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 */
tomoyo_print_bprm(struct linux_binprm * bprm,struct tomoyo_page_dump * dump)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 */
tomoyo_filetype(const umode_t mode)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 */
tomoyo_print_header(struct tomoyo_request_info * r)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=%llu perm=0%o }",
199 (i >> 1) + 1,
200 from_kuid(&init_user_ns, stat->uid),
201 from_kgid(&init_user_ns, stat->gid),
202 stat->ino, 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=%llu major=%u minor=%u perm=0%o type=%s",
207 (i >> 1) + 1,
208 from_kuid(&init_user_ns, stat->uid),
209 from_kgid(&init_user_ns, stat->gid),
210 stat->ino, MAJOR(dev), MINOR(dev),
211 mode & S_IALLUGO, tomoyo_filetype(mode));
212 if (S_ISCHR(mode) || S_ISBLK(mode)) {
213 dev = stat->rdev;
214 pos += snprintf(buffer + pos,
215 tomoyo_buffer_len - 1 - pos,
216 " dev_major=%u dev_minor=%u",
217 MAJOR(dev), MINOR(dev));
218 }
219 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
220 " }");
221 }
222 no_obj_info:
223 if (pos < tomoyo_buffer_len - 1)
224 return buffer;
225 kfree(buffer);
226 return NULL;
227 }
228
229 /**
230 * tomoyo_init_log - Allocate buffer for audit logs.
231 *
232 * @r: Pointer to "struct tomoyo_request_info".
233 * @len: Buffer size needed for @fmt and @args.
234 * @fmt: The printf()'s format string.
235 * @args: va_list structure for @fmt.
236 *
237 * Returns pointer to allocated memory.
238 *
239 * This function uses kzalloc(), so caller must kfree() if this function
240 * didn't return NULL.
241 */
tomoyo_init_log(struct tomoyo_request_info * r,int len,const char * fmt,va_list args)242 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
243 va_list args)
244 {
245 char *buf = NULL;
246 char *bprm_info = NULL;
247 const char *header = NULL;
248 char *realpath = NULL;
249 const char *symlink = NULL;
250 int pos;
251 const char *domainname = r->domain->domainname->name;
252
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
261 realpath = tomoyo_realpath_from_path(&file->f_path);
262 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
263 if (!realpath || !bprm_info)
264 goto out;
265 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
266 len += strlen(realpath) + 80 + strlen(bprm_info);
267 } else if (r->obj && r->obj->symlink_target) {
268 symlink = r->obj->symlink_target->name;
269 /* +18 is for " symlink.target=\"%s\"" */
270 len += 18 + strlen(symlink);
271 }
272 len = kmalloc_size_roundup(len);
273 buf = kzalloc(len, GFP_NOFS);
274 if (!buf)
275 goto out;
276 len--;
277 pos = snprintf(buf, len, "%s", header);
278 if (realpath) {
279 struct linux_binprm *bprm = r->ee->bprm;
280
281 pos += snprintf(buf + pos, len - pos,
282 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
283 realpath, bprm->argc, bprm->envc, bprm_info);
284 } else if (symlink)
285 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
286 symlink);
287 pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
288 vsnprintf(buf + pos, len - pos, fmt, args);
289 out:
290 kfree(realpath);
291 kfree(bprm_info);
292 kfree(header);
293 return buf;
294 }
295
296 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
297 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
298
299 /* Structure for audit log. */
300 struct tomoyo_log {
301 struct list_head list;
302 char *log;
303 int size;
304 };
305
306 /* The list for "struct tomoyo_log". */
307 static LIST_HEAD(tomoyo_log);
308
309 /* Lock for "struct list_head tomoyo_log". */
310 static DEFINE_SPINLOCK(tomoyo_log_lock);
311
312 /* Length of "struct list_head tomoyo_log". */
313 static unsigned int tomoyo_log_count;
314
315 /**
316 * tomoyo_get_audit - Get audit mode.
317 *
318 * @ns: Pointer to "struct tomoyo_policy_namespace".
319 * @profile: Profile number.
320 * @index: Index number of functionality.
321 * @matched_acl: Pointer to "struct tomoyo_acl_info".
322 * @is_granted: True if granted log, false otherwise.
323 *
324 * Returns true if this request should be audited, false otherwise.
