alpha/osf_sys: remove unused MAX_SELECT_SECONDS
[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/slab.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 /* Audit filter lists, defined in <linux/audit.h> */
48 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
49         LIST_HEAD_INIT(audit_filter_list[0]),
50         LIST_HEAD_INIT(audit_filter_list[1]),
51         LIST_HEAD_INIT(audit_filter_list[2]),
52         LIST_HEAD_INIT(audit_filter_list[3]),
53         LIST_HEAD_INIT(audit_filter_list[4]),
54         LIST_HEAD_INIT(audit_filter_list[5]),
55 #if AUDIT_NR_FILTERS != 6
56 #error Fix audit_filter_list initialiser
57 #endif
58 };
59 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
60         LIST_HEAD_INIT(audit_rules_list[0]),
61         LIST_HEAD_INIT(audit_rules_list[1]),
62         LIST_HEAD_INIT(audit_rules_list[2]),
63         LIST_HEAD_INIT(audit_rules_list[3]),
64         LIST_HEAD_INIT(audit_rules_list[4]),
65         LIST_HEAD_INIT(audit_rules_list[5]),
66 };
67
68 DEFINE_MUTEX(audit_filter_mutex);
69
70 static inline void audit_free_rule(struct audit_entry *e)
71 {
72         int i;
73         struct audit_krule *erule = &e->rule;
74
75         /* some rules don't have associated watches */
76         if (erule->watch)
77                 audit_put_watch(erule->watch);
78         if (erule->fields)
79                 for (i = 0; i < erule->field_count; i++) {
80                         struct audit_field *f = &erule->fields[i];
81                         kfree(f->lsm_str);
82                         security_audit_rule_free(f->lsm_rule);
83                 }
84         kfree(erule->fields);
85         kfree(erule->filterkey);
86         kfree(e);
87 }
88
89 void audit_free_rule_rcu(struct rcu_head *head)
90 {
91         struct audit_entry *e = container_of(head, struct audit_entry, rcu);
92         audit_free_rule(e);
93 }
94
95 /* Initialize an audit filterlist entry. */
96 static inline struct audit_entry *audit_init_entry(u32 field_count)
97 {
98         struct audit_entry *entry;
99         struct audit_field *fields;
100
101         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102         if (unlikely(!entry))
103                 return NULL;
104
105         fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106         if (unlikely(!fields)) {
107                 kfree(entry);
108                 return NULL;
109         }
110         entry->rule.fields = fields;
111
112         return entry;
113 }
114
115 /* Unpack a filter field's string representation from user-space
116  * buffer. */
117 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
118 {
119         char *str;
120
121         if (!*bufp || (len == 0) || (len > *remain))
122                 return ERR_PTR(-EINVAL);
123
124         /* Of the currently implemented string fields, PATH_MAX
125          * defines the longest valid length.
126          */
127         if (len > PATH_MAX)
128                 return ERR_PTR(-ENAMETOOLONG);
129
130         str = kmalloc(len + 1, GFP_KERNEL);
131         if (unlikely(!str))
132                 return ERR_PTR(-ENOMEM);
133
134         memcpy(str, *bufp, len);
135         str[len] = 0;
136         *bufp += len;
137         *remain -= len;
138
139         return str;
140 }
141
142 /* Translate an inode field to kernel respresentation. */
143 static inline int audit_to_inode(struct audit_krule *krule,
144                                  struct audit_field *f)
145 {
146         if (krule->listnr != AUDIT_FILTER_EXIT ||
147             krule->watch || krule->inode_f || krule->tree ||
148             (f->op != Audit_equal && f->op != Audit_not_equal))
149                 return -EINVAL;
150
151         krule->inode_f = f;
152         return 0;
153 }
154
155 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
156
157 int __init audit_register_class(int class, unsigned *list)
158 {
159         __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
160         if (!p)
161                 return -ENOMEM;
162         while (*list != ~0U) {
163                 unsigned n = *list++;
164                 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
165                         kfree(p);
166                         return -EINVAL;
167                 }
168                 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
169         }
170         if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
171                 kfree(p);
172                 return -EINVAL;
173         }
174         classes[class] = p;
175         return 0;
176 }
177
178 int audit_match_class(int class, unsigned syscall)
179 {
180         if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
181                 return 0;
182         if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
183                 return 0;
184         return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
185 }
186
187 #ifdef CONFIG_AUDITSYSCALL
188 static inline int audit_match_class_bits(int class, u32 *mask)
189 {
190         int i;
191
192         if (classes[class]) {
193                 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194                         if (mask[i] & classes[class][i])
195                                 return 0;
196         }
197         return 1;
198 }
199
200 static int audit_match_signal(struct audit_entry *entry)
201 {
202         struct audit_field *arch = entry->rule.arch_f;
203
204         if (!arch) {
205                 /* When arch is unspecified, we must check both masks on biarch
206                  * as syscall number alone is ambiguous. */
207                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
208                                                entry->rule.mask) &&
209                         audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
210                                                entry->rule.mask));
211         }
212
213         switch(audit_classify_arch(arch->val)) {
214         case 0: /* native */
215                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216                                                entry->rule.mask));
217         case 1: /* 32bit on biarch */
218                 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
219                                                entry->rule.mask));
220         default:
221                 return 1;
222         }
223 }
224 #endif
225
226 /* Common user-space to kernel rule translation. */
227 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
228 {
