Audit: dereferencing krule as if it were an audit_watch
[linux-2.6.git] / kernel / auditfilter.c
1 /* auditfilter.c -- filtering of audit events
2  *
3  * Copyright 2003-2004 Red Hat, Inc.
4  * Copyright 2005 Hewlett-Packard Development Company, L.P.
5  * Copyright 2005 IBM Corporation
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  */
21
22 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.h>
26 #include <linux/fs.h>
27 #include <linux/namei.h>
28 #include <linux/netlink.h>
29 #include <linux/sched.h>
30 #include <linux/inotify.h>
31 #include <linux/security.h>
32 #include "audit.h"
33
34 /*
35  * Locking model:
36  *
37  * audit_filter_mutex:
38  *              Synchronizes writes and blocking reads of audit's filterlist
39  *              data.  Rcu is used to traverse the filterlist and access
40  *              contents of structs audit_entry, audit_watch and opaque
41  *              LSM rules during filtering.  If modified, these structures
42  *              must be copied and replace their counterparts in the filterlist.
43  *              An audit_parent struct is not accessed during filtering, so may
44  *              be written directly provided audit_filter_mutex is held.
45  */
46
47 /*
48  * Reference counting:
49  *
50  * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED
51  *      event.  Each audit_watch holds a reference to its associated parent.
52  *
53  * audit_watch: if added to lists, lifetime is from audit_init_watch() to
54  *      audit_remove_watch().  Additionally, an audit_watch may exist
55  *      temporarily to assist in searching existing filter data.  Each
56  *      audit_krule holds a reference to its associated watch.
57  */
58
59 struct audit_parent {
60         struct list_head        ilist;  /* entry in inotify registration list */
61         struct list_head        watches; /* associated watches */
62         struct inotify_watch    wdata;  /* inotify watch data */
63         unsigned                flags;  /* status flags */
64 };
65
66 /*
67  * audit_parent status flags:
68  *
69  * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to
70  * a filesystem event to ensure we're adding audit watches to a valid parent.
71  * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot
72  * receive them while we have nameidata, but must be used for IN_MOVE_SELF which
73  * we can receive while holding nameidata.
74  */
75 #define AUDIT_PARENT_INVALID    0x001
76
77 /* Audit filter lists, defined in <linux/audit.h> */
78 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
79         LIST_HEAD_INIT(audit_filter_list[0]),
80         LIST_HEAD_INIT(audit_filter_list[1]),
81         LIST_HEAD_INIT(audit_filter_list[2]),
82         LIST_HEAD_INIT(audit_filter_list[3]),
83         LIST_HEAD_INIT(audit_filter_list[4]),
84         LIST_HEAD_INIT(audit_filter_list[5]),
85 #if AUDIT_NR_FILTERS != 6
86 #error Fix audit_filter_list initialiser
87 #endif
88 };
89 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
90         LIST_HEAD_INIT(audit_rules_list[0]),
91         LIST_HEAD_INIT(audit_rules_list[1]),
92         LIST_HEAD_INIT(audit_rules_list[2]),
93         LIST_HEAD_INIT(audit_rules_list[3]),
94         LIST_HEAD_INIT(audit_rules_list[4]),
95         LIST_HEAD_INIT(audit_rules_list[5]),
96 };
97
98 DEFINE_MUTEX(audit_filter_mutex);
99
100 /* Inotify events we care about. */
101 #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
102
103 void audit_free_parent(struct inotify_watch *i_watch)
104 {
105         struct audit_parent *parent;
106
107         parent = container_of(i_watch, struct audit_parent, wdata);
108         WARN_ON(!list_empty(&parent->watches));
109         kfree(parent);
110 }
111
112 static inline void audit_get_watch(struct audit_watch *watch)
113 {
114         atomic_inc(&watch->count);
115 }
116
117 static void audit_put_watch(struct audit_watch *watch)
118 {
119         if (atomic_dec_and_test(&watch->count)) {
120                 WARN_ON(watch->parent);
121                 WARN_ON(!list_empty(&watch->rules));
122                 kfree(watch->path);
123                 kfree(watch);
124         }
125 }
126
127 static void audit_remove_watch(struct audit_watch *watch)
128 {
129         list_del(&watch->wlist);
130         put_inotify_watch(&watch->parent->wdata);
131         watch->parent = NULL;
132         audit_put_watch(watch); /* match initial get */
133 }
134
135 static inline void audit_free_rule(struct audit_entry *e)
136 {
137         int i;
138         struct audit_krule *erule = &e->rule;
139         /* some rules don't have associated watches */
140         if (erule->watch)
141                 audit_put_watch(erule->watch);
142         if (erule->fields)
143                 for (i = 0; i < erule->field_count; i++) {
144                         struct audit_field *f = &erule->fields[i];
145                         kfree(f->lsm_str);
146                         security_audit_rule_free(f->lsm_rule);
147                 }
148         kfree(erule->fields);
149         kfree(erule->filterkey);
150         kfree(e);
151 }
152
153 void audit_free_rule_rcu(struct rcu_head *head)
154 {
155         struct audit_entry *e = container_of(head, struct audit_entry, rcu);
156         audit_free_rule(e);
157 }
158
159 /* Initialize a parent watch entry. */
160 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
161 {
162         struct audit_parent *parent;
163         s32 wd;
164
165         parent = kzalloc(sizeof(*parent), GFP_KERNEL);
166         if (unlikely(!parent))
167                 return ERR_PTR(-ENOMEM);
168
169         INIT_LIST_HEAD(&parent->watches);
170         parent->flags = 0;
171
172         inotify_init_watch(&parent->wdata);
173         /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
174         get_inotify_watch(&parent->wdata);
175         wd = inotify_add_watch(audit_ih, &parent->wdata,
176                                ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
177         if (wd < 0) {
178                 audit_free_parent(&parent->wdata);
179                 return ERR_PTR(wd);
180         }
181
182         return parent;
183 }
184
185 /* Initialize a watch entry. */
186 static struct audit_watch *audit_init_watch(char *path)
187 {
188         struct audit_watch *watch;
189
190         watch = kzalloc(sizeof(*watch), GFP_KERNEL);
191         if (unlikely(!watch))
192                 return ERR_PTR(-ENOMEM);
193
194         INIT_LIST_HEAD(&watch->rules);
195         atomic_set(&watch->count, 1);
196         watch->path = path;
197         watch->dev = (dev_t)-1;
198         watch->ino = (unsigned long)-1;
199
200         return watch;
201 }
202
203 /* Initialize an audit filterlist entry. */
204 static inline struct audit_entry *audit_init_entry(u32 field_count)
205 {
206         struct audit_entry *entry;
207         struct audit_field *fields;
208
209         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
210         if (unlikely(!entry))
211                 return NULL;
212
213         fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
214         if (unlikely(!fields)) {
215                 kfree(entry);
216                 return NULL;
217         }
218         entry->rule.fields = fields;
219
220         return entry;
221 }
222
223 /* Unpack a filter field's string representation from user-space
224  * buffer. */
225 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
226 {
227         char *str;
228
229         if (!*bufp || (len == 0) || (len > *remain))
230                 return ERR_PTR(-EINVAL);
231
232         /* Of the currently implemented string fields, PATH_MAX
233          * defines the longest valid length.
