1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * common LSM auditing functions |
4 | * |
5 | * Based on code written for SELinux by : |
6 | * Stephen Smalley, <sds@tycho.nsa.gov> |
7 | * James Morris <jmorris@redhat.com> |
8 | * Author : Etienne Basset, <etienne.basset@ensta.org> |
9 | */ |
10 | |
11 | #include <linux/types.h> |
12 | #include <linux/stddef.h> |
13 | #include <linux/kernel.h> |
14 | #include <linux/gfp.h> |
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> |
30 | #include <linux/security.h> |
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 | */ |
40 | int 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 | ad->u.net->v4info.saddr = ih->saddr; |
48 | ad->u.net->v4info.daddr = ih->daddr; |
49 | |
50 | if (proto) |
51 | *proto = ih->protocol; |
52 | /* non initial fragment */ |
53 | if (ntohs(ih->frag_off) & IP_OFFSET) |
54 | return 0; |
55 | |
56 | switch (ih->protocol) { |
57 | case IPPROTO_TCP: { |
58 | struct tcphdr *th = tcp_hdr(skb); |
59 | |
60 | ad->u.net->sport = th->source; |
61 | ad->u.net->dport = th->dest; |
62 | break; |
63 | } |
64 | case IPPROTO_UDP: { |
65 | struct udphdr *uh = udp_hdr(skb); |
66 | |
67 | ad->u.net->sport = uh->source; |
68 | ad->u.net->dport = uh->dest; |
69 | break; |
70 | } |
71 | case IPPROTO_DCCP: { |
72 | struct dccp_hdr *dh = dccp_hdr(skb); |
73 | |
74 | ad->u.net->sport = dh->dccph_sport; |
75 | ad->u.net->dport = dh->dccph_dport; |
76 | break; |
77 | } |
78 | case IPPROTO_SCTP: { |
79 | struct sctphdr *sh = sctp_hdr(skb); |
80 | |
81 | ad->u.net->sport = sh->source; |
82 | ad->u.net->dport = sh->dest; |
83 | break; |
84 | } |
85 | default: |
86 | ret = -EINVAL; |
87 | } |
88 | return ret; |
89 | } |
90 | #if IS_ENABLED(CONFIG_IPV6) |
91 | /** |
92 | * ipv6_skb_to_auditdata : fill auditdata from skb |
93 | * @skb : the skb |
94 | * @ad : the audit data to fill |
95 | * @proto : the layer 4 protocol |
96 | * |
97 | * return 0 on success |
98 | */ |
99 | int ipv6_skb_to_auditdata(struct sk_buff *skb, |
100 | struct common_audit_data *ad, u8 *proto) |
101 | { |
102 | int offset, ret = 0; |
103 | struct ipv6hdr *ip6; |
104 | u8 nexthdr; |
105 | __be16 frag_off; |
106 | |
107 | ip6 = ipv6_hdr(skb); |
108 | ad->u.net->v6info.saddr = ip6->saddr; |
109 | ad->u.net->v6info.daddr = ip6->daddr; |
110 | /* IPv6 can have several extension header before the Transport header |
111 | * skip them */ |
112 | offset = skb_network_offset(skb); |
113 | offset += sizeof(*ip6); |
114 | nexthdr = ip6->nexthdr; |
115 | offset = ipv6_skip_exthdr(skb, start: offset, nexthdrp: &nexthdr, frag_offp: &frag_off); |
116 | if (offset < 0) |
117 | return 0; |
118 | if (proto) |
119 | *proto = nexthdr; |
120 | switch (nexthdr) { |
121 | case IPPROTO_TCP: { |
122 | struct tcphdr _tcph, *th; |
123 | |
124 | th = skb_header_pointer(skb, offset, len: sizeof(_tcph), buffer: &_tcph); |
125 | if (th == NULL) |
126 | break; |
127 | |
128 | ad->u.net->sport = th->source; |
129 | ad->u.net->dport = th->dest; |
130 | break; |
131 | } |
132 | case IPPROTO_UDP: { |
133 | struct udphdr _udph, *uh; |
134 | |
135 | uh = skb_header_pointer(skb, offset, len: sizeof(_udph), buffer: &_udph); |
136 | if (uh == NULL) |
137 | break; |
138 | |
139 | ad->u.net->sport = uh->source; |
140 | ad->u.net->dport = uh->dest; |
141 | break; |
142 | } |
143 | case IPPROTO_DCCP: { |
144 | struct dccp_hdr _dccph, *dh; |
145 | |
146 | dh = skb_header_pointer(skb, offset, len: sizeof(_dccph), buffer: &_dccph); |
