SELinux: Convert avc_audit to use lsm_audit.h

Convert avc_audit in security/selinux/avc.c to use lsm_audit.h,
for better maintainability.

 - changed selinux to use common_audit_data instead of
    avc_audit_data
 - eliminated code in avc.c and used code from lsm_audit.h instead.

Had to add a LSM_AUDIT_NO_AUDIT to lsm_audit.h so that avc_audit
can call common_lsm_audit and do the pre and post callbacks without
doing the actual dump.  This makes it so that the patched version
behaves the same way as the unpatched version.

Also added a denied field to the selinux_audit_data private space,
once again to make it so that the patched version behaves like the
unpatched.

I've tested and confirmed that AVCs look the same before and after
this patch.
Signed-off-by: Thomas Liu <tliu@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>

include/linux/lsm_audit.h

@@ -33,6 +33,7 @@ struct common_audit_data {
 #define LSM_AUDIT_DATA_IPC     4
 #define LSM_AUDIT_DATA_TASK    5
 #define LSM_AUDIT_DATA_KEY     6
+#define LSM_AUDIT_NO_AUDIT     7
 	struct task_struct *tsk;
 	union 	{
 		struct {
@@ -86,6 +87,7 @@ struct common_audit_data {
 			u16 tclass;
 			u32 requested;
 			u32 audited;
+			u32 denied;
 			struct av_decision *avd;
 			int result;
 		} selinux_audit_data;

security/Makefile

@@ -16,9 +16,7 @@ obj-$(CONFIG_SECURITYFS)		+= inode.o
 # Must precede capability.o in order to stack properly.
 obj-$(CONFIG_SECURITY_SELINUX)		+= selinux/built-in.o
 obj-$(CONFIG_SECURITY_SMACK)		+= smack/built-in.o
-ifeq ($(CONFIG_AUDIT),y)
-obj-$(CONFIG_SECURITY_SMACK)		+= lsm_audit.o
-endif
+obj-$(CONFIG_AUDIT)			+= lsm_audit.o
 obj-$(CONFIG_SECURITY_TOMOYO)		+= tomoyo/built-in.o
 obj-$(CONFIG_SECURITY_ROOTPLUG)		+= root_plug.o
 obj-$(CONFIG_CGROUP_DEVICE)		+= device_cgroup.o

security/lsm_audit.c

@@ -220,6 +220,8 @@ static void dump_common_audit_data(struct audit_buffer *ab,
 	}
 
 	switch (a->type) {
+	case LSM_AUDIT_NO_AUDIT:
+		return;
 	case LSM_AUDIT_DATA_IPC:
 		audit_log_format(ab, " key=%d ", a->u.ipc_id);
 		break;

security/selinux/avc.c

@@ -492,23 +492,35 @@ static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_dec
 	return node;
 }
 
-static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
-				       struct in6_addr *addr, __be16 port,
-				       char *name1, char *name2)
+/**
+ * avc_audit_pre_callback - SELinux specific information
+ * will be called by generic audit code
+ * @ab: the audit buffer
+ * @a: audit_data
+ */
+static void avc_audit_pre_callback(struct audit_buffer *ab, void *a)
 {
-	if (!ipv6_addr_any(addr))
-		audit_log_format(ab, " %s=%pI6", name1, addr);
-	if (port)
-		audit_log_format(ab, " %s=%d", name2, ntohs(port));
+	struct common_audit_data *ad = a;
+	audit_log_format(ab, "avc:  %s ",
+			 ad->selinux_audit_data.denied ? "denied" : "granted");
+	avc_dump_av(ab, ad->selinux_audit_data.tclass,
+			ad->selinux_audit_data.audited);
+	audit_log_format(ab, " for ");
 }
 
-static inline void avc_print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
-				       __be16 port, char *name1, char *name2)
+/**
+ * avc_audit_post_callback - SELinux specific information
+ * will be called by generic audit code
+ * @ab: the audit buffer
+ * @a: audit_data
+ */
+static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
 {
-	if (addr)
-		audit_log_format(ab, " %s=%pI4", name1, &addr);
-	if (port)
-		audit_log_format(ab, " %s=%d", name2, ntohs(port));
+	struct common_audit_data *ad = a;
+	audit_log_format(ab, " ");
+	avc_dump_query(ab, ad->selinux_audit_data.ssid,
+			   ad->selinux_audit_data.tsid,
+			   ad->selinux_audit_data.tclass);
 }
 