234          */
235         if (len > PATH_MAX)
236                 return ERR_PTR(-ENAMETOOLONG);
237
238         str = kmalloc(len + 1, GFP_KERNEL);
239         if (unlikely(!str))
240                 return ERR_PTR(-ENOMEM);
241
242         memcpy(str, *bufp, len);
243         str[len] = 0;
244         *bufp += len;
245         *remain -= len;
246
247         return str;
248 }
249
250 /* Translate an inode field to kernel respresentation. */
251 static inline int audit_to_inode(struct audit_krule *krule,
252                                  struct audit_field *f)
253 {
254         if (krule->listnr != AUDIT_FILTER_EXIT ||
255             krule->watch || krule->inode_f || krule->tree ||
256             (f->op != Audit_equal && f->op != Audit_not_equal))
257                 return -EINVAL;
258
259         krule->inode_f = f;
260         return 0;
261 }
262
263 /* Translate a watch string to kernel respresentation. */
264 static int audit_to_watch(struct audit_krule *krule, char *path, int len,
265                           u32 op)
266 {
267         struct audit_watch *watch;
268
269         if (!audit_ih)
270                 return -EOPNOTSUPP;
271
272         if (path[0] != '/' || path[len-1] == '/' ||
273             krule->listnr != AUDIT_FILTER_EXIT ||
274             op != Audit_equal ||
275             krule->inode_f || krule->watch || krule->tree)
276                 return -EINVAL;
277
278         watch = audit_init_watch(path);
279         if (IS_ERR(watch))
280                 return PTR_ERR(watch);
281
282         audit_get_watch(watch);
283         krule->watch = watch;
284
285         return 0;
286 }
287
288 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
289
290 int __init audit_register_class(int class, unsigned *list)
291 {
292         __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
293         if (!p)
294                 return -ENOMEM;
295         while (*list != ~0U) {
296                 unsigned n = *list++;
297                 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
298                         kfree(p);
299                         return -EINVAL;
300                 }
301                 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
302         }
303         if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
304                 kfree(p);
305                 return -EINVAL;
306         }
307         classes[class] = p;
308         return 0;
309 }
310
311 int audit_match_class(int class, unsigned syscall)
312 {
313         if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
314                 return 0;
315         if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
316                 return 0;
317         return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
318 }
319
320 #ifdef CONFIG_AUDITSYSCALL
321 static inline int audit_match_class_bits(int class, u32 *mask)
322 {
323         int i;
324
325         if (classes[class]) {
326                 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
327                         if (mask[i] & classes[class][i])
328                                 return 0;
329         }
330         return 1;
331 }
332
333 static int audit_match_signal(struct audit_entry *entry)
334 {
335         struct audit_field *arch = entry->rule.arch_f;
336
337         if (!arch) {
338                 /* When arch is unspecified, we must check both masks on biarch
339                  * as syscall number alone is ambiguous. */
340                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
341                                                entry->rule.mask) &&
342                         audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
343                                                entry->rule.mask));
344         }
345
346         switch(audit_classify_arch(arch->val)) {
347         case 0: /* native */
348                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
349                                                entry->rule.mask));
350         case 1: /* 32bit on biarch */
351                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
352                                                entry->rule.mask));
353         default:
354                 return 1;
355         }
356 }
357 #endif
358
359 /* Common user-space to kernel rule translation. */
360 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
361 {
362         unsigned listnr;
363         struct audit_entry *entry;
364         int i, err;
365
366         err = -EINVAL;
367         listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
368         switch(listnr) {
369         default:
370                 goto exit_err;
371         case AUDIT_FILTER_USER:
372         case AUDIT_FILTER_TYPE:
373 #ifdef CONFIG_AUDITSYSCALL
374         case AUDIT_FILTER_ENTRY:
375         case AUDIT_FILTER_EXIT:
376         case AUDIT_FILTER_TASK:
377 #endif
378                 ;
379         }
380         if (unlikely(rule->action == AUDIT_POSSIBLE)) {
381                 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
382                 goto exit_err;
383         }
384         if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
385                 goto exit_err;
386         if (rule->field_count > AUDIT_MAX_FIELDS)
387                 goto exit_err;
388
389         err = -ENOMEM;
390         entry = audit_init_entry(rule->field_count);
391         if (!entry)
392                 goto exit_err;
393
394         entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
395         entry->rule.listnr = listnr;
396         entry->rule.action = rule->action;
397         entry->rule.field_count = rule->field_count;
398
399         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
400                 entry->rule.mask[i] = rule->mask[i];
401
402         for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
403                 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
404                 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
405                 __u32 *class;
406
407                 if (!(*p & AUDIT_BIT(bit)))
408                         continue;
409                 *p &= ~AUDIT_BIT(bit);
410                 class = classes[i];
411                 if (class) {
412                         int j;
413                         for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
414                                 entry->rule.mask[j] |= class[j];
415                 }
416         }
417
418         return entry;
419
420 exit_err:
421         return ERR_PTR(err);
422 }
423
424 static u32 audit_ops[] =
425 {
426         [Audit_equal] = AUDIT_EQUAL,
427         [Audit_not_equal] = AUDIT_NOT_EQUAL,
428         [Audit_bitmask] = AUDIT_BIT_MASK,
429         [Audit_bittest] = AUDIT_BIT_TEST,
430         [Audit_lt] = AUDIT_LESS_THAN,
431         [Audit_gt] = AUDIT_GREATER_THAN,
432         [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
433         [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
434 };
435
436 static u32 audit_to_op(u32 op)
437 {
438         u32 n;
439         for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
440                 ;
441         return n;
442 }
443
444
445 /* Translate struct audit_rule to kernel's rule respresentation.
