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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 | 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 | ||
185 | static inline void print_ipv6_addr(struct audit_buffer *ab, | |
186 | const 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 | ||
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 | */ | |
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 | break; | |
245 | } | |
246 | case LSM_AUDIT_DATA_FILE: { | |
247 | struct inode *inode; | |
248 | ||
249 | audit_log_d_path(ab, " path=", &a->u.file->f_path); | |
250 | ||
251 | inode = file_inode(a->u.file); | |
252 | if (inode) { | |
253 | audit_log_format(ab, " dev="); | |
254 | audit_log_untrustedstring(ab, inode->i_sb->s_id); | |
255 | audit_log_format(ab, " ino=%lu", inode->i_ino); | |
256 | } | |
257 | break; | |
258 | } | |
259 | case LSM_AUDIT_DATA_IOCTL_OP: { | |
260 | struct inode *inode; | |
261 | ||
262 | audit_log_d_path(ab, " path=", &a->u.op->path); | |
263 | ||
264 | inode = a->u.op->path.dentry->d_inode; | |
265 | if (inode) { | |
266 | audit_log_format(ab, " dev="); | |
267 | audit_log_untrustedstring(ab, inode->i_sb->s_id); | |
268 | audit_log_format(ab, " ino=%lu", inode->i_ino); | |
269 | } | |
270 | ||
271 | audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); | |
272 | break; | |
273 | } | |
274 | case LSM_AUDIT_DATA_DENTRY: { | |
275 | struct inode *inode; | |
276 | ||
277 | audit_log_format(ab, " name="); | |
278 | spin_lock(&a->u.dentry->d_lock); | |
279 | audit_log_untrustedstring(ab, a->u.dentry->d_name.name); | |
280 | spin_unlock(&a->u.dentry->d_lock); | |
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 | rcu_read_lock(); | |
295 | inode = a->u.inode; | |
296 | dentry = d_find_alias_rcu(inode); | |
297 | if (dentry) { | |
298 | audit_log_format(ab, " name="); | |
299 | spin_lock(&dentry->d_lock); | |
300 | audit_log_untrustedstring(ab, dentry->d_name.name); | |
301 | spin_unlock(&dentry->d_lock); | |
302 | } | |
303 | audit_log_format(ab, " dev="); | |
304 | audit_log_untrustedstring(ab, inode->i_sb->s_id); | |
305 | audit_log_format(ab, " ino=%lu", inode->i_ino); | |
306 | rcu_read_unlock(); | |
307 | break; | |
308 | } | |
309 | case LSM_AUDIT_DATA_TASK: { | |
310 | struct task_struct *tsk = a->u.tsk; | |
311 | if (tsk) { | |
312 | pid_t pid = task_tgid_nr(tsk); | |
313 | if (pid) { | |
314 | char comm[sizeof(tsk->comm)]; | |
315 | audit_log_format(ab, " opid=%d ocomm=", pid); | |
316 | audit_log_untrustedstring(ab, | |
317 | memcpy(comm, tsk->comm, sizeof(comm))); | |
318 | } | |
319 | } | |
320 | break; | |
321 | } | |
322 | case LSM_AUDIT_DATA_NET: | |
323 | if (a->u.net->sk) { | |
324 | const struct sock *sk = a->u.net->sk; | |
325 | struct unix_sock *u; | |
326 | struct unix_address *addr; | |
327 | int len = 0; | |
328 | char *p = NULL; | |
329 | ||
330 | switch (sk->sk_family) { | |
331 | case AF_INET: { | |
332 | struct inet_sock *inet = inet_sk(sk); | |
333 | ||
334 | print_ipv4_addr(ab, inet->inet_rcv_saddr, | |
335 | inet->inet_sport, | |
336 | "laddr", "lport"); | |
337 | print_ipv4_addr(ab, inet->inet_daddr, | |
338 | inet->inet_dport, | |
339 | "faddr", "fport"); | |
340 | break; | |
341 | } | |
342 | #if IS_ENABLED(CONFIG_IPV6) | |
343 | case AF_INET6: { | |
344 | struct inet_sock *inet = inet_sk(sk); | |
345 | ||
346 | print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, | |
347 | inet->inet_sport, | |
348 | "laddr", "lport"); | |
349 | print_ipv6_addr(ab, &sk->sk_v6_daddr, | |
350 | inet->inet_dport, | |
351 | "faddr", "fport"); | |
352 | break; | |
353 | } | |
354 | #endif | |
355 | case AF_UNIX: | |
356 | u = unix_sk(sk); | |
357 | addr = smp_load_acquire(&u->addr); | |