 /**
@@ -532,13 +544,10 @@ static inline void avc_print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
  */
 void avc_audit(u32 ssid, u32 tsid,
 	       u16 tclass, u32 requested,
-	       struct av_decision *avd, int result, struct avc_audit_data *a)
+	       struct av_decision *avd, int result, struct common_audit_data *a)
 {
-	struct task_struct *tsk = current;
-	struct inode *inode = NULL;
+	struct common_audit_data stack_data;
 	u32 denied, audited;
-	struct audit_buffer *ab;
-
 	denied = requested & ~avd->allowed;
 	if (denied) {
 		audited = denied;
@@ -551,144 +560,20 @@ void avc_audit(u32 ssid, u32 tsid,
 		if (!(audited & avd->auditallow))
 			return;
 	}
-
-	ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
-	if (!ab)
-		return;		/* audit_panic has been called */
-	audit_log_format(ab, "avc:  %s ", denied ? "denied" : "granted");
-	avc_dump_av(ab, tclass, audited);
-	audit_log_format(ab, " for ");
-	if (a && a->tsk)
-		tsk = a->tsk;
-	if (tsk && tsk->pid) {
-		audit_log_format(ab, " pid=%d comm=", tsk->pid);
-		audit_log_untrustedstring(ab, tsk->comm);
-	}
-	if (a) {
-		switch (a->type) {
-		case AVC_AUDIT_DATA_IPC:
-			audit_log_format(ab, " key=%d", a->u.ipc_id);
-			break;
-		case AVC_AUDIT_DATA_CAP:
-			audit_log_format(ab, " capability=%d", a->u.cap);
-			break;
-		case AVC_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 AVC_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);
-
-					avc_print_ipv4_addr(ab, inet->rcv_saddr,
-							    inet->sport,
-							    "laddr", "lport");
-					avc_print_ipv4_addr(ab, inet->daddr,
-							    inet->dport,
-							    "faddr", "fport");
-					break;
-				}
-				case AF_INET6: {
-					struct inet_sock *inet = inet_sk(sk);
-					struct ipv6_pinfo *inet6 = inet6_sk(sk);
-
-					avc_print_ipv6_addr(ab, &inet6->rcv_saddr,
-							    inet->sport,
-							    "laddr", "lport");
-					avc_print_ipv6_addr(ab, &inet6->daddr,
-							    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:
-				avc_print_ipv4_addr(ab, a->u.net.v4info.saddr,
-						    a->u.net.sport,
-						    "saddr", "src");
-				avc_print_ipv4_addr(ab, a->u.net.v4info.daddr,
-						    a->u.net.dport,
-						    "daddr", "dest");
-				break;
-			case AF_INET6:
-				avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr,
-						    a->u.net.sport,
-						    "saddr", "src");
-				avc_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;
-		}
+	if (!a) {
+		a = &stack_data;
+		memset(a, 0, sizeof(*a));
+		a->type = LSM_AUDIT_NO_AUDIT;
 	}
-	audit_log_format(ab, " ");
-	avc_dump_query(ab, ssid, tsid, tclass);
-	audit_log_end(ab);
+	a->selinux_audit_data.tclass = tclass;
+	a->selinux_audit_data.requested = requested;
+	a->selinux_audit_data.ssid = ssid;
+	a->selinux_audit_data.tsid = tsid;
+	a->selinux_audit_data.audited = audited;
+	a->selinux_audit_data.denied = denied;
+	a->lsm_pre_audit = avc_audit_pre_callback;
+	a->lsm_post_audit = avc_audit_post_callback;
+	common_lsm_audit(a);
 }
 
 /**
@@ -956,7 +841,7 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid,
  * another -errno upon other errors.
  */
 int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
-		 u32 requested, struct avc_audit_data *auditdata)
+		 u32 requested, struct common_audit_data *auditdata)
 {
 	struct av_decision avd;
 	int rc;

security/selinux/include/avc.h

@@ -13,6 +13,7 @@
 #include <linux/spinlock.h>
 #include <linux/init.h>
 #include <linux/audit.h>
+#include <linux/lsm_audit.h>
 #include <linux/in6.h>
 #include <linux/path.h>
 #include <asm/system.h>
@@ -36,48 +37,6 @@ struct inode;
 struct sock;
 struct sk_buff;
 