147 | if (dh == NULL) |
148 | break; |
149 | |
150 | ad->u.net->sport = dh->dccph_sport; |
151 | ad->u.net->dport = dh->dccph_dport; |
152 | break; |
153 | } |
154 | case IPPROTO_SCTP: { |
155 | struct sctphdr _sctph, *sh; |
156 | |
157 | sh = skb_header_pointer(skb, offset, len: sizeof(_sctph), buffer: &_sctph); |
158 | if (sh == NULL) |
159 | break; |
160 | ad->u.net->sport = sh->source; |
161 | ad->u.net->dport = sh->dest; |
162 | break; |
163 | } |
164 | default: |
165 | ret = -EINVAL; |
166 | } |
167 | return ret; |
168 | } |
169 | #endif |
170 | |
171 | |
172 | static inline void print_ipv6_addr(struct audit_buffer *ab, |
173 | const struct in6_addr *addr, __be16 port, |
174 | char *name1, char *name2) |
175 | { |
176 | if (!ipv6_addr_any(a: addr)) |
177 | audit_log_format(ab, fmt: " %s=%pI6c" , name1, addr); |
178 | if (port) |
179 | audit_log_format(ab, fmt: " %s=%d" , name2, ntohs(port)); |
180 | } |
181 | |
182 | static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr, |
183 | __be16 port, char *name1, char *name2) |
184 | { |
185 | if (addr) |
186 | audit_log_format(ab, fmt: " %s=%pI4" , name1, &addr); |
187 | if (port) |
188 | audit_log_format(ab, fmt: " %s=%d" , name2, ntohs(port)); |
189 | } |
190 | |
191 | /** |
192 | * dump_common_audit_data - helper to dump common audit data |
193 | * @ab : the audit buffer |
194 | * @a : common audit data |
195 | * |
196 | */ |
197 | static void dump_common_audit_data(struct audit_buffer *ab, |
198 | struct common_audit_data *a) |
199 | { |
200 | char comm[sizeof(current->comm)]; |
201 | |
202 | /* |
203 | * To keep stack sizes in check force programmers to notice if they |
204 | * start making this union too large! See struct lsm_network_audit |
205 | * as an example of how to deal with large data. |
206 | */ |
207 | BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2); |
208 | |
209 | audit_log_format(ab, fmt: " pid=%d comm=" , task_tgid_nr(current)); |
210 | audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm))); |
211 | |
212 | switch (a->type) { |
213 | case LSM_AUDIT_DATA_NONE: |
214 | return; |
215 | case LSM_AUDIT_DATA_IPC: |
216 | audit_log_format(ab, fmt: " ipc_key=%d " , a->u.ipc_id); |
217 | break; |
218 | case LSM_AUDIT_DATA_CAP: |
219 | audit_log_format(ab, fmt: " capability=%d " , a->u.cap); |
220 | break; |
221 | case LSM_AUDIT_DATA_PATH: { |
222 | struct inode *inode; |
223 | |
224 | audit_log_d_path(ab, prefix: " path=" , path: &a->u.path); |
225 | |
226 | inode = d_backing_inode(upper: a->u.path.dentry); |
227 | if (inode) { |
228 | audit_log_format(ab, fmt: " dev=" ); |
229 | audit_log_untrustedstring(ab, string: inode->i_sb->s_id); |
230 | audit_log_format(ab, fmt: " ino=%lu" , inode->i_ino); |
231 | } |
232 | break; |
233 | } |
234 | case LSM_AUDIT_DATA_FILE: { |
235 | struct inode *inode; |
236 | |
237 | audit_log_d_path(ab, prefix: " path=" , path: &a->u.file->f_path); |
238 | |
239 | inode = file_inode(f: a->u.file); |
240 | if (inode) { |
241 | audit_log_format(ab, fmt: " dev=" ); |
242 | audit_log_untrustedstring(ab, string: inode->i_sb->s_id); |
243 | audit_log_format(ab, fmt: " ino=%lu" , inode->i_ino); |
244 | } |
245 | break; |
246 | } |
247 | case LSM_AUDIT_DATA_IOCTL_OP: { |
248 | struct inode *inode; |
249 | |
250 | audit_log_d_path(ab, prefix: " path=" , path: &a->u.op->path); |
251 | |
252 | inode = a->u.op->path.dentry->d_inode; |
253 | if (inode) { |
