Add audit uid to netlink credentials

Most audit control messages are sent over netlink.In order to properly
log the identity of the sender of audit control messages, we would like
to add the loginuid to the netlink_creds structure, as per the attached
patch.

Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

include/linux/audit.h

@@ -184,7 +184,7 @@ extern void audit_inode(const char *name, const struct inode *inode);
 
 				/* Private API (for audit.c only) */
 extern int  audit_receive_filter(int type, int pid, int uid, int seq,
-				 void *data);
+				 void *data, uid_t loginuid);
 extern void audit_get_stamp(struct audit_context *ctx,
 			    struct timespec *t, unsigned int *serial);
 extern int  audit_set_loginuid(struct audit_context *ctx, uid_t loginuid);

include/linux/netlink.h

@@ -110,6 +110,7 @@ struct netlink_skb_parms
 	__u32			dst_pid;
 	__u32			dst_groups;
 	kernel_cap_t		eff_cap;
+	__u32			loginuid;	/* Login (audit) uid */
 };
 
 #define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))

kernel/audit.c

@@ -239,36 +239,36 @@ void audit_log_lost(const char *message)
 
 }
 
-static int audit_set_rate_limit(int limit)
+static int audit_set_rate_limit(int limit, uid_t loginuid)
 {
 	int old		 = audit_rate_limit;
 	audit_rate_limit = limit;
-	audit_log(current->audit_context, "audit_rate_limit=%d old=%d",
-		  audit_rate_limit, old);
+	audit_log(NULL, "audit_rate_limit=%d old=%d by auid %u",
+			audit_rate_limit, old, loginuid);
 	return old;
 }
 
-static int audit_set_backlog_limit(int limit)
+static int audit_set_backlog_limit(int limit, uid_t loginuid)
 {
 	int old		 = audit_backlog_limit;
 	audit_backlog_limit = limit;
-	audit_log(current->audit_context, "audit_backlog_limit=%d old=%d",
-		  audit_backlog_limit, old);
+	audit_log(NULL, "audit_backlog_limit=%d old=%d by auid %u",
+			audit_backlog_limit, old, loginuid);
 	return old;
 }
 
-static int audit_set_enabled(int state)
+static int audit_set_enabled(int state, uid_t loginuid)
 {
 	int old		 = audit_enabled;
 	if (state != 0 && state != 1)
 		return -EINVAL;
 	audit_enabled = state;
-	audit_log(current->audit_context, "audit_enabled=%d old=%d",
-		  audit_enabled, old);
+	audit_log(NULL, "audit_enabled=%d old=%d by auid %u",
+		  audit_enabled, old, loginuid);
 	return old;
 }
 
-static int audit_set_failure(int state)
+static int audit_set_failure(int state, uid_t loginuid)
 {
 	int old		 = audit_failure;
 	if (state != AUDIT_FAIL_SILENT
@@ -276,8 +276,8 @@ static int audit_set_failure(int state)
 	    && state != AUDIT_FAIL_PANIC)
 		return -EINVAL;
 	audit_failure = state;
-	audit_log(current->audit_context, "audit_failure=%d old=%d",
-		  audit_failure, old);
+	audit_log(NULL, "audit_failure=%d old=%d by auid %u",
+		  audit_failure, old, loginuid);
 	return old;
 }
 
@@ -344,6 +344,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	int			err;
 	struct audit_buffer	*ab;
 	u16			msg_type = nlh->nlmsg_type;
+	uid_t			loginuid; /* loginuid of sender */
 
 	err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type);
 	if (err)
@@ -351,6 +352,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 	pid  = NETLINK_CREDS(skb)->pid;
 	uid  = NETLINK_CREDS(skb)->uid;
+	loginuid = NETLINK_CB(skb).loginuid;
 	seq  = nlh->nlmsg_seq;
 	data = NLMSG_DATA(nlh);
 
@@ -371,34 +373,36 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 			return -EINVAL;
 		status_get   = (struct audit_status *)data;
 		if (status_get->mask & AUDIT_STATUS_ENABLED) {
-			err = audit_set_enabled(status_get->enabled);
+			err = audit_set_enabled(status_get->enabled, loginuid);
 			if (err < 0) return err;
 		}
 		if (status_get->mask & AUDIT_STATUS_FAILURE) {
-			err = audit_set_failure(status_get->failure);
+			err = audit_set_failure(status_get->failure, loginuid);
 			if (err < 0) return err;
 		}
 		if (status_get->mask & AUDIT_STATUS_PID) {
 			int old   = audit_pid;
 			audit_pid = status_get->pid;
-			audit_log(current->audit_context,
-				  "audit_pid=%d old=%d", audit_pid, old);
+			audit_log(NULL, "audit_pid=%d old=%d by auid %u",
+				  audit_pid, old, loginuid);
 		}
 		if (status_get->mask & AUDIT_STATUS_RATE_LIMIT)
-			audit_set_rate_limit(status_get->rate_limit);
+			audit_set_rate_limit(status_get->rate_limit, loginuid);
 		if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
-			audit_set_backlog_limit(status_get->backlog_limit);
+			audit_set_backlog_limit(status_get->backlog_limit,
+							loginuid);
 		break;
 	case AUDIT_USER:
 		ab = audit_log_start(NULL);
 		if (!ab)
 			break;	/* audit_panic has been called */
 		audit_log_format(ab,
-				 "user pid=%d uid=%d length=%d msg='%.1024s'",
+				 "user pid=%d uid=%d length=%d loginuid=%u"
+				 " msg='%.1024s'",
 				 pid, uid,
 				 (int)(nlh->nlmsg_len
 				       - ((char *)data - (char *)nlh)),
-				 (char *)data);
+				 loginuid, (char *)data);
 		ab->type = AUDIT_USER;
 		ab->pid  = pid;
 		audit_log_end(ab);
@@ -411,7 +415,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	case AUDIT_LIST:
 #ifdef CONFIG_AUDITSYSCALL
 		err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
-					   uid, seq, data);
+					   uid, seq, data, loginuid);
 #else
 		err = -EOPNOTSUPP;
 #endif

kernel/auditsc.c

@@ -251,7 +251,8 @@ static int audit_copy_rule(struct audit_rule *d, struct audit_rule *s)
 	return 0;
 }
 
-int audit_receive_filter(int type, int pid, int uid, int seq, void *data)
+int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
+							uid_t loginuid)
 {
 	u32		   flags;
 	struct audit_entry *entry;
@@ -286,6 +287,7 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data)
 			err = audit_add_rule(entry, &audit_entlist);
 		if (!err && (flags & AUDIT_AT_EXIT))
 			err = audit_add_rule(entry, &audit_extlist);
+		audit_log(NULL, "auid %u added an audit rule\n", loginuid);
 		break;
 	case AUDIT_DEL:
 		flags =((struct audit_rule *)data)->flags;
@@ -295,6 +297,7 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data)
 			err = audit_del_rule(data, &audit_entlist);
 		if (!err && (flags & AUDIT_AT_EXIT))
 			err = audit_del_rule(data, &audit_extlist);
+		audit_log(NULL, "auid %u removed an audit rule\n", loginuid);
 		break;
 	default:
 		return -EINVAL;

net/netlink/af_netlink.c

@@ -905,6 +905,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
 	NETLINK_CB(skb).groups	= nlk->groups;
 	NETLINK_CB(skb).dst_pid = dst_pid;
 	NETLINK_CB(skb).dst_groups = dst_groups;
+	NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
 	memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
 
 	/* What can I do? Netlink is asynchronous, so that