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Etienne Basset6e837fb2009-04-08 20:39:40 +02001/*
2 * common LSM auditing functions
3 *
4 * Based on code written for SELinux by :
5 * Stephen Smalley, <sds@epoch.ncsc.mil>
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090017#include <linux/gfp.h>
Etienne Basset6e837fb2009-04-08 20:39:40 +020018#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
Eric Paris48c62af2012-04-02 13:15:44 -040052 ad->u.net->v4info.saddr = ih->saddr;
53 ad->u.net->v4info.daddr = ih->daddr;
Etienne Basset6e837fb2009-04-08 20:39:40 +020054
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
Eric Paris48c62af2012-04-02 13:15:44 -040067 ad->u.net->sport = th->source;
68 ad->u.net->dport = th->dest;
Etienne Basset6e837fb2009-04-08 20:39:40 +020069 break;
70 }
71 case IPPROTO_UDP: {
72 struct udphdr *uh = udp_hdr(skb);
73 if (uh == NULL)
74 break;
75
Eric Paris48c62af2012-04-02 13:15:44 -040076 ad->u.net->sport = uh->source;
77 ad->u.net->dport = uh->dest;
Etienne Basset6e837fb2009-04-08 20:39:40 +020078 break;
79 }
80 case IPPROTO_DCCP: {
81 struct dccp_hdr *dh = dccp_hdr(skb);
82 if (dh == NULL)
83 break;
84
Eric Paris48c62af2012-04-02 13:15:44 -040085 ad->u.net->sport = dh->dccph_sport;
86 ad->u.net->dport = dh->dccph_dport;
Etienne Basset6e837fb2009-04-08 20:39:40 +020087 break;
88 }
89 case IPPROTO_SCTP: {
90 struct sctphdr *sh = sctp_hdr(skb);
91 if (sh == NULL)
92 break;
Eric Paris48c62af2012-04-02 13:15:44 -040093 ad->u.net->sport = sh->source;
94 ad->u.net->dport = sh->dest;
Etienne Basset6e837fb2009-04-08 20:39:40 +020095 break;
96 }
97 default:
98 ret = -EINVAL;
99 }
100 return ret;
101}
102#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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;
Jesse Gross75f28112011-11-30 17:05:51 -0800117 __be16 frag_off;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200118
119 ip6 = ipv6_hdr(skb);
120 if (ip6 == NULL)
121 return -EINVAL;
Eric Paris48c62af2012-04-02 13:15:44 -0400122 ad->u.net->v6info.saddr = ip6->saddr;
123 ad->u.net->v6info.daddr = ip6->daddr;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200124 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;
Jesse Gross75f28112011-11-30 17:05:51 -0800130 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200131 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
Eric Paris48c62af2012-04-02 13:15:44 -0400143 ad->u.net->sport = th->source;
144 ad->u.net->dport = th->dest;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200145 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
Eric Paris48c62af2012-04-02 13:15:44 -0400154 ad->u.net->sport = uh->source;
155 ad->u.net->dport = uh->dest;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200156 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
Eric Paris48c62af2012-04-02 13:15:44 -0400165 ad->u.net->sport = dh->dccph_sport;
166 ad->u.net->dport = dh->dccph_dport;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200167 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;
Eric Paris48c62af2012-04-02 13:15:44 -0400175 ad->u.net->sport = sh->source;
176 ad->u.net->dport = sh->dest;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200177 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))
Paul Moored8116592009-09-23 13:46:00 -0400192 audit_log_format(ab, " %s=%pI6c", name1, addr);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200193 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{
Richard Guy Briggs5deeb5c2015-04-14 11:01:02 -0400214 char comm[sizeof(current->comm)];
Etienne Basset6e837fb2009-04-08 20:39:40 +0200215
Eric Paris07f62eb2012-04-04 15:01:43 -0400216 /*
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
Richard Guy Briggs5deeb5c2015-04-14 11:01:02 -0400223 audit_log_format(ab, " pid=%d comm=", task_pid_nr(current));
224 audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm)));
Etienne Basset6e837fb2009-04-08 20:39:40 +0200225
226 switch (a->type) {
