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d2912cb1 1// SPDX-License-Identifier: GPL-2.0-only
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2/*
3 * common LSM auditing functions
4 *
5 * Based on code written for SELinux by :
5d728015 6 * Stephen Smalley, <sds@tycho.nsa.gov>
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7 * James Morris <jmorris@redhat.com>
8 * Author : Etienne Basset, <etienne.basset@ensta.org>
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9 */
10
11#include <linux/types.h>
12#include <linux/stddef.h>
13#include <linux/kernel.h>
5a0e3ad6 14#include <linux/gfp.h>
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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>
59438b46 30#include <linux/security.h>
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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 */
40int 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
48c62af6
EP
50 ad->u.net->v4info.saddr = ih->saddr;
51 ad->u.net->v4info.daddr = ih->daddr;
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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
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EP
65 ad->u.net->sport = th->source;
66 ad->u.net->dport = th->dest;
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67 break;
68 }
69 case IPPROTO_UDP: {
70 struct udphdr *uh = udp_hdr(skb);
71 if (uh == NULL)
72 break;
73
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EP
74 ad->u.net->sport = uh->source;
75 ad->u.net->dport = uh->dest;
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76 break;
77 }
78 case IPPROTO_DCCP: {
79 struct dccp_hdr *dh = dccp_hdr(skb);
80 if (dh == NULL)
81 break;
82
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EP
83 ad->u.net->sport = dh->dccph_sport;
84 ad->u.net->dport = dh->dccph_dport;
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85 break;
86 }
87 case IPPROTO_SCTP: {
88 struct sctphdr *sh = sctp_hdr(skb);
89 if (sh == NULL)
90 break;
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EP
91 ad->u.net->sport = sh->source;
92 ad->u.net->dport = sh->dest;
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93 break;
94 }
95 default:
96 ret = -EINVAL;
97 }
98 return ret;
99}
1a93a6ea 100#if IS_ENABLED(CONFIG_IPV6)
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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 */
109int 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;
75f2811c 115 __be16 frag_off;
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116
117 ip6 = ipv6_hdr(skb);
118 if (ip6 == NULL)
119 return -EINVAL;
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120 ad->u.net->v6info.saddr = ip6->saddr;
121 ad->u.net->v6info.daddr = ip6->daddr;
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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;
75f2811c 128 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
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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
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EP
141 ad->u.net->sport = th->source;
142 ad->u.net->dport = th->dest;
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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
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EP
152 ad->u.net->sport = uh->source;
153 ad->u.net->dport = uh->dest;
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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
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EP
163 ad->u.net->sport = dh->dccph_sport;
164 ad->u.net->dport = dh->dccph_dport;
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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;
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EP
173 ad->u.net->sport = sh->source;
174 ad->u.net->dport = sh->dest;
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175 break;
176 }
177 default:
178 ret = -EINVAL;
179 }
180 return ret;
181}
182#endif
183
184
185static inline void print_ipv6_addr(struct audit_buffer *ab,
41dd9596 186 const struct in6_addr *addr, __be16 port,
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187 char *name1, char *name2)
188{
189 if (!ipv6_addr_any(addr))
d8116591 190 audit_log_format(ab, " %s=%pI6c", name1, addr);
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191 if (port)
192 audit_log_format(ab, " %s=%d", name2, ntohs(port));
193}
194
195static 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 */
209static void dump_common_audit_data(struct audit_buffer *ab,
210 struct common_audit_data *a)
211{
5deeb5ce 212 char comm[sizeof(current->comm)];
6e837fb1 213
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EP
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
fa2bea2f 221 audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
5deeb5ce 222 audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm)));
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223
224 switch (a->type) {
cb84aa9b 225 case LSM_AUDIT_DATA_NONE:
2bf49690 226 return;
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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;
f48b7399 233 case LSM_AUDIT_DATA_PATH: {
f48b7399
EP
234 struct inode *inode;
235
c158a35c 236 audit_log_d_path(ab, " path=", &a->u.path);
a269434d 237
c6f493d6 238 inode = d_backing_inode(a->u.path.dentry);
41fdc305
KC
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 }
a269434d
EP
244 break;
245 }
43af5de7
VG
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 }
671a2781
JVS
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
