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 ad->u.net->v4info.saddr = ih->saddr;
48 ad->u.net->v4info.daddr = ih->daddr;
49
50 if (proto)
51 *proto = ih->protocol;
52 /* non initial fragment */
53 if (ntohs(ih->frag_off) & IP_OFFSET)
54 return 0;
55
56 switch (ih->protocol) {
57 case IPPROTO_TCP: {
58 struct tcphdr *th = tcp_hdr(skb);
59
60 ad->u.net->sport = th->source;
61 ad->u.net->dport = th->dest;
62 break;
63 }
64 case IPPROTO_UDP: {
65 struct udphdr *uh = udp_hdr(skb);
66
67 ad->u.net->sport = uh->source;
68 ad->u.net->dport = uh->dest;
69 break;
70 }
71 case IPPROTO_DCCP: {
72 struct dccp_hdr *dh = dccp_hdr(skb);
73
74 ad->u.net->sport = dh->dccph_sport;
75 ad->u.net->dport = dh->dccph_dport;
76 break;
77 }
78 case IPPROTO_SCTP: {
79 struct sctphdr *sh = sctp_hdr(skb);
80
81 ad->u.net->sport = sh->source;
82 ad->u.net->dport = sh->dest;
83 break;
84 }
85 default:
86 ret = -EINVAL;
87 }
88 return ret;
89 }
90 #if IS_ENABLED(CONFIG_IPV6)
91 /**
92 * ipv6_skb_to_auditdata : fill auditdata from skb
93 * @skb : the skb
94 * @ad : the audit data to fill
95 * @proto : the layer 4 protocol
96 *
97 * return 0 on success
98 */
ipv6_skb_to_auditdata(struct sk_buff * skb,struct common_audit_data * ad,u8 * proto)99 int ipv6_skb_to_auditdata(struct sk_buff *skb,
100 struct common_audit_data *ad, u8 *proto)
101 {
102 int offset, ret = 0;
103 struct ipv6hdr *ip6;
104 u8 nexthdr;
105 __be16 frag_off;
106
107 ip6 = ipv6_hdr(skb);
108 ad->u.net->v6info.saddr = ip6->saddr;
109 ad->u.net->v6info.daddr = ip6->daddr;
110 /* IPv6 can have several extension header before the Transport header
111 * skip them */
112 offset = skb_network_offset(skb);
113 offset += sizeof(*ip6);
114 nexthdr = ip6->nexthdr;
115 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
116 if (offset < 0)
117 return 0;
118 if (proto)
119 *proto = nexthdr;
120 switch (nexthdr) {
121 case IPPROTO_TCP: {
122 struct tcphdr _tcph, *th;
123
124 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
125 if (th == NULL)
126 break;
127
128 ad->u.net->sport = th->source;
129 ad->u.net->dport = th->dest;
130 break;
131 }
132 case IPPROTO_UDP: {
133 struct udphdr _udph, *uh;
134
135 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
136 if (uh == NULL)
137 break;
138
139 ad->u.net->sport = uh->source;
140 ad->u.net->dport = uh->dest;
141 break;
142 }
143 case IPPROTO_DCCP: {
144 struct dccp_hdr _dccph, *dh;
145
146 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
147 if (dh == NULL)
148 break;
149
150 ad->u.net->sport = dh->dccph_sport;
151 ad->u.net->dport = dh->dccph_dport;
152 break;
153 }
154 case IPPROTO_SCTP: {
155 struct sctphdr _sctph, *sh;
156
157 sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
158 if (sh == NULL)
159 break;
160 ad->u.net->sport = sh->source;
161 ad->u.net->dport = sh->dest;
162 break;
163 }
164 default:
165 ret = -EINVAL;
166 }
167 return ret;
168 }
169 #endif
170
171
print_ipv6_addr(struct audit_buffer * ab,const struct in6_addr * addr,__be16 port,char * name1,char * name2)172 static inline void print_ipv6_addr(struct audit_buffer *ab,
173 const struct in6_addr *addr, __be16 port,
174 char *name1, char *name2)
175 {
176 if (!ipv6_addr_any(addr))
177 audit_log_format(ab, " %s=%pI6c", name1, addr);
178 if (port)
179 audit_log_format(ab, " %s=%d", name2, ntohs(port));
180 }
181
print_ipv4_addr(struct audit_buffer * ab,__be32 addr,__be16 port,char * name1,char * name2)182 static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
183 __be16 port, char *name1, char *name2)
184 {
185 if (addr)
186 audit_log_format(ab, " %s=%pI4", name1, &addr);
187 if (port)
188 audit_log_format(ab, " %s=%d", name2, ntohs(port));
189 }
190
191 /**
192 * dump_common_audit_data - helper to dump common audit data
193 * @a : common audit data
194 *
195 */
dump_common_audit_data(struct audit_buffer * ab,struct common_audit_data * a)196 static void dump_common_audit_data(struct audit_buffer *ab,
197 struct common_audit_data *a)
198 {
199 char comm[sizeof(current->comm)];
200
201 /*
202 * To keep stack sizes in check force programers to notice if they
203 * start making this union too large! See struct lsm_network_audit
204 * as an example of how to deal with large data.
