security/lsm_audit.c - linux - Git at Google

 /*
  * 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 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_PATH: {
 		struct dentry *dentry = a->u.path.dentry;
 		struct inode *inode;

 		if (a->u.path.mnt) {
 			audit_log_d_path(ab, "path=", &a->u.path);
 		} else {
 			audit_log_format(ab, " name=");
 			audit_log_untrustedstring(ab,
 					 dentry->d_name.name);
 		}
 		inode = dentry->d_inode;
 		if (inode)
 			audit_log_format(ab, " dev=%s ino=%lu",
 					inode->i_sb->s_id,
 					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=%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);
 }
	/*
	* 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 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_PATH: {
	struct dentry *dentry = a->u.path.dentry;
	struct inode *inode;

	if (a->u.path.mnt) {
	audit_log_d_path(ab, "path=", &a->u.path);
	} else {
	audit_log_format(ab, " name=");
	audit_log_untrustedstring(ab,
	dentry->d_name.name);
	}
	inode = dentry->d_inode;
	if (inode)
	audit_log_format(ab, " dev=%s ino=%lu",
	inode->i_sb->s_id,
	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=%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);
	}