blob: 44a20c218409289448c9860397bfda476de8c150
1 | /* |
2 | * common LSM auditing functions |
3 | * |
4 | * Based on code written for SELinux by : |
5 | * Stephen Smalley, <sds@epoch.ncsc.mil> |
6 | * James Morris <jmorris@redhat.com> |
7 | * Author : Etienne Basset, <etienne.basset@ensta.org> |
8 | * |
9 | * This program is free software; you can redistribute it and/or modify |
10 | * it under the terms of the GNU General Public License version 2, |
11 | * as published by the Free Software Foundation. |
12 | */ |
13 | |
14 | #include <linux/types.h> |
15 | #include <linux/stddef.h> |
16 | #include <linux/kernel.h> |
17 | #include <linux/gfp.h> |
18 | #include <linux/fs.h> |
19 | #include <linux/init.h> |
20 | #include <net/sock.h> |
21 | #include <linux/un.h> |
22 | #include <net/af_unix.h> |
23 | #include <linux/audit.h> |
24 | #include <linux/ipv6.h> |
25 | #include <linux/ip.h> |
26 | #include <net/ip.h> |
27 | #include <net/ipv6.h> |
28 | #include <linux/tcp.h> |
29 | #include <linux/udp.h> |
30 | #include <linux/dccp.h> |
31 | #include <linux/sctp.h> |
32 | #include <linux/lsm_audit.h> |
33 | |
34 | /** |
35 | * ipv4_skb_to_auditdata : fill auditdata from skb |
36 | * @skb : the skb |
37 | * @ad : the audit data to fill |
38 | * @proto : the layer 4 protocol |
39 | * |
40 | * return 0 on success |
41 | */ |
42 | int ipv4_skb_to_auditdata(struct sk_buff *skb, |
43 | struct common_audit_data *ad, u8 *proto) |
44 | { |
45 | int ret = 0; |
46 | struct iphdr *ih; |
47 | |
48 | ih = ip_hdr(skb); |
49 | if (ih == NULL) |
50 | return -EINVAL; |
51 | |
52 | ad->u.net->v4info.saddr = ih->saddr; |
53 | ad->u.net->v4info.daddr = ih->daddr; |
54 | |
55 | if (proto) |
56 | *proto = ih->protocol; |
57 | /* non initial fragment */ |
58 | if (ntohs(ih->frag_off) & IP_OFFSET) |
59 | return 0; |
60 | |
61 | switch (ih->protocol) { |
62 | case IPPROTO_TCP: { |
63 | struct tcphdr *th = tcp_hdr(skb); |
64 | if (th == NULL) |
65 | break; |
66 | |
67 | ad->u.net->sport = th->source; |
68 | ad->u.net->dport = th->dest; |
69 | break; |
70 | } |
71 | case IPPROTO_UDP: { |
72 | struct udphdr *uh = udp_hdr(skb); |
73 | if (uh == NULL) |
74 | break; |
75 | |
76 | ad->u.net->sport = uh->source; |
77 | ad->u.net->dport = uh->dest; |
78 | break; |
79 | } |
80 | case IPPROTO_DCCP: { |
81 | struct dccp_hdr *dh = dccp_hdr(skb); |
82 | if (dh == NULL) |
83 | break; |
84 | |
85 | ad->u.net->sport = dh->dccph_sport; |
86 | ad->u.net->dport = dh->dccph_dport; |
87 | break; |
88 | } |
89 | case IPPROTO_SCTP: { |
90 | struct sctphdr *sh = sctp_hdr(skb); |
91 | if (sh == NULL) |
92 | break; |
93 | ad->u.net->sport = sh->source; |
94 | ad->u.net->dport = sh->dest; |
95 | break; |
96 | } |
97 | default: |
98 | ret = -EINVAL; |
99 | } |
100 | return ret; |
101 | } |
102 | #if IS_ENABLED(CONFIG_IPV6) |
103 | /** |
104 | * ipv6_skb_to_auditdata : fill auditdata from skb |
105 | * @skb : the skb |
106 | * @ad : the audit data to fill |
107 | * @proto : the layer 4 protocol |
108 | * |
109 | * return 0 on success |
110 | */ |
111 | int ipv6_skb_to_auditdata(struct sk_buff *skb, |
112 | struct common_audit_data *ad, u8 *proto) |
113 | { |
114 | int offset, ret = 0; |
115 | struct ipv6hdr *ip6; |
116 | u8 nexthdr; |
117 | __be16 frag_off; |
118 | |
119 | ip6 = ipv6_hdr(skb); |