446  * Exists for backward compatibility with userspace. */
447 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
448 {
449         struct audit_entry *entry;
450         int err = 0;
451         int i;
452
453         entry = audit_to_entry_common(rule);
454         if (IS_ERR(entry))
455                 goto exit_nofree;
456
457         for (i = 0; i < rule->field_count; i++) {
458                 struct audit_field *f = &entry->rule.fields[i];
459                 u32 n;
460
461                 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
462
463                 /* Support for legacy operators where
464                  * AUDIT_NEGATE bit signifies != and otherwise assumes == */
465                 if (n & AUDIT_NEGATE)
466                         f->op = Audit_not_equal;
467                 else if (!n)
468                         f->op = Audit_equal;
469                 else
470                         f->op = audit_to_op(n);
471
472                 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
473
474                 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
475                 f->val = rule->values[i];
476
477                 err = -EINVAL;
478                 if (f->op == Audit_bad)
479                         goto exit_free;
480
481                 switch(f->type) {
482                 default:
483                         goto exit_free;
484                 case AUDIT_PID:
485                 case AUDIT_UID:
486                 case AUDIT_EUID:
487                 case AUDIT_SUID:
488                 case AUDIT_FSUID:
489                 case AUDIT_GID:
490                 case AUDIT_EGID:
491                 case AUDIT_SGID:
492                 case AUDIT_FSGID:
493                 case AUDIT_LOGINUID:
494                 case AUDIT_PERS:
495                 case AUDIT_MSGTYPE:
496                 case AUDIT_PPID:
497                 case AUDIT_DEVMAJOR:
498                 case AUDIT_DEVMINOR:
499                 case AUDIT_EXIT:
500                 case AUDIT_SUCCESS:
501                         /* bit ops are only useful on syscall args */
502                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
503                                 goto exit_free;
504                         break;
505                 case AUDIT_ARG0:
506                 case AUDIT_ARG1:
507                 case AUDIT_ARG2:
508                 case AUDIT_ARG3:
509                         break;
510                 /* arch is only allowed to be = or != */
511                 case AUDIT_ARCH:
512                         if (f->op != Audit_not_equal && f->op != Audit_equal)
513                                 goto exit_free;
514                         entry->rule.arch_f = f;
515                         break;
516                 case AUDIT_PERM:
517                         if (f->val & ~15)
518                                 goto exit_free;
519                         break;
520                 case AUDIT_FILETYPE:
521                         if ((f->val & ~S_IFMT) > S_IFMT)
522                                 goto exit_free;
523                         break;
524                 case AUDIT_INODE:
525                         err = audit_to_inode(&entry->rule, f);
526                         if (err)
527                                 goto exit_free;
528                         break;
529                 }
530         }
531
532         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
533                 entry->rule.inode_f = NULL;
534
535 exit_nofree:
536         return entry;
537
538 exit_free:
539         audit_free_rule(entry);
540         return ERR_PTR(err);
541 }
542
543 /* Translate struct audit_rule_data to kernel's rule respresentation. */
544 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
545                                                size_t datasz)
546 {
547         int err = 0;
548         struct audit_entry *entry;
549         void *bufp;
550         size_t remain = datasz - sizeof(struct audit_rule_data);
551         int i;
552         char *str;
553
554         entry = audit_to_entry_common((struct audit_rule *)data);
555         if (IS_ERR(entry))
556                 goto exit_nofree;
557
558         bufp = data->buf;
559         entry->rule.vers_ops = 2;
560         for (i = 0; i < data->field_count; i++) {
561                 struct audit_field *f = &entry->rule.fields[i];
562
563                 err = -EINVAL;
564
565                 f->op = audit_to_op(data->fieldflags[i]);
566                 if (f->op == Audit_bad)
567                         goto exit_free;
568
569                 f->type = data->fields[i];
570                 f->val = data->values[i];
571                 f->lsm_str = NULL;
572                 f->lsm_rule = NULL;
573                 switch(f->type) {
574                 case AUDIT_PID:
575                 case AUDIT_UID:
576                 case AUDIT_EUID:
577                 case AUDIT_SUID:
578                 case AUDIT_FSUID:
579                 case AUDIT_GID:
580                 case AUDIT_EGID:
581                 case AUDIT_SGID:
582                 case AUDIT_FSGID:
583                 case AUDIT_LOGINUID:
584                 case AUDIT_PERS:
585                 case AUDIT_MSGTYPE:
586                 case AUDIT_PPID:
587                 case AUDIT_DEVMAJOR:
588                 case AUDIT_DEVMINOR:
589                 case AUDIT_EXIT:
590                 case AUDIT_SUCCESS:
591                 case AUDIT_ARG0:
592                 case AUDIT_ARG1:
593                 case AUDIT_ARG2:
594                 case AUDIT_ARG3:
595                         break;
596                 case AUDIT_ARCH:
597                         entry->rule.arch_f = f;
598                         break;
599                 case AUDIT_SUBJ_USER:
600                 case AUDIT_SUBJ_ROLE:
601                 case AUDIT_SUBJ_TYPE:
602                 case AUDIT_SUBJ_SEN:
603                 case AUDIT_SUBJ_CLR:
604                 case AUDIT_OBJ_USER:
605                 case AUDIT_OBJ_ROLE:
606                 case AUDIT_OBJ_TYPE:
607                 case AUDIT_OBJ_LEV_LOW:
608                 case AUDIT_OBJ_LEV_HIGH:
609                         str = audit_unpack_string(&bufp, &remain, f->val);
610                         if (IS_ERR(str))
611                                 goto exit_free;
612                         entry->rule.buflen += f->val;
613
614                         err = security_audit_rule_init(f->type, f->op, str,
615                                                        (void **)&f->lsm_rule);
616                         /* Keep currently invalid fields around in case they
617                          * become valid after a policy reload. */
618                         if (err == -EINVAL) {
619                                 printk(KERN_WARNING "audit rule for LSM "
620                                        "\'%s\' is invalid\n",  str);
621                                 err = 0;
622                         }
623                         if (err) {
624                                 kfree(str);
625                                 goto exit_free;
626                         } else
627                                 f->lsm_str = str;
628                         break;
629                 case AUDIT_WATCH:
630                         str = audit_unpack_string(&bufp, &remain, f->val);
631                         if (IS_ERR(str))
632                                 goto exit_free;
633                         entry->rule.buflen += f->val;
634
635                         err = audit_to_watch(&entry->rule, str, f->val, f->op);
636                         if (err) {
637                                 kfree(str);
638                                 goto exit_free;
639                         }
640                         break;
641                 case AUDIT_DIR:
642                         str = audit_unpack_string(&bufp, &remain, f->val);
643                         if (IS_ERR(str))
644                                 goto exit_free;
645                         entry->rule.buflen += f->val;
646
647                         err = audit_make_tree(&entry->rule, str, f->op);
648                         kfree(str);
649                         if (err)
650                                 goto exit_free;
651                         break;
652                 case AUDIT_INODE:
653                         err = audit_to_inode(&entry->rule, f);
654                         if (err)
655                                 goto exit_free;
656                         break;
657                 case AUDIT_FILTERKEY:
658                         err = -EINVAL;
659                         if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
660                                 goto exit_free;
661                         str = audit_unpack_string(&bufp, &remain, f->val);
662                         if (IS_ERR(str))
663                                 goto exit_free;
664                         entry->rule.buflen += f->val;
665                         entry->rule.filterkey = str;
666                         break;
667                 case AUDIT_PERM:
668                         if (f->val & ~15)
669                                 goto exit_free;
670                         break;
671                 case AUDIT_FILETYPE:
672                         if ((f->val & ~S_IFMT) > S_IFMT)
673                                 goto exit_free;
674                         break;
675                 default:
676                         goto exit_free;
677                 }
678         }
679
680         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
681                 entry->rule.inode_f = NULL;
682
683 exit_nofree:
684         return entry;
685
686 exit_free:
687         audit_free_rule(entry);
688         return ERR_PTR(err);
689 }
690
691 /* Pack a filter field's string representation into data block. */
692 static inline size_t audit_pack_string(void **bufp, const char *str)
693 {
694         size_t len = strlen(str);
695
696         memcpy(*bufp, str, len);
697         *bufp += len;
698
699         return len;
700 }
701
702 /* Translate kernel rule respresentation to struct audit_rule.