358 | if (!addr) | |
359 | break; | |
360 | if (u->path.dentry) { | |
361 | audit_log_d_path(ab, " path=", &u->path); | |
362 | break; | |
363 | } | |
364 | len = addr->len-sizeof(short); | |
365 | p = &addr->name->sun_path[0]; | |
366 | audit_log_format(ab, " path="); | |
367 | if (*p) | |
368 | audit_log_untrustedstring(ab, p); | |
369 | else | |
370 | audit_log_n_hex(ab, p, len); | |
371 | break; | |
372 | } | |
373 | } | |
374 | ||
375 | switch (a->u.net->family) { | |
376 | case AF_INET: | |
377 | print_ipv4_addr(ab, a->u.net->v4info.saddr, | |
378 | a->u.net->sport, | |
379 | "saddr", "src"); | |
380 | print_ipv4_addr(ab, a->u.net->v4info.daddr, | |
381 | a->u.net->dport, | |
382 | "daddr", "dest"); | |
383 | break; | |
384 | case AF_INET6: | |
385 | print_ipv6_addr(ab, &a->u.net->v6info.saddr, | |
386 | a->u.net->sport, | |
387 | "saddr", "src"); | |
388 | print_ipv6_addr(ab, &a->u.net->v6info.daddr, | |
389 | a->u.net->dport, | |
390 | "daddr", "dest"); | |
391 | break; | |
392 | } | |
393 | if (a->u.net->netif > 0) { | |
394 | struct net_device *dev; | |
395 | ||
396 | /* NOTE: we always use init's namespace */ | |
397 | dev = dev_get_by_index(&init_net, a->u.net->netif); | |
398 | if (dev) { | |
399 | audit_log_format(ab, " netif=%s", dev->name); | |
400 | dev_put(dev); | |
401 | } | |
402 | } | |
403 | break; | |
404 | #ifdef CONFIG_KEYS | |
405 | case LSM_AUDIT_DATA_KEY: | |
406 | audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); | |
407 | if (a->u.key_struct.key_desc) { | |
408 | audit_log_format(ab, " key_desc="); | |
409 | audit_log_untrustedstring(ab, a->u.key_struct.key_desc); | |
410 | } | |
411 | break; | |
412 | #endif | |
413 | case LSM_AUDIT_DATA_KMOD: | |
414 | audit_log_format(ab, " kmod="); | |
415 | audit_log_untrustedstring(ab, a->u.kmod_name); | |
416 | break; | |
417 | case LSM_AUDIT_DATA_IBPKEY: { | |
418 | struct in6_addr sbn_pfx; | |
419 | ||
420 | memset(&sbn_pfx.s6_addr, 0, | |
421 | sizeof(sbn_pfx.s6_addr)); | |
422 | memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, | |
423 | sizeof(a->u.ibpkey->subnet_prefix)); | |
424 | audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c", | |
425 | a->u.ibpkey->pkey, &sbn_pfx); | |
426 | break; | |
427 | } | |
428 | case LSM_AUDIT_DATA_IBENDPORT: | |
429 | audit_log_format(ab, " device=%s port_num=%u", | |
430 | a->u.ibendport->dev_name, | |
431 | a->u.ibendport->port); | |
432 | break; | |
433 | case LSM_AUDIT_DATA_LOCKDOWN: | |
434 | audit_log_format(ab, " lockdown_reason=\"%s\"", | |
435 | lockdown_reasons[a->u.reason]); | |
436 | break; | |
437 | } /* switch (a->type) */ | |
438 | } | |
439 | ||
440 | /** | |
441 | * common_lsm_audit - generic LSM auditing function | |
442 | * @a: auxiliary audit data | |
443 | * @pre_audit: lsm-specific pre-audit callback | |
444 | * @post_audit: lsm-specific post-audit callback | |
445 | * | |
446 | * setup the audit buffer for common security information | |
447 | * uses callback to print LSM specific information | |
448 | */ | |
449 | void common_lsm_audit(struct common_audit_data *a, | |
450 | void (*pre_audit)(struct audit_buffer *, void *), | |
451 | void (*post_audit)(struct audit_buffer *, void *)) | |
452 | { | |
453 | struct audit_buffer *ab; | |
454 | ||
455 | if (a == NULL) | |
456 | return; | |
457 | /* we use GFP_ATOMIC so we won't sleep */ | |
458 | ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN, | |
459 | AUDIT_AVC); | |
460 | ||
461 | if (ab == NULL) | |
462 | return; | |
463 | ||
464 | if (pre_audit) | |
465 | pre_audit(ab, a); | |
466 | ||
467 | dump_common_audit_data(ab, a); | |
468 | ||
469 | if (post_audit) | |
470 | post_audit(ab, a); | |
471 | ||
472 | audit_log_end(ab); | |
473 | } |