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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 | */ | |
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 | */ | |
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 | /* IPv6 can have several extension header before the Transport header | |
123 | * skip them */ | |
124 | offset = skb_network_offset(skb); | |
125 | offset += sizeof(*ip6); | |
126 | nexthdr = ip6->nexthdr; | |
127 | offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); | |
128 | if (offset < 0) | |
129 | return 0; | |
130 | if (proto) | |
131 | *proto = nexthdr; | |
132 | switch (nexthdr) { | |
133 | case IPPROTO_TCP: { | |
134 | struct tcphdr _tcph, *th; | |
135 | ||
136 | th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph); | |
137 | if (th == NULL) | |
138 | break; | |
139 | ||
140 | ad->u.net->sport = th->source; | |
141 | ad->u.net->dport = th->dest; | |
142 | break; | |
143 | } | |
144 | case IPPROTO_UDP: { | |
145 | struct udphdr _udph, *uh; | |
146 | ||
147 | uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph); | |
148 | if (uh == NULL) | |
149 | break; | |
150 | ||
151 | ad->u.net->sport = uh->source; | |
152 | ad->u.net->dport = uh->dest; | |
153 | break; | |
154 | } | |
155 | case IPPROTO_DCCP: { | |
156 | struct dccp_hdr _dccph, *dh; | |
157 | ||
158 | dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph); | |
159 | if (dh == NULL) | |
160 | break; | |
161 | ||
162 | ad->u.net->sport = dh->dccph_sport; | |
163 | ad->u.net->dport = dh->dccph_dport; | |
164 | break; | |
165 | } | |
166 | case IPPROTO_SCTP: { | |
167 | struct sctphdr _sctph, *sh; | |
168 | ||
169 | sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); | |
170 | if (sh == NULL) | |
171 | break; | |
172 | ad->u.net->sport = sh->source; | |
173 | ad->u.net->dport = sh->dest; | |
174 | break; | |
175 | } | |
176 | default: | |
177 | ret = -EINVAL; | |
178 | } | |
179 | return ret; | |
180 | } | |
181 | #endif | |
182 | ||
183 | ||
184 | static inline void print_ipv6_addr(struct audit_buffer *ab, | |
185 | const struct in6_addr *addr, __be16 port, | |
186 | char *name1, char *name2) | |
187 | { | |
188 | if (!ipv6_addr_any(addr)) | |
189 | audit_log_format(ab, " %s=%pI6c", name1, addr); | |
190 | if (port) | |
191 | audit_log_format(ab, " %s=%d", name2, ntohs(port)); | |
192 | } | |
193 | ||
194 | static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr, | |
195 | __be16 port, char *name1, char *name2) | |
196 | { | |
197 | if (addr) | |
198 | audit_log_format(ab, " %s=%pI4", name1, &addr); | |
199 | if (port) | |
200 | audit_log_format(ab, " %s=%d", name2, ntohs(port)); | |
201 | } | |
202 | ||
203 | /** | |
204 | * dump_common_audit_data - helper to dump common audit data | |
205 | * @a : common audit data | |
206 | * | |
207 | */ | |
208 | static void dump_common_audit_data(struct audit_buffer *ab, | |
209 | struct common_audit_data *a) | |
210 | { | |
211 | char comm[sizeof(current->comm)]; | |
212 | ||
213 | /* | |
214 | * To keep stack sizes in check force programers to notice if they | |
215 | * start making this union too large! See struct lsm_network_audit | |
216 | * as an example of how to deal with large data. | |
217 | */ | |
218 | BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2); | |
219 | ||
220 | audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current)); | |
221 | audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm))); | |
222 | ||
223 | switch (a->type) { | |
224 | case LSM_AUDIT_DATA_NONE: | |
225 | return; | |
226 | case LSM_AUDIT_DATA_IPC: | |
227 | audit_log_format(ab, " key=%d ", a->u.ipc_id); | |
228 | break; | |
229 | case LSM_AUDIT_DATA_CAP: | |
230 | audit_log_format(ab, " capability=%d ", a->u.cap); | |
231 | break; | |
232 | case LSM_AUDIT_DATA_PATH: { | |
