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authorDavid Woodhouse <dwmw2@infradead.org>2005-12-15 13:33:52 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2006-03-20 14:08:54 -0500
commitfe7752bab26a9ac0651b695ad4f55659761f68f7 (patch)
treeb2e516a52232c978fc824b226418d8a28460b8a8
parentee436dc46a762f430e37952d375a23d87735f73f (diff)
[PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL
This fixes the per-user and per-message-type filtering when syscall auditing isn't enabled. [AV: folded followup fix from the same author] Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat
-rw-r--r--include/linux/audit.h18
-rw-r--r--kernel/Makefile2
-rw-r--r--kernel/audit.c1
-rw-r--r--kernel/audit.h70
-rw-r--r--kernel/auditfilter.c378
-rw-r--r--kernel/auditsc.c380
6 files changed, 459 insertions, 390 deletions
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 1912d8e8ae90..fbc21d6267f3 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -278,8 +278,6 @@ static inline void audit_inode_child(const char *dname,
278} 278}
279 279
280 /* Private API (for audit.c only) */ 280 /* Private API (for audit.c only) */
281extern int audit_receive_filter(int type, int pid, int uid, int seq,
282 void *data, uid_t loginuid);
283extern unsigned int audit_serial(void); 281extern unsigned int audit_serial(void);
284extern void auditsc_get_stamp(struct audit_context *ctx, 282extern void auditsc_get_stamp(struct audit_context *ctx,
285 struct timespec *t, unsigned int *serial); 283 struct timespec *t, unsigned int *serial);
@@ -290,8 +288,6 @@ extern int audit_socketcall(int nargs, unsigned long *args);
290extern int audit_sockaddr(int len, void *addr); 288extern int audit_sockaddr(int len, void *addr);
291extern int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt); 289extern int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt);
292extern void audit_signal_info(int sig, struct task_struct *t); 290extern void audit_signal_info(int sig, struct task_struct *t);
293extern int audit_filter_user(struct netlink_skb_parms *cb, int type);
294extern int audit_filter_type(int type);
295extern int audit_set_macxattr(const char *name); 291extern int audit_set_macxattr(const char *name);
296#else 292#else
297#define audit_alloc(t) ({ 0; }) 293#define audit_alloc(t) ({ 0; })
@@ -304,7 +300,6 @@ extern int audit_set_macxattr(const char *name);
304#define __audit_inode_child(d,i,p) do { ; } while (0) 300#define __audit_inode_child(d,i,p) do { ; } while (0)
305#define audit_inode(n,i,f) do { ; } while (0) 301#define audit_inode(n,i,f) do { ; } while (0)
306#define audit_inode_child(d,i,p) do { ; } while (0) 302#define audit_inode_child(d,i,p) do { ; } while (0)
307#define audit_receive_filter(t,p,u,s,d,l) ({ -EOPNOTSUPP; })
308#define auditsc_get_stamp(c,t,s) do { BUG(); } while (0) 303#define auditsc_get_stamp(c,t,s) do { BUG(); } while (0)
