1 /*
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>
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 */
ipv4_skb_to_auditdata(struct sk_buff * skb,struct common_audit_data * ad,u8 * proto)42 int 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 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 */
ipv6_skb_to_auditdata(struct sk_buff * skb,struct common_audit_data * ad,u8 * proto)111 int 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
118 ip6 = ipv6_hdr(skb);
119 if (ip6 == NULL)
120 return -EINVAL;
121 ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr);
122 ipv6_addr_copy(&ad->u.net.v6info.daddr, &ip6->daddr);
123 ret = 0;
124 /* IPv6 can have several extension header before the Transport header
125 * skip them */
126 offset = skb_network_offset(skb);
127 offset += sizeof(*ip6);
128 nexthdr = ip6->nexthdr;
129 offset = ipv6_skip_exthdr(skb, offset, &nexthdr);
130 if (offset < 0)
131 return 0;
132 if (proto)
133 *proto = nexthdr;
134 switch (nexthdr) {
135 case IPPROTO_TCP: {
136 struct tcphdr _tcph, *th;
137
138 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
139 if (th == NULL)
140 break;
141
142 ad->u.net.sport = th->source;
143 ad->u.net.dport = th->dest;
144 break;
145 }
146 case IPPROTO_UDP: {
147 struct udphdr _udph, *uh;
148
149 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
150 if (uh == NULL)
151 break;
152
153 ad->u.net.sport = uh->source;
154 ad->u.net.dport = uh->dest;
155 break;
156 }
157 case IPPROTO_DCCP: {
158 struct dccp_hdr _dccph, *dh;
159
160 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
161 if (dh == NULL)
162 break;
163
164 ad->u.net.sport = dh->dccph_sport;
165 ad->u.net.dport = dh->dccph_dport;
166 break;
167 }
168 case IPPROTO_SCTP: {
169 struct sctphdr _sctph, *sh;
170
171 sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
172 if (sh == NULL)
173 break;
174 ad->u.net.sport = sh->source;
175 ad->u.net.dport = sh->dest;
176 break;
177 }
178 default:
179 ret = -EINVAL;
180 }
181 return ret;
182 }
183 #endif
184
185
print_ipv6_addr(struct audit_buffer * ab,struct in6_addr * addr,__be16 port,char * name1,char * name2)186 static inline void print_ipv6_addr(struct audit_buffer *ab,
187 struct in6_addr *addr, __be16 port,
188 char *name1, char *name2)
189 {
190 if (!ipv6_addr_any(addr))
191 audit_log_format(ab, " %s=%pI6c", name1, addr);
192 if (port)
193 audit_log_format(ab, " %s=%d", name2, ntohs(port));
194 }
195
print_ipv4_addr(struct audit_buffer * ab,__be32 addr,__be16 port,char * name1,char * name2)196 static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
197 __be16 port, char *name1, char *name2)
198 {
199 if (addr)
200 audit_log_format(ab, " %s=%pI4", name1, &addr);
201 if (port)
202 audit_log_format(ab, " %s=%d", name2, ntohs(port));
203 }
204
205 /**
206 * dump_common_audit_data - helper to dump common audit data
207 * @a : common audit data
208 *
209 */
dump_common_audit_data(struct audit_buffer * ab,struct common_audit_data * a)210 static void dump_common_audit_data(struct audit_buffer *ab,
211 struct common_audit_data *a)
212 {
213 struct inode *inode = NULL;
214 struct task_struct *tsk = current;
215
216 if (a->tsk)
217 tsk = a->tsk;
218 if (tsk && tsk->pid) {
219 audit_log_format(ab, " pid=%d comm=", tsk->pid);
220 audit_log_untrustedstring(ab, tsk->comm);
221 }
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_FS:
233 if (a->u.fs.path.dentry) {
234 struct dentry *dentry = a->u.fs.path.dentry;
235 if (a->u.fs.path.mnt) {
236 audit_log_d_path(ab, "path=", &a->u.fs.path);
237 } else {
238 audit_log_format(ab, " name=");
239 audit_log_untrustedstring(ab,
240 dentry->d_name.name);
241 }
242 inode = dentry->d_inode;