703  * Exists for backward compatibility with userspace. */
704 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
705 {
706         struct audit_rule *rule;
707         int i;
708
709         rule = kzalloc(sizeof(*rule), GFP_KERNEL);
710         if (unlikely(!rule))
711                 return NULL;
712
713         rule->flags = krule->flags | krule->listnr;
714         rule->action = krule->action;
715         rule->field_count = krule->field_count;
716         for (i = 0; i < rule->field_count; i++) {
717                 rule->values[i] = krule->fields[i].val;
718                 rule->fields[i] = krule->fields[i].type;
719
720                 if (krule->vers_ops == 1) {
721                         if (krule->fields[i].op == Audit_not_equal)
722                                 rule->fields[i] |= AUDIT_NEGATE;
723                 } else {
724                         rule->fields[i] |= audit_ops[krule->fields[i].op];
725                 }
726         }
727         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
728
729         return rule;
730 }
731
732 /* Translate kernel rule respresentation to struct audit_rule_data. */
733 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
734 {
735         struct audit_rule_data *data;
736         void *bufp;
737         int i;
738
739         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
740         if (unlikely(!data))
741                 return NULL;
742         memset(data, 0, sizeof(*data));
743
744         data->flags = krule->flags | krule->listnr;
745         data->action = krule->action;
746         data->field_count = krule->field_count;
747         bufp = data->buf;
748         for (i = 0; i < data->field_count; i++) {
749                 struct audit_field *f = &krule->fields[i];
750
751                 data->fields[i] = f->type;
752                 data->fieldflags[i] = audit_ops[f->op];
753                 switch(f->type) {
754                 case AUDIT_SUBJ_USER:
755                 case AUDIT_SUBJ_ROLE:
756                 case AUDIT_SUBJ_TYPE:
757                 case AUDIT_SUBJ_SEN:
758                 case AUDIT_SUBJ_CLR:
759                 case AUDIT_OBJ_USER:
760                 case AUDIT_OBJ_ROLE:
761                 case AUDIT_OBJ_TYPE:
762                 case AUDIT_OBJ_LEV_LOW:
763                 case AUDIT_OBJ_LEV_HIGH:
764                         data->buflen += data->values[i] =
765                                 audit_pack_string(&bufp, f->lsm_str);
766                         break;
767                 case AUDIT_WATCH:
768                         data->buflen += data->values[i] =
769                                 audit_pack_string(&bufp, krule->watch->path);
770                         break;
771                 case AUDIT_DIR:
772                         data->buflen += data->values[i] =
773                                 audit_pack_string(&bufp,
774                                                   audit_tree_path(krule->tree));
775                         break;
776                 case AUDIT_FILTERKEY:
777                         data->buflen += data->values[i] =
778                                 audit_pack_string(&bufp, krule->filterkey);
779                         break;
780                 default:
781                         data->values[i] = f->val;
782                 }
783         }
784         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
785
786         return data;
787 }
788
789 /* Compare two rules in kernel format.  Considered success if rules
790  * don't match. */
791 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
792 {
793         int i;
794
795         if (a->flags != b->flags ||
796             a->listnr != b->listnr ||
797             a->action != b->action ||
798             a->field_count != b->field_count)
799                 return 1;
800
801         for (i = 0; i < a->field_count; i++) {
802                 if (a->fields[i].type != b->fields[i].type ||
803                     a->fields[i].op != b->fields[i].op)
804                         return 1;
805
806                 switch(a->fields[i].type) {
807                 case AUDIT_SUBJ_USER:
808                 case AUDIT_SUBJ_ROLE:
809                 case AUDIT_SUBJ_TYPE:
810                 case AUDIT_SUBJ_SEN:
811                 case AUDIT_SUBJ_CLR:
812                 case AUDIT_OBJ_USER:
813                 case AUDIT_OBJ_ROLE:
814                 case AUDIT_OBJ_TYPE:
815                 case AUDIT_OBJ_LEV_LOW:
816                 case AUDIT_OBJ_LEV_HIGH:
817                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
818                                 return 1;
819                         break;
820                 case AUDIT_WATCH:
821                         if (strcmp(a->watch->path, b->watch->path))
822                                 return 1;
823                         break;
824                 case AUDIT_DIR:
825                         if (strcmp(audit_tree_path(a->tree),
826                                    audit_tree_path(b->tree)))
827                                 return 1;
828                         break;
829                 case AUDIT_FILTERKEY:
830                         /* both filterkeys exist based on above type compare */
831                         if (strcmp(a->filterkey, b->filterkey))
832                                 return 1;
833                         break;
834                 default:
835                         if (a->fields[i].val != b->fields[i].val)
836                                 return 1;
837                 }
838         }
839
840         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
841                 if (a->mask[i] != b->mask[i])
842                         return 1;
843
844         return 0;
845 }
846
847 /* Duplicate the given audit watch.  The new watch's rules list is initialized
848  * to an empty list and wlist is undefined. */
849 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
850 {
851         char *path;
852         struct audit_watch *new;
853
854         path = kstrdup(old->path, GFP_KERNEL);
855         if (unlikely(!path))
856                 return ERR_PTR(-ENOMEM);
857
858         new = audit_init_watch(path);
859         if (IS_ERR(new)) {
860                 kfree(path);
861                 goto out;
862         }
863
864         new->dev = old->dev;
865         new->ino = old->ino;
866         get_inotify_watch(&old->parent->wdata);
867         new->parent = old->parent;
868
869 out:
870         return new;
871 }
872
873 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
874  * re-initialized. */
875 static inline int audit_dupe_lsm_field(struct audit_field *df,
876                                            struct audit_field *sf)
877 {
878         int ret = 0;
879         char *lsm_str;
880
881         /* our own copy of lsm_str */
882         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
883         if (unlikely(!lsm_str))
884                 return -ENOMEM;
885         df->lsm_str = lsm_str;
886
887         /* our own (refreshed) copy of lsm_rule */
888         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
889                                        (void **)&df->lsm_rule);
890         /* Keep currently invalid fields around in case they
891          * become valid after a policy reload. */
892         if (ret == -EINVAL) {
893                 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
894                        "invalid\n", df->lsm_str);
895                 ret = 0;
896         }
897
898         return ret;
899 }
900
901 /* Duplicate an audit rule.  This will be a deep copy with the exception
902  * of the watch - that pointer is carried over.  The LSM specific fields
903  * will be updated in the copy.  The point is to be able to replace the old
904  * rule with the new rule in the filterlist, then free the old rule.
905  * The rlist element is undefined; list manipulations are handled apart from
906  * the initial copy. */
907 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
908                                            struct audit_watch *watch)
909 {
910         u32 fcount = old->field_count;
911         struct audit_entry *entry;
912         struct audit_krule *new;
913         char *fk;
914         int i, err = 0;
915
916         entry = audit_init_entry(fcount);
917         if (unlikely(!entry))
918                 return ERR_PTR(-ENOMEM);
919
920         new = &entry->rule;
921         new->vers_ops = old->vers_ops;
922         new->flags = old->flags;
923         new->listnr = old->listnr;
924         new->action = old->action;
925         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
926                 new->mask[i] = old->mask[i];
927         new->prio = old->prio;
928         new->buflen = old->buflen;
929         new->inode_f = old->inode_f;
930         new->watch = NULL;
931         new->field_count = old->field_count;
932         /*
933          * note that we are OK with not refcounting here; audit_match_tree()
934          * never dereferences tree and we can't get false positives there
935          * since we'd have to have rule gone from the list *and* removed
936          * before the chunks found by lookup had been allocated, i.e. before
937          * the beginning of list scan.