120 | if (ip6 == NULL) |
121 | return -EINVAL; |
122 | ad->u.net->v6info.saddr = ip6->saddr; |
123 | ad->u.net->v6info.daddr = ip6->daddr; |
124 | ret = 0; |
125 | /* IPv6 can have several extension header before the Transport header |
126 | * skip them */ |
127 | offset = skb_network_offset(skb); |
128 | offset += sizeof(*ip6); |
129 | nexthdr = ip6->nexthdr; |
130 | offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); |
131 | if (offset < 0) |
132 | return 0; |
133 | if (proto) |
134 | *proto = nexthdr; |
135 | switch (nexthdr) { |
136 | case IPPROTO_TCP: { |
137 | struct tcphdr _tcph, *th; |
138 | |
139 | th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph); |
140 | if (th == NULL) |
141 | break; |
142 | |
143 | ad->u.net->sport = th->source; |
144 | ad->u.net->dport = th->dest; |
145 | break; |
146 | } |
147 | case IPPROTO_UDP: { |
148 | struct udphdr _udph, *uh; |
149 | |
150 | uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph); |
151 | if (uh == NULL) |
152 | break; |
153 | |
154 | ad->u.net->sport = uh->source; |
155 | ad->u.net->dport = uh->dest; |
156 | break; |
157 | } |
158 | case IPPROTO_DCCP: { |
159 | struct dccp_hdr _dccph, *dh; |
160 | |
161 | dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph); |
162 | if (dh == NULL) |
163 | break; |
164 | |
165 | ad->u.net->sport = dh->dccph_sport; |
166 | ad->u.net->dport = dh->dccph_dport; |
167 | break; |
168 | } |
169 | case IPPROTO_SCTP: { |
170 | struct sctphdr _sctph, *sh; |
171 | |
172 | sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); |
173 | if (sh == NULL) |
174 | break; |
175 | ad->u.net->sport = sh->source; |
176 | ad->u.net->dport = sh->dest; |
177 | break; |
178 | } |
179 | default: |
180 | ret = -EINVAL; |
181 | } |
182 | return ret; |
183 | } |
184 | #endif |
185 | |
186 | |
187 | static inline void print_ipv6_addr(struct audit_buffer *ab, |
188 | struct in6_addr *addr, __be16 port, |
189 | char *name1, char *name2) |
190 | { |
191 | if (!ipv6_addr_any(addr)) |
192 | audit_log_format(ab, " %s=%pI6c", name1, addr); |
193 | if (port) |
194 | audit_log_format(ab, " %s=%d", name2, ntohs(port)); |
195 | } |
196 | |
197 | static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr, |
198 | __be16 port, char *name1, char *name2) |
199 | { |
200 | if (addr) |
201 | audit_log_format(ab, " %s=%pI4", name1, &addr); |
202 | if (port) |
203 | audit_log_format(ab, " %s=%d", name2, ntohs(port)); |
204 | } |
205 | |
206 | /** |
207 | * dump_common_audit_data - helper to dump common audit data |
208 | * @a : common audit data |
209 | * |
210 | */ |
211 | static void dump_common_audit_data(struct audit_buffer *ab, |
212 | struct common_audit_data *a) |
213 | { |
214 | char comm[sizeof(current->comm)]; |
215 | |
216 | /* |
217 | * To keep stack sizes in check force programers to notice if they |
218 | * start making this union too large! See struct lsm_network_audit |
219 | * as an example of how to deal with large data. |
220 | */ |
221 | BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2); |
222 | |
223 | audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current)); |
224 | audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm))); |
225 | |
226 | switch (a->type) { |
227 | case LSM_AUDIT_DATA_NONE: |
228 | return; |
229 | case LSM_AUDIT_DATA_IPC: |