229         unsigned listnr;
230         struct audit_entry *entry;
231         int i, err;
232
233         err = -EINVAL;
234         listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
235         switch(listnr) {
236         default:
237                 goto exit_err;
238         case AUDIT_FILTER_USER:
239         case AUDIT_FILTER_TYPE:
240 #ifdef CONFIG_AUDITSYSCALL
241         case AUDIT_FILTER_ENTRY:
242         case AUDIT_FILTER_EXIT:
243         case AUDIT_FILTER_TASK:
244 #endif
245                 ;
246         }
247         if (unlikely(rule->action == AUDIT_POSSIBLE)) {
248                 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
249                 goto exit_err;
250         }
251         if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
252                 goto exit_err;
253         if (rule->field_count > AUDIT_MAX_FIELDS)
254                 goto exit_err;
255
256         err = -ENOMEM;
257         entry = audit_init_entry(rule->field_count);
258         if (!entry)
259                 goto exit_err;
260
261         entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
262         entry->rule.listnr = listnr;
263         entry->rule.action = rule->action;
264         entry->rule.field_count = rule->field_count;
265
266         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
267                 entry->rule.mask[i] = rule->mask[i];
268
269         for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
270                 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
271                 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
272                 __u32 *class;
273
274                 if (!(*p & AUDIT_BIT(bit)))
275                         continue;
276                 *p &= ~AUDIT_BIT(bit);
277                 class = classes[i];
278                 if (class) {
279                         int j;
280                         for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
281                                 entry->rule.mask[j] |= class[j];
282                 }
283         }
284
285         return entry;
286
287 exit_err:
288         return ERR_PTR(err);
289 }
290
291 static u32 audit_ops[] =
292 {
293         [Audit_equal] = AUDIT_EQUAL,
294         [Audit_not_equal] = AUDIT_NOT_EQUAL,
295         [Audit_bitmask] = AUDIT_BIT_MASK,
296         [Audit_bittest] = AUDIT_BIT_TEST,
297         [Audit_lt] = AUDIT_LESS_THAN,
298         [Audit_gt] = AUDIT_GREATER_THAN,
299         [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
300         [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
301 };
302
303 static u32 audit_to_op(u32 op)
304 {
305         u32 n;
306         for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
307                 ;
308         return n;
309 }
310
311
312 /* Translate struct audit_rule to kernel's rule respresentation.
313  * Exists for backward compatibility with userspace. */
314 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
315 {
316         struct audit_entry *entry;
317         int err = 0;
318         int i;
319
320         entry = audit_to_entry_common(rule);
321         if (IS_ERR(entry))
322                 goto exit_nofree;
323
324         for (i = 0; i < rule->field_count; i++) {
325                 struct audit_field *f = &entry->rule.fields[i];
326                 u32 n;
327
328                 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
329
330                 /* Support for legacy operators where
331                  * AUDIT_NEGATE bit signifies != and otherwise assumes == */
332                 if (n & AUDIT_NEGATE)
333                         f->op = Audit_not_equal;
334                 else if (!n)
335                         f->op = Audit_equal;
336                 else
337                         f->op = audit_to_op(n);
338
339                 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
340
341                 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
342                 f->val = rule->values[i];
343
344                 err = -EINVAL;
345                 if (f->op == Audit_bad)
346                         goto exit_free;
347
348                 switch(f->type) {
349                 default:
350                         goto exit_free;
351                 case AUDIT_PID:
352                 case AUDIT_UID:
353                 case AUDIT_EUID:
354                 case AUDIT_SUID:
355                 case AUDIT_FSUID:
356                 case AUDIT_GID:
357                 case AUDIT_EGID:
358                 case AUDIT_SGID:
359                 case AUDIT_FSGID:
360                 case AUDIT_LOGINUID:
361                 case AUDIT_PERS:
362                 case AUDIT_MSGTYPE:
363                 case AUDIT_PPID:
364                 case AUDIT_DEVMAJOR:
365                 case AUDIT_DEVMINOR:
366                 case AUDIT_EXIT:
367                 case AUDIT_SUCCESS:
368                         /* bit ops are only useful on syscall args */
369                         if (f->op == Audit_bitmask || f->op == Audit_bittest)
370                                 goto exit_free;
371                         break;
372                 case AUDIT_ARG0:
373                 case AUDIT_ARG1:
374                 case AUDIT_ARG2:
375                 case AUDIT_ARG3:
376                         break;
377                 /* arch is only allowed to be = or != */
378                 case AUDIT_ARCH:
379                         if (f->op != Audit_not_equal && f->op != Audit_equal)
380                                 goto exit_free;
381                         entry->rule.arch_f = f;
382                         break;
383                 case AUDIT_PERM:
384                         if (f->val & ~15)
385                                 goto exit_free;
386                         break;
387                 case AUDIT_FILETYPE:
388                         if ((f->val & ~S_IFMT) > S_IFMT)
389                                 goto exit_free;
390                         break;
391                 case AUDIT_INODE:
392                         err = audit_to_inode(&entry->rule, f);
393                         if (err)
394                                 goto exit_free;
395                         break;
396                 }
397         }
398
399         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
400                 entry->rule.inode_f = NULL;
401
402 exit_nofree:
403         return entry;
404
405 exit_free:
406         audit_free_rule(entry);
407         return ERR_PTR(err);
408 }
409