254 | audit_log_format(ab, fmt: " dev=" ); |
255 | audit_log_untrustedstring(ab, string: inode->i_sb->s_id); |
256 | audit_log_format(ab, fmt: " ino=%lu" , inode->i_ino); |
257 | } |
258 | |
259 | audit_log_format(ab, fmt: " ioctlcmd=0x%hx" , a->u.op->cmd); |
260 | break; |
261 | } |
262 | case LSM_AUDIT_DATA_DENTRY: { |
263 | struct inode *inode; |
264 | |
265 | audit_log_format(ab, fmt: " name=" ); |
266 | spin_lock(lock: &a->u.dentry->d_lock); |
267 | audit_log_untrustedstring(ab, string: a->u.dentry->d_name.name); |
268 | spin_unlock(lock: &a->u.dentry->d_lock); |
269 | |
270 | inode = d_backing_inode(upper: a->u.dentry); |
271 | if (inode) { |
272 | audit_log_format(ab, fmt: " dev=" ); |
273 | audit_log_untrustedstring(ab, string: inode->i_sb->s_id); |
274 | audit_log_format(ab, fmt: " ino=%lu" , inode->i_ino); |
275 | } |
276 | break; |
277 | } |
278 | case LSM_AUDIT_DATA_INODE: { |
279 | struct dentry *dentry; |
280 | struct inode *inode; |
281 | |
282 | rcu_read_lock(); |
283 | inode = a->u.inode; |
284 | dentry = d_find_alias_rcu(inode); |
285 | if (dentry) { |
286 | audit_log_format(ab, fmt: " name=" ); |
287 | spin_lock(lock: &dentry->d_lock); |
288 | audit_log_untrustedstring(ab, string: dentry->d_name.name); |
289 | spin_unlock(lock: &dentry->d_lock); |
290 | } |
291 | audit_log_format(ab, fmt: " dev=" ); |
292 | audit_log_untrustedstring(ab, string: inode->i_sb->s_id); |
293 | audit_log_format(ab, fmt: " ino=%lu" , inode->i_ino); |
294 | rcu_read_unlock(); |
295 | break; |
296 | } |
297 | case LSM_AUDIT_DATA_TASK: { |
298 | struct task_struct *tsk = a->u.tsk; |
299 | if (tsk) { |
300 | pid_t pid = task_tgid_nr(tsk); |
301 | if (pid) { |
302 | char comm[sizeof(tsk->comm)]; |
303 | audit_log_format(ab, fmt: " opid=%d ocomm=" , pid); |
304 | audit_log_untrustedstring(ab, |
305 | memcpy(comm, tsk->comm, sizeof(comm))); |
306 | } |
307 | } |
308 | break; |
309 | } |
310 | case LSM_AUDIT_DATA_NET: |
311 | if (a->u.net->sk) { |
312 | const struct sock *sk = a->u.net->sk; |
313 | const struct unix_sock *u; |
314 | struct unix_address *addr; |
315 | int len = 0; |
316 | char *p = NULL; |
317 | |
318 | switch (sk->sk_family) { |
319 | case AF_INET: { |
320 | const struct inet_sock *inet = inet_sk(sk); |
321 | |
322 | print_ipv4_addr(ab, addr: inet->inet_rcv_saddr, |
323 | port: inet->inet_sport, |
324 | name1: "laddr" , name2: "lport" ); |
325 | print_ipv4_addr(ab, addr: inet->inet_daddr, |
326 | port: inet->inet_dport, |
327 | name1: "faddr" , name2: "fport" ); |
328 | break; |
329 | } |
330 | #if IS_ENABLED(CONFIG_IPV6) |
331 | case AF_INET6: { |
332 | const struct inet_sock *inet = inet_sk(sk); |
333 | |
334 | print_ipv6_addr(ab, addr: &sk->sk_v6_rcv_saddr, |
335 | port: inet->inet_sport, |
336 | name1: "laddr" , name2: "lport" ); |
337 | print_ipv6_addr(ab, addr: &sk->sk_v6_daddr, |
338 | port: inet->inet_dport, |
339 | name1: "faddr" , name2: "fport" ); |
340 | break; |
341 | } |
342 | #endif |
343 | case AF_UNIX: |
344 | u = unix_sk(sk); |
345 | addr = smp_load_acquire(&u->addr); |
346 | if (!addr) |
347 | break; |
348 | if (u->path.dentry) { |
349 | audit_log_d_path(ab, prefix: " path=" , path: &u->path); |
350 | break; |
351 | } |
352 | len = addr->len-sizeof(short); |
353 | p = &addr->name->sun_path[0]; |
354 | audit_log_format(ab, fmt: " path=" ); |
355 | if (*p) |
356 | audit_log_untrustedstring(ab, string: p); |
357 | else |
358 | audit_log_n_hex(ab, buf: p, len); |
359 | break; |