-/* Auxiliary data to use in generating the audit record. */
-struct avc_audit_data {
-	char    type;
-#define AVC_AUDIT_DATA_FS   1
-#define AVC_AUDIT_DATA_NET  2
-#define AVC_AUDIT_DATA_CAP  3
-#define AVC_AUDIT_DATA_IPC  4
-	struct task_struct *tsk;
-	union 	{
-		struct {
-			struct path path;
-			struct inode *inode;
-		} fs;
-		struct {
-			int netif;
-			struct sock *sk;
-			u16 family;
-			__be16 dport;
-			__be16 sport;
-			union {
-				struct {
-					__be32 daddr;
-					__be32 saddr;
-				} v4;
-				struct {
-					struct in6_addr daddr;
-					struct in6_addr saddr;
-				} v6;
-			} fam;
-		} net;
-		int cap;
-		int ipc_id;
-	} u;
-};
-
-#define v4info fam.v4
-#define v6info fam.v6
-
-/* Initialize an AVC audit data structure. */
-#define AVC_AUDIT_DATA_INIT(_d,_t) \
-	{ memset((_d), 0, sizeof(struct avc_audit_data)); (_d)->type = AVC_AUDIT_DATA_##_t; }
-
 /*
  * AVC statistics
  */
@@ -98,7 +57,9 @@ void __init avc_init(void);
 
 void avc_audit(u32 ssid, u32 tsid,
 	       u16 tclass, u32 requested,
-	       struct av_decision *avd, int result, struct avc_audit_data *auditdata);
+	       struct av_decision *avd,
+	       int result,
+	       struct common_audit_data *a);
 
 #define AVC_STRICT 1 /* Ignore permissive mode. */
 int avc_has_perm_noaudit(u32 ssid, u32 tsid,
@@ -108,7 +69,7 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid,
 
 int avc_has_perm(u32 ssid, u32 tsid,
 		 u16 tclass, u32 requested,
-		 struct avc_audit_data *auditdata);
+		 struct common_audit_data *auditdata);
 
 u32 avc_policy_seqno(void);
 

security/selinux/include/netlabel.h

@@ -59,7 +59,7 @@ int selinux_netlbl_socket_post_create(struct sock *sk, u16 family);
 int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
 				struct sk_buff *skb,
 				u16 family,
-				struct avc_audit_data *ad);
+				struct common_audit_data *ad);
 int selinux_netlbl_socket_setsockopt(struct socket *sock,
 				     int level,
 				     int optname);
@@ -129,7 +129,7 @@ static inline int selinux_netlbl_socket_post_create(struct sock *sk,
 static inline int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
 					      struct sk_buff *skb,
 					      u16 family,
-					      struct avc_audit_data *ad)
+					      struct common_audit_data *ad)
 {
 	return 0;
 }

security/selinux/include/xfrm.h

@@ -41,9 +41,9 @@ static inline int selinux_xfrm_enabled(void)
 }
 
 int selinux_xfrm_sock_rcv_skb(u32 sid, struct sk_buff *skb,
-			struct avc_audit_data *ad);
+			struct common_audit_data *ad);
 int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
-			struct avc_audit_data *ad, u8 proto);
+			struct common_audit_data *ad, u8 proto);
 int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall);
 
 static inline void selinux_xfrm_notify_policyload(void)
@@ -57,13 +57,13 @@ static inline int selinux_xfrm_enabled(void)
 }
 
 static inline int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
-			struct avc_audit_data *ad)
+			struct common_audit_data *ad)
 {
 	return 0;
 }
 
 static inline int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
-			struct avc_audit_data *ad, u8 proto)
+			struct common_audit_data *ad, u8 proto)
 {
 	return 0;
 }

security/selinux/netlabel.c

@@ -342,7 +342,7 @@ int selinux_netlbl_socket_post_create(struct sock *sk, u16 family)
 int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
 				struct sk_buff *skb,
 				u16 family,
-				struct avc_audit_data *ad)
+				struct common_audit_data *ad)
 {
 	int rc;
 	u32 nlbl_sid;

security/selinux/xfrm.c

@@ -401,7 +401,7 @@ int selinux_xfrm_state_delete(struct xfrm_state *x)
  * gone thru the IPSec process.
  */
 int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
-				struct avc_audit_data *ad)
+				struct common_audit_data *ad)
 {
 	int i, rc = 0;
 	struct sec_path *sp;
@@ -442,7 +442,7 @@ int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
  * checked in the selinux_xfrm_state_pol_flow_match hook above.
  */
 int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
-					struct avc_audit_data *ad, u8 proto)
+					struct common_audit_data *ad, u8 proto)
 {
 	struct dst_entry *dst;
 	int rc = 0;