205 */
206 BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2);
207
208 audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
209 audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm)));
210
211 switch (a->type) {
212 case LSM_AUDIT_DATA_NONE:
213 return;
214 case LSM_AUDIT_DATA_IPC:
215 audit_log_format(ab, " ipc_key=%d ", a->u.ipc_id);
216 break;
217 case LSM_AUDIT_DATA_CAP:
218 audit_log_format(ab, " capability=%d ", a->u.cap);
219 break;
220 case LSM_AUDIT_DATA_PATH: {
221 struct inode *inode;
222
223 audit_log_d_path(ab, " path=", &a->u.path);
224
225 inode = d_backing_inode(a->u.path.dentry);
226 if (inode) {
227 audit_log_format(ab, " dev=");
228 audit_log_untrustedstring(ab, inode->i_sb->s_id);
229 audit_log_format(ab, " ino=%lu", inode->i_ino);
230 }
231 break;
232 }
233 case LSM_AUDIT_DATA_FILE: {
234 struct inode *inode;
235
236 audit_log_d_path(ab, " path=", &a->u.file->f_path);
237
238 inode = file_inode(a->u.file);
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_IOCTL_OP: {
247 struct inode *inode;
248
249 audit_log_d_path(ab, " path=", &a->u.op->path);
250
251 inode = a->u.op->path.dentry->d_inode;
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
258 audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd);
259 break;
260 }
261 case LSM_AUDIT_DATA_DENTRY: {
262 struct inode *inode;
263
264 audit_log_format(ab, " name=");
265 spin_lock(&a->u.dentry->d_lock);
266 audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
267 spin_unlock(&a->u.dentry->d_lock);
268
269 inode = d_backing_inode(a->u.dentry);
270 if (inode) {
271 audit_log_format(ab, " dev=");
272 audit_log_untrustedstring(ab, inode->i_sb->s_id);
273 audit_log_format(ab, " ino=%lu", inode->i_ino);
274 }
275 break;
276 }
277 case LSM_AUDIT_DATA_INODE: {
278 struct dentry *dentry;
279 struct inode *inode;
280
281 rcu_read_lock();
282 inode = a->u.inode;
283 dentry = d_find_alias_rcu(inode);
284 if (dentry) {
285 audit_log_format(ab, " name=");
286 spin_lock(&dentry->d_lock);
287 audit_log_untrustedstring(ab, dentry->d_name.name);
288 spin_unlock(&dentry->d_lock);
289 }
290 audit_log_format(ab, " dev=");
291 audit_log_untrustedstring(ab, inode->i_sb->s_id);
292 audit_log_format(ab, " ino=%lu", inode->i_ino);
293 rcu_read_unlock();
294 break;
295 }
296 case LSM_AUDIT_DATA_TASK: {
297 struct task_struct *tsk = a->u.tsk;
298 if (tsk) {
299 pid_t pid = task_tgid_nr(tsk);
300 if (pid) {
301 char comm[sizeof(tsk->comm)];
302 audit_log_format(ab, " opid=%d ocomm=", pid);
303 audit_log_untrustedstring(ab,
304 memcpy(comm, tsk->comm, sizeof(comm)));
305 }
306 }
307 break;
308 }
309 case LSM_AUDIT_DATA_NET:
310 if (a->u.net->sk) {
311 const struct sock *sk = a->u.net->sk;
312 struct unix_sock *u;
313 struct unix_address *addr;
314 int len = 0;
315 char *p = NULL;
316
317 switch (sk->sk_family) {
318 case AF_INET: {
319 struct inet_sock *inet = inet_sk(sk);
320
321 print_ipv4_addr(ab, inet->inet_rcv_saddr,
322 inet->inet_sport,
323 "laddr", "lport");
324 print_ipv4_addr(ab, inet->inet_daddr,
325 inet->inet_dport,
326 "faddr", "fport");
327 break;
328 }
329 #if IS_ENABLED(CONFIG_IPV6)
330 case AF_INET6: {
331 struct inet_sock *inet = inet_sk(sk);
332
333 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
334 inet->inet_sport,
335 "laddr", "lport");
336 print_ipv6_addr(ab, &sk->sk_v6_daddr,
337 inet->inet_dport,
338 "faddr", "fport");
