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 */
42int 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 */
111int 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
187static 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
197static 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 */
211static 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 case LSM_AUDIT_DATA_IBPKEY: {
416 struct in6_addr sbn_pfx;
417
418 memset(&sbn_pfx.s6_addr, 0,
419 sizeof(sbn_pfx.s6_addr));
420 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix,
421 sizeof(a->u.ibpkey->subnet_prefix));
422 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c",
423 a->u.ibpkey->pkey, &sbn_pfx);
424 break;
425 }
426 case LSM_AUDIT_DATA_IBENDPORT:
427 audit_log_format(ab, " device=%s port_num=%u",
428 a->u.ibendport->dev_name,
429 a->u.ibendport->port);
430 break;
431 } /* switch (a->type) */
432}
433
434/**
435 * common_lsm_audit - generic LSM auditing function
436 * @a: auxiliary audit data
437 * @pre_audit: lsm-specific pre-audit callback
438 * @post_audit: lsm-specific post-audit callback
439 *
440 * setup the audit buffer for common security information
441 * uses callback to print LSM specific information
442 */
443void common_lsm_audit(struct common_audit_data *a,
444 void (*pre_audit)(struct audit_buffer *, void *),
445 void (*post_audit)(struct audit_buffer *, void *))
446{
447 struct audit_buffer *ab;
448
449 if (a == NULL)
450 return;
451 /* we use GFP_ATOMIC so we won't sleep */
452 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN,
453 AUDIT_AVC);
454
455 if (ab == NULL)
456 return;
457
458 if (pre_audit)
459 pre_audit(ab, a);
460
461 dump_common_audit_data(ab, a);
462
463 if (post_audit)
464 post_audit(ab, a);
465
466 audit_log_end(ab);
467}
468