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) + '';
71 *cp++ = ((c >> 3) & 7) + '';
72 *cp++ = (c & 7) + '';
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 }
480
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.