summaryrefslogtreecommitdiffstats
path: root/security/lsm_audit.c
blob: 234bc2ab450c61b42b1db2b53f631ab72bc48a39 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
/*
 * common LSM auditing functions
 *
 * Based on code written for SELinux by :
 *			Stephen Smalley, <sds@epoch.ncsc.mil>
 * 			James Morris <jmorris@redhat.com>
 * Author : Etienne Basset, <etienne.basset@ensta.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2,
 * as published by the Free Software Foundation.
 */

#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <net/sock.h>
#include <linux/un.h>
#include <net/af_unix.h>
#include <linux/audit.h>
#include <linux/ipv6.h>
#include <linux/ip.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/sctp.h>
#include <linux/lsm_audit.h>

/**
 * ipv4_skb_to_auditdata : fill auditdata from skb
 * @skb : the skb
 * @ad : the audit data to fill
 * @proto : the layer 4 protocol
 *
 * return  0 on success
 */
int ipv4_skb_to_auditdata(struct sk_buff *skb,
		struct common_audit_data *ad, u8 *proto)
{
	int ret = 0;
	struct iphdr *ih;

	ih = ip_hdr(skb);
	if (ih == NULL)
		return -EINVAL;

	ad->u.net->v4info.saddr = ih->saddr;
	ad->u.net->v4info.daddr = ih->daddr;

	if (proto)
		*proto = ih->protocol;
	/* non initial fragment */
	if (ntohs(ih->frag_off) & IP_OFFSET)
		return 0;

	switch (ih->protocol) {
	case IPPROTO_TCP: {
		struct tcphdr *th = tcp_hdr(skb);
		if (th == NULL)
			break;

		ad->u.net->sport = th->source;
		ad->u.net->dport = th->dest;
		break;
	}
	case IPPROTO_UDP: {
		struct udphdr *uh = udp_hdr(skb);
		if (uh == NULL)
			break;

		ad->u.net->sport = uh->source;
		ad->u.net->dport = uh->dest;
		break;
	}
	case IPPROTO_DCCP: {
		struct dccp_hdr *dh = dccp_hdr(skb);
		if (dh == NULL)
			break;

		ad->u.net->sport = dh->dccph_sport;
		ad->u.net->dport = dh->dccph_dport;
		break;
	}
	case IPPROTO_SCTP: {
		struct sctphdr *sh = sctp_hdr(skb);
		if (sh == NULL)
			break;
		ad->u.net->sport = sh->source;
		ad->u.net->dport = sh->dest;
		break;
	}
	default:
		ret = -EINVAL;
	}
	return ret;
}
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
/**
 * ipv6_skb_to_auditdata : fill auditdata from skb
 * @skb : the skb
 * @ad : the audit data to fill
 * @proto : the layer 4 protocol
 *
 * return  0 on success
 */
int ipv6_skb_to_auditdata(struct sk_buff *skb,
		struct common_audit_data *ad, u8 *proto)
{
	int offset, ret = 0;
	struct ipv6hdr *ip6;
	u8 nexthdr;
	__be16 frag_off;

	ip6 = ipv6_hdr(skb);
	if (ip6 == NULL)
		return -EINVAL;
	ad->u.net->v6info.saddr = ip6->saddr;
	ad->u.net->v6info.daddr = ip6->daddr;
	ret = 0;
	/* IPv6 can have several extension header before the Transport header
	 * skip them */
	offset = skb_network_offset(skb);
	offset += sizeof(*ip6);
	nexthdr = ip6->nexthdr;
	offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
	if (offset < 0)
		return 0;
	if (proto)
		*proto = nexthdr;
	switch (nexthdr) {
	case IPPROTO_TCP: {
		struct tcphdr _tcph, *th;

		th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
		if (th == NULL)
			break;

		ad->u.net->sport = th->source;
		ad->u.net->dport = th->dest;
		break;
	}
	case IPPROTO_UDP: {
		struct udphdr _udph, *uh;

		uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
		if (uh == NULL)
			break;

		ad->u.net->sport = uh->source;
		ad->u.net->dport = uh->dest;
		break;
	}
	case IPPROTO_DCCP: {
		struct dccp_hdr _dccph, *dh;

		dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
		if (dh == NULL)
			break;

		ad->u.net->sport = dh->dccph_sport;
		ad->u.net->dport = dh->dccph_dport;
		break;
	}
	case IPPROTO_SCTP: {
		struct sctphdr _sctph, *sh;

		sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
		if (sh == NULL)
			break;
		ad->u.net->sport = sh->source;
		ad->u.net->dport = sh->dest;
		break;
	}
	default:
		ret = -EINVAL;
	}
	return ret;
}
#endif


static inline void print_ipv6_addr(struct audit_buffer *ab,
				   struct in6_addr *addr, __be16 port,
				   char *name1, char *name2)
{
	if (!ipv6_addr_any(addr))
		audit_log_format(ab, " %s=%pI6c", name1, addr);
	if (port)
		audit_log_format(ab, " %s=%d", name2, ntohs(port));
}

static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
				   __be16 port, char *name1, char *name2)
{
	if (addr)
		audit_log_format(ab, " %s=%pI4", name1, &addr);
	if (port)
		audit_log_format(ab, " %s=%d", name2, ntohs(port));
}

/**
 * dump_common_audit_data - helper to dump common audit data
 * @a : common audit data
 *
 */
static void dump_common_audit_data(struct audit_buffer *ab,
				   struct common_audit_data *a)
{
	struct task_struct *tsk = current;

	/*
	 * To keep stack sizes in check force programers to notice if they
	 * start making this union too large!  See struct lsm_network_audit
	 * as an example of how to deal with large data.
	 */
	BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2);

	audit_log_format(ab, " pid=%d comm=", tsk->pid);
	audit_log_untrustedstring(ab, tsk->comm);

	switch (a->type) {
	case LSM_AUDIT_DATA_NONE:
		return;
	case LSM_AUDIT_DATA_IPC:
		audit_log_format(ab, " key=%d ", a->u.ipc_id);
		break;
	case LSM_AUDIT_DATA_CAP:
		audit_log_format(ab, " capability=%d ", a->u.cap);
		break;
	case LSM_AUDIT_DATA_PATH: {
		struct inode *inode;

		audit_log_d_path(ab, " path=", &a->u.path);

		inode = a->u.path.dentry->d_inode;
		if (inode) {
			audit_log_format(ab, " dev=");
			audit_log_untrustedstring(ab, inode->i_sb->s_id);
			audit_log_format(ab, " ino=%lu", inode->i_ino);
		}
		break;
	}
	case LSM_AUDIT_DATA_DENTRY: {
		struct inode *inode;

		audit_log_format(ab, " name=");
		audit_log_untrustedstring(ab, a->u.dentry->d_name.name);

		inode = a->u.dentry->d_inode;
		if (inode) {
			audit_log_format(ab, " dev=");
			audit_log_untrustedstring(ab, inode->i_sb->s_id);
			audit_log_format(ab, " ino=%lu", inode->i_ino);
		}
		break;
	}
	case LSM_AUDIT_DATA_INODE: {
		struct dentry *dentry;
		struct inode *inode;

		inode = a->u.inode;
		dentry = d_find_alias(inode);
		if (dentry) {
			audit_log_format(ab, " name=");
			audit_log_untrustedstring(ab,
					 dentry->d_name.name);
			dput(dentry);
		}
		audit_log_format(ab, " dev=");
		audit_log_untrustedstring(ab, inode->i_sb->s_id);
		audit_log_format(ab, " ino=%lu", inode->i_ino);
		break;
	}
	case LSM_AUDIT_DATA_TASK:
		tsk = a->u.tsk;
		if (tsk && tsk->pid) {
			audit_log_format(ab, " pid=%d comm=", tsk->pid);
			audit_log_untrustedstring(ab, tsk->comm);
		}
		break;
	case LSM_AUDIT_DATA_NET:
		if (a->u.net->sk) {
			struct sock *sk = a->u.net->sk;
			struct unix_sock *u;
			int len = 0;
			char *p = NULL;