938          */
939         new->tree = old->tree;
940         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
941
942         /* deep copy this information, updating the lsm_rule fields, because
943          * the originals will all be freed when the old rule is freed. */
944         for (i = 0; i < fcount; i++) {
945                 switch (new->fields[i].type) {
946                 case AUDIT_SUBJ_USER:
947                 case AUDIT_SUBJ_ROLE:
948                 case AUDIT_SUBJ_TYPE:
949                 case AUDIT_SUBJ_SEN:
950                 case AUDIT_SUBJ_CLR:
951                 case AUDIT_OBJ_USER:
952                 case AUDIT_OBJ_ROLE:
953                 case AUDIT_OBJ_TYPE:
954                 case AUDIT_OBJ_LEV_LOW:
955                 case AUDIT_OBJ_LEV_HIGH:
956                         err = audit_dupe_lsm_field(&new->fields[i],
957                                                        &old->fields[i]);
958                         break;
959                 case AUDIT_FILTERKEY:
960                         fk = kstrdup(old->filterkey, GFP_KERNEL);
961                         if (unlikely(!fk))
962                                 err = -ENOMEM;
963                         else
964                                 new->filterkey = fk;
965                 }
966                 if (err) {
967                         audit_free_rule(entry);
968                         return ERR_PTR(err);
969                 }
970         }
971
972         if (watch) {
973                 audit_get_watch(watch);
974                 new->watch = watch;
975         }
976
977         return entry;
978 }
979
980 static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
981 {
982         if (audit_enabled) {
983                 struct audit_buffer *ab;
984                 ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
985                 audit_log_format(ab, "auid=%u ses=%u op=",
986                                  audit_get_loginuid(current),
987                                  audit_get_sessionid(current));
988                 audit_log_string(ab, op);
989                 audit_log_format(ab, " path=");
990                 audit_log_untrustedstring(ab, w->path);
991                 if (r->filterkey) {
992                         audit_log_format(ab, " key=");
993                         audit_log_untrustedstring(ab, r->filterkey);
994                 } else
995                         audit_log_format(ab, " key=(null)");
996                 audit_log_format(ab, " list=%d res=1", r->listnr);
997                 audit_log_end(ab);
998         }
999 }
1000
1001 /* Update inode info in audit rules based on filesystem event. */
1002 static void audit_update_watch(struct audit_parent *parent,
1003                                const char *dname, dev_t dev,
1004                                unsigned long ino, unsigned invalidating)
1005 {
1006         struct audit_watch *owatch, *nwatch, *nextw;
1007         struct audit_krule *r, *nextr;
1008         struct audit_entry *oentry, *nentry;
1009
1010         mutex_lock(&audit_filter_mutex);
1011         list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
1012                 if (audit_compare_dname_path(dname, owatch->path, NULL))
1013                         continue;
1014
1015                 /* If the update involves invalidating rules, do the inode-based
1016                  * filtering now, so we don't omit records. */
1017                 if (invalidating && current->audit_context)
1018                         audit_filter_inodes(current, current->audit_context);
1019
1020                 nwatch = audit_dupe_watch(owatch);
1021                 if (IS_ERR(nwatch)) {
1022                         mutex_unlock(&audit_filter_mutex);
1023                         audit_panic("error updating watch, skipping");
1024                         return;
1025                 }
1026                 nwatch->dev = dev;
1027                 nwatch->ino = ino;
1028
1029                 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
1030
1031                         oentry = container_of(r, struct audit_entry, rule);
1032                         list_del(&oentry->rule.rlist);
1033                         list_del_rcu(&oentry->list);
1034
1035                         nentry = audit_dupe_rule(&oentry->rule, nwatch);
1036                         if (IS_ERR(nentry)) {
1037                                 list_del(&oentry->rule.list);
1038                                 audit_panic("error updating watch, removing");
1039                         } else {
1040                                 int h = audit_hash_ino((u32)ino);
1041                                 list_add(&nentry->rule.rlist, &nwatch->rules);
1042                                 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
1043                                 list_replace(&oentry->rule.list,
1044                                              &nentry->rule.list);
1045                         }
1046
1047                         audit_watch_log_rule_change(r, owatch, "updated rules");
1048
1049                         call_rcu(&oentry->rcu, audit_free_rule_rcu);
1050                 }
1051
1052                 audit_remove_watch(owatch);
1053                 goto add_watch_to_parent; /* event applies to a single watch */
1054         }
1055         mutex_unlock(&audit_filter_mutex);
1056         return;
1057
1058 add_watch_to_parent:
1059         list_add(&nwatch->wlist, &parent->watches);
1060         mutex_unlock(&audit_filter_mutex);
1061         return;
1062 }
1063
1064 /* Remove all watches & rules associated with a parent that is going away. */
1065 static void audit_remove_parent_watches(struct audit_parent *parent)
1066 {
1067         struct audit_watch *w, *nextw;
1068         struct audit_krule *r, *nextr;
1069         struct audit_entry *e;
1070
1071         mutex_lock(&audit_filter_mutex);
1072         parent->flags |= AUDIT_PARENT_INVALID;
1073         list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
1074                 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
1075                         e = container_of(r, struct audit_entry, rule);
1076                         audit_watch_log_rule_change(r, w, "remove rule");
1077                         list_del(&r->rlist);
1078                         list_del(&r->list);
1079                         list_del_rcu(&e->list);
1080                         call_rcu(&e->rcu, audit_free_rule_rcu);
1081                 }
1082                 audit_remove_watch(w);
1083         }
1084         mutex_unlock(&audit_filter_mutex);
1085 }
1086
1087 /* Unregister inotify watches for parents on in_list.
1088  * Generates an IN_IGNORED event. */
1089 static void audit_inotify_unregister(struct list_head *in_list)
1090 {
1091         struct audit_parent *p, *n;
1092
1093         list_for_each_entry_safe(p, n, in_list, ilist) {
1094                 list_del(&p->ilist);
1095                 inotify_rm_watch(audit_ih, &p->wdata);
1096                 /* the unpin matching the pin in audit_do_del_rule() */
1097                 unpin_inotify_watch(&p->wdata);
1098         }
1099 }
1100
1101 /* Find an existing audit rule.
1102  * Caller must hold audit_filter_mutex to prevent stale rule data. */
1103 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1104                                            struct list_head **p)
1105 {
1106         struct audit_entry *e, *found = NULL;
1107         struct list_head *list;
1108         int h;
1109
1110         if (entry->rule.inode_f) {
1111                 h = audit_hash_ino(entry->rule.inode_f->val);
1112                 *p = list = &audit_inode_hash[h];
1113         } else if (entry->rule.watch) {
1114                 /* we don't know the inode number, so must walk entire hash */
1115                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1116                         list = &audit_inode_hash[h];
1117                         list_for_each_entry(e, list, list)
1118                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1119                                         found = e;
1120                                         goto out;
1121                                 }
1122                 }
1123                 goto out;
1124         } else {
1125                 *p = list = &audit_filter_list[entry->rule.listnr];
1126         }
1127
1128         list_for_each_entry(e, list, list)
1129                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1130                         found = e;
1131                         goto out;
1132                 }
1133
1134 out:
1135         return found;
1136 }
1137
1138 /* Get path information necessary for adding watches. */
1139 static int audit_get_nd(char *path, struct nameidata **ndp,
1140                         struct nameidata **ndw)
1141 {
1142         struct nameidata *ndparent, *ndwatch;
1143         int err;
1144
1145         ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1146         if (unlikely(!ndparent))
1147                 return -ENOMEM;
1148
1149         ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1150         if (unlikely(!ndwatch)) {
1151                 kfree(ndparent);
1152                 return -ENOMEM;
1153         }
1154
1155         err = path_lookup(path, LOOKUP_PARENT, ndparent);
1156         if (err) {
1157                 kfree(ndparent);
1158                 kfree(ndwatch);
1159                 return err;
1160         }
1161
1162         err = path_lookup(path, 0, ndwatch);
1163         if (err) {
1164                 kfree(ndwatch);
1165                 ndwatch = NULL;
1166         }
1167
1168         *ndp = ndparent;
1169         *ndw = ndwatch;
1170
1171         return 0;
1172 }
1173
1174 /* Release resources used for watch path information. */
1175 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1176 {
1177         if (ndp) {
1178                 path_put(&ndp->path);
1179                 kfree(ndp);
1180         }
1181         if (ndw) {
1182                 path_put(&ndw->path);
1183                 kfree(ndw);
1184         }
1185 }
1186
1187 /* Associate the given rule with an existing parent inotify_watch.
