[net-next-2.6.git] / security / lsm_audit.c

/*
 * 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;

	ip6 = ipv6_hdr(skb);
	if (ip6 == NULL)
		return -EINVAL;
	ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr);
	ipv6_addr_copy(&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);
	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 inode *inode = NULL;
	struct task_struct *tsk = current;

	if (a->tsk)
		tsk = a->tsk;
	if (tsk && tsk->pid) {
		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_FS:
		if (a->u.fs.path.dentry) {
			struct dentry *dentry = a->u.fs.path.dentry;
			if (a->u.fs.path.mnt) {
				audit_log_d_path(ab, "path=", &a->u.fs.path);
			} else {
				audit_log_format(ab, " name=");
				audit_log_untrustedstring(ab,
						 dentry->d_name.name);
			}
			inode = dentry->d_inode;
		} else if (a->u.fs.inode) {
			struct dentry *dentry;
			inode = a->u.fs.inode;
			dentry = d_find_alias(inode);
			if (dentry) {
				audit_log_format(ab, " name=");
				audit_log_untrustedstring(ab,
						 dentry->d_name.name);
				dput(dentry);
			}
		}
		if (inode)
			audit_log_format(ab, " dev=%s ino=%lu",
					inode->i_sb->s_id,
					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;
			}
			case AF_INET6: {
				struct inet_sock *inet = inet_sk(sk);
				struct ipv6_pinfo *inet6 = inet6_sk(sk);

				print_ipv6_addr(ab, &inet6->rcv_saddr,
						inet->inet_sport,
						"laddr", "lport");
				print_ipv6_addr(ab, &inet6->daddr,
						inet->inet_dport,
						"faddr", "fport");
				break;
			}
			case AF_UNIX:
				u = unix_sk(sk);
				if (u->dentry) {
					struct path path = {
						.dentry = u->dentry,
						.mnt = u->mnt
					};
					audit_log_d_path(ab, "path=", &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
 *
 * setup the audit buffer for common security information
 * uses callback to print LSM specific information
 */
void common_lsm_audit(struct common_audit_data *a)
{
	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 (a->lsm_pre_audit)
		a->lsm_pre_audit(ab, a);

	dump_common_audit_data(ab, a);

	if (a->lsm_post_audit)
		a->lsm_post_audit(ab, a);

	audit_log_end(ab);
}
Commit	Line	Data
6e837fb1 EB	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>
5a0e3ad6	17	#include <linux/gfp.h>
6e837fb1 EB	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
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
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))
d8116591	191	audit_log_format(ab, " %s=%pI6c", name1, addr);
6e837fb1 EB	192	if (port)
	193	audit_log_format(ab, " %s=%d", name2, ntohs(port));
	194	}
	195
	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	*/
	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) {
cb84aa9b	224	case LSM_AUDIT_DATA_NONE:
2bf49690	225	return;
6e837fb1 EB	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
c720c7e8 ED	277	print_ipv4_addr(ab, inet->inet_rcv_saddr,
c720c7e8 ED	278	inet->inet_sport,
6e837fb1	279	"laddr", "lport");
c720c7e8 ED	280	print_ipv4_addr(ab, inet->inet_daddr,
c720c7e8 ED	281	inet->inet_dport,
6e837fb1 EB	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,
c720c7e8	290	inet->inet_sport,
6e837fb1 EB	291	"laddr", "lport");
6e837fb1 EB	292	print_ipv6_addr(ab, &inet6->daddr,
c720c7e8	293	inet->inet_dport,
6e837fb1 EB	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
dd8dbf2e EP	358	case LSM_AUDIT_DATA_KMOD:
	359	audit_log_format(ab, " kmod=");
	360	audit_log_untrustedstring(ab, a->u.kmod_name);
	361	break;
6e837fb1 EB	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	*/
	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	}