1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * common LSM auditing functions
4 *
5 * Based on code written for SELinux by :
6 * Stephen Smalley, <sds@tycho.nsa.gov>
7 * James Morris <jmorris@redhat.com>
8 * Author : Etienne Basset, <etienne.basset@ensta.org>
9 */
10
11 #include <linux/types.h>
12 #include <linux/stddef.h>
13 #include <linux/kernel.h>
14 #include <linux/gfp.h>
15 #include <linux/fs.h>
16 #include <linux/init.h>
17 #include <net/sock.h>
18 #include <linux/un.h>
19 #include <net/af_unix.h>
20 #include <linux/audit.h>
21 #include <linux/ipv6.h>
22 #include <linux/ip.h>
23 #include <net/ip.h>
24 #include <net/ipv6.h>
25 #include <linux/tcp.h>
26 #include <linux/udp.h>
27 #include <linux/dccp.h>
28 #include <linux/sctp.h>
29 #include <linux/lsm_audit.h>
30 #include <linux/security.h>
31
32 /**
33 * ipv4_skb_to_auditdata : fill auditdata from skb
34 * @skb : the skb
35 * @ad : the audit data to fill
36 * @proto : the layer 4 protocol
37 *
38 * return 0 on success
39 */
ipv4_skb_to_auditdata(struct sk_buff * skb,struct common_audit_data * ad,u8 * proto)40 int ipv4_skb_to_auditdata(struct sk_buff *skb,
41 struct common_audit_data *ad, u8 *proto)
42 {
43 int ret = 0;
44 struct iphdr *ih;
45
46 ih = ip_hdr(skb);
47 if (ih == NULL)
48 return -EINVAL;
49
50 ad->u.net->v4info.saddr = ih->saddr;
51 ad->u.net->v4info.daddr = ih->daddr;
52
53 if (proto)
54 *proto = ih->protocol;
55 /* non initial fragment */
56 if (ntohs(ih->frag_off) & IP_OFFSET)
57 return 0;
58
59 switch (ih->protocol) {
60 case IPPROTO_TCP: {
61 struct tcphdr *th = tcp_hdr(skb);
62 if (th == NULL)
63 break;
64
65 ad->u.net->sport = th->source;
66 ad->u.net->dport = th->dest;
67 break;
68 }
69 case IPPROTO_UDP: {
70 struct udphdr *uh = udp_hdr(skb);
71 if (uh == NULL)
72 break;
73
74 ad->u.net->sport = uh->source;
75 ad->u.net->dport = uh->dest;
76 break;
77 }
78 case IPPROTO_DCCP: {
79 struct dccp_hdr *dh = dccp_hdr(skb);
80 if (dh == NULL)
81 break;
82
83 ad->u.net->sport = dh->dccph_sport;
84 ad->u.net->dport = dh->dccph_dport;
85 break;
86 }
87 case IPPROTO_SCTP: {
88 struct sctphdr *sh = sctp_hdr(skb);
89 if (sh == NULL)
90 break;
91 ad->u.net->sport = sh->source;
92 ad->u.net->dport = sh->dest;
93 break;
94 }
95 default:
96 ret = -EINVAL;
97 }
98 return ret;
99 }
100 #if IS_ENABLED(CONFIG_IPV6)
101 /**
102 * ipv6_skb_to_auditdata : fill auditdata from skb
103 * @skb : the skb
104 * @ad : the audit data to fill
105 * @proto : the layer 4 protocol
106 *
107 * return 0 on success
108 */
ipv6_skb_to_auditdata(struct sk_buff * skb,struct common_audit_data * ad,u8 * proto)109 int ipv6_skb_to_auditdata(struct sk_buff *skb,
110 struct common_audit_data *ad, u8 *proto)
111 {
112 int offset, ret = 0;
113 struct ipv6hdr *ip6;
114 u8 nexthdr;
115 __be16 frag_off;
116
117 ip6 = ipv6_hdr(skb);
118 if (ip6 == NULL)
119 return -EINVAL;
120 ad->u.net->v6info.saddr = ip6->saddr;
121 ad->u.net->v6info.daddr = ip6->daddr;
122 ret = 0;
123 /* IPv6 can have several extension header before the Transport header
124 * skip them */
125 offset = skb_network_offset(skb);
126 offset += sizeof(*ip6);
127 nexthdr = ip6->nexthdr;
128 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
129 if (offset < 0)
130 return 0;
131 if (proto)
132 *proto = nexthdr;
133 switch (nexthdr) {
134 case IPPROTO_TCP: {
135 struct tcphdr _tcph, *th;
136
137 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
138 if (th == NULL)
139 break;
140
141 ad->u.net->sport = th->source;
142 ad->u.net->dport = th->dest;
143 break;
144 }
145 case IPPROTO_UDP: {
146 struct udphdr _udph, *uh;
147
148 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
149 if (uh == NULL)
150 break;
151
152 ad->u.net->sport = uh->source;
153 ad->u.net->dport = uh->dest;
154 break;
155 }
156 case IPPROTO_DCCP: {
157 struct dccp_hdr _dccph, *dh;
158
159 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
160 if (dh == NULL)
161 break;
162
163 ad->u.net->sport = dh->dccph_sport;
164 ad->u.net->dport = dh->dccph_dport;
165 break;
166 }
167 case IPPROTO_SCTP: {