233 | struct inode *inode; | |
234 | ||
235 | audit_log_d_path(ab, " path=", &a->u.path); | |
236 | ||
237 | inode = d_backing_inode(a->u.path.dentry); | |
238 | if (inode) { | |
239 | audit_log_format(ab, " dev="); | |
240 | audit_log_untrustedstring(ab, inode->i_sb->s_id); | |
241 | audit_log_format(ab, " ino=%lu", inode->i_ino); | |
242 | } | |
243 | break; | |
244 | } | |
245 | case LSM_AUDIT_DATA_FILE: { | |
246 | struct inode *inode; | |
247 | ||
248 | audit_log_d_path(ab, " path=", &a->u.file->f_path); | |
249 | ||
250 | inode = file_inode(a->u.file); | |
251 | if (inode) { | |
252 | audit_log_format(ab, " dev="); | |
253 | audit_log_untrustedstring(ab, inode->i_sb->s_id); | |
254 | audit_log_format(ab, " ino=%lu", inode->i_ino); | |
255 | } | |
256 | break; | |
257 | } | |
258 | case LSM_AUDIT_DATA_IOCTL_OP: { | |
259 | struct inode *inode; | |
260 | ||
261 | audit_log_d_path(ab, " path=", &a->u.op->path); | |
262 | ||
263 | inode = a->u.op->path.dentry->d_inode; | |
264 | if (inode) { | |
265 | audit_log_format(ab, " dev="); | |
266 | audit_log_untrustedstring(ab, inode->i_sb->s_id); | |
267 | audit_log_format(ab, " ino=%lu", inode->i_ino); | |
268 | } | |
269 | ||
270 | audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); | |
271 | break; | |
272 | } | |
273 | case LSM_AUDIT_DATA_DENTRY: { | |
274 | struct inode *inode; | |
275 | ||
276 | audit_log_format(ab, " name="); | |
277 | spin_lock(&a->u.dentry->d_lock); | |
278 | audit_log_untrustedstring(ab, a->u.dentry->d_name.name); | |
279 | spin_unlock(&a->u.dentry->d_lock); | |
280 | ||
281 | inode = d_backing_inode(a->u.dentry); | |
282 | if (inode) { | |
283 | audit_log_format(ab, " dev="); | |
284 | audit_log_untrustedstring(ab, inode->i_sb->s_id); | |
285 | audit_log_format(ab, " ino=%lu", inode->i_ino); | |
286 | } | |
287 | break; | |
288 | } | |
289 | case LSM_AUDIT_DATA_INODE: { | |
290 | struct dentry *dentry; | |
291 | struct inode *inode; | |
292 | ||
293 | rcu_read_lock(); | |
294 | inode = a->u.inode; | |
295 | dentry = d_find_alias_rcu(inode); | |
296 | if (dentry) { | |
297 | audit_log_format(ab, " name="); | |
298 | spin_lock(&dentry->d_lock); | |
299 | audit_log_untrustedstring(ab, dentry->d_name.name); | |
300 | spin_unlock(&dentry->d_lock); | |
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 | rcu_read_unlock(); | |
306 | break; | |
307 | } | |
308 | case LSM_AUDIT_DATA_TASK: { | |
309 | struct task_struct *tsk = a->u.tsk; | |
310 | if (tsk) { | |
311 | pid_t pid = task_tgid_nr(tsk); | |
312 | if (pid) { | |
313 | char comm[sizeof(tsk->comm)]; | |
314 | audit_log_format(ab, " opid=%d ocomm=", pid); | |
315 | audit_log_untrustedstring(ab, | |
316 | memcpy(comm, tsk->comm, sizeof(comm))); | |
317 | } | |
318 | } | |
319 | break; | |
320 | } | |
321 | case LSM_AUDIT_DATA_NET: | |
322 | if (a->u.net->sk) { | |
323 | const struct sock *sk = a->u.net->sk; | |
324 | struct unix_sock *u; | |
325 | struct unix_address *addr; | |
326 | int len = 0; | |
327 | char *p = NULL; | |
328 | ||
329 | switch (sk->sk_family) { | |
330 | case AF_INET: { | |
331 | struct inet_sock *inet = inet_sk(sk); | |
332 | ||
333 | print_ipv4_addr(ab, inet->inet_rcv_saddr, | |
334 | inet->inet_sport, | |
335 | "laddr", "lport"); | |
336 | print_ipv4_addr(ab, inet->inet_daddr, | |
337 | inet->inet_dport, | |
338 | "faddr", "fport"); | |
339 | break; | |
340 | } | |
341 | #if IS_ENABLED(CONFIG_IPV6) | |
342 | case AF_INET6: { | |
343 | struct inet_sock *inet = inet_sk(sk); | |
344 | ||
345 | print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, | |
346 | inet->inet_sport, | |
347 | "laddr", "lport"); | |
348 | print_ipv6_addr(ab, &sk->sk_v6_daddr, | |
349 | inet->inet_dport, | |
350 | "faddr", "fport"); | |
351 | break; | |
352 | } | |
353 | #endif | |
354 | case AF_UNIX: | |