410 /* Translate struct audit_rule_data to kernel's rule respresentation. */
411 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
412                                                size_t datasz)
413 {
414         int err = 0;
415         struct audit_entry *entry;
416         void *bufp;
417         size_t remain = datasz - sizeof(struct audit_rule_data);
418         int i;
419         char *str;
420
421         entry = audit_to_entry_common((struct audit_rule *)data);
422         if (IS_ERR(entry))
423                 goto exit_nofree;
424
425         bufp = data->buf;
426         entry->rule.vers_ops = 2;
427         for (i = 0; i < data->field_count; i++) {
428                 struct audit_field *f = &entry->rule.fields[i];
429
430                 err = -EINVAL;
431
432                 f->op = audit_to_op(data->fieldflags[i]);
433                 if (f->op == Audit_bad)
434                         goto exit_free;
435
436                 f->type = data->fields[i];
437                 f->val = data->values[i];
438                 f->lsm_str = NULL;
439                 f->lsm_rule = NULL;
440                 switch(f->type) {
441                 case AUDIT_PID:
442                 case AUDIT_UID:
443                 case AUDIT_EUID:
444                 case AUDIT_SUID:
445                 case AUDIT_FSUID:
446                 case AUDIT_GID:
447                 case AUDIT_EGID:
448                 case AUDIT_SGID:
449                 case AUDIT_FSGID:
450                 case AUDIT_LOGINUID:
451                 case AUDIT_PERS:
452                 case AUDIT_MSGTYPE:
453                 case AUDIT_PPID:
454                 case AUDIT_DEVMAJOR:
455                 case AUDIT_DEVMINOR:
456                 case AUDIT_EXIT:
457                 case AUDIT_SUCCESS:
458                 case AUDIT_ARG0:
459                 case AUDIT_ARG1:
460                 case AUDIT_ARG2:
461                 case AUDIT_ARG3:
462                         break;
463                 case AUDIT_ARCH:
464                         entry->rule.arch_f = f;
465                         break;
466                 case AUDIT_SUBJ_USER:
467                 case AUDIT_SUBJ_ROLE:
468                 case AUDIT_SUBJ_TYPE:
469                 case AUDIT_SUBJ_SEN:
470                 case AUDIT_SUBJ_CLR:
471                 case AUDIT_OBJ_USER:
472                 case AUDIT_OBJ_ROLE:
473                 case AUDIT_OBJ_TYPE:
474                 case AUDIT_OBJ_LEV_LOW:
475                 case AUDIT_OBJ_LEV_HIGH:
476                         str = audit_unpack_string(&bufp, &remain, f->val);
477                         if (IS_ERR(str))
478                                 goto exit_free;
479                         entry->rule.buflen += f->val;
480
481                         err = security_audit_rule_init(f->type, f->op, str,
482                                                        (void **)&f->lsm_rule);
483                         /* Keep currently invalid fields around in case they
484                          * become valid after a policy reload. */
485                         if (err == -EINVAL) {
486                                 printk(KERN_WARNING "audit rule for LSM "
487                                        "\'%s\' is invalid\n",  str);
488                                 err = 0;
489                         }
490                         if (err) {
491                                 kfree(str);
492                                 goto exit_free;
493                         } else
494                                 f->lsm_str = str;
495                         break;
496                 case AUDIT_WATCH:
497                         str = audit_unpack_string(&bufp, &remain, f->val);
498                         if (IS_ERR(str))
499                                 goto exit_free;
500                         entry->rule.buflen += f->val;
501
502                         err = audit_to_watch(&entry->rule, str, f->val, f->op);
503                         if (err) {
504                                 kfree(str);
505                                 goto exit_free;
506                         }
507                         break;
508                 case AUDIT_DIR:
509                         str = audit_unpack_string(&bufp, &remain, f->val);
510                         if (IS_ERR(str))
511                                 goto exit_free;
512                         entry->rule.buflen += f->val;
513
514                         err = audit_make_tree(&entry->rule, str, f->op);
515                         kfree(str);
516                         if (err)
517                                 goto exit_free;
518                         break;
519                 case AUDIT_INODE:
520                         err = audit_to_inode(&entry->rule, f);
521                         if (err)
522                                 goto exit_free;
523                         break;
524                 case AUDIT_FILTERKEY:
525                         err = -EINVAL;
526                         if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
527                                 goto exit_free;
528                         str = audit_unpack_string(&bufp, &remain, f->val);
529                         if (IS_ERR(str))
530                                 goto exit_free;
531                         entry->rule.buflen += f->val;
532                         entry->rule.filterkey = str;
533                         break;
534                 case AUDIT_PERM:
535                         if (f->val & ~15)
536                                 goto exit_free;
537                         break;
538                 case AUDIT_FILETYPE:
539                         if ((f->val & ~S_IFMT) > S_IFMT)
540                                 goto exit_free;
541                         break;
542                 default:
543                         goto exit_free;
544                 }
545         }
546
547         if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
548                 entry->rule.inode_f = NULL;
549
550 exit_nofree:
551         return entry;
552
553 exit_free:
554         audit_free_rule(entry);
555         return ERR_PTR(err);
556 }
557
558 /* Pack a filter field's string representation into data block. */
559 static inline size_t audit_pack_string(void **bufp, const char *str)
560 {
561         size_t len = strlen(str);
562
563         memcpy(*bufp, str, len);
564         *bufp += len;
565
566         return len;
567 }
568
569 /* Translate kernel rule respresentation to struct audit_rule.