168 struct sctphdr _sctph, *sh;
169
170 sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
171 if (sh == NULL)
172 break;
173 ad->u.net->sport = sh->source;
174 ad->u.net->dport = sh->dest;
175 break;
176 }
177 default:
178 ret = -EINVAL;
179 }
180 return ret;
181 }
182 #endif
183
184
print_ipv6_addr(struct audit_buffer * ab,struct in6_addr * addr,__be16 port,char * name1,char * name2)185 static inline void print_ipv6_addr(struct audit_buffer *ab,
186 struct in6_addr *addr, __be16 port,
187 char *name1, char *name2)
188 {
189 if (!ipv6_addr_any(addr))
190 audit_log_format(ab, " %s=%pI6c", name1, addr);
191 if (port)
192 audit_log_format(ab, " %s=%d", name2, ntohs(port));
193 }
194
print_ipv4_addr(struct audit_buffer * ab,__be32 addr,__be16 port,char * name1,char * name2)195 static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
196 __be16 port, char *name1, char *name2)
197 {
198 if (addr)
199 audit_log_format(ab, " %s=%pI4", name1, &addr);
200 if (port)
201 audit_log_format(ab, " %s=%d", name2, ntohs(port));
202 }
203
204 /**
205 * dump_common_audit_data - helper to dump common audit data
206 * @a : common audit data
207 *
208 */
dump_common_audit_data(struct audit_buffer * ab,struct common_audit_data * a)209 static void dump_common_audit_data(struct audit_buffer *ab,
210 struct common_audit_data *a)
211 {
212 char comm[sizeof(current->comm)];
213
214 /*
215 * To keep stack sizes in check force programers to notice if they
216 * start making this union too large! See struct lsm_network_audit
217 * as an example of how to deal with large data.
218 */
219 BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2);
220
221 audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
222 audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm)));
223
224 switch (a->type) {
225 case LSM_AUDIT_DATA_NONE:
226 return;
227 case LSM_AUDIT_DATA_IPC:
228 audit_log_format(ab, " key=%d ", a->u.ipc_id);
229 break;
230 case LSM_AUDIT_DATA_CAP:
231 audit_log_format(ab, " capability=%d ", a->u.cap);
232 break;
233 case LSM_AUDIT_DATA_PATH: {
234 struct inode *inode;
235
236 audit_log_d_path(ab, " path=", &a->u.path);
237
238 inode = d_backing_inode(a->u.path.dentry);
239 if (inode) {
240 audit_log_format(ab, " dev=");
241 audit_log_untrustedstring(ab, inode->i_sb->s_id);
242 audit_log_format(ab, " ino=%lu", inode->i_ino);
243 }
244 audit_getcwd();
245 break;
246 }
247 case LSM_AUDIT_DATA_FILE: {
248 struct inode *inode;
249
250 audit_log_d_path(ab, " path=", &a->u.file->f_path);
251
252 inode = file_inode(a->u.file);
253 if (inode) {
254 audit_log_format(ab, " dev=");
255 audit_log_untrustedstring(ab, inode->i_sb->s_id);
256 audit_log_format(ab, " ino=%lu", inode->i_ino);
257 }
258 audit_getcwd();
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 audit_getcwd();
275 break;
276 }
277 case LSM_AUDIT_DATA_DENTRY: {
278 struct inode *inode;
279
280 audit_log_format(ab, " name=");
281 audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
282
283 inode = d_backing_inode(a->u.dentry);
284 if (inode) {
285 audit_log_format(ab, " dev=");
286 audit_log_untrustedstring(ab, inode->i_sb->s_id);
287 audit_log_format(ab, " ino=%lu", inode->i_ino);
288 }
289 audit_getcwd();
290 break;
291 }
292 case LSM_AUDIT_DATA_INODE: {
293 struct dentry *dentry;
294 struct inode *inode;
295
296 inode = a->u.inode;
297 dentry = d_find_alias(inode);
298 if (dentry) {
299 audit_log_format(ab, " name=");
300 audit_log_untrustedstring(ab,
301 dentry->d_name.name);
302 dput(dentry);
303 }
304 audit_log_format(ab, " dev=");
305 audit_log_untrustedstring(ab, inode->i_sb->s_id);
306 audit_log_format(ab, " ino=%lu", inode->i_ino);
307 audit_getcwd();
308 break;
309 }
310 case LSM_AUDIT_DATA_TASK: {
311 struct task_struct *tsk = a->u.tsk;
312 if (tsk) {
313 pid_t pid = task_tgid_nr(tsk);
314 if (pid) {
315 char comm[sizeof(tsk->comm)];
316 audit_log_format(ab, " opid=%d ocomm=", pid);
317 audit_log_untrustedstring(ab,
318 memcpy(comm, tsk->comm, sizeof(comm)));
319 }
320 }
321 break;
322 }
