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 /* 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
print_ipv6_addr(struct audit_buffer * ab,const struct in6_addr * addr,__be16 port,char * name1,char * name2)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
print_ipv4_addr(struct audit_buffer * ab,__be32 addr,__be16 port,char * name1,char * name2)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 */
dump_common_audit_data(struct audit_buffer * ab,struct common_audit_data * a)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 */
common_lsm_audit(struct common_audit_data * a,void (* pre_audit)(struct audit_buffer *,void *),void (* post_audit)(struct audit_buffer *,void *))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 }
473