309#define audit_get_loginuid(c) ({ -1; }) 304#define audit_get_loginuid(c) ({ -1; })
310#define audit_ipc_perms(q,u,g,m,i) ({ 0; }) 305#define audit_ipc_perms(q,u,g,m,i) ({ 0; })
@@ -312,7 +307,6 @@ extern int audit_set_macxattr(const char *name);
312#define audit_sockaddr(len, addr) ({ 0; }) 307#define audit_sockaddr(len, addr) ({ 0; })
313#define audit_avc_path(dentry, mnt) ({ 0; }) 308#define audit_avc_path(dentry, mnt) ({ 0; })
314#define audit_signal_info(s,t) do { ; } while (0) 309#define audit_signal_info(s,t) do { ; } while (0)
315#define audit_filter_user(cb,t) ({ 1; })
316#define audit_set_macxattr(n) do { ; } while (0) 310#define audit_set_macxattr(n) do { ; } while (0)
317#endif 311#endif
318 312
@@ -337,13 +331,11 @@ extern void audit_log_d_path(struct audit_buffer *ab,
337 const char *prefix, 331 const char *prefix,
338 struct dentry *dentry, 332 struct dentry *dentry,
339 struct vfsmount *vfsmnt); 333 struct vfsmount *vfsmnt);
340 /* Private API (for auditsc.c only) */ 334 /* Private API (for audit.c only) */
341extern void audit_send_reply(int pid, int seq, int type, 335extern int audit_filter_user(struct netlink_skb_parms *cb, int type);
342 int done, int multi, 336extern int audit_filter_type(int type);
343 void *payload, int size); 337extern int audit_receive_filter(int type, int pid, int uid, int seq,
344extern void audit_log_lost(const char *message); 338 void *data, uid_t loginuid);
345extern void audit_panic(const char *message);
346extern struct semaphore audit_netlink_sem;
347#else 339#else
348#define audit_log(c,g,t,f,...) do { ; } while (0) 340#define audit_log(c,g,t,f,...) do { ; } while (0)
349#define audit_log_start(c,g,t) ({ NULL; }) 341#define audit_log_start(c,g,t) ({ NULL; })
diff --git a/kernel/Makefile b/kernel/Makefile
index 4ae0fbde815d..58cf129e5622 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -26,7 +26,7 @@ obj-$(CONFIG_COMPAT) += compat.o
26obj-$(CONFIG_CPUSETS) += cpuset.o 26obj-$(CONFIG_CPUSETS) += cpuset.o
27obj-$(CONFIG_IKCONFIG) += configs.o 27obj-$(CONFIG_IKCONFIG) += configs.o
28obj-$(CONFIG_STOP_MACHINE) += stop_machine.o 28obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
29obj-$(CONFIG_AUDIT) += audit.o 29obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
30obj-$(CONFIG_AUDITSYSCALL) += auditsc.o 30obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
31obj-$(CONFIG_KPROBES) += kprobes.o 31obj-$(CONFIG_KPROBES) += kprobes.o
32obj-$(CONFIG_SYSFS) += ksysfs.o 32obj-$(CONFIG_SYSFS) += ksysfs.o
diff --git a/kernel/audit.c b/kernel/audit.c
index 45c123ef77a7..07c5d2bdd38c 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -305,6 +305,7 @@ static int kauditd_thread(void *dummy)
305 remove_wait_queue(&kauditd_wait, &wait); 305 remove_wait_queue(&kauditd_wait, &wait);
306 } 306 }
307 } 307 }
308 return 0;