570  * Exists for backward compatibility with userspace. */
571 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
572 {
573         struct audit_rule *rule;
574         int i;
575
576         rule = kzalloc(sizeof(*rule), GFP_KERNEL);
577         if (unlikely(!rule))
578                 return NULL;
579
580         rule->flags = krule->flags | krule->listnr;
581         rule->action = krule->action;
582         rule->field_count = krule->field_count;
583         for (i = 0; i < rule->field_count; i++) {
584                 rule->values[i] = krule->fields[i].val;
585                 rule->fields[i] = krule->fields[i].type;
586
587                 if (krule->vers_ops == 1) {
588                         if (krule->fields[i].op == Audit_not_equal)
589                                 rule->fields[i] |= AUDIT_NEGATE;
590                 } else {
591                         rule->fields[i] |= audit_ops[krule->fields[i].op];
592                 }
593         }
594         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
595
596         return rule;
597 }
598
599 /* Translate kernel rule respresentation to struct audit_rule_data. */
600 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
601 {
602         struct audit_rule_data *data;
603         void *bufp;
604         int i;
605
606         data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
607         if (unlikely(!data))
608                 return NULL;
609         memset(data, 0, sizeof(*data));
610
611         data->flags = krule->flags | krule->listnr;
612         data->action = krule->action;
613         data->field_count = krule->field_count;
614         bufp = data->buf;
615         for (i = 0; i < data->field_count; i++) {
616                 struct audit_field *f = &krule->fields[i];
617
618                 data->fields[i] = f->type;
619                 data->fieldflags[i] = audit_ops[f->op];
620                 switch(f->type) {
621                 case AUDIT_SUBJ_USER:
622                 case AUDIT_SUBJ_ROLE:
623                 case AUDIT_SUBJ_TYPE:
624                 case AUDIT_SUBJ_SEN:
625                 case AUDIT_SUBJ_CLR:
626                 case AUDIT_OBJ_USER:
627                 case AUDIT_OBJ_ROLE:
628                 case AUDIT_OBJ_TYPE:
629                 case AUDIT_OBJ_LEV_LOW:
630                 case AUDIT_OBJ_LEV_HIGH:
631                         data->buflen += data->values[i] =
632                                 audit_pack_string(&bufp, f->lsm_str);
633                         break;
634                 case AUDIT_WATCH:
635                         data->buflen += data->values[i] =
636                                 audit_pack_string(&bufp,
637                                                   audit_watch_path(krule->watch));
638                         break;
639                 case AUDIT_DIR:
640                         data->buflen += data->values[i] =
641                                 audit_pack_string(&bufp,
642                                                   audit_tree_path(krule->tree));
643                         break;
644                 case AUDIT_FILTERKEY:
645                         data->buflen += data->values[i] =
646                                 audit_pack_string(&bufp, krule->filterkey);
647                         break;
648                 default:
649                         data->values[i] = f->val;
650                 }
651         }
652         for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
653
654         return data;
655 }
656
657 /* Compare two rules in kernel format.  Considered success if rules
658  * don't match. */
659 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
660 {
661         int i;
662
663         if (a->flags != b->flags ||
664             a->listnr != b->listnr ||
665             a->action != b->action ||
666             a->field_count != b->field_count)
667                 return 1;
668
669         for (i = 0; i < a->field_count; i++) {
670                 if (a->fields[i].type != b->fields[i].type ||
671                     a->fields[i].op != b->fields[i].op)
672                         return 1;
673
674                 switch(a->fields[i].type) {
675                 case AUDIT_SUBJ_USER:
676                 case AUDIT_SUBJ_ROLE:
677                 case AUDIT_SUBJ_TYPE:
678                 case AUDIT_SUBJ_SEN:
679                 case AUDIT_SUBJ_CLR:
680                 case AUDIT_OBJ_USER:
681                 case AUDIT_OBJ_ROLE:
682                 case AUDIT_OBJ_TYPE:
683                 case AUDIT_OBJ_LEV_LOW:
684                 case AUDIT_OBJ_LEV_HIGH:
685                         if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
686                                 return 1;
687                         break;
688                 case AUDIT_WATCH:
689                         if (strcmp(audit_watch_path(a->watch),
690                                    audit_watch_path(b->watch)))
691                                 return 1;
692                         break;
693                 case AUDIT_DIR:
694                         if (strcmp(audit_tree_path(a->tree),
695                                    audit_tree_path(b->tree)))
696                                 return 1;
697                         break;
698                 case AUDIT_FILTERKEY:
699                         /* both filterkeys exist based on above type compare */
700                         if (strcmp(a->filterkey, b->filterkey))
701                                 return 1;
702                         break;
703                 default:
704                         if (a->fields[i].val != b->fields[i].val)
705                                 return 1;
706                 }
707         }
708
709         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
710                 if (a->mask[i] != b->mask[i])
711                         return 1;
712
713         return 0;
714 }
715
716 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
717  * re-initialized. */
718 static inline int audit_dupe_lsm_field(struct audit_field *df,
719                                            struct audit_field *sf)
720 {
721         int ret = 0;
722         char *lsm_str;
723
724         /* our own copy of lsm_str */
725         lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
726         if (unlikely(!lsm_str))
727                 return -ENOMEM;
728         df->lsm_str = lsm_str;
729
730         /* our own (refreshed) copy of lsm_rule */
731         ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
732                                        (void **)&df->lsm_rule);
733         /* Keep currently invalid fields around in case they
734          * become valid after a policy reload. */
735         if (ret == -EINVAL) {
736                 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
737                        "invalid\n", df->lsm_str);
738                 ret = 0;
739         }
740
741         return ret;
742 }
743
744 /* Duplicate an audit rule.  This will be a deep copy with the exception
745  * of the watch - that pointer is carried over.  The LSM specific fields
746  * will be updated in the copy.  The point is to be able to replace the old
747  * rule with the new rule in the filterlist, then free the old rule.