1188  * Caller must hold audit_filter_mutex. */
1189 static void audit_add_to_parent(struct audit_krule *krule,
1190                                 struct audit_parent *parent)
1191 {
1192         struct audit_watch *w, *watch = krule->watch;
1193         int watch_found = 0;
1194
1195         list_for_each_entry(w, &parent->watches, wlist) {
1196                 if (strcmp(watch->path, w->path))
1197                         continue;
1198
1199                 watch_found = 1;
1200
1201                 /* put krule's and initial refs to temporary watch */
1202                 audit_put_watch(watch);
1203                 audit_put_watch(watch);
1204
1205                 audit_get_watch(w);
1206                 krule->watch = watch = w;
1207                 break;
1208         }
1209
1210         if (!watch_found) {
1211                 get_inotify_watch(&parent->wdata);
1212                 watch->parent = parent;
1213
1214                 list_add(&watch->wlist, &parent->watches);
1215         }
1216         list_add(&krule->rlist, &watch->rules);
1217 }
1218
1219 /* Find a matching watch entry, or add this one.
1220  * Caller must hold audit_filter_mutex. */
1221 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1222                            struct nameidata *ndw)
1223 {
1224         struct audit_watch *watch = krule->watch;
1225         struct inotify_watch *i_watch;
1226         struct audit_parent *parent;
1227         int ret = 0;
1228
1229         /* update watch filter fields */
1230         if (ndw) {
1231                 watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
1232                 watch->ino = ndw->path.dentry->d_inode->i_ino;
1233         }
1234
1235         /* The audit_filter_mutex must not be held during inotify calls because
1236          * we hold it during inotify event callback processing.  If an existing
1237          * inotify watch is found, inotify_find_watch() grabs a reference before
1238          * returning.
1239          */
1240         mutex_unlock(&audit_filter_mutex);
1241
1242         if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
1243                                &i_watch) < 0) {
1244                 parent = audit_init_parent(ndp);
1245                 if (IS_ERR(parent)) {
1246                         /* caller expects mutex locked */
1247                         mutex_lock(&audit_filter_mutex);
1248                         return PTR_ERR(parent);
1249                 }
1250         } else
1251                 parent = container_of(i_watch, struct audit_parent, wdata);
1252
1253         mutex_lock(&audit_filter_mutex);
1254
1255         /* parent was moved before we took audit_filter_mutex */
1256         if (parent->flags & AUDIT_PARENT_INVALID)
1257                 ret = -ENOENT;
1258         else
1259                 audit_add_to_parent(krule, parent);
1260
1261         /* match get in audit_init_parent or inotify_find_watch */
1262         put_inotify_watch(&parent->wdata);
1263         return ret;
1264 }
1265
1266 static u64 prio_low = ~0ULL/2;
1267 static u64 prio_high = ~0ULL/2 - 1;
1268
1269 /* Add rule to given filterlist if not a duplicate. */
1270 static inline int audit_add_rule(struct audit_entry *entry)
1271 {
1272         struct audit_entry *e;
1273         struct audit_watch *watch = entry->rule.watch;
1274         struct audit_tree *tree = entry->rule.tree;
1275         struct nameidata *ndp = NULL, *ndw = NULL;
1276         struct list_head *list;
1277         int h, err;
1278 #ifdef CONFIG_AUDITSYSCALL
1279         int dont_count = 0;
1280
1281         /* If either of these, don't count towards total */
1282         if (entry->rule.listnr == AUDIT_FILTER_USER ||
1283                 entry->rule.listnr == AUDIT_FILTER_TYPE)
1284                 dont_count = 1;
1285 #endif
1286
1287         mutex_lock(&audit_filter_mutex);
1288         e = audit_find_rule(entry, &list);
1289         mutex_unlock(&audit_filter_mutex);
1290         if (e) {
1291                 err = -EEXIST;
1292                 /* normally audit_add_tree_rule() will free it on failure */
1293                 if (tree)
1294                         audit_put_tree(tree);
1295                 goto error;
1296         }
1297
1298         /* Avoid calling path_lookup under audit_filter_mutex. */
1299         if (watch) {
1300                 err = audit_get_nd(watch->path, &ndp, &ndw);
1301                 if (err)
1302                         goto error;
1303         }
1304
1305         mutex_lock(&audit_filter_mutex);
1306         if (watch) {
1307                 /* audit_filter_mutex is dropped and re-taken during this call */
1308                 err = audit_add_watch(&entry->rule, ndp, ndw);
1309                 if (err) {
1310                         mutex_unlock(&audit_filter_mutex);
1311                         goto error;
1312                 }
1313                 /* entry->rule.watch may have changed during audit_add_watch() */
1314                 watch = entry->rule.watch;
1315                 h = audit_hash_ino((u32)watch->ino);
1316                 list = &audit_inode_hash[h];
1317         }
1318         if (tree) {
1319                 err = audit_add_tree_rule(&entry->rule);
1320                 if (err) {
1321                         mutex_unlock(&audit_filter_mutex);
1322                         goto error;
1323                 }
1324         }
1325
1326         entry->rule.prio = ~0ULL;
1327         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
1328                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
1329                         entry->rule.prio = ++prio_high;
1330                 else
1331                         entry->rule.prio = --prio_low;
1332         }
1333
1334         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1335                 list_add(&entry->rule.list,
1336                          &audit_rules_list[entry->rule.listnr]);
1337                 list_add_rcu(&entry->list, list);
1338                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1339         } else {
1340                 list_add_tail(&entry->rule.list,
1341                               &audit_rules_list[entry->rule.listnr]);
1342                 list_add_tail_rcu(&entry->list, list);
1343         }
1344 #ifdef CONFIG_AUDITSYSCALL
1345         if (!dont_count)
1346                 audit_n_rules++;
1347
1348         if (!audit_match_signal(entry))
1349                 audit_signals++;
1350 #endif
1351         mutex_unlock(&audit_filter_mutex);
1352
1353         audit_put_nd(ndp, ndw);         /* NULL args OK */
1354         return 0;
1355
1356 error:
1357         audit_put_nd(ndp, ndw);         /* NULL args OK */
1358         if (watch)
1359                 audit_put_watch(watch); /* tmp watch, matches initial get */
1360         return err;
1361 }
1362
1363 /* Remove an existing rule from filterlist. */
1364 static inline int audit_del_rule(struct audit_entry *entry)
1365 {
1366         struct audit_entry  *e;
1367         struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1368         struct audit_tree *tree = entry->rule.tree;
1369         struct list_head *list;
1370         LIST_HEAD(inotify_list);
1371         int ret = 0;
1372 #ifdef CONFIG_AUDITSYSCALL
1373         int dont_count = 0;
1374
1375         /* If either of these, don't count towards total */
1376         if (entry->rule.listnr == AUDIT_FILTER_USER ||
1377                 entry->rule.listnr == AUDIT_FILTER_TYPE)
1378                 dont_count = 1;
1379 #endif
1380
1381         mutex_lock(&audit_filter_mutex);
1382         e = audit_find_rule(entry, &list);
1383         if (!e) {
1384                 mutex_unlock(&audit_filter_mutex);
1385                 ret = -ENOENT;
1386                 goto out;
1387         }
1388
1389         watch = e->rule.watch;
1390         if (watch) {
1391                 struct audit_parent *parent = watch->parent;
1392
1393                 list_del(&e->rule.rlist);
1394
1395                 if (list_empty(&watch->rules)) {
1396                         audit_remove_watch(watch);
1397
1398                         if (list_empty(&parent->watches)) {
1399                                 /* Put parent on the inotify un-registration
1400                                  * list.  Grab a reference before releasing
1401                                  * audit_filter_mutex, to be released in
1402                                  * audit_inotify_unregister().