Eric Pariscb84aa92010-04-27 17:20:38 -0400227 case LSM_AUDIT_DATA_NONE:
Thomas Liu2bf49692009-07-14 12:14:09 -0400228 return;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200229 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;
Eric Parisf48b7392011-04-25 12:54:27 -0400235 case LSM_AUDIT_DATA_PATH: {
Eric Parisf48b7392011-04-25 12:54:27 -0400236 struct inode *inode;
237
Kees Cookc158a352012-01-06 14:07:10 -0800238 audit_log_d_path(ab, " path=", &a->u.path);
Eric Parisa2694342011-04-25 13:10:27 -0400239
David Howellsc6f493d2015-03-17 22:26:22 +0000240 inode = d_backing_inode(a->u.path.dentry);
Kees Cook41fdc302012-01-07 10:41:04 -0800241 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 }
Eric Parisa2694342011-04-25 13:10:27 -0400246 break;
247 }
248 case LSM_AUDIT_DATA_DENTRY: {
249 struct inode *inode;
250
251 audit_log_format(ab, " name=");
252 audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
253
David Howellsc6f493d2015-03-17 22:26:22 +0000254 inode = d_backing_inode(a->u.dentry);
Kees Cook41fdc302012-01-07 10:41:04 -0800255 if (inode) {
256 audit_log_format(ab, " dev=");
257 audit_log_untrustedstring(ab, inode->i_sb->s_id);
258 audit_log_format(ab, " ino=%lu", inode->i_ino);
259 }
Etienne Basset6e837fb2009-04-08 20:39:40 +0200260 break;
Eric Parisf48b7392011-04-25 12:54:27 -0400261 }
262 case LSM_AUDIT_DATA_INODE: {
263 struct dentry *dentry;
264 struct inode *inode;
265
266 inode = a->u.inode;
267 dentry = d_find_alias(inode);
268 if (dentry) {
269 audit_log_format(ab, " name=");
270 audit_log_untrustedstring(ab,
271 dentry->d_name.name);
272 dput(dentry);
273 }
Kees Cook41fdc302012-01-07 10:41:04 -0800274 audit_log_format(ab, " dev=");
275 audit_log_untrustedstring(ab, inode->i_sb->s_id);
276 audit_log_format(ab, " ino=%lu", inode->i_ino);
Eric Parisf48b7392011-04-25 12:54:27 -0400277 break;
278 }
Richard Guy Briggs5deeb5c2015-04-14 11:01:02 -0400279 case LSM_AUDIT_DATA_TASK: {
280 struct task_struct *tsk = a->u.tsk;
Richard Guy Briggsf1dc4862013-12-11 13:52:26 -0500281 if (tsk) {
282 pid_t pid = task_pid_nr(tsk);
283 if (pid) {
Richard Guy Briggs5deeb5c2015-04-14 11:01:02 -0400284 char comm[sizeof(tsk->comm)];
Richard Guy Briggsf1dc4862013-12-11 13:52:26 -0500285 audit_log_format(ab, " pid=%d comm=", pid);
Richard Guy Briggs5deeb5c2015-04-14 11:01:02 -0400286 audit_log_untrustedstring(ab,
287 memcpy(comm, tsk->comm, sizeof(comm)));
Richard Guy Briggsf1dc4862013-12-11 13:52:26 -0500288 }
Etienne Basset6e837fb2009-04-08 20:39:40 +0200289 }
290 break;
Richard Guy Briggs5deeb5c2015-04-14 11:01:02 -0400291 }
Etienne Basset6e837fb2009-04-08 20:39:40 +0200292 case LSM_AUDIT_DATA_NET:
Eric Paris48c62af2012-04-02 13:15:44 -0400293 if (a->u.net->sk) {
294 struct sock *sk = a->u.net->sk;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200295 struct unix_sock *u;
296 int len = 0;
297 char *p = NULL;
298
299 switch (sk->sk_family) {
300 case AF_INET: {
301 struct inet_sock *inet = inet_sk(sk);
302
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000303 print_ipv4_addr(ab, inet->inet_rcv_saddr,
304 inet->inet_sport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200305 "laddr", "lport");
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000306 print_ipv4_addr(ab, inet->inet_daddr,
307 inet->inet_dport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200308 "faddr", "fport");
309 break;
310 }
Eric Dumazetc2bb06d2013-10-09 03:05:48 -0700311#if IS_ENABLED(CONFIG_IPV6)
Etienne Basset6e837fb2009-04-08 20:39:40 +0200312 case AF_INET6: {
313 struct inet_sock *inet = inet_sk(sk);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200314
Eric Dumazetefe42082013-10-03 15:42:29 -0700315 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000316 inet->inet_sport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200317 "laddr", "lport");
Eric Dumazetefe42082013-10-03 15:42:29 -0700318 print_ipv6_addr(ab, &sk->sk_v6_daddr,