748  * The rlist element is undefined; list manipulations are handled apart from
749  * the initial copy. */
750 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
751 {
752         u32 fcount = old->field_count;
753         struct audit_entry *entry;
754         struct audit_krule *new;
755         char *fk;
756         int i, err = 0;
757
758         entry = audit_init_entry(fcount);
759         if (unlikely(!entry))
760                 return ERR_PTR(-ENOMEM);
761
762         new = &entry->rule;
763         new->vers_ops = old->vers_ops;
764         new->flags = old->flags;
765         new->listnr = old->listnr;
766         new->action = old->action;
767         for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
768                 new->mask[i] = old->mask[i];
769         new->prio = old->prio;
770         new->buflen = old->buflen;
771         new->inode_f = old->inode_f;
772         new->field_count = old->field_count;
773
774         /*
775          * note that we are OK with not refcounting here; audit_match_tree()
776          * never dereferences tree and we can't get false positives there
777          * since we'd have to have rule gone from the list *and* removed
778          * before the chunks found by lookup had been allocated, i.e. before
779          * the beginning of list scan.
780          */
781         new->tree = old->tree;
782         memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
783
784         /* deep copy this information, updating the lsm_rule fields, because
785          * the originals will all be freed when the old rule is freed. */
786         for (i = 0; i < fcount; i++) {
787                 switch (new->fields[i].type) {
788                 case AUDIT_SUBJ_USER:
789                 case AUDIT_SUBJ_ROLE:
790                 case AUDIT_SUBJ_TYPE:
791                 case AUDIT_SUBJ_SEN:
792                 case AUDIT_SUBJ_CLR:
793                 case AUDIT_OBJ_USER:
794                 case AUDIT_OBJ_ROLE:
795                 case AUDIT_OBJ_TYPE:
796                 case AUDIT_OBJ_LEV_LOW:
797                 case AUDIT_OBJ_LEV_HIGH:
798                         err = audit_dupe_lsm_field(&new->fields[i],
799                                                        &old->fields[i]);
800                         break;
801                 case AUDIT_FILTERKEY:
802                         fk = kstrdup(old->filterkey, GFP_KERNEL);
803                         if (unlikely(!fk))
804                                 err = -ENOMEM;
805                         else
806                                 new->filterkey = fk;
807                 }
808                 if (err) {
809                         audit_free_rule(entry);
810                         return ERR_PTR(err);
811                 }
812         }
813
814         if (old->watch) {
815                 audit_get_watch(old->watch);
816                 new->watch = old->watch;
817         }
818
819         return entry;
820 }
821
822 /* Find an existing audit rule.
823  * Caller must hold audit_filter_mutex to prevent stale rule data. */
824 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
825                                            struct list_head **p)
826 {
827         struct audit_entry *e, *found = NULL;
828         struct list_head *list;
829         int h;
830
831         if (entry->rule.inode_f) {
832                 h = audit_hash_ino(entry->rule.inode_f->val);
833                 *p = list = &audit_inode_hash[h];
834         } else if (entry->rule.watch) {
835                 /* we don't know the inode number, so must walk entire hash */
836                 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
837                         list = &audit_inode_hash[h];
838                         list_for_each_entry(e, list, list)
839                                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
840                                         found = e;
841                                         goto out;
842                                 }
843                 }
844                 goto out;
845         } else {
846                 *p = list = &audit_filter_list[entry->rule.listnr];
847         }
848
849         list_for_each_entry(e, list, list)
850                 if (!audit_compare_rule(&entry->rule, &e->rule)) {
851                         found = e;
852                         goto out;
853                 }
854
855 out:
856         return found;
857 }
858
859 static u64 prio_low = ~0ULL/2;
860 static u64 prio_high = ~0ULL/2 - 1;
861
862 /* Add rule to given filterlist if not a duplicate. */
863 static inline int audit_add_rule(struct audit_entry *entry)
864 {
865         struct audit_entry *e;
866         struct audit_watch *watch = entry->rule.watch;
867         struct audit_tree *tree = entry->rule.tree;
868         struct list_head *list;
869         int err;
870 #ifdef CONFIG_AUDITSYSCALL
871         int dont_count = 0;
872
873         /* If either of these, don't count towards total */
874         if (entry->rule.listnr == AUDIT_FILTER_USER ||
875                 entry->rule.listnr == AUDIT_FILTER_TYPE)
876                 dont_count = 1;
877 #endif
878
879         mutex_lock(&audit_filter_mutex);
880         e = audit_find_rule(entry, &list);
881         if (e) {
882                 mutex_unlock(&audit_filter_mutex);
883                 err = -EEXIST;
884                 /* normally audit_add_tree_rule() will free it on failure */
885                 if (tree)
886                         audit_put_tree(tree);
887                 goto error;
888         }
889
890         if (watch) {
891                 /* audit_filter_mutex is dropped and re-taken during this call */
892                 err = audit_add_watch(&entry->rule, &list);
893                 if (err) {
894                         mutex_unlock(&audit_filter_mutex);
895                         goto error;
896                 }
897         }
898         if (tree) {
899                 err = audit_add_tree_rule(&entry->rule);
900                 if (err) {
