Merge branch 'overlayfs.v25' of git://git.kernel.org/pub/scm/linux/kernel/git/mszered...
[sfrench/cifs-2.6.git] / security / lsm_audit.c
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  */
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  */
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         __be16 frag_off;
118
119         ip6 = ipv6_hdr(skb);
120         if (ip6 == NULL)
121                 return -EINVAL;
122         ad->u.net->v6info.saddr = ip6->saddr;
123         ad->u.net->v6info.daddr = ip6->daddr;
124         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;
130         offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
131         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
143                 ad->u.net->sport = th->source;
144                 ad->u.net->dport = th->dest;
145                 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
154                 ad->u.net->sport = uh->source;
155                 ad->u.net->dport = uh->dest;
156                 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
165                 ad->u.net->sport = dh->dccph_sport;
166                 ad->u.net->dport = dh->dccph_dport;
167                 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;
175                 ad->u.net->sport = sh->source;
176                 ad->u.net->dport = sh->dest;
177                 break;
178         }
179         default:
180                 ret = -EINVAL;
181         }
182         return ret;
183 }
184 #endif
185
186
187 static 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))
192                 audit_log_format(ab, " %s=%pI6c", name1, addr);
193         if (port)
194                 audit_log_format(ab, " %s=%d", name2, ntohs(port));
195 }
196
197 static 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  */
211 static void dump_common_audit_data(struct audit_buffer *ab,
212                                    struct common_audit_data *a)
213 {
214         struct task_struct *tsk = current;
215
216         /*
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
223         audit_log_format(ab, " pid=%d comm=", task_pid_nr(tsk));
224         audit_log_untrustedstring(ab, tsk->comm);
225
226         switch (a->type) {
227         case LSM_AUDIT_DATA_NONE:
228                 return;
229         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;
235         case LSM_AUDIT_DATA_PATH: {
236                 struct inode *inode;
237
238                 audit_log_d_path(ab, " path=", &a->u.path);
239
240                 inode = a->u.path.dentry->d_inode;
241                 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                 }
246                 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
254                 inode = a->u.dentry->d_inode;
255                 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                 }
260                 break;
261         }
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                 }
274                 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);
277                 break;
278         }
279         case LSM_AUDIT_DATA_TASK:
280                 tsk = a->u.tsk;
281                 if (tsk) {
282                         pid_t pid = task_pid_nr(tsk);
283                         if (pid) {
284                                 audit_log_format(ab, " pid=%d comm=", pid);
285                                 audit_log_untrustedstring(ab, tsk->comm);
286                         }
287                 }
288                 break;
289         case LSM_AUDIT_DATA_NET:
290                 if (a->u.net->sk) {
291                         struct sock *sk = a->u.net->sk;
292                         struct unix_sock *u;
293                         int len = 0;
294                         char *p = NULL;
295
296                         switch (sk->sk_family) {
297                         case AF_INET: {
298                                 struct inet_sock *inet = inet_sk(sk);
299
300                                 print_ipv4_addr(ab, inet->inet_rcv_saddr,
301                                                 inet->inet_sport,
302                                                 "laddr", "lport");
303                                 print_ipv4_addr(ab, inet->inet_daddr,
304                                                 inet->inet_dport,
305                                                 "faddr", "fport");
306                                 break;
307                         }
308 #if IS_ENABLED(CONFIG_IPV6)
309                         case AF_INET6: {
310                                 struct inet_sock *inet = inet_sk(sk);
311
312                                 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
313                                                 inet->inet_sport,
314                                                 "laddr", "lport");
315                                 print_ipv6_addr(ab, &sk->sk_v6_daddr,
316                                                 inet->inet_dport,
317                                                 "faddr", "fport");
318                                 break;
319                         }
320 #endif
321                         case AF_UNIX:
322                                 u = unix_sk(sk);
323                                 if (u->path.dentry) {
324                                         audit_log_d_path(ab, " path=", &u->path);
325                                         break;
326                                 }
327                                 if (!u->addr)
328                                         break;
329                                 len = u->addr->len-sizeof(short);
330                                 p = &u->addr->name->sun_path[0];
331                                 audit_log_format(ab, " path=");
332                                 if (*p)
333                                         audit_log_untrustedstring(ab, p);
334                                 else
335                                         audit_log_n_hex(ab, p, len);
336                                 break;
337                         }
338                 }
339
340                 switch (a->u.net->family) {
341                 case AF_INET:
342                         print_ipv4_addr(ab, a->u.net->v4info.saddr,
343                                         a->u.net->sport,
344                                         "saddr", "src");
345                         print_ipv4_addr(ab, a->u.net->v4info.daddr,
346                                         a->u.net->dport,
347                                         "daddr", "dest");
348                         break;
349                 case AF_INET6:
350                         print_ipv6_addr(ab, &a->u.net->v6info.saddr,
351                                         a->u.net->sport,
352                                         "saddr", "src");
353                         print_ipv6_addr(ab, &a->u.net->v6info.daddr,
354                                         a->u.net->dport,
355                                         "daddr", "dest");
356                         break;
357                 }
358                 if (a->u.net->netif > 0) {
359                         struct net_device *dev;
360
361                         /* NOTE: we always use init's namespace */
362                         dev = dev_get_by_index(&init_net, a->u.net->netif);
363                         if (dev) {
364                                 audit_log_format(ab, " netif=%s", dev->name);
365                                 dev_put(dev);
366                         }
367                 }
368                 break;
369 #ifdef CONFIG_KEYS
370         case LSM_AUDIT_DATA_KEY:
371                 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
372                 if (a->u.key_struct.key_desc) {
373                         audit_log_format(ab, " key_desc=");
374                         audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
375                 }
376                 break;
377 #endif
378         case LSM_AUDIT_DATA_KMOD:
379                 audit_log_format(ab, " kmod=");
380                 audit_log_untrustedstring(ab, a->u.kmod_name);
381                 break;
382         } /* switch (a->type) */
383 }
384
385 /**
386  * common_lsm_audit - generic LSM auditing function
387  * @a:  auxiliary audit data
388  * @pre_audit: lsm-specific pre-audit callback
389  * @post_audit: lsm-specific post-audit callback
390  *
391  * setup the audit buffer for common security information
392  * uses callback to print LSM specific information
393  */
394 void common_lsm_audit(struct common_audit_data *a,
395         void (*pre_audit)(struct audit_buffer *, void *),
396         void (*post_audit)(struct audit_buffer *, void *))
397 {
398         struct audit_buffer *ab;
399
400         if (a == NULL)
401                 return;
402         /* we use GFP_ATOMIC so we won't sleep */
403         ab = audit_log_start(current->audit_context, GFP_ATOMIC | __GFP_NOWARN,
404                              AUDIT_AVC);
405
406         if (ab == NULL)
407                 return;
408
409         if (pre_audit)
410                 pre_audit(ab, a);
411
412         dump_common_audit_data(ab, a);
413
414         if (post_audit)
415                 post_audit(ab, a);
416
417         audit_log_end(ab);
418 }