325 */
tomoyo_get_audit(const struct tomoyo_policy_namespace * ns,const u8 profile,const u8 index,const struct tomoyo_acl_info * matched_acl,const bool is_granted)326 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
327 const u8 profile, const u8 index,
328 const struct tomoyo_acl_info *matched_acl,
329 const bool is_granted)
330 {
331 u8 mode;
332 const u8 category = tomoyo_index2category[index] +
333 TOMOYO_MAX_MAC_INDEX;
334 struct tomoyo_profile *p;
335
336 if (!tomoyo_policy_loaded)
337 return false;
338 p = tomoyo_profile(ns, profile);
339 if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
340 return false;
341 if (is_granted && matched_acl && matched_acl->cond &&
342 matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
343 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
344 mode = p->config[index];
345 if (mode == TOMOYO_CONFIG_USE_DEFAULT)
346 mode = p->config[category];
347 if (mode == TOMOYO_CONFIG_USE_DEFAULT)
348 mode = p->default_config;
349 if (is_granted)
350 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
351 return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
352 }
353
354 /**
355 * tomoyo_write_log2 - Write an audit log.
356 *
357 * @r: Pointer to "struct tomoyo_request_info".
358 * @len: Buffer size needed for @fmt and @args.
359 * @fmt: The printf()'s format string.
360 * @args: va_list structure for @fmt.
361 *
362 * Returns nothing.
363 */
tomoyo_write_log2(struct tomoyo_request_info * r,int len,const char * fmt,va_list args)364 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
365 va_list args)
366 {
367 char *buf;
368 struct tomoyo_log *entry;
369 bool quota_exceeded = false;
370
371 if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
372 r->matched_acl, r->granted))
373 goto out;
374 buf = tomoyo_init_log(r, len, fmt, args);
375 if (!buf)
376 goto out;
377 entry = kzalloc_obj(*entry, GFP_NOFS);
378 if (!entry) {
379 kfree(buf);
380 goto out;
381 }
382 entry->log = buf;
383 len = kmalloc_size_roundup(strlen(buf) + 1);
384 /*
385 * The entry->size is used for memory quota checks.
386 * Don't go beyond strlen(entry->log).
387 */
388 entry->size = len + kmalloc_size_roundup(sizeof(*entry));
389 spin_lock(&tomoyo_log_lock);
390 if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
391 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
392 tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
393 quota_exceeded = true;
394 } else {
395 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
396 list_add_tail(&entry->list, &tomoyo_log);
397 tomoyo_log_count++;
398 }
399 spin_unlock(&tomoyo_log_lock);
400 if (quota_exceeded) {
401 kfree(buf);
402 kfree(entry);
403 goto out;
404 }
405 wake_up(&tomoyo_log_wait);
406 out:
407 return;
408 }
409
410 /**
411 * tomoyo_write_log - Write an audit log.
412 *
413 * @r: Pointer to "struct tomoyo_request_info".
414 * @fmt: The printf()'s format string, followed by parameters.
415 *
416 * Returns nothing.
417 */
tomoyo_write_log(struct tomoyo_request_info * r,const char * fmt,...)418 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
419 {
420 va_list args;
421 int len;
422
423 va_start(args, fmt);
424 len = vsnprintf(NULL, 0, fmt, args) + 1;
425 va_end(args);
426 va_start(args, fmt);
427 tomoyo_write_log2(r, len, fmt, args);
428 va_end(args);
429 }
430
431 /**
432 * tomoyo_read_log - Read an audit log.
433 *
434 * @head: Pointer to "struct tomoyo_io_buffer".
435 *
436 * Returns nothing.
437 */
tomoyo_read_log(struct tomoyo_io_buffer * head)438 void tomoyo_read_log(struct tomoyo_io_buffer *head)
439 {
440 struct tomoyo_log *ptr = NULL;
441
442 if (head->r.w_pos)
443 return;
444 kfree(head->read_buf);
445 head->read_buf = NULL;
446 spin_lock(&tomoyo_log_lock);
447 if (!list_empty(&tomoyo_log)) {
448 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
449 list_del(&ptr->list);
450 tomoyo_log_count--;
451 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
452 }
453 spin_unlock(&tomoyo_log_lock);
454 if (ptr) {
455 head->read_buf = ptr->log;
456 head->r.w[head->r.w_pos++] = head->read_buf;
457 kfree(ptr);
458 }
459 }
460
461 /**
462 * tomoyo_poll_log - Wait for an audit log.
463 *
464 * @file: Pointer to "struct file".
465 * @wait: Pointer to "poll_table". Maybe NULL.
466 *
467 * Returns EPOLLIN | EPOLLRDNORM when ready to read an audit log.
468 */
tomoyo_poll_log(struct file * file,poll_table * wait)469 __poll_t tomoyo_poll_log(struct file *file, poll_table *wait)
470 {
471 if (tomoyo_log_count)
472 return EPOLLIN | EPOLLRDNORM;
473 poll_wait(file, &tomoyo_log_wait, wait);
474 if (tomoyo_log_count)
475 return EPOLLIN | EPOLLRDNORM;
476 return 0;
477 }
478