901                         mutex_unlock(&audit_filter_mutex);
902                         goto error;
903                 }
904         }
905
906         entry->rule.prio = ~0ULL;
907         if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
908                 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
909                         entry->rule.prio = ++prio_high;
910                 else
911                         entry->rule.prio = --prio_low;
912         }
913
914         if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
915                 list_add(&entry->rule.list,
916                          &audit_rules_list[entry->rule.listnr]);
917                 list_add_rcu(&entry->list, list);
918                 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
919         } else {
920                 list_add_tail(&entry->rule.list,
921                               &audit_rules_list[entry->rule.listnr]);
922                 list_add_tail_rcu(&entry->list, list);
923         }
924 #ifdef CONFIG_AUDITSYSCALL
925         if (!dont_count)
926                 audit_n_rules++;
927
928         if (!audit_match_signal(entry))
929                 audit_signals++;
930 #endif
931         mutex_unlock(&audit_filter_mutex);
932
933         return 0;
934
935 error:
936         if (watch)
937                 audit_put_watch(watch); /* tmp watch, matches initial get */
938         return err;
939 }
940
941 /* Remove an existing rule from filterlist. */
942 static inline int audit_del_rule(struct audit_entry *entry)
943 {
944         struct audit_entry  *e;
945         struct audit_watch *watch = entry->rule.watch;
946         struct audit_tree *tree = entry->rule.tree;
947         struct list_head *list;
948         int ret = 0;
949 #ifdef CONFIG_AUDITSYSCALL
950         int dont_count = 0;
951
952         /* If either of these, don't count towards total */
953         if (entry->rule.listnr == AUDIT_FILTER_USER ||
954                 entry->rule.listnr == AUDIT_FILTER_TYPE)
955                 dont_count = 1;
956 #endif
957
958         mutex_lock(&audit_filter_mutex);
959         e = audit_find_rule(entry, &list);
960         if (!e) {
961                 mutex_unlock(&audit_filter_mutex);
962                 ret = -ENOENT;
963                 goto out;
964         }
965
966         if (e->rule.watch)
967                 audit_remove_watch_rule(&e->rule);
968
969         if (e->rule.tree)
970                 audit_remove_tree_rule(&e->rule);
971
972         list_del_rcu(&e->list);
973         list_del(&e->rule.list);
974         call_rcu(&e->rcu, audit_free_rule_rcu);
975
976 #ifdef CONFIG_AUDITSYSCALL
977         if (!dont_count)
978                 audit_n_rules--;
979
980         if (!audit_match_signal(entry))
981                 audit_signals--;
982 #endif
983         mutex_unlock(&audit_filter_mutex);
984
985 out:
986         if (watch)
987                 audit_put_watch(watch); /* match initial get */
988         if (tree)
989                 audit_put_tree(tree);   /* that's the temporary one */
990
991         return ret;
992 }
993
994 /* List rules using struct audit_rule.  Exists for backward
995  * compatibility with userspace. */
996 static void audit_list(int pid, int seq, struct sk_buff_head *q)
997 {
998         struct sk_buff *skb;
999         struct audit_krule *r;
1000         int i;
1001
1002         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1003          * iterator to sync with list writers. */
1004         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1005                 list_for_each_entry(r, &audit_rules_list[i], list) {
1006                         struct audit_rule *rule;
1007
1008                         rule = audit_krule_to_rule(r);
1009                         if (unlikely(!rule))
1010                                 break;
1011                         skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1012                                          rule, sizeof(*rule));
1013                         if (skb)
1014                                 skb_queue_tail(q, skb);
1015                         kfree(rule);
1016                 }
1017         }
1018         skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1019         if (skb)
1020                 skb_queue_tail(q, skb);
1021 }
1022
1023 /* List rules using struct audit_rule_data. */
1024 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1025 {
1026         struct sk_buff *skb;
1027         struct audit_krule *r;
1028         int i;
1029
1030         /* This is a blocking read, so use audit_filter_mutex instead of rcu
1031          * iterator to sync with list writers. */
1032         for (i=0; i<AUDIT_NR_FILTERS; i++) {
1033                 list_for_each_entry(r, &audit_rules_list[i], list) {
1034                         struct audit_rule_data *data;
1035
1036                         data = audit_krule_to_data(r);
1037                         if (unlikely(!data))
1038                                 break;
1039                         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1040                                          data, sizeof(*data) + data->buflen);
1041                         if (skb)
1042                                 skb_queue_tail(q, skb);
1043                         kfree(data);
1044                 }
1045         }
1046         skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1047         if (skb)
1048                 skb_queue_tail(q, skb);
1049 }
1050
1051 /* Log rule additions and removals */
1052 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1053                                   char *action, struct audit_krule *rule,
1054                                   int res)
1055 {
1056         struct audit_buffer *ab;
1057
1058         if (!audit_enabled)
1059                 return;
1060
1061         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1062         if (!ab)
1063                 return;
1064         audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1065         if (sid) {