308} 309}
309 310
310/** 311/**
diff --git a/kernel/audit.h b/kernel/audit.h
new file mode 100644
index 000000000000..7643e46daeb2
--- /dev/null
+++ b/kernel/audit.h
@@ -0,0 +1,70 @@
1/* audit -- definition of audit_context structure and supporting types
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/fs.h>
23#include <linux/audit.h>
24
25/* 0 = no checking
26 1 = put_count checking
27 2 = verbose put_count checking
28*/
29#define AUDIT_DEBUG 0
30
31/* At task start time, the audit_state is set in the audit_context using
32 a per-task filter. At syscall entry, the audit_state is augmented by
33 the syscall filter. */
34enum audit_state {
35 AUDIT_DISABLED, /* Do not create per-task audit_context.
36 * No syscall-specific audit records can
37 * be generated. */
38 AUDIT_SETUP_CONTEXT, /* Create the per-task audit_context,
39 * but don't necessarily fill it in at
40 * syscall entry time (i.e., filter
41 * instead). */
42 AUDIT_BUILD_CONTEXT, /* Create the per-task audit_context,
43 * and always fill it in at syscall
44 * entry time. This makes a full
45 * syscall record available if some
46 * other part of the kernel decides it
47 * should be recorded. */
48 AUDIT_RECORD_CONTEXT /* Create the per-task audit_context,
49 * always fill it in at syscall entry
50 * time, and always write out the audit
51 * record at syscall exit time. */
52};
53
54/* Rule lists */
55struct audit_entry {
56 struct list_head list;
57 struct rcu_head rcu;
58 struct audit_rule rule;
59};
60
61
62extern int audit_pid;
63extern int audit_comparator(const u32 left, const u32 op, const u32 right);
64
65extern void audit_send_reply(int pid, int seq, int type,
66 int done, int multi,
67 void *payload, int size);
68extern void audit_log_lost(const char *message);
69extern void audit_panic(const char *message);
70extern struct semaphore audit_netlink_sem;
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
new file mode 100644
index 000000000000..7f347c360876
--- /dev/null
+++ b/kernel/auditfilter.c
@@ -0,0 +1,378 @@
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/netlink.h>
26#include "audit.h"
27
28/* There are three lists of rules -- one to search at task creation
29 * time, one to search at syscall entry time, and another to search at
30 * syscall exit time. */
31struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
32 LIST_HEAD_INIT(audit_filter_list[0]),
33 LIST_HEAD_INIT(audit_filter_list[1]),
34 LIST_HEAD_INIT(audit_filter_list[2]),
35 LIST_HEAD_INIT(audit_filter_list[3]),
36 LIST_HEAD_INIT(audit_filter_list[4]),
37 LIST_HEAD_INIT(audit_filter_list[5]),
38#if AUDIT_NR_FILTERS != 6
39#error Fix audit_filter_list initialiser
40#endif
41};
42
43/* Copy rule from user-space to kernel-space. Called from
44 * audit_add_rule during AUDIT_ADD. */
45static inline int audit_copy_rule(struct audit_rule *d, struct audit_rule *s)
46{
47 int i;
48
49 if (s->action != AUDIT_NEVER
50 && s->action != AUDIT_POSSIBLE
51 && s->action != AUDIT_ALWAYS)
52 return -1;
53 if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS)
54 return -1;
55 if ((s->flags & ~AUDIT_FILTER_PREPEND) >= AUDIT_NR_FILTERS)
56 return -1;
57
58 d->flags = s->flags;
59 d->action = s->action;
60 d->field_count = s->field_count;
61 for (i = 0; i < d->field_count; i++) {
62 d->fields[i] = s->fields[i];
63 d->values[i] = s->values[i];
64 }
65 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i];
66 return 0;
67}
68
69/* Check to see if two rules are identical. It is called from
70 * audit_add_rule during AUDIT_ADD and
71 * audit_del_rule during AUDIT_DEL. */
72static inline int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
73{
74 int i;
75
76 if (a->flags != b->flags)
77 return 1;
78
79 if (a->action != b->action)
80 return 1;
81
82 if (a->field_count != b->field_count)
83 return 1;
84
85 for (i = 0; i < a->field_count; i++) {
86 if (a->fields[i] != b->fields[i]
87 || a->values[i] != b->values[i])
88 return 1;
89 }
90
91 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
92 if (a->mask[i] != b->mask[i])
93 return 1;
94
95 return 0;
96}
97
98/* Note that audit_add_rule and audit_del_rule are called via
99 * audit_receive() in audit.c, and are protected by
