Merge tag 'afs-next-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowel...
[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@tycho.nsa.gov>
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 IS_ENABLED(CONFIG_IPV6)
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         char comm[sizeof(current->comm)];
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_tgid_nr(current));
224         audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(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 = d_backing_inode(a->u.path.dentry);
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_FILE: {
249                 struct inode *inode;
250
251                 audit_log_d_path(ab, " path=", &a->u.file->f_path);
252
253                 inode = file_inode(a->u.file);
254                 if (inode) {
255                         audit_log_format(ab, " dev=");
256                         audit_log_untrustedstring(ab, inode->i_sb->s_id);
257                         audit_log_format(ab, " ino=%lu", inode->i_ino);
258                 }
259                 break;
260         }
261         case LSM_AUDIT_DATA_IOCTL_OP: {
262                 struct inode *inode;
263
264                 audit_log_d_path(ab, " path=", &a->u.op->path);
265
266                 inode = a->u.op->path.dentry->d_inode;
267                 if (inode) {
268                         audit_log_format(ab, " dev=");
269                         audit_log_untrustedstring(ab, inode->i_sb->s_id);
270                         audit_log_format(ab, " ino=%lu", inode->i_ino);
271                 }
272
273                 audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd);
274                 break;
275         }
276         case LSM_AUDIT_DATA_DENTRY: {
277                 struct inode *inode;
278
279                 audit_log_format(ab, " name=");
280                 audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
281
282                 inode = d_backing_inode(a->u.dentry);
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                 }
288                 break;
289         }
290         case LSM_AUDIT_DATA_INODE: {
291                 struct dentry *dentry;
292                 struct inode *inode;
293
294                 inode = a->u.inode;
295                 dentry = d_find_alias(inode);
296                 if (dentry) {
297                         audit_log_format(ab, " name=");
298                         audit_log_untrustedstring(ab,
299                                          dentry->d_name.name);
300                         dput(dentry);
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                 break;
306         }
307         case LSM_AUDIT_DATA_TASK: {
308                 struct task_struct *tsk = a->u.tsk;
309                 if (tsk) {
310                         pid_t pid = task_tgid_nr(tsk);
311                         if (pid) {
312                                 char comm[sizeof(tsk->comm)];
313                                 audit_log_format(ab, " opid=%d ocomm=", pid);
314                                 audit_log_untrustedstring(ab,
315                                     memcpy(comm, tsk->comm, sizeof(comm)));
316                         }
317                 }
318                 break;
319         }
320         case LSM_AUDIT_DATA_NET:
321                 if (a->u.net->sk) {
322                         struct sock *sk = a->u.net->sk;
323                         struct unix_sock *u;
324                         struct unix_address *addr;
325                         int len = 0;
326                         char *p = NULL;
327
328                         switch (sk->sk_family) {
329                         case AF_INET: {
330                                 struct inet_sock *inet = inet_sk(sk);
331
332                                 print_ipv4_addr(ab, inet->inet_rcv_saddr,
333                                                 inet->inet_sport,
334                                                 "laddr", "lport");
335                                 print_ipv4_addr(ab, inet->inet_daddr,
336                                                 inet->inet_dport,
337                                                 "faddr", "fport");
338                                 break;
339                         }
340 #if IS_ENABLED(CONFIG_IPV6)
341                         case AF_INET6: {
342                                 struct inet_sock *inet = inet_sk(sk);
343
344                                 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
345                                                 inet->inet_sport,
346                                                 "laddr", "lport");
347                                 print_ipv6_addr(ab, &sk->sk_v6_daddr,
348                                                 inet->inet_dport,
349                                                 "faddr", "fport");
350                                 break;
351                         }
352 #endif
353                         case AF_UNIX:
354                                 u = unix_sk(sk);
355                                 addr = smp_load_acquire(&u->addr);
356                                 if (!addr)
357                                         break;
358                                 if (u->path.dentry) {
359                                         audit_log_d_path(ab, " path=", &u->path);
360                                         break;
361                                 }
362                                 len = addr->len-sizeof(short);
363                                 p = &addr->name->sun_path[0];
364                                 audit_log_format(ab, " path=");
365                                 if (*p)
366                                         audit_log_untrustedstring(ab, p);
367                                 else
368                                         audit_log_n_hex(ab, p, len);
369                                 break;
370                         }
371                 }
372
373                 switch (a->u.net->family) {
374                 case AF_INET:
375                         print_ipv4_addr(ab, a->u.net->v4info.saddr,
376                                         a->u.net->sport,
377                                         "saddr", "src");
378                         print_ipv4_addr(ab, a->u.net->v4info.daddr,
379                                         a->u.net->dport,
380                                         "daddr", "dest");
381                         break;
382                 case AF_INET6:
383                         print_ipv6_addr(ab, &a->u.net->v6info.saddr,
384                                         a->u.net->sport,
385                                         "saddr", "src");
386                         print_ipv6_addr(ab, &a->u.net->v6info.daddr,
387                                         a->u.net->dport,
388                                         "daddr", "dest");
389                         break;
390                 }
391                 if (a->u.net->netif > 0) {
392                         struct net_device *dev;
393
394                         /* NOTE: we always use init's namespace */
395                         dev = dev_get_by_index(&init_net, a->u.net->netif);
396                         if (dev) {
397                                 audit_log_format(ab, " netif=%s", dev->name);
398                                 dev_put(dev);
399                         }
400                 }
401                 break;
402 #ifdef CONFIG_KEYS
403         case LSM_AUDIT_DATA_KEY:
404                 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
405                 if (a->u.key_struct.key_desc) {
406                         audit_log_format(ab, " key_desc=");
407                         audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
408                 }
409                 break;
410 #endif
411         case LSM_AUDIT_DATA_KMOD:
412                 audit_log_format(ab, " kmod=");
413                 audit_log_untrustedstring(ab, a->u.kmod_name);
414                 break;
415         case LSM_AUDIT_DATA_IBPKEY: {
416                 struct in6_addr sbn_pfx;
417
418                 memset(&sbn_pfx.s6_addr, 0,
419                        sizeof(sbn_pfx.s6_addr));
420                 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix,
421                        sizeof(a->u.ibpkey->subnet_prefix));
422                 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c",
423                                  a->u.ibpkey->pkey, &sbn_pfx);
424                 break;
425         }
426         case LSM_AUDIT_DATA_IBENDPORT:
427                 audit_log_format(ab, " device=%s port_num=%u",
428                                  a->u.ibendport->dev_name,
429                                  a->u.ibendport->port);
430                 break;
431         } /* switch (a->type) */
432 }
433
434 /**
435  * common_lsm_audit - generic LSM auditing function
436  * @a:  auxiliary audit data
437  * @pre_audit: lsm-specific pre-audit callback
438  * @post_audit: lsm-specific post-audit callback
439  *
440  * setup the audit buffer for common security information
441  * uses callback to print LSM specific information
442  */
443 void common_lsm_audit(struct common_audit_data *a,
444         void (*pre_audit)(struct audit_buffer *, void *),
445         void (*post_audit)(struct audit_buffer *, void *))
446 {
447         struct audit_buffer *ab;
448
449         if (a == NULL)
450                 return;
451         /* we use GFP_ATOMIC so we won't sleep */
452         ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN,
453                              AUDIT_AVC);
454
455         if (ab == NULL)
456                 return;
457
458         if (pre_audit)
459                 pre_audit(ab, a);
460
461         dump_common_audit_data(ab, a);
462
463         if (post_audit)
464                 post_audit(ab, a);
465
466         audit_log_end(ab);
467 }