360 | } |
361 | } |
362 | |
363 | switch (a->u.net->family) { |
364 | case AF_INET: |
365 | print_ipv4_addr(ab, addr: a->u.net->v4info.saddr, |
366 | port: a->u.net->sport, |
367 | name1: "saddr" , name2: "src" ); |
368 | print_ipv4_addr(ab, addr: a->u.net->v4info.daddr, |
369 | port: a->u.net->dport, |
370 | name1: "daddr" , name2: "dest" ); |
371 | break; |
372 | case AF_INET6: |
373 | print_ipv6_addr(ab, addr: &a->u.net->v6info.saddr, |
374 | port: a->u.net->sport, |
375 | name1: "saddr" , name2: "src" ); |
376 | print_ipv6_addr(ab, addr: &a->u.net->v6info.daddr, |
377 | port: a->u.net->dport, |
378 | name1: "daddr" , name2: "dest" ); |
379 | break; |
380 | } |
381 | if (a->u.net->netif > 0) { |
382 | struct net_device *dev; |
383 | |
384 | /* NOTE: we always use init's namespace */ |
385 | dev = dev_get_by_index(net: &init_net, ifindex: a->u.net->netif); |
386 | if (dev) { |
387 | audit_log_format(ab, fmt: " netif=%s" , dev->name); |
388 | dev_put(dev); |
389 | } |
390 | } |
391 | break; |
392 | #ifdef CONFIG_KEYS |
393 | case LSM_AUDIT_DATA_KEY: |
394 | audit_log_format(ab, fmt: " key_serial=%u" , a->u.key_struct.key); |
395 | if (a->u.key_struct.key_desc) { |
396 | audit_log_format(ab, fmt: " key_desc=" ); |
397 | audit_log_untrustedstring(ab, string: a->u.key_struct.key_desc); |
398 | } |
399 | break; |
400 | #endif |
401 | case LSM_AUDIT_DATA_KMOD: |
402 | audit_log_format(ab, fmt: " kmod=" ); |
403 | audit_log_untrustedstring(ab, string: a->u.kmod_name); |
404 | break; |
405 | case LSM_AUDIT_DATA_IBPKEY: { |
406 | struct in6_addr sbn_pfx; |
407 | |
408 | memset(&sbn_pfx.s6_addr, 0, |
409 | sizeof(sbn_pfx.s6_addr)); |
410 | memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, |
411 | sizeof(a->u.ibpkey->subnet_prefix)); |
412 | audit_log_format(ab, fmt: " pkey=0x%x subnet_prefix=%pI6c" , |
413 | a->u.ibpkey->pkey, &sbn_pfx); |
414 | break; |
415 | } |
416 | case LSM_AUDIT_DATA_IBENDPORT: |
417 | audit_log_format(ab, fmt: " device=%s port_num=%u" , |
418 | a->u.ibendport->dev_name, |
419 | a->u.ibendport->port); |
420 | break; |
421 | case LSM_AUDIT_DATA_LOCKDOWN: |
422 | audit_log_format(ab, fmt: " lockdown_reason=\"%s\"" , |
423 | lockdown_reasons[a->u.reason]); |
424 | break; |
425 | case LSM_AUDIT_DATA_ANONINODE: |
426 | audit_log_format(ab, fmt: " anonclass=%s" , a->u.anonclass); |
427 | break; |
428 | } /* switch (a->type) */ |
429 | } |
430 | |
431 | /** |
432 | * common_lsm_audit - generic LSM auditing function |
433 | * @a: auxiliary audit data |
434 | * @pre_audit: lsm-specific pre-audit callback |
435 | * @post_audit: lsm-specific post-audit callback |
436 | * |
437 | * setup the audit buffer for common security information |
438 | * uses callback to print LSM specific information |
439 | */ |
440 | void common_lsm_audit(struct common_audit_data *a, |
441 | void (*pre_audit)(struct audit_buffer *, void *), |
442 | void (*post_audit)(struct audit_buffer *, void *)) |
443 | { |
444 | struct audit_buffer *ab; |
445 | |
446 | if (a == NULL) |
447 | return; |
448 | /* we use GFP_ATOMIC so we won't sleep */ |
449 | ab = audit_log_start(ctx: audit_context(), GFP_ATOMIC | __GFP_NOWARN, |
450 | AUDIT_AVC); |
451 | |
452 | if (ab == NULL) |
453 | return; |
454 | |
455 | if (pre_audit) |
456 | pre_audit(ab, a); |
457 | |
458 | dump_common_audit_data(ab, a); |
459 | |
460 | if (post_audit) |
461 | post_audit(ab, a); |
462 | |
463 | audit_log_end(ab); |
464 | } |
465 | |