100 * audit_netlink_sem. */
101static inline int audit_add_rule(struct audit_rule *rule,
102 struct list_head *list)
103{
104 struct audit_entry *entry;
105 int i;
106
107 /* Do not use the _rcu iterator here, since this is the only
108 * addition routine. */
109 list_for_each_entry(entry, list, list) {
110 if (!audit_compare_rule(rule, &entry->rule)) {
111 return -EEXIST;
112 }
113 }
114
115 for (i = 0; i < rule->field_count; i++) {
116 if (rule->fields[i] & AUDIT_UNUSED_BITS)
117 return -EINVAL;
118 if ( rule->fields[i] & AUDIT_NEGATE )
119 rule->fields[i] |= AUDIT_NOT_EQUAL;
120 else if ( (rule->fields[i] & AUDIT_OPERATORS) == 0 )
121 rule->fields[i] |= AUDIT_EQUAL;
122 rule->fields[i] &= (~AUDIT_NEGATE);
123 }
124
125 if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL)))
126 return -ENOMEM;
127 if (audit_copy_rule(&entry->rule, rule)) {
128 kfree(entry);
129 return -EINVAL;
130 }
131
132 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
133 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
134 list_add_rcu(&entry->list, list);
135 } else {
136 list_add_tail_rcu(&entry->list, list);
137 }
138
139 return 0;
140}
141
142static inline void audit_free_rule(struct rcu_head *head)
143{
144 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
145 kfree(e);
146}
147
148/* Note that audit_add_rule and audit_del_rule are called via
149 * audit_receive() in audit.c, and are protected by
150 * audit_netlink_sem. */
151static inline int audit_del_rule(struct audit_rule *rule,
152 struct list_head *list)
153{
154 struct audit_entry *e;
155
156 /* Do not use the _rcu iterator here, since this is the only
157 * deletion routine. */
158 list_for_each_entry(e, list, list) {
159 if (!audit_compare_rule(rule, &e->rule)) {
160 list_del_rcu(&e->list);
161 call_rcu(&e->rcu, audit_free_rule);
162 return 0;
163 }
164 }
165 return -ENOENT; /* No matching rule */
166}
167
168static int audit_list_rules(void *_dest)
169{
170 int pid, seq;
171 int *dest = _dest;
172 struct audit_entry *entry;
173 int i;
174
175 pid = dest[0];
176 seq = dest[1];
177 kfree(dest);
178
179 down(&audit_netlink_sem);
180
181 /* The *_rcu iterators not needed here because we are
182 always called with audit_netlink_sem held. */
183 for (i=0; i<AUDIT_NR_FILTERS; i++) {
184 list_for_each_entry(entry, &audit_filter_list[i], list)
185 audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
186 &entry->rule, sizeof(entry->rule));
187 }
188 audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
189
190 up(&audit_netlink_sem);
191 return 0;
192}
193
194/**
195 * audit_receive_filter - apply all rules to the specified message type
196 * @type: audit message type
197 * @pid: target pid for netlink audit messages
198 * @uid: target uid for netlink audit messages
199 * @seq: netlink audit message sequence (serial) number
200 * @data: payload data
201 * @loginuid: loginuid of sender
202 */
203int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
204 uid_t loginuid)
205{
206 struct task_struct *tsk;
207 int *dest;
208 int err = 0;
209 unsigned listnr;
210
211 switch (type) {
212 case AUDIT_LIST:
213 /* We can't just spew out the rules here because we might fill
214 * the available socket buffer space and deadlock waiting for
215 * auditctl to read from it... which isn't ever going to
216 * happen if we're actually running in the context of auditctl
217 * trying to _send_ the stuff */
218
219 dest = kmalloc(2 * sizeof(int), GFP_KERNEL);
220 if (!dest)
221 return -ENOMEM;
222 dest[0] = pid;
223 dest[1] = seq;
224
225 tsk = kthread_run(audit_list_rules, dest, "audit_list_rules");
226 if (IS_ERR(tsk)) {
227 kfree(dest);
228 err = PTR_ERR(tsk);
229 }
230 break;
231 case AUDIT_ADD:
232 listnr = ((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
233 switch(listnr) {
234 default:
235 return -EINVAL;
236
237 case AUDIT_FILTER_USER:
238 case AUDIT_FILTER_TYPE:
239#ifdef CONFIG_AUDITSYSCALL
240 case AUDIT_FILTER_ENTRY:
241 case AUDIT_FILTER_EXIT:
242 case AUDIT_FILTER_TASK:
243#endif
244 ;
245 }
246 err = audit_add_rule(data, &audit_filter_list[listnr]);
247 if (!err)
248 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