1066                 char *ctx = NULL;
1067                 u32 len;
1068                 if (security_secid_to_secctx(sid, &ctx, &len))
1069                         audit_log_format(ab, " ssid=%u", sid);
1070                 else {
1071                         audit_log_format(ab, " subj=%s", ctx);
1072                         security_release_secctx(ctx, len);
1073                 }
1074         }
1075         audit_log_format(ab, " op=");
1076         audit_log_string(ab, action);
1077         audit_log_key(ab, rule->filterkey);
1078         audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1079         audit_log_end(ab);
1080 }
1081
1082 /**
1083  * audit_receive_filter - apply all rules to the specified message type
1084  * @type: audit message type
1085  * @pid: target pid for netlink audit messages
1086  * @uid: target uid for netlink audit messages
1087  * @seq: netlink audit message sequence (serial) number
1088  * @data: payload data
1089  * @datasz: size of payload data
1090  * @loginuid: loginuid of sender
1091  * @sessionid: sessionid for netlink audit message
1092  * @sid: SE Linux Security ID of sender
1093  */
1094 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1095                          size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1096 {
1097         struct task_struct *tsk;
1098         struct audit_netlink_list *dest;
1099         int err = 0;
1100         struct audit_entry *entry;
1101
1102         switch (type) {
1103         case AUDIT_LIST:
1104         case AUDIT_LIST_RULES:
1105                 /* We can't just spew out the rules here because we might fill
1106                  * the available socket buffer space and deadlock waiting for
1107                  * auditctl to read from it... which isn't ever going to
1108                  * happen if we're actually running in the context of auditctl
1109                  * trying to _send_ the stuff */
1110
1111                 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1112                 if (!dest)
1113                         return -ENOMEM;
1114                 dest->pid = pid;
1115                 skb_queue_head_init(&dest->q);
1116
1117                 mutex_lock(&audit_filter_mutex);
1118                 if (type == AUDIT_LIST)
1119                         audit_list(pid, seq, &dest->q);
1120                 else
1121                         audit_list_rules(pid, seq, &dest->q);
1122                 mutex_unlock(&audit_filter_mutex);
1123
1124                 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1125                 if (IS_ERR(tsk)) {
1126                         skb_queue_purge(&dest->q);
1127                         kfree(dest);
1128                         err = PTR_ERR(tsk);
1129                 }
1130                 break;
1131         case AUDIT_ADD:
1132         case AUDIT_ADD_RULE:
1133                 if (type == AUDIT_ADD)
1134                         entry = audit_rule_to_entry(data);
1135                 else
1136                         entry = audit_data_to_entry(data, datasz);
1137                 if (IS_ERR(entry))
1138                         return PTR_ERR(entry);
1139
1140                 err = audit_add_rule(entry);
1141                 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1142                                       &entry->rule, !err);
1143
1144                 if (err)
1145                         audit_free_rule(entry);
1146                 break;
1147         case AUDIT_DEL:
1148         case AUDIT_DEL_RULE:
1149                 if (type == AUDIT_DEL)
1150                         entry = audit_rule_to_entry(data);
1151                 else
1152                         entry = audit_data_to_entry(data, datasz);
1153                 if (IS_ERR(entry))
1154                         return PTR_ERR(entry);
1155
1156                 err = audit_del_rule(entry);
1157                 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1158                                       &entry->rule, !err);
1159
1160                 audit_free_rule(entry);
1161                 break;
1162         default:
1163                 return -EINVAL;
1164         }
1165
1166         return err;
1167 }
1168
1169 int audit_comparator(u32 left, u32 op, u32 right)
1170 {
1171         switch (op) {
1172         case Audit_equal:
1173                 return (left == right);
1174         case Audit_not_equal:
1175                 return (left != right);
1176         case Audit_lt:
1177                 return (left < right);
1178         case Audit_le:
1179                 return (left <= right);
1180         case Audit_gt:
1181                 return (left > right);
1182         case Audit_ge:
1183                 return (left >= right);
1184         case Audit_bitmask:
1185                 return (left & right);
1186         case Audit_bittest:
1187                 return ((left & right) == right);
1188         default:
1189                 BUG();
1190                 return 0;
1191         }
1192 }
1193
1194 /* Compare given dentry name with last component in given path,
1195  * return of 0 indicates a match. */
1196 int audit_compare_dname_path(const char *dname, const char *path,
1197                              int *dirlen)
1198 {
1199         int dlen, plen;
1200         const char *p;
1201
1202         if (!dname || !path)
1203                 return 1;
1204
1205         dlen = strlen(dname);
1206         plen = strlen(path);
1207         if (plen < dlen)
1208                 return 1;
1209
1210         /* disregard trailing slashes */
1211         p = path + plen - 1;
1212         while ((*p == '/') && (p > path))
1213                 p--;
1214
1215         /* find last path component */
1216         p = p - dlen + 1;
1217         if (p < path)
1218                 return 1;
1219         else if (p > path) {
1220                 if (*--p != '/')
1221                         return 1;
1222                 else
1223                         p++;
1224         }
1225
1226         /* return length of path's directory component */