8b31f456 271 audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd);
671a2781
JVS
272 break;
273 }
a269434d
EP
274 case LSM_AUDIT_DATA_DENTRY: {
275 struct inode *inode;
276
277 audit_log_format(ab, " name=");
d36a1dd9 278 spin_lock(&a->u.dentry->d_lock);
a269434d 279 audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
d36a1dd9 280 spin_unlock(&a->u.dentry->d_lock);
a269434d 281
c6f493d6 282 inode = d_backing_inode(a->u.dentry);
41fdc305
KC
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 }
6e837fb1 288 break;
f48b7399
EP
289 }
290 case LSM_AUDIT_DATA_INODE: {
291 struct dentry *dentry;
292 struct inode *inode;
293
23d8f5b6 294 rcu_read_lock();
f48b7399 295 inode = a->u.inode;
23d8f5b6 296 dentry = d_find_alias_rcu(inode);
f48b7399
EP
297 if (dentry) {
298 audit_log_format(ab, " name=");
d36a1dd9
AV
299 spin_lock(&dentry->d_lock);
300 audit_log_untrustedstring(ab, dentry->d_name.name);
301 spin_unlock(&dentry->d_lock);
f48b7399 302 }
41fdc305
KC
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);
23d8f5b6 306 rcu_read_unlock();
f48b7399
EP
307 break;
308 }
5deeb5ce
RGB
309 case LSM_AUDIT_DATA_TASK: {
310 struct task_struct *tsk = a->u.tsk;
f1dc4867 311 if (tsk) {
fa2bea2f 312 pid_t pid = task_tgid_nr(tsk);
f1dc4867 313 if (pid) {
5deeb5ce 314 char comm[sizeof(tsk->comm)];
5c5bc97e 315 audit_log_format(ab, " opid=%d ocomm=", pid);
5deeb5ce
RGB
316 audit_log_untrustedstring(ab,
317 memcpy(comm, tsk->comm, sizeof(comm)));
f1dc4867 318 }
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319 }
320 break;
5deeb5ce 321 }
6e837fb1 322 case LSM_AUDIT_DATA_NET:
48c62af6 323 if (a->u.net->sk) {
41dd9596 324 const struct sock *sk = a->u.net->sk;
6e837fb1 325 struct unix_sock *u;
ae3b5641 326 struct unix_address *addr;
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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
c720c7e8
ED
334 print_ipv4_addr(ab, inet->inet_rcv_saddr,
335 inet->inet_sport,
6e837fb1 336 "laddr", "lport");
c720c7e8
ED
337 print_ipv4_addr(ab, inet->inet_daddr,
338 inet->inet_dport,
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EB
339 "faddr", "fport");
340 break;
341 }
c2bb06db 342#if IS_ENABLED(CONFIG_IPV6)
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343 case AF_INET6: {
344 struct inet_sock *inet = inet_sk(sk);
6e837fb1 345
efe4208f 346 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
c720c7e8 347 inet->inet_sport,
6e837fb1 348 "laddr", "lport");
efe4208f 349 print_ipv6_addr(ab, &sk->sk_v6_daddr,
c720c7e8 350 inet->inet_dport,
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351 "faddr", "fport");
352 break;
353 }
c2bb06db 354#endif
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EB
355 case AF_UNIX:
356 u = unix_sk(sk);
ae3b5641
AV
357 addr = smp_load_acquire(&u->addr);
358 if (!addr)
359 break;
40ffe67d
AV
360 if (u->path.dentry) {
361 audit_log_d_path(ab, " path=", &u->path);
6e837fb1
EB
362 break;
363 }
ae3b5641
AV
364 len = addr->len-sizeof(short);
365 p = &addr->name->sun_path[0];
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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
48c62af6 375 switch (a->u.net->family) {
6e837fb1 376 case AF_INET:
48c62af6
EP
377 print_ipv4_addr(ab, a->u.net->v4info.saddr,
378 a->u.net->sport,
6e837fb1 379 "saddr", "src");
48c62af6
EP
380 print_ipv4_addr(ab, a->u.net->v4info.daddr,
381 a->u.net->dport,
6e837fb1
EB
382 "daddr", "dest");
383 break;
384 case AF_INET6:
48c62af6
EP
385 print_ipv6_addr(ab, &a->u.net->v6info.saddr,
386 a->u.net->sport,
6e837fb1 387 "saddr", "src");
48c62af6
EP
388 print_ipv6_addr(ab, &a->u.net->v6info.daddr,
389 a->u.net->dport,
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EB
390 "daddr", "dest");
391 break;
392 }
48c62af6 393 if (a->u.net->netif > 0) {
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394 struct net_device *dev;
395
396 /* NOTE: we always use init's namespace */
48c62af6 397 dev = dev_get_by_index(&init_net, a->u.net->netif);
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EB
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
dd8dbf2e
EP
413 case LSM_AUDIT_DATA_KMOD:
414 audit_log_format(ab, " kmod=");
415 audit_log_untrustedstring(ab, a->u.kmod_name);
416 break;
cfc4d882
DJ
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 }
ab861dfc
DJ
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;
59438b46 433 case LSM_AUDIT_DATA_LOCKDOWN:
f1d9b23c
RGB
434 audit_log_format(ab, " lockdown_reason=\"%s\"",
435 lockdown_reasons[a->u.reason]);
59438b46 436 break;
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EB
437 } /* switch (a->type) */
438}
439
440/**
441 * common_lsm_audit - generic LSM auditing function
442 * @a: auxiliary audit data
b61c37f5
LT
443 * @pre_audit: lsm-specific pre-audit callback
444 * @post_audit: lsm-specific post-audit callback
6e837fb1
EB
445 *
446 * setup the audit buffer for common security information
447 * uses callback to print LSM specific information
448 */
b61c37f5
LT
449void common_lsm_audit(struct common_audit_data *a,
450 void (*pre_audit)(struct audit_buffer *, void *),
451 void (*post_audit)(struct audit_buffer *, void *))
6e837fb1
EB
452{
453 struct audit_buffer *ab;
454
455 if (a == NULL)
456 return;
457 /* we use GFP_ATOMIC so we won't sleep */
cdfb6b34 458 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN,
a20b62bd 459 AUDIT_AVC);
6e837fb1
EB
460
461 if (ab == NULL)
462 return;
463
b61c37f5
LT
464 if (pre_audit)
465 pre_audit(ab, a);
6e837fb1
EB
466
467 dump_common_audit_data(ab, a);
468
b61c37f5
LT
469 if (post_audit)
470 post_audit(ab, a);
6e837fb1
EB
471
472 audit_log_end(ab);
473}