249 "auid=%u added an audit rule\n", loginuid);
250 break;
251 case AUDIT_DEL:
252 listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
253 if (listnr >= AUDIT_NR_FILTERS)
254 return -EINVAL;
255
256 err = audit_del_rule(data, &audit_filter_list[listnr]);
257 if (!err)
258 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
259 "auid=%u removed an audit rule\n", loginuid);
260 break;
261 default:
262 return -EINVAL;
263 }
264
265 return err;
266}
267
268int audit_comparator(const u32 left, const u32 op, const u32 right)
269{
270 switch (op) {
271 case AUDIT_EQUAL:
272 return (left == right);
273 case AUDIT_NOT_EQUAL:
274 return (left != right);
275 case AUDIT_LESS_THAN:
276 return (left < right);
277 case AUDIT_LESS_THAN_OR_EQUAL:
278 return (left <= right);
279 case AUDIT_GREATER_THAN:
280 return (left > right);
281 case AUDIT_GREATER_THAN_OR_EQUAL:
282 return (left >= right);
283 default:
284 return -EINVAL;
285 }
286}
287
288
289
290static int audit_filter_user_rules(struct netlink_skb_parms *cb,
291 struct audit_rule *rule,
292 enum audit_state *state)
293{
294 int i;
295
296 for (i = 0; i < rule->field_count; i++) {
297 u32 field = rule->fields[i] & ~AUDIT_OPERATORS;
298 u32 op = rule->fields[i] & AUDIT_OPERATORS;
299 u32 value = rule->values[i];
300 int result = 0;
301
302 switch (field) {
303 case AUDIT_PID:
304 result = audit_comparator(cb->creds.pid, op, value);
305 break;
306 case AUDIT_UID:
307 result = audit_comparator(cb->creds.uid, op, value);
308 break;
309 case AUDIT_GID:
310 result = audit_comparator(cb->creds.gid, op, value);
311 break;
312 case AUDIT_LOGINUID:
313 result = audit_comparator(cb->loginuid, op, value);
314 break;
315 }
316
317 if (!result)
318 return 0;
319 }
320 switch (rule->action) {
321 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
322 case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break;
323 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
324 }
325 return 1;
326}
327
328int audit_filter_user(struct netlink_skb_parms *cb, int type)
329{
330 struct audit_entry *e;
331 enum audit_state state;
332 int ret = 1;
333
334 rcu_read_lock();
335 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
336 if (audit_filter_user_rules(cb, &e->rule, &state)) {
337 if (state == AUDIT_DISABLED)
338 ret = 0;
339 break;
340 }
341 }
342 rcu_read_unlock();
343
344 return ret; /* Audit by default */
345}
346
347int audit_filter_type(int type)
348{
349 struct audit_entry *e;
350 int result = 0;
351
352 rcu_read_lock();
353 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
354 goto unlock_and_return;
355
356 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
357 list) {
358 struct audit_rule *rule = &e->rule;
359 int i;
360 for (i = 0; i < rule->field_count; i++) {
361 u32 field = rule->fields[i] & ~AUDIT_OPERATORS;
362 u32 op = rule->fields[i] & AUDIT_OPERATORS;
363 u32 value = rule->values[i];
364 if ( field == AUDIT_MSGTYPE ) {
365 result = audit_comparator(type, op, value);
366 if (!result)
367 break;
368 }
369 }
370 if (result)
371 goto unlock_and_return;
372 }
373unlock_and_return:
374 rcu_read_unlock();
375 return result;
376}
377
378
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4ef14515da35..17719b303638 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -52,17 +52,15 @@
52#include <linux/audit.h> 52#include <linux/audit.h>
53#include <linux/personality.h> 53#include <linux/personality.h>
54#include <linux/time.h> 54#include <linux/time.h>
55#include <linux/kthread.h>
56#include <linux/netlink.h> 55#include <linux/netlink.h>
57#include <linux/compiler.h> 56#include <linux/compiler.h>
58#include <asm/unistd.h> 57#include <asm/unistd.h>
59#include <linux/security.h> 58#include <linux/security.h>
59#include <linux/list.h>
60 60
61/* 0 = no checking 61#include "audit.h"
62 1 = put_count checking 62
63 2 = verbose put_count checking 63extern struct list_head audit_filter_list[];
64*/
65#define AUDIT_DEBUG 0
66 64
67/* No syscall auditing will take place unless audit_enabled != 0. */ 65/* No syscall auditing will take place unless audit_enabled != 0. */
68extern int audit_enabled; 66extern int audit_enabled;
@@ -76,29 +74,6 @@ extern int audit_enabled;