230 | audit_log_format(ab, " key=%d ", a->u.ipc_id); |
231 | break; |
232 | case LSM_AUDIT_DATA_CAP: |
233 | audit_log_format(ab, " capability=%d ", a->u.cap); |
234 | break; |
235 | case LSM_AUDIT_DATA_PATH: { |
236 | struct inode *inode; |
237 | |
238 | audit_log_d_path(ab, " path=", &a->u.path); |
239 | |
240 | inode = d_backing_inode(a->u.path.dentry); |
241 | if (inode) { |
242 | audit_log_format(ab, " dev="); |
243 | audit_log_untrustedstring(ab, inode->i_sb->s_id); |
244 | audit_log_format(ab, " ino=%lu", inode->i_ino); |
245 | } |
246 | break; |
247 | } |
248 | case LSM_AUDIT_DATA_FILE: { |
249 | struct inode *inode; |
250 | |
251 | audit_log_d_path(ab, " path=", &a->u.file->f_path); |
252 | |
253 | inode = file_inode(a->u.file); |
254 | if (inode) { |
255 | audit_log_format(ab, " dev="); |
256 | audit_log_untrustedstring(ab, inode->i_sb->s_id); |
257 | audit_log_format(ab, " ino=%lu", inode->i_ino); |
258 | } |
259 | break; |
260 | } |
261 | case LSM_AUDIT_DATA_IOCTL_OP: { |
262 | struct inode *inode; |
263 | |
264 | audit_log_d_path(ab, " path=", &a->u.op->path); |
265 | |
266 | inode = a->u.op->path.dentry->d_inode; |
267 | if (inode) { |
268 | audit_log_format(ab, " dev="); |
269 | audit_log_untrustedstring(ab, inode->i_sb->s_id); |
270 | audit_log_format(ab, " ino=%lu", inode->i_ino); |
271 | } |
272 | |
273 | audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); |
274 | break; |
275 | } |
276 | case LSM_AUDIT_DATA_DENTRY: { |
277 | struct inode *inode; |
278 | |
279 | audit_log_format(ab, " name="); |
280 | audit_log_untrustedstring(ab, a->u.dentry->d_name.name); |
281 | |
282 | inode = d_backing_inode(a->u.dentry); |
283 | if (inode) { |
284 | audit_log_format(ab, " dev="); |
285 | audit_log_untrustedstring(ab, inode->i_sb->s_id); |
286 | audit_log_format(ab, " ino=%lu", inode->i_ino); |
287 | } |
288 | break; |
289 | } |
290 | case LSM_AUDIT_DATA_INODE: { |
291 | struct dentry *dentry; |
292 | struct inode *inode; |
293 | |
294 | inode = a->u.inode; |
295 | dentry = d_find_alias(inode); |
296 | if (dentry) { |
297 | audit_log_format(ab, " name="); |
298 | audit_log_untrustedstring(ab, |
299 | dentry->d_name.name); |
300 | dput(dentry); |
301 | } |
302 | audit_log_format(ab, " dev="); |
303 | audit_log_untrustedstring(ab, inode->i_sb->s_id); |
304 | audit_log_format(ab, " ino=%lu", inode->i_ino); |
305 | break; |
306 | } |
307 | case LSM_AUDIT_DATA_TASK: { |
308 | struct task_struct *tsk = a->u.tsk; |
309 | if (tsk) { |
310 | pid_t pid = task_tgid_nr(tsk); |
311 | if (pid) { |
312 | char comm[sizeof(tsk->comm)]; |
313 | audit_log_format(ab, " opid=%d ocomm=", pid); |
314 | audit_log_untrustedstring(ab, |
315 | memcpy(comm, tsk->comm, sizeof(comm))); |
316 | } |
317 | } |
318 | break; |
319 | } |
320 | case LSM_AUDIT_DATA_NET: |
321 | if (a->u.net->sk) { |
322 | struct sock *sk = a->u.net->sk; |
323 | struct unix_sock *u; |
324 | struct unix_address *addr; |
325 | int len = 0; |
326 | char *p = NULL; |
327 | |
328 | switch (sk->sk_family) { |
329 | case AF_INET: { |
330 | struct inet_sock *inet = inet_sk(sk); |
331 | |
332 | print_ipv4_addr(ab, inet->inet_rcv_saddr, |
333 | inet->inet_sport, |
334 | "laddr", "lport"); |
335 | print_ipv4_addr(ab, inet->inet_daddr, |
336 | inet->inet_dport, |
337 | "faddr", "fport"); |