339 break;
340 }
341 #endif
342 case AF_UNIX:
343 u = unix_sk(sk);
344 addr = smp_load_acquire(&u->addr);
345 if (!addr)
346 break;
347 if (u->path.dentry) {
348 audit_log_d_path(ab, " path=", &u->path);
349 break;
350 }
351 len = addr->len-sizeof(short);
352 p = &addr->name->sun_path[0];
353 audit_log_format(ab, " path=");
354 if (*p)
355 audit_log_untrustedstring(ab, p);
356 else
357 audit_log_n_hex(ab, p, len);
358 break;
359 }
360 }
361
362 switch (a->u.net->family) {
363 case AF_INET:
364 print_ipv4_addr(ab, a->u.net->v4info.saddr,
365 a->u.net->sport,
366 "saddr", "src");
367 print_ipv4_addr(ab, a->u.net->v4info.daddr,
368 a->u.net->dport,
369 "daddr", "dest");
370 break;
371 case AF_INET6:
372 print_ipv6_addr(ab, &a->u.net->v6info.saddr,
373 a->u.net->sport,
374 "saddr", "src");
375 print_ipv6_addr(ab, &a->u.net->v6info.daddr,
376 a->u.net->dport,
377 "daddr", "dest");
378 break;
379 }
380 if (a->u.net->netif > 0) {
381 struct net_device *dev;
382
383 /* NOTE: we always use init's namespace */
384 dev = dev_get_by_index(&init_net, a->u.net->netif);
385 if (dev) {
386 audit_log_format(ab, " netif=%s", dev->name);
387 dev_put(dev);
388 }
389 }
390 break;
391 #ifdef CONFIG_KEYS
392 case LSM_AUDIT_DATA_KEY:
393 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
394 if (a->u.key_struct.key_desc) {
395 audit_log_format(ab, " key_desc=");
396 audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
397 }
398 break;
399 #endif
400 case LSM_AUDIT_DATA_KMOD:
401 audit_log_format(ab, " kmod=");
402 audit_log_untrustedstring(ab, a->u.kmod_name);
403 break;
404 case LSM_AUDIT_DATA_IBPKEY: {
405 struct in6_addr sbn_pfx;
406
407 memset(&sbn_pfx.s6_addr, 0,
408 sizeof(sbn_pfx.s6_addr));
409 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix,
410 sizeof(a->u.ibpkey->subnet_prefix));
411 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c",
412 a->u.ibpkey->pkey, &sbn_pfx);
413 break;
414 }
415 case LSM_AUDIT_DATA_IBENDPORT:
416 audit_log_format(ab, " device=%s port_num=%u",
417 a->u.ibendport->dev_name,
418 a->u.ibendport->port);
419 break;
420 case LSM_AUDIT_DATA_LOCKDOWN:
421 audit_log_format(ab, " lockdown_reason=\"%s\"",
422 lockdown_reasons[a->u.reason]);
423 break;
424 case LSM_AUDIT_DATA_ANONINODE:
425 audit_log_format(ab, " anonclass=%s", a->u.anonclass);
426 break;
427 } /* switch (a->type) */
428 }
429
430 /**
431 * common_lsm_audit - generic LSM auditing function
432 * @a: auxiliary audit data
433 * @pre_audit: lsm-specific pre-audit callback
434 * @post_audit: lsm-specific post-audit callback
435 *
436 * setup the audit buffer for common security information
437 * uses callback to print LSM specific information
438 */
common_lsm_audit(struct common_audit_data * a,void (* pre_audit)(struct audit_buffer *,void *),void (* post_audit)(struct audit_buffer *,void *))439 void common_lsm_audit(struct common_audit_data *a,
440 void (*pre_audit)(struct audit_buffer *, void *),
441 void (*post_audit)(struct audit_buffer *, void *))
442 {
443 struct audit_buffer *ab;
444
445 if (a == NULL)
446 return;
447 /* we use GFP_ATOMIC so we won't sleep */
448 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN,
449 AUDIT_AVC);
450
451 if (ab == NULL)
452 return;
453
454 if (pre_audit)
455 pre_audit(ab, a);
456
457 dump_common_audit_data(ab, a);
458
459 if (post_audit)
460 post_audit(ab, a);
461
462 audit_log_end(ab);
463 }
464