76 * path_lookup. */ 74 * path_lookup. */
77#define AUDIT_NAMES_RESERVED 7 75#define AUDIT_NAMES_RESERVED 7
78 76
79/* At task start time, the audit_state is set in the audit_context using
80 a per-task filter. At syscall entry, the audit_state is augmented by
81 the syscall filter. */
82enum audit_state {
83 AUDIT_DISABLED, /* Do not create per-task audit_context.
84 * No syscall-specific audit records can
85 * be generated. */
86 AUDIT_SETUP_CONTEXT, /* Create the per-task audit_context,
87 * but don't necessarily fill it in at
88 * syscall entry time (i.e., filter
89 * instead). */
90 AUDIT_BUILD_CONTEXT, /* Create the per-task audit_context,
91 * and always fill it in at syscall
92 * entry time. This makes a full
93 * syscall record available if some
94 * other part of the kernel decides it
95 * should be recorded. */
96 AUDIT_RECORD_CONTEXT /* Create the per-task audit_context,
97 * always fill it in at syscall entry
98 * time, and always write out the audit
99 * record at syscall exit time. */
100};
101
102/* When fs/namei.c:getname() is called, we store the pointer in name and 77/* When fs/namei.c:getname() is called, we store the pointer in name and
103 * we don't let putname() free it (instead we free all of the saved 78 * we don't let putname() free it (instead we free all of the saved
104 * pointers at syscall exit time). 79 * pointers at syscall exit time).
@@ -183,264 +158,6 @@ struct audit_context {
183#endif 158#endif
184}; 159};
185 160
186 /* Public API */
187/* There are three lists of rules -- one to search at task creation
188 * time, one to search at syscall entry time, and another to search at
189 * syscall exit time. */
190static struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
191 LIST_HEAD_INIT(audit_filter_list[0]),
192 LIST_HEAD_INIT(audit_filter_list[1]),
193 LIST_HEAD_INIT(audit_filter_list[2]),
194 LIST_HEAD_INIT(audit_filter_list[3]),
195 LIST_HEAD_INIT(audit_filter_list[4]),
196 LIST_HEAD_INIT(audit_filter_list[5]),
197#if AUDIT_NR_FILTERS != 6
198#error Fix audit_filter_list initialiser
199#endif
200};
201
202struct audit_entry {
203 struct list_head list;
204 struct rcu_head rcu;
205 struct audit_rule rule;
206};
207
208extern int audit_pid;
209
210/* Copy rule from user-space to kernel-space. Called from
211 * audit_add_rule during AUDIT_ADD. */
212static inline int audit_copy_rule(struct audit_rule *d, struct audit_rule *s)
213{
214 int i;
215
216 if (s->action != AUDIT_NEVER
217 && s->action != AUDIT_POSSIBLE
218 && s->action != AUDIT_ALWAYS)
219 return -1;
220 if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS)
221 return -1;
222 if ((s->flags & ~AUDIT_FILTER_PREPEND) >= AUDIT_NR_FILTERS)
223 return -1;
224
225 d->flags = s->flags;
226 d->action = s->action;
227 d->field_count = s->field_count;
228 for (i = 0; i < d->field_count; i++) {
229 d->fields[i] = s->fields[i];
230 d->values[i] = s->values[i];
231 }
232 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i];
233 return 0;
234}
235
236/* Check to see if two rules are identical. It is called from
237 * audit_add_rule during AUDIT_ADD and
238 * audit_del_rule during AUDIT_DEL. */
239static inline int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
240{
241 int i;
242
243 if (a->flags != b->flags)
244 return 1;
245
246 if (a->action != b->action)
247 return 1;
248
249 if (a->field_count != b->field_count)
250 return 1;
251
252 for (i = 0; i < a->field_count; i++) {
253 if (a->fields[i] != b->fields[i]
254 || a->values[i] != b->values[i])
255 return 1;
256 }
257
258 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
259 if (a->mask[i] != b->mask[i])
260 return 1;
261
262 return 0;
263}
264
265/* Note that audit_add_rule and audit_del_rule are called via
266 * audit_receive() in audit.c, and are protected by
267 * audit_netlink_sem. */
268static inline int audit_add_rule(struct audit_rule *rule,