			switch (sk->sk_family) {
			case AF_INET: {
				struct inet_sock *inet = inet_sk(sk);

				print_ipv4_addr(ab, inet->inet_rcv_saddr,
						inet->inet_sport,
						"laddr", "lport");
				print_ipv4_addr(ab, inet->inet_daddr,
						inet->inet_dport,
						"faddr", "fport");
				break;
			}
#if IS_ENABLED(CONFIG_IPV6)
			case AF_INET6: {
				struct inet_sock *inet = inet_sk(sk);

				print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
						inet->inet_sport,
						"laddr", "lport");
				print_ipv6_addr(ab, &sk->sk_v6_daddr,
						inet->inet_dport,
						"faddr", "fport");
				break;
			}
#endif
			case AF_UNIX:
				u = unix_sk(sk);
				if (u->path.dentry) {
					audit_log_d_path(ab, " path=", &u->path);
					break;
				}
				if (!u->addr)
					break;
				len = u->addr->len-sizeof(short);
				p = &u->addr->name->sun_path[0];
				audit_log_format(ab, " path=");
				if (*p)
					audit_log_untrustedstring(ab, p);
				else
					audit_log_n_hex(ab, p, len);
				break;
			}
		}

		switch (a->u.net->family) {
		case AF_INET:
			print_ipv4_addr(ab, a->u.net->v4info.saddr,
					a->u.net->sport,
					"saddr", "src");
			print_ipv4_addr(ab, a->u.net->v4info.daddr,
					a->u.net->dport,
					"daddr", "dest");
			break;
		case AF_INET6:
			print_ipv6_addr(ab, &a->u.net->v6info.saddr,
					a->u.net->sport,
					"saddr", "src");
			print_ipv6_addr(ab, &a->u.net->v6info.daddr,
					a->u.net->dport,
					"daddr", "dest");
			break;
		}
		if (a->u.net->netif > 0) {
			struct net_device *dev;

			/* NOTE: we always use init's namespace */
			dev = dev_get_by_index(&init_net, a->u.net->netif);
			if (dev) {
				audit_log_format(ab, " netif=%s", dev->name);
				dev_put(dev);
			}
		}
		break;
#ifdef CONFIG_KEYS
	case LSM_AUDIT_DATA_KEY:
		audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
		if (a->u.key_struct.key_desc) {
			audit_log_format(ab, " key_desc=");
			audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
		}
		break;
#endif
	case LSM_AUDIT_DATA_KMOD:
		audit_log_format(ab, " kmod=");
		audit_log_untrustedstring(ab, a->u.kmod_name);
		break;
	} /* switch (a->type) */
}

/**
 * common_lsm_audit - generic LSM auditing function
 * @a:  auxiliary audit data
 * @pre_audit: lsm-specific pre-audit callback
 * @post_audit: lsm-specific post-audit callback
 *
 * setup the audit buffer for common security information
 * uses callback to print LSM specific information
 */
void common_lsm_audit(struct common_audit_data *a,
	void (*pre_audit)(struct audit_buffer *, void *),
	void (*post_audit)(struct audit_buffer *, void *))
{
	struct audit_buffer *ab;

	if (a == NULL)
		return;
	/* we use GFP_ATOMIC so we won't sleep */
	ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);

	if (ab == NULL)
		return;

	if (pre_audit)
		pre_audit(ab, a);

	dump_common_audit_data(ab, a);

	if (post_audit)
		post_audit(ab, a);

	audit_log_end(ab);
}
OpenPOWER on IntegriCloud