323 case LSM_AUDIT_DATA_NET:
324 if (a->u.net->sk) {
325 struct sock *sk = a->u.net->sk;
326 struct unix_sock *u;
327 struct unix_address *addr;
328 int len = 0;
329 char *p = NULL;
330
331 switch (sk->sk_family) {
332 case AF_INET: {
333 struct inet_sock *inet = inet_sk(sk);
334
335 print_ipv4_addr(ab, inet->inet_rcv_saddr,
336 inet->inet_sport,
337 "laddr", "lport");
338 print_ipv4_addr(ab, inet->inet_daddr,
339 inet->inet_dport,
340 "faddr", "fport");
341 break;
342 }
343 #if IS_ENABLED(CONFIG_IPV6)
344 case AF_INET6: {
345 struct inet_sock *inet = inet_sk(sk);
346
347 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
348 inet->inet_sport,
349 "laddr", "lport");
350 print_ipv6_addr(ab, &sk->sk_v6_daddr,
351 inet->inet_dport,
352 "faddr", "fport");
353 break;
354 }
355 #endif
356 case AF_UNIX:
357 u = unix_sk(sk);
358 addr = smp_load_acquire(&u->addr);
359 if (!addr)
360 break;
361 if (u->path.dentry) {
362 audit_log_d_path(ab, " path=", &u->path);
363 break;
364 }
365 len = addr->len-sizeof(short);
366 p = &addr->name->sun_path[0];
367 audit_log_format(ab, " path=");
368 if (*p)
369 audit_log_untrustedstring(ab, p);
370 else
371 audit_log_n_hex(ab, p, len);
372 break;
373 }
374 }
375
376 switch (a->u.net->family) {
377 case AF_INET:
378 print_ipv4_addr(ab, a->u.net->v4info.saddr,
379 a->u.net->sport,
380 "saddr", "src");
381 print_ipv4_addr(ab, a->u.net->v4info.daddr,
382 a->u.net->dport,
383 "daddr", "dest");
384 break;
385 case AF_INET6:
386 print_ipv6_addr(ab, &a->u.net->v6info.saddr,
387 a->u.net->sport,
388 "saddr", "src");
389 print_ipv6_addr(ab, &a->u.net->v6info.daddr,
390 a->u.net->dport,
391 "daddr", "dest");
392 break;
393 }
394 if (a->u.net->netif > 0) {
395 struct net_device *dev;
396
397 /* NOTE: we always use init's namespace */
398 dev = dev_get_by_index(&init_net, a->u.net->netif);
399 if (dev) {
400 audit_log_format(ab, " netif=%s", dev->name);
401 dev_put(dev);
402 }
403 }
404 break;
405 #ifdef CONFIG_KEYS
406 case LSM_AUDIT_DATA_KEY:
407 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
408 if (a->u.key_struct.key_desc) {
409 audit_log_format(ab, " key_desc=");
410 audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
411 }
412 break;
413 #endif
414 case LSM_AUDIT_DATA_KMOD:
415 audit_log_format(ab, " kmod=");
416 audit_log_untrustedstring(ab, a->u.kmod_name);
417 break;
418 case LSM_AUDIT_DATA_IBPKEY: {
419 struct in6_addr sbn_pfx;
420
421 memset(&sbn_pfx.s6_addr, 0,
422 sizeof(sbn_pfx.s6_addr));
423 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix,
424 sizeof(a->u.ibpkey->subnet_prefix));
425 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c",
426 a->u.ibpkey->pkey, &sbn_pfx);
427 break;
428 }
429 case LSM_AUDIT_DATA_IBENDPORT:
430 audit_log_format(ab, " device=%s port_num=%u",
431 a->u.ibendport->dev_name,
432 a->u.ibendport->port);
433 break;
434 case LSM_AUDIT_DATA_LOCKDOWN:
435 audit_log_format(ab, " lockdown_reason=\"%s\"",
436 lockdown_reasons[a->u.reason]);
437 break;
438 } /* switch (a->type) */
439 }
440
441 /**
442 * common_lsm_audit - generic LSM auditing function
443 * @a: auxiliary audit data
444 * @pre_audit: lsm-specific pre-audit callback
445 * @post_audit: lsm-specific post-audit callback
446 *
447 * setup the audit buffer for common security information
448 * uses callback to print LSM specific information
449 */
common_lsm_audit(struct common_audit_data * a,void (* pre_audit)(struct audit_buffer *,void *),void (* post_audit)(struct audit_buffer *,void *))450 void common_lsm_audit(struct common_audit_data *a,
451 void (*pre_audit)(struct audit_buffer *, void *),
452 void (*post_audit)(struct audit_buffer *, void *))
453 {
454 struct audit_buffer *ab;
455
456 if (a == NULL)
457 return;
458 /* we use GFP_ATOMIC so we won't sleep */
459 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN,
460 AUDIT_AVC);
461
462 if (ab == NULL)
463 return;
464
465 if (pre_audit)
466 pre_audit(ab, a);
467
468 dump_common_audit_data(ab, a);
469
470 if (post_audit)
471 post_audit(ab, a);
472
473 audit_log_end(ab);
474 }
475