269 struct list_head *list)
270{
271 struct audit_entry *entry;
272 int i;
273
274 /* Do not use the _rcu iterator here, since this is the only
275 * addition routine. */
276 list_for_each_entry(entry, list, list) {
277 if (!audit_compare_rule(rule, &entry->rule)) {
278 return -EEXIST;
279 }
280 }
281
282 for (i = 0; i < rule->field_count; i++) {
283 if (rule->fields[i] & AUDIT_UNUSED_BITS)
284 return -EINVAL;
285 if ( rule->fields[i] & AUDIT_NEGATE )
286 rule->fields[i] |= AUDIT_NOT_EQUAL;
287 else if ( (rule->fields[i] & AUDIT_OPERATORS) == 0 )
288 rule->fields[i] |= AUDIT_EQUAL;
289 rule->fields[i] &= (~AUDIT_NEGATE);
290 }
291
292 if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL)))
293 return -ENOMEM;
294 if (audit_copy_rule(&entry->rule, rule)) {
295 kfree(entry);
296 return -EINVAL;
297 }
298
299 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
300 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
301 list_add_rcu(&entry->list, list);
302 } else {
303 list_add_tail_rcu(&entry->list, list);
304 }
305
306 return 0;
307}
308
309static inline void audit_free_rule(struct rcu_head *head)
310{
311 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
312 kfree(e);
313}
314
315/* Note that audit_add_rule and audit_del_rule are called via
316 * audit_receive() in audit.c, and are protected by
317 * audit_netlink_sem. */
318static inline int audit_del_rule(struct audit_rule *rule,
319 struct list_head *list)
320{
321 struct audit_entry *e;
322
323 /* Do not use the _rcu iterator here, since this is the only
324 * deletion routine. */
325 list_for_each_entry(e, list, list) {
326 if (!audit_compare_rule(rule, &e->rule)) {
327 list_del_rcu(&e->list);
328 call_rcu(&e->rcu, audit_free_rule);
329 return 0;
330 }
331 }
332 return -ENOENT; /* No matching rule */
333}
334
335static int audit_list_rules(void *_dest)
336{
337 int pid, seq;
338 int *dest = _dest;
339 struct audit_entry *entry;
340 int i;
341
342 pid = dest[0];
343 seq = dest[1];
344 kfree(dest);
345
346 down(&audit_netlink_sem);
347
348 /* The *_rcu iterators not needed here because we are
349 always called with audit_netlink_sem held. */
350 for (i=0; i<AUDIT_NR_FILTERS; i++) {
351 list_for_each_entry(entry, &audit_filter_list[i], list)
352 audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
353 &entry->rule, sizeof(entry->rule));
354 }
355 audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
356
357 up(&audit_netlink_sem);
358 return 0;
359}
360
361/**
362 * audit_receive_filter - apply all rules to the specified message type
363 * @type: audit message type
364 * @pid: target pid for netlink audit messages
365 * @uid: target uid for netlink audit messages
366 * @seq: netlink audit message sequence (serial) number
367 * @data: payload data
368 * @loginuid: loginuid of sender
369 */
370int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
371 uid_t loginuid)
372{
373 struct task_struct *tsk;
374 int *dest;
375 int err = 0;
376 unsigned listnr;
377
378 switch (type) {
379 case AUDIT_LIST:
380 /* We can't just spew out the rules here because we might fill
381 * the available socket buffer space and deadlock waiting for
382 * auditctl to read from it... which isn't ever going to
383 * happen if we're actually running in the context of auditctl
384 * trying to _send_ the stuff */
385
386 dest = kmalloc(2 * sizeof(int), GFP_KERNEL);
387 if (!dest)
388 return -ENOMEM;
389 dest[0] = pid;
390 dest[1] = seq;
391
392 tsk = kthread_run(audit_list_rules, dest, "audit_list_rules");
393 if (IS_ERR(tsk)) {
394 kfree(dest);
395 err = PTR_ERR(tsk);
396 }
397 break;
398 case AUDIT_ADD:
399 listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
400 if (listnr >= AUDIT_NR_FILTERS)
401 return -EINVAL;
402
403 err = audit_add_rule(data, &audit_filter_list[listnr]);
404 if (!err)
405 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