1403                                  * If filesystem is going away, just leave
1404                                  * the sucker alone, eviction will take
1405                                  * care of it.
1406                                  */
1407                                 if (pin_inotify_watch(&parent->wdata))
1408                                         list_add(&parent->ilist, &inotify_list);
1409                         }
1410                 }
1411         }
1412
1413         if (e->rule.tree)
1414                 audit_remove_tree_rule(&e->rule);
1415
1416         list_del_rcu(&e->list);
1417         list_del(&e->rule.list);
1418         call_rcu(&e->rcu, audit_free_rule_rcu);
1419
1420 #ifdef CONFIG_AUDITSYSCALL
1421         if (!dont_count)
1422                 audit_n_rules--;
1423
1424         if (!audit_match_signal(entry))
1425                 audit_signals--;
1426 #endif
1427         mutex_unlock(&audit_filter_mutex);
1428
1429         if (!list_empty(&inotify_list))
1430                 audit_inotify_unregister(&inotify_list);
1431
1432 out:
1433         if (tmp_watch)
1434                 audit_put_watch(tmp_watch); /* match initial get */
1435         if (tree)
1436                 audit_put_tree(tree);   /* that's the temporary one */
1437
1438         return ret;
1439 }
1440
1441 /* List rules using struct audit_rule.  Exists for backward
1442  * compatibility with userspace. */
1443 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1444 {
1445         struct sk_buff *skb;
1446         struct audit_krule *r;
1447         int i;
1448
1449         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1450          * iterator to sync with list writers. */
1451         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1452                 list_for_each_entry(r, &audit_rules_list[i], list) {
1453                         struct audit_rule *rule;
1454
1455                         rule = audit_krule_to_rule(r);
1456                         if (unlikely(!rule))
1457                                 break;
1458                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1459                                          rule, sizeof(*rule));
1460                         if (skb)
1461                                 skb_queue_tail(q, skb);
1462                         kfree(rule);
1463                 }
1464         }
1465         skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1466         if (skb)
1467                 skb_queue_tail(q, skb);
1468 }
1469
1470 /* List rules using struct audit_rule_data. */
1471 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1472 {
1473         struct sk_buff *skb;
1474         struct audit_krule *r;
1475         int i;
1476
1477         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1478          * iterator to sync with list writers. */
1479         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1480                 list_for_each_entry(r, &audit_rules_list[i], list) {
1481                         struct audit_rule_data *data;
1482
1483                         data = audit_krule_to_data(r);
1484                         if (unlikely(!data))
1485                                 break;
1486                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1487                                          data, sizeof(*data) + data->buflen);
1488                         if (skb)
1489                                 skb_queue_tail(q, skb);
1490                         kfree(data);
1491                 }
1492         }
1493         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1494         if (skb)
1495                 skb_queue_tail(q, skb);
1496 }
1497
1498 /* Log rule additions and removals */
1499 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1500                                   char *action, struct audit_krule *rule,
1501                                   int res)
1502 {
1503         struct audit_buffer *ab;
1504
1505         if (!audit_enabled)
1506                 return;
1507
1508         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1509         if (!ab)
1510                 return;
1511         audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1512         if (sid) {
1513                 char *ctx = NULL;
1514                 u32 len;
1515                 if (security_secid_to_secctx(sid, &ctx, &len))
1516                         audit_log_format(ab, " ssid=%u", sid);
1517                 else {
1518                         audit_log_format(ab, " subj=%s", ctx);
1519                         security_release_secctx(ctx, len);
1520                 }
1521         }
1522         audit_log_format(ab, " op=%s rule key=", action);
1523         if (rule->filterkey)
1524                 audit_log_untrustedstring(ab, rule->filterkey);
1525         else
1526                 audit_log_format(ab, "(null)");
1527         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1528         audit_log_end(ab);
1529 }
1530
1531 /**
1532  * audit_receive_filter - apply all rules to the specified message type
1533  * @type: audit message type
1534  * @pid: target pid for netlink audit messages
1535  * @uid: target uid for netlink audit messages
1536  * @seq: netlink audit message sequence (serial) number
1537  * @data: payload data
1538  * @datasz: size of payload data
1539  * @loginuid: loginuid of sender
1540  * @sessionid: sessionid for netlink audit message
1541  * @sid: SE Linux Security ID of sender
1542  */
1543 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1544                          size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1545 {
1546         struct task_struct *tsk;
1547         struct audit_netlink_list *dest;
1548         int err = 0;
1549         struct audit_entry *entry;
1550
1551         switch (type) {
1552         case AUDIT_LIST:
1553         case AUDIT_LIST_RULES:
1554                 /* We can't just spew out the rules here because we might fill
1555                  * the available socket buffer space and deadlock waiting for
1556                  * auditctl to read from it... which isn't ever going to
1557                  * happen if we're actually running in the context of auditctl
1558                  * trying to _send_ the stuff */
1559
1560                 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1561                 if (!dest)
1562                         return -ENOMEM;
1563                 dest->pid = pid;
1564                 skb_queue_head_init(&dest->q);
1565
1566                 mutex_lock(&audit_filter_mutex);
1567                 if (type == AUDIT_LIST)
1568                         audit_list(pid, seq, &dest->q);
1569                 else
1570                         audit_list_rules(pid, seq, &dest->q);
1571                 mutex_unlock(&audit_filter_mutex);
1572
1573                 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1574                 if (IS_ERR(tsk)) {
1575                         skb_queue_purge(&dest->q);
1576                         kfree(dest);
1577                         err = PTR_ERR(tsk);
1578                 }
1579                 break;
1580         case AUDIT_ADD:
1581         case AUDIT_ADD_RULE:
1582                 if (type == AUDIT_ADD)
1583                         entry = audit_rule_to_entry(data);
1584                 else
1585                         entry = audit_data_to_entry(data, datasz);
1586                 if (IS_ERR(entry))
1587                         return PTR_ERR(entry);
1588
1589                 err = audit_add_rule(entry);
1590                 audit_log_rule_change(loginuid, sessionid, sid, "add",
1591                                       &entry->rule, !err);
1592
1593                 if (err)
1594                         audit_free_rule(entry);
1595                 break;
1596         case AUDIT_DEL:
1597         case AUDIT_DEL_RULE:
1598                 if (type == AUDIT_DEL)
1599                         entry = audit_rule_to_entry(data);
1600                 else
1601                         entry = audit_data_to_entry(data, datasz);
1602                 if (IS_ERR(entry))
1603                         return PTR_ERR(entry);
1604
1605                 err = audit_del_rule(entry);
1606                 audit_log_rule_change(loginuid, sessionid, sid, "remove",
1607                                       &entry->rule, !err);
1608
1609                 audit_free_rule(entry);
1610                 break;
1611         default:
1612                 return -EINVAL;
1613         }
1614
1615         return err;
1616 }
1617
1618 int audit_comparator(u32 left, u32 op, u32 right)