1227         if (dirlen)
1228                 *dirlen = p - path;
1229         return strncmp(p, dname, dlen);
1230 }
1231
1232 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1233                                    struct audit_krule *rule,
1234                                    enum audit_state *state)
1235 {
1236         int i;
1237
1238         for (i = 0; i < rule->field_count; i++) {
1239                 struct audit_field *f = &rule->fields[i];
1240                 int result = 0;
1241
1242                 switch (f->type) {
1243                 case AUDIT_PID:
1244                         result = audit_comparator(cb->creds.pid, f->op, f->val);
1245                         break;
1246                 case AUDIT_UID:
1247                         result = audit_comparator(cb->creds.uid, f->op, f->val);
1248                         break;
1249                 case AUDIT_GID:
1250                         result = audit_comparator(cb->creds.gid, f->op, f->val);
1251                         break;
1252                 case AUDIT_LOGINUID:
1253                         result = audit_comparator(cb->loginuid, f->op, f->val);
1254                         break;
1255                 case AUDIT_SUBJ_USER:
1256                 case AUDIT_SUBJ_ROLE:
1257                 case AUDIT_SUBJ_TYPE:
1258                 case AUDIT_SUBJ_SEN:
1259                 case AUDIT_SUBJ_CLR:
1260                         if (f->lsm_rule)
1261                                 result = security_audit_rule_match(cb->sid,
1262                                                                    f->type,
1263                                                                    f->op,
1264                                                                    f->lsm_rule,
1265                                                                    NULL);
1266                         break;
1267                 }
1268
1269                 if (!result)
1270                         return 0;
1271         }
1272         switch (rule->action) {
1273         case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
1274         case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1275         }
1276         return 1;
1277 }
1278
1279 int audit_filter_user(struct netlink_skb_parms *cb)
1280 {
1281         enum audit_state state = AUDIT_DISABLED;
1282         struct audit_entry *e;
1283         int ret = 1;
1284
1285         rcu_read_lock();
1286         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1287                 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1288                         if (state == AUDIT_DISABLED)
1289                                 ret = 0;
1290                         break;
1291                 }
1292         }
1293         rcu_read_unlock();
1294
1295         return ret; /* Audit by default */
1296 }
1297
1298 int audit_filter_type(int type)
1299 {
1300         struct audit_entry *e;
1301         int result = 0;
1302
1303         rcu_read_lock();
1304         if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1305                 goto unlock_and_return;
1306
1307         list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1308                                 list) {
1309                 int i;
1310                 for (i = 0; i < e->rule.field_count; i++) {
1311                         struct audit_field *f = &e->rule.fields[i];
1312                         if (f->type == AUDIT_MSGTYPE) {
1313                                 result = audit_comparator(type, f->op, f->val);
1314                                 if (!result)
1315                                         break;
1316                         }
1317                 }
1318                 if (result)
1319                         goto unlock_and_return;
1320         }
1321 unlock_and_return:
1322         rcu_read_unlock();
1323         return result;
1324 }
1325
1326 static int update_lsm_rule(struct audit_krule *r)
1327 {
1328         struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1329         struct audit_entry *nentry;
1330         int err = 0;
1331
1332         if (!security_audit_rule_known(r))
1333                 return 0;
1334
1335         nentry = audit_dupe_rule(r);
1336         if (IS_ERR(nentry)) {
1337                 /* save the first error encountered for the
1338                  * return value */
1339                 err = PTR_ERR(nentry);
1340                 audit_panic("error updating LSM filters");
1341                 if (r->watch)
1342                         list_del(&r->rlist);
1343                 list_del_rcu(&entry->list);
1344                 list_del(&r->list);
1345         } else {
1346                 if (r->watch || r->tree)
1347                         list_replace_init(&r->rlist, &nentry->rule.rlist);
1348                 list_replace_rcu(&entry->list, &nentry->list);
1349                 list_replace(&r->list, &nentry->rule.list);
1350         }
1351         call_rcu(&entry->rcu, audit_free_rule_rcu);
1352
1353         return err;
1354 }
1355
1356 /* This function will re-initialize the lsm_rule field of all applicable rules.
1357  * It will traverse the filter lists serarching for rules that contain LSM
1358  * specific filter fields.  When such a rule is found, it is copied, the
1359  * LSM field is re-initialized, and the old rule is replaced with the
1360  * updated rule. */
1361 int audit_update_lsm_rules(void)
1362 {
1363         struct audit_krule *r, *n;
1364         int i, err = 0;
1365
1366         /* audit_filter_mutex synchronizes the writers */
1367         mutex_lock(&audit_filter_mutex);
1368
1369         for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1370                 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1371                         int res = update_lsm_rule(r);
1372                         if (!err)
1373                                 err = res;
1374                 }
1375         }
1376         mutex_unlock(&audit_filter_mutex);
1377
1378         return err;
1379 }