1 /*
2 * common LSM auditing functions
3 *
4 * Based on code written for SELinux by :
5 * Stephen Smalley, <sds@tycho.nsa.gov>
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 */
ipv4_skb_to_auditdata(struct sk_buff * skb,struct common_audit_data * ad,u8 * proto)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 */
ipv6_skb_to_auditdata(struct sk_buff * skb,struct common_audit_data * ad,u8 * proto)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
print_ipv6_addr(struct audit_buffer * ab,struct in6_addr * addr,__be16 port,char * name1,char * name2)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
print_ipv4_addr(struct audit_buffer * ab,__be32 addr,__be16 port,char * name1,char * name2)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 */
dump_common_audit_data(struct audit_buffer * ab,struct common_audit_data * a)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 int len = 0;
325 char *p = NULL;
326
327 switch (sk->sk_family) {
328 case AF_INET: {
329 struct inet_sock *inet = inet_sk(sk);
330
331 print_ipv4_addr(ab, inet->inet_rcv_saddr,
332 inet->inet_sport,
333 "laddr", "lport");
334 print_ipv4_addr(ab, inet->inet_daddr,
335 inet->inet_dport,
336 "faddr", "fport");
337 break;
338 }
339 #if IS_ENABLED(CONFIG_IPV6)
340 case AF_INET6: {
341 struct inet_sock *inet = inet_sk(sk);
342
343 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
344 inet->inet_sport,
345 "laddr", "lport");
346 print_ipv6_addr(ab, &sk->sk_v6_daddr,
347 inet->inet_dport,
348 "faddr", "fport");
349 break;
350 }
351 #endif
352 case AF_UNIX:
353 u = unix_sk(sk);
354 if (u->path.dentry) {
355 audit_log_d_path(ab, " path=", &u->path);
356 break;
357 }
358 if (!u->addr)
359 break;
360 len = u->addr->len-sizeof(short);
361 p = &u->addr->name->sun_path[0];
362 audit_log_format(ab, " path=");
363 if (*p)
364 audit_log_untrustedstring(ab, p);
365 else
366 audit_log_n_hex(ab, p, len);
367 break;
368 }
369 }
370
371 switch (a->u.net->family) {
372 case AF_INET:
373 print_ipv4_addr(ab, a->u.net->v4info.saddr,
374 a->u.net->sport,
375 "saddr", "src");
376 print_ipv4_addr(ab, a->u.net->v4info.daddr,
377 a->u.net->dport,
378 "daddr", "dest");
379 break;
380 case AF_INET6:
381 print_ipv6_addr(ab, &a->u.net->v6info.saddr,
382 a->u.net->sport,
383 "saddr", "src");
384 print_ipv6_addr(ab, &a->u.net->v6info.daddr,
385 a->u.net->dport,
386 "daddr", "dest");
387 break;
388 }
389 if (a->u.net->netif > 0) {
390 struct net_device *dev;
391
392 /* NOTE: we always use init's namespace */
393 dev = dev_get_by_index(&init_net, a->u.net->netif);
394 if (dev) {
395 audit_log_format(ab, " netif=%s", dev->name);
396 dev_put(dev);
397 }
398 }
399 break;
400 #ifdef CONFIG_KEYS
401 case LSM_AUDIT_DATA_KEY:
402 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
403 if (a->u.key_struct.key_desc) {
404 audit_log_format(ab, " key_desc=");
405 audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
406 }
407 break;
408 #endif
409 case LSM_AUDIT_DATA_KMOD:
410 audit_log_format(ab, " kmod=");
411 audit_log_untrustedstring(ab, a->u.kmod_name);
412 break;
413 case LSM_AUDIT_DATA_IBPKEY: {
414 struct in6_addr sbn_pfx;
415
416 memset(&sbn_pfx.s6_addr, 0,
417 sizeof(sbn_pfx.s6_addr));
418 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix,
419 sizeof(a->u.ibpkey->subnet_prefix));
420 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c",
421 a->u.ibpkey->pkey, &sbn_pfx);
422 break;
423 }
424 case LSM_AUDIT_DATA_IBENDPORT:
425 audit_log_format(ab, " device=%s port_num=%u",
426 a->u.ibendport->dev_name,
427 a->u.ibendport->port);
428 break;
429 } /* switch (a->type) */
430 }
431
432 /**
433 * common_lsm_audit - generic LSM auditing function
434 * @a: auxiliary audit data
435 * @pre_audit: lsm-specific pre-audit callback
436 * @post_audit: lsm-specific post-audit callback
437 *
438 * setup the audit buffer for common security information
439 * uses callback to print LSM specific information
440 */
common_lsm_audit(struct common_audit_data * a,void (* pre_audit)(struct audit_buffer *,void *),void (* post_audit)(struct audit_buffer *,void *))441 void common_lsm_audit(struct common_audit_data *a,
442 void (*pre_audit)(struct audit_buffer *, void *),
443 void (*post_audit)(struct audit_buffer *, void *))
444 {
445 struct audit_buffer *ab;
446
447 if (a == NULL)
448 return;
449 /* we use GFP_ATOMIC so we won't sleep */
450 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN,
451 AUDIT_AVC);
452
453 if (ab == NULL)
454 return;
455
456 if (pre_audit)
457 pre_audit(ab, a);
458
459 dump_common_audit_data(ab, a);
460
461 if (post_audit)
462 post_audit(ab, a);
463
464 audit_log_end(ab);
465 }
466