406 "auid=%u added an audit rule\n", loginuid);
407 break;
408 case AUDIT_DEL:
409 listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
410 if (listnr >= AUDIT_NR_FILTERS)
411 return -EINVAL;
412
413 err = audit_del_rule(data, &audit_filter_list[listnr]);
414 if (!err)
415 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
416 "auid=%u removed an audit rule\n", loginuid);
417 break;
418 default:
419 return -EINVAL;
420 }
421
422 return err;
423}
424
425static int audit_comparator(const u32 left, const u32 op, const u32 right)
426{
427 switch (op) {
428 case AUDIT_EQUAL:
429 return (left == right);
430 case AUDIT_NOT_EQUAL:
431 return (left != right);
432 case AUDIT_LESS_THAN:
433 return (left < right);
434 case AUDIT_LESS_THAN_OR_EQUAL:
435 return (left <= right);
436 case AUDIT_GREATER_THAN:
437 return (left > right);
438 case AUDIT_GREATER_THAN_OR_EQUAL:
439 return (left >= right);
440 default:
441 return -EINVAL;
442 }
443}
444 161
445/* Compare a task_struct with an audit_rule. Return 1 on match, 0 162/* Compare a task_struct with an audit_rule. Return 1 on match, 0
446 * otherwise. */ 163 * otherwise. */
@@ -613,95 +330,6 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk,
613 return AUDIT_BUILD_CONTEXT; 330 return AUDIT_BUILD_CONTEXT;
614} 331}
615 332
616static int audit_filter_user_rules(struct netlink_skb_parms *cb,
617 struct audit_rule *rule,
618 enum audit_state *state)
619{
620 int i;
621
622 for (i = 0; i < rule->field_count; i++) {
623 u32 field = rule->fields[i] & ~AUDIT_OPERATORS;
624 u32 op = rule->fields[i] & AUDIT_OPERATORS;
625 u32 value = rule->values[i];
626 int result = 0;
627
628 switch (field) {
629 case AUDIT_PID:
630 result = audit_comparator(cb->creds.pid, op, value);
631 break;
632 case AUDIT_UID:
633 result = audit_comparator(cb->creds.uid, op, value);
634 break;
635 case AUDIT_GID:
636 result = audit_comparator(cb->creds.gid, op, value);
637 break;
638 case AUDIT_LOGINUID:
639 result = audit_comparator(cb->loginuid, op, value);
640 break;
641 }
642
643 if (!result)
644 return 0;
645 }
646 switch (rule->action) {
647 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
648 case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break;
649 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
650 }
651 return 1;
652}
653
654int audit_filter_user(struct netlink_skb_parms *cb, int type)
655{
656 struct audit_entry *e;
657 enum audit_state state;
658 int ret = 1;
659
660 rcu_read_lock();
661 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
662 if (audit_filter_user_rules(cb, &e->rule, &state)) {
663 if (state == AUDIT_DISABLED)
664 ret = 0;
665 break;
666 }
667 }
668 rcu_read_unlock();
669
670 return ret; /* Audit by default */
671}
672
673int audit_filter_type(int type)
674{
675 struct audit_entry *e;
676 int result = 0;
677
678 rcu_read_lock();
679 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
680 goto unlock_and_return;
681
682 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
683 list) {
684 struct audit_rule *rule = &e->rule;
685 int i;
686 for (i = 0; i < rule->field_count; i++) {
687 u32 field = rule->fields[i] & ~AUDIT_OPERATORS;
688 u32 op = rule->fields[i] & AUDIT_OPERATORS;
689 u32 value = rule->values[i];
690 if ( field == AUDIT_MSGTYPE ) {
691 result = audit_comparator(type, op, value);
692 if (!result)
693 break;
694 }
695 }
696 if (result)
697 goto unlock_and_return;
698 }
699unlock_and_return:
700 rcu_read_unlock();
701 return result;
702}
703
704
705/* This should be called with task_lock() held. */ 333/* This should be called with task_lock() held. */
706static inline struct audit_context *audit_get_context(struct task_struct *tsk, 334static inline struct audit_context *audit_get_context(struct task_struct *tsk,
707 int return_valid, 335 int return_valid,
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-10 23:03:25 -0500