf;
 458                kfree(ptr);
 459        }
 460}
 461
 462/**
 463 * tomoyo_poll_log - Wait for an audit log.
 464 *
 465 * @file: Pointer to "struct file".
 466 * @wait: Pointer to "poll_table". Maybe NULL.
 467 *
 468 * Returns EPOLLIN | EPOLLRDNORM when ready to read an audit log.
 469 */
 470__poll_t tomoyo_poll_log(struct file *file, poll_table *wait)
 471{
 472        if (tomoyo_log_count)
 473                return EPOLLIN | EPOLLRDNORM;
 474        poll_wait(file, &tomoyo_log_wait, wait);
 475        if (tomoyo_log_count)
 476                return EPOLLIN | EPOLLRDNORM;
 477        return 0;
 478}
 479