338 | break; |
339 | } |
340 | #if IS_ENABLED(CONFIG_IPV6) |
341 | case AF_INET6: { |
342 | struct inet_sock *inet = inet_sk(sk); |
343 | |
344 | print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, |
345 | inet->inet_sport, |
346 | "laddr", "lport"); |
347 | print_ipv6_addr(ab, &sk->sk_v6_daddr, |
348 | inet->inet_dport, |
349 | "faddr", "fport"); |
350 | break; |
351 | } |
352 | #endif |
353 | case AF_UNIX: |
354 | u = unix_sk(sk); |
355 | addr = smp_load_acquire(&u->addr); |
356 | if (!addr) |
357 | break; |
358 | if (u->path.dentry) { |
359 | audit_log_d_path(ab, " path=", &u->path); |
360 | break; |
361 | } |
362 | len = addr->len-sizeof(short); |
363 | p = &addr->name->sun_path[0]; |
364 | audit_log_format(ab, " path="); |
365 | if (*p) |
366 | audit_log_untrustedstring(ab, p); |
367 | else |
368 | audit_log_n_hex(ab, p, len); |
369 | break; |
370 | } |
371 | } |
372 | |
373 | switch (a->u.net->family) { |
374 | case AF_INET: |
375 | print_ipv4_addr(ab, a->u.net->v4info.saddr, |
376 | a->u.net->sport, |
377 | "saddr", "src"); |
378 | print_ipv4_addr(ab, a->u.net->v4info.daddr, |
379 | a->u.net->dport, |
380 | "daddr", "dest"); |
381 | break; |
382 | case AF_INET6: |
383 | print_ipv6_addr(ab, &a->u.net->v6info.saddr, |
384 | a->u.net->sport, |
385 | "saddr", "src"); |
386 | print_ipv6_addr(ab, &a->u.net->v6info.daddr, |
387 | a->u.net->dport, |
388 | "daddr", "dest"); |
389 | break; |
390 | } |
391 | if (a->u.net->netif > 0) { |
392 | struct net_device *dev; |
393 | |
394 | /* NOTE: we always use init's namespace */ |
395 | dev = dev_get_by_index(&init_net, a->u.net->netif); |
396 | if (dev) { |
397 | audit_log_format(ab, " netif=%s", dev->name); |
398 | dev_put(dev); |
399 | } |
400 | } |
401 | break; |
402 | #ifdef CONFIG_KEYS |
403 | case LSM_AUDIT_DATA_KEY: |
404 | audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); |
405 | if (a->u.key_struct.key_desc) { |
406 | audit_log_format(ab, " key_desc="); |
407 | audit_log_untrustedstring(ab, a->u.key_struct.key_desc); |
408 | } |
409 | break; |
410 | #endif |
411 | case LSM_AUDIT_DATA_KMOD: |
412 | audit_log_format(ab, " kmod="); |
413 | audit_log_untrustedstring(ab, a->u.kmod_name); |
414 | break; |
415 | } /* switch (a->type) */ |
416 | } |
417 | |
418 | /** |
419 | * common_lsm_audit - generic LSM auditing function |
420 | * @a: auxiliary audit data |
421 | * @pre_audit: lsm-specific pre-audit callback |
422 | * @post_audit: lsm-specific post-audit callback |
423 | * |
424 | * setup the audit buffer for common security information |
425 | * uses callback to print LSM specific information |
426 | */ |
427 | void common_lsm_audit(struct common_audit_data *a, |
428 | void (*pre_audit)(struct audit_buffer *, void *), |
429 | void (*post_audit)(struct audit_buffer *, void *)) |
430 | { |
431 | struct audit_buffer *ab; |
432 | |
433 | if (a == NULL) |
434 | return; |
435 | /* we use GFP_ATOMIC so we won't sleep */ |
436 | ab = audit_log_start(current->audit_context, GFP_ATOMIC | __GFP_NOWARN, |
437 | AUDIT_AVC); |
438 | |
439 | if (ab == NULL) |
440 | return; |
441 | |
442 | if (pre_audit) |
443 | pre_audit(ab, a); |
444 | |
445 | dump_common_audit_data(ab, a); |
446 | |
447 | if (post_audit) |
448 | post_audit(ab, a); |
449 | |
450 | audit_log_end(ab); |
451 | } |
452 |