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000319 inet->inet_dport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200320 "faddr", "fport");
321 break;
322 }
Eric Dumazetc2bb06d2013-10-09 03:05:48 -0700323#endif
Etienne Basset6e837fb2009-04-08 20:39:40 +0200324 case AF_UNIX:
325 u = unix_sk(sk);
Al Viro40ffe672012-03-14 21:54:32 -0400326 if (u->path.dentry) {
327 audit_log_d_path(ab, " path=", &u->path);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200328 break;
329 }
330 if (!u->addr)
331 break;
332 len = u->addr->len-sizeof(short);
333 p = &u->addr->name->sun_path[0];
334 audit_log_format(ab, " path=");
335 if (*p)
336 audit_log_untrustedstring(ab, p);
337 else
338 audit_log_n_hex(ab, p, len);
339 break;
340 }
341 }
342
Eric Paris48c62af2012-04-02 13:15:44 -0400343 switch (a->u.net->family) {
Etienne Basset6e837fb2009-04-08 20:39:40 +0200344 case AF_INET:
Eric Paris48c62af2012-04-02 13:15:44 -0400345 print_ipv4_addr(ab, a->u.net->v4info.saddr,
346 a->u.net->sport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200347 "saddr", "src");
Eric Paris48c62af2012-04-02 13:15:44 -0400348 print_ipv4_addr(ab, a->u.net->v4info.daddr,
349 a->u.net->dport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200350 "daddr", "dest");
351 break;
352 case AF_INET6:
Eric Paris48c62af2012-04-02 13:15:44 -0400353 print_ipv6_addr(ab, &a->u.net->v6info.saddr,
354 a->u.net->sport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200355 "saddr", "src");
Eric Paris48c62af2012-04-02 13:15:44 -0400356 print_ipv6_addr(ab, &a->u.net->v6info.daddr,
357 a->u.net->dport,
Etienne Basset6e837fb2009-04-08 20:39:40 +0200358 "daddr", "dest");
359 break;
360 }
Eric Paris48c62af2012-04-02 13:15:44 -0400361 if (a->u.net->netif > 0) {
Etienne Basset6e837fb2009-04-08 20:39:40 +0200362 struct net_device *dev;
363
364 /* NOTE: we always use init's namespace */
Eric Paris48c62af2012-04-02 13:15:44 -0400365 dev = dev_get_by_index(&init_net, a->u.net->netif);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200366 if (dev) {
367 audit_log_format(ab, " netif=%s", dev->name);
368 dev_put(dev);
369 }
370 }
371 break;
372#ifdef CONFIG_KEYS
373 case LSM_AUDIT_DATA_KEY:
374 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
375 if (a->u.key_struct.key_desc) {
376 audit_log_format(ab, " key_desc=");
377 audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
378 }
379 break;
380#endif
Eric Parisdd8dbf22009-11-03 16:35:32 +1100381 case LSM_AUDIT_DATA_KMOD:
382 audit_log_format(ab, " kmod=");
383 audit_log_untrustedstring(ab, a->u.kmod_name);
384 break;
Etienne Basset6e837fb2009-04-08 20:39:40 +0200385 } /* switch (a->type) */
386}
387
388/**
389 * common_lsm_audit - generic LSM auditing function
390 * @a: auxiliary audit data
Linus Torvaldsb61c37f2012-04-02 15:48:12 -0700391 * @pre_audit: lsm-specific pre-audit callback
392 * @post_audit: lsm-specific post-audit callback
Etienne Basset6e837fb2009-04-08 20:39:40 +0200393 *
394 * setup the audit buffer for common security information
395 * uses callback to print LSM specific information
396 */
Linus Torvaldsb61c37f2012-04-02 15:48:12 -0700397void common_lsm_audit(struct common_audit_data *a,
398 void (*pre_audit)(struct audit_buffer *, void *),
399 void (*post_audit)(struct audit_buffer *, void *))
Etienne Basset6e837fb2009-04-08 20:39:40 +0200400{
401 struct audit_buffer *ab;
402
403 if (a == NULL)
404 return;
405 /* we use GFP_ATOMIC so we won't sleep */
Richard Guy Briggsa20b62b2013-10-01 21:14:54 -0400406 ab = audit_log_start(current->audit_context, GFP_ATOMIC | __GFP_NOWARN,
407 AUDIT_AVC);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200408
409 if (ab == NULL)
410 return;
411
Linus Torvaldsb61c37f2012-04-02 15:48:12 -0700412 if (pre_audit)
413 pre_audit(ab, a);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200414
415 dump_common_audit_data(ab, a);
416
Linus Torvaldsb61c37f2012-04-02 15:48:12 -0700417 if (post_audit)
418 post_audit(ab, a);
Etienne Basset6e837fb2009-04-08 20:39:40 +0200419
420 audit_log_end(ab);
421}