243 } else if (a->u.fs.inode) {
244 struct dentry *dentry;
245 inode = a->u.fs.inode;
246 dentry = d_find_alias(inode);
247 if (dentry) {
248 audit_log_format(ab, " name=");
249 audit_log_untrustedstring(ab,
250 dentry->d_name.name);
251 dput(dentry);
252 }
253 }
254 if (inode)
255 audit_log_format(ab, " dev=%s ino=%lu",
256 inode->i_sb->s_id,
257 inode->i_ino);
258 break;
259 case LSM_AUDIT_DATA_TASK:
260 tsk = a->u.tsk;
261 if (tsk && tsk->pid) {
262 audit_log_format(ab, " pid=%d comm=", tsk->pid);
263 audit_log_untrustedstring(ab, tsk->comm);
264 }
265 break;
266 case LSM_AUDIT_DATA_NET:
267 if (a->u.net.sk) {
268 struct sock *sk = a->u.net.sk;
269 struct unix_sock *u;
270 int len = 0;
271 char *p = NULL;
272
273 switch (sk->sk_family) {
274 case AF_INET: {
275 struct inet_sock *inet = inet_sk(sk);
276
277 print_ipv4_addr(ab, inet->inet_rcv_saddr,
278 inet->inet_sport,
279 "laddr", "lport");
280 print_ipv4_addr(ab, inet->inet_daddr,
281 inet->inet_dport,
282 "faddr", "fport");
283 break;
284 }
285 case AF_INET6: {
286 struct inet_sock *inet = inet_sk(sk);
287 struct ipv6_pinfo *inet6 = inet6_sk(sk);
288
289 print_ipv6_addr(ab, &inet6->rcv_saddr,
290 inet->inet_sport,
291 "laddr", "lport");
292 print_ipv6_addr(ab, &inet6->daddr,
293 inet->inet_dport,
294 "faddr", "fport");
295 break;
296 }
297 case AF_UNIX:
298 u = unix_sk(sk);
299 if (u->dentry) {
300 struct path path = {
301 .dentry = u->dentry,
302 .mnt = u->mnt
303 };
304 audit_log_d_path(ab, "path=", &path);
305 break;
306 }
307 if (!u->addr)
308 break;
309 len = u->addr->len-sizeof(short);
310 p = &u->addr->name->sun_path[0];
311 audit_log_format(ab, " path=");
312 if (*p)
313 audit_log_untrustedstring(ab, p);
314 else
315 audit_log_n_hex(ab, p, len);
316 break;
317 }
318 }
319
320 switch (a->u.net.family) {
321 case AF_INET:
322 print_ipv4_addr(ab, a->u.net.v4info.saddr,
323 a->u.net.sport,
324 "saddr", "src");
325 print_ipv4_addr(ab, a->u.net.v4info.daddr,
326 a->u.net.dport,
327 "daddr", "dest");
328 break;
329 case AF_INET6:
330 print_ipv6_addr(ab, &a->u.net.v6info.saddr,
331 a->u.net.sport,
332 "saddr", "src");
333 print_ipv6_addr(ab, &a->u.net.v6info.daddr,
334 a->u.net.dport,
335 "daddr", "dest");
336 break;
337 }
338 if (a->u.net.netif > 0) {
339 struct net_device *dev;
340
341 /* NOTE: we always use init's namespace */
342 dev = dev_get_by_index(&init_net, a->u.net.netif);
343 if (dev) {
344 audit_log_format(ab, " netif=%s", dev->name);
345 dev_put(dev);
346 }
347 }
348 break;
349 #ifdef CONFIG_KEYS
350 case LSM_AUDIT_DATA_KEY:
351 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
352 if (a->u.key_struct.key_desc) {
353 audit_log_format(ab, " key_desc=");
354 audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
355 }
356 break;
357 #endif
358 case LSM_AUDIT_DATA_KMOD:
359 audit_log_format(ab, " kmod=");
360 audit_log_untrustedstring(ab, a->u.kmod_name);
361 break;
362 } /* switch (a->type) */
363 }
364
365 /**
366 * common_lsm_audit - generic LSM auditing function
367 * @a: auxiliary audit data
368 *
369 * setup the audit buffer for common security information
370 * uses callback to print LSM specific information
371 */
common_lsm_audit(struct common_audit_data * a)372 void common_lsm_audit(struct common_audit_data *a)
373 {
374 struct audit_buffer *ab;
375
376 if (a == NULL)
377 return;
378 /* we use GFP_ATOMIC so we won't sleep */
379 ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
380
381 if (ab == NULL)
382 return;
383
384 if (a->lsm_pre_audit)
385 a->lsm_pre_audit(ab, a);
386
387 dump_common_audit_data(ab, a);
388
389 if (a->lsm_post_audit)
390 a->lsm_post_audit(ab, a);
391
392 audit_log_end(ab);
393 }
394