GNU Linux-libre 6.9-gnu
[releases.git] / 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 }