355 | u = unix_sk(sk); | |
356 | addr = smp_load_acquire(&u->addr); | |
357 | if (!addr) | |
358 | break; | |
359 | if (u->path.dentry) { | |
360 | audit_log_d_path(ab, " path=", &u->path); | |
361 | break; | |
362 | } | |
363 | len = addr->len-sizeof(short); | |
364 | p = &addr->name->sun_path[0]; | |
365 | audit_log_format(ab, " path="); | |
366 | if (*p) | |
367 | audit_log_untrustedstring(ab, p); | |
368 | else | |
369 | audit_log_n_hex(ab, p, len); | |
370 | break; | |
371 | } | |
372 | } | |
373 | ||
374 | switch (a->u.net->family) { | |
375 | case AF_INET: | |
376 | print_ipv4_addr(ab, a->u.net->v4info.saddr, | |
377 | a->u.net->sport, | |
378 | "saddr", "src"); | |
379 | print_ipv4_addr(ab, a->u.net->v4info.daddr, | |
380 | a->u.net->dport, | |
381 | "daddr", "dest"); | |
382 | break; | |
383 | case AF_INET6: | |
384 | print_ipv6_addr(ab, &a->u.net->v6info.saddr, | |
385 | a->u.net->sport, | |
386 | "saddr", "src"); | |
387 | print_ipv6_addr(ab, &a->u.net->v6info.daddr, | |
388 | a->u.net->dport, | |
389 | "daddr", "dest"); | |
390 | break; | |
391 | } | |
392 | if (a->u.net->netif > 0) { | |
393 | struct net_device *dev; | |
394 | ||
395 | /* NOTE: we always use init's namespace */ | |
396 | dev = dev_get_by_index(&init_net, a->u.net->netif); | |
397 | if (dev) { | |
398 | audit_log_format(ab, " netif=%s", dev->name); | |
399 | dev_put(dev); | |
400 | } | |
401 | } | |
402 | break; | |
403 | #ifdef CONFIG_KEYS | |
404 | case LSM_AUDIT_DATA_KEY: | |
405 | audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); | |
406 | if (a->u.key_struct.key_desc) { | |
407 | audit_log_format(ab, " key_desc="); | |
408 | audit_log_untrustedstring(ab, a->u.key_struct.key_desc); | |
409 | } | |
410 | break; | |
411 | #endif | |
412 | case LSM_AUDIT_DATA_KMOD: | |
413 | audit_log_format(ab, " kmod="); | |
414 | audit_log_untrustedstring(ab, a->u.kmod_name); | |
415 | break; | |
416 | case LSM_AUDIT_DATA_IBPKEY: { | |
417 | struct in6_addr sbn_pfx; | |
418 | ||
419 | memset(&sbn_pfx.s6_addr, 0, | |
420 | sizeof(sbn_pfx.s6_addr)); | |
421 | memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, | |
422 | sizeof(a->u.ibpkey->subnet_prefix)); | |
423 | audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c", | |
424 | a->u.ibpkey->pkey, &sbn_pfx); | |
425 | break; | |
426 | } | |
427 | case LSM_AUDIT_DATA_IBENDPORT: | |
428 | audit_log_format(ab, " device=%s port_num=%u", | |
429 | a->u.ibendport->dev_name, | |
430 | a->u.ibendport->port); | |
431 | break; | |
432 | case LSM_AUDIT_DATA_LOCKDOWN: | |
433 | audit_log_format(ab, " lockdown_reason=\"%s\"", | |
434 | lockdown_reasons[a->u.reason]); | |
435 | break; | |
436 | } /* switch (a->type) */ | |
437 | } | |
438 | ||
439 | /** | |
440 | * common_lsm_audit - generic LSM auditing function | |
441 | * @a: auxiliary audit data | |
442 | * @pre_audit: lsm-specific pre-audit callback | |
443 | * @post_audit: lsm-specific post-audit callback | |
444 | * | |
445 | * setup the audit buffer for common security information | |
446 | * uses callback to print LSM specific information | |
447 | */ | |
448 | void common_lsm_audit(struct common_audit_data *a, | |
449 | void (*pre_audit)(struct audit_buffer *, void *), | |
450 | void (*post_audit)(struct audit_buffer *, void *)) | |
451 | { | |
452 | struct audit_buffer *ab; | |
453 | ||
454 | if (a == NULL) | |
455 | return; | |
456 | /* we use GFP_ATOMIC so we won't sleep */ | |
457 | ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN, | |
458 | AUDIT_AVC); | |
459 | ||
460 | if (ab == NULL) | |
461 | return; | |
462 | ||
463 | if (pre_audit) | |
464 | pre_audit(ab, a); | |
465 | ||
466 | dump_common_audit_data(ab, a); | |
467 | ||
468 | if (post_audit) | |
469 | post_audit(ab, a); | |
470 | ||
471 | audit_log_end(ab); | |
472 | } |