1619 {
1620         switch (op) {
1621         case Audit_equal:
1622                 return (left == right);
1623         case Audit_not_equal:
1624                 return (left != right);
1625         case Audit_lt:
1626                 return (left < right);
1627         case Audit_le:
1628                 return (left <= right);
1629         case Audit_gt:
1630                 return (left > right);
1631         case Audit_ge:
1632                 return (left >= right);
1633         case Audit_bitmask:
1634                 return (left & right);
1635         case Audit_bittest:
1636                 return ((left & right) == right);
1637         default:
1638                 BUG();
1639                 return 0;
1640         }
1641 }
1642
1643 /* Compare given dentry name with last component in given path,
1644  * return of 0 indicates a match. */
1645 int audit_compare_dname_path(const char *dname, const char *path,
1646                              int *dirlen)
1647 {
1648         int dlen, plen;
1649         const char *p;
1650
1651         if (!dname || !path)
1652                 return 1;
1653
1654         dlen = strlen(dname);
1655         plen = strlen(path);
1656         if (plen < dlen)
1657                 return 1;
1658
1659         /* disregard trailing slashes */
1660         p = path + plen - 1;
1661         while ((*p == '/') && (p > path))
1662                 p--;
1663
1664         /* find last path component */
1665         p = p - dlen + 1;
1666         if (p < path)
1667                 return 1;
1668         else if (p > path) {
1669                 if (*--p != '/')
1670                         return 1;
1671                 else
1672                         p++;
1673         }
1674
1675         /* return length of path's directory component */
1676         if (dirlen)
1677                 *dirlen = p - path;
1678         return strncmp(p, dname, dlen);
1679 }
1680
1681 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1682                                    struct audit_krule *rule,
1683                                    enum audit_state *state)
1684 {
1685         int i;
1686
1687         for (i = 0; i < rule->field_count; i++) {
1688                 struct audit_field *f = &rule->fields[i];
1689                 int result = 0;
1690
1691                 switch (f->type) {
1692                 case AUDIT_PID:
1693                         result = audit_comparator(cb->creds.pid, f->op, f->val);
1694                         break;
1695                 case AUDIT_UID:
1696                         result = audit_comparator(cb->creds.uid, f->op, f->val);
1697                         break;
1698                 case AUDIT_GID:
1699                         result = audit_comparator(cb->creds.gid, f->op, f->val);
1700                         break;
1701                 case AUDIT_LOGINUID:
1702                         result = audit_comparator(cb->loginuid, f->op, f->val);
1703                         break;
1704                 }
1705
1706                 if (!result)
1707                         return 0;
1708         }
1709         switch (rule->action) {
1710         case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1711         case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1712         }
1713         return 1;
1714 }
1715
1716 int audit_filter_user(struct netlink_skb_parms *cb)
1717 {
1718         enum audit_state state = AUDIT_DISABLED;
1719         struct audit_entry *e;
1720         int ret = 1;
1721
1722         rcu_read_lock();
1723         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1724                 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1725                         if (state == AUDIT_DISABLED)
1726                                 ret = 0;
1727                         break;
1728                 }
1729         }
1730         rcu_read_unlock();
1731
1732         return ret; /* Audit by default */
1733 }
1734
1735 int audit_filter_type(int type)
1736 {
1737         struct audit_entry *e;
1738         int result = 0;
1739
1740         rcu_read_lock();
1741         if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1742                 goto unlock_and_return;
1743
1744         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1745                                 list) {
1746                 int i;
1747                 for (i = 0; i < e->rule.field_count; i++) {
1748                         struct audit_field *f = &e->rule.fields[i];
1749                         if (f->type == AUDIT_MSGTYPE) {
1750                                 result = audit_comparator(type, f->op, f->val);
1751                                 if (!result)
1752                                         break;
1753                         }
1754                 }
1755                 if (result)
1756                         goto unlock_and_return;
1757         }
1758 unlock_and_return:
1759         rcu_read_unlock();
1760         return result;
1761 }
1762
1763 static int update_lsm_rule(struct audit_krule *r)
1764 {
1765         struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1766         struct audit_entry *nentry;
1767         struct audit_watch *watch;
1768         struct audit_tree *tree;
1769         int err = 0;
1770
1771         if (!security_audit_rule_known(r))
1772                 return 0;
1773
1774         watch = r->watch;
1775         tree = r->tree;
1776         nentry = audit_dupe_rule(r, watch);
1777         if (IS_ERR(nentry)) {
1778                 /* save the first error encountered for the
1779                  * return value */
1780                 err = PTR_ERR(nentry);
1781                 audit_panic("error updating LSM filters");
1782                 if (watch)
1783                         list_del(&r->rlist);
1784                 list_del_rcu(&entry->list);
1785                 list_del(&r->list);
1786         } else {
1787                 if (watch) {
1788                         list_add(&nentry->rule.rlist, &watch->rules);
1789                         list_del(&r->rlist);
1790                 } else if (tree)
1791                         list_replace_init(&r->rlist, &nentry->rule.rlist);
1792                 list_replace_rcu(&entry->list, &nentry->list);
1793                 list_replace(&r->list, &nentry->rule.list);
1794         }
1795         call_rcu(&entry->rcu, audit_free_rule_rcu);
1796
1797         return err;
1798 }
1799
1800 /* This function will re-initialize the lsm_rule field of all applicable rules.
1801  * It will traverse the filter lists serarching for rules that contain LSM
1802  * specific filter fields.  When such a rule is found, it is copied, the
1803  * LSM field is re-initialized, and the old rule is replaced with the
1804  * updated rule. */
1805 int audit_update_lsm_rules(void)
1806 {
1807         struct audit_krule *r, *n;
1808         int i, err = 0;
1809
1810         /* audit_filter_mutex synchronizes the writers */
1811         mutex_lock(&audit_filter_mutex);
1812
1813         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1814                 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1815                         int res = update_lsm_rule(r);
1816                         if (!err)
1817                                 err = res;
1818                 }
1819         }
1820         mutex_unlock(&audit_filter_mutex);
1821
1822         return err;
1823 }
1824
1825 /* Update watch data in audit rules based on inotify events. */
1826 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1827                          u32 cookie, const char *dname, struct inode *inode)
1828 {
1829         struct audit_parent *parent;
1830
1831         parent = container_of(i_watch, struct audit_parent, wdata);
1832
1833         if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1834                 audit_update_watch(parent, dname, inode->i_sb->s_dev,
1835                                    inode->i_ino, 0);
1836         else if (mask & (IN_DELETE|IN_MOVED_FROM))
1837                 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1838         /* inotify automatically removes the watch and sends IN_IGNORED */
1839         else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1840                 audit_remove_parent_watches(parent);
1841         /* inotify does not remove the watch, so remove it manually */
1842         else if(mask & IN_MOVE_SELF) {
1843                 audit_remove_parent_watches(parent);
1844                 inotify_remove_watch_locked(audit_ih, i_watch);
1845         } else if (mask & IN_IGNORED)
1846                 put_inotify_watch(i_watch);
1847 }