audit: add syscall information to CONFIG_CHANGE records

Tie syscall information to all CONFIG_CHANGE calls since they are all a
result of user actions.

Exclude user records from syscall context:
Since the function audit_log_common_recv_msg() is shared by a number of
AUDIT_CONFIG_CHANGE and the entire range of AUDIT_USER_* record types,
and since the AUDIT_CONFIG_CHANGE message type has been converted to a
syscall accompanied record type, special-case the AUDIT_USER_* range of
messages so they remain standalone records.

See: https://github.com/linux-audit/audit-kernel/issues/59
See: https://github.com/linux-audit/audit-kernel/issues/50

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: fix line lengths in kernel/audit.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 19 insertions, 9 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index d412fb4ae6d5..c2a7662cc254 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -396,7 +396,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
 	struct audit_buffer *ab;
 	int rc = 0;
 
-	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 	if (unlikely(!ab))
 		return rc;
 	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
@@ -1053,7 +1053,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 	return err;
 }
 
-static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
+static void audit_log_common_recv_msg(struct audit_context *context,
+					struct audit_buffer **ab, u16 msg_type)
 {
 	uid_t uid = from_kuid(&init_user_ns, current_uid());
 	pid_t pid = task_tgid_nr(current);
@@ -1063,7 +1064,7 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
 		return;
 	}
 
-	*ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
+	*ab = audit_log_start(context, GFP_KERNEL, msg_type);
 	if (unlikely(!*ab))
 		return;
 	audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
@@ -1071,6 +1072,12 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
 	audit_log_task_context(*ab);
 }
 
+static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
+					   u16 msg_type)
+{
+	audit_log_common_recv_msg(NULL, ab, msg_type);
+}
+
 int is_audit_feature_set(int i)
 {
 	return af.features & AUDIT_FEATURE_TO_MASK(i);
@@ -1338,7 +1345,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 				if (err)
 					break;
 			}
-			audit_log_common_recv_msg(&ab, msg_type);
+			audit_log_user_recv_msg(&ab, msg_type);
 			if (msg_type != AUDIT_USER_TTY)
 				audit_log_format(ab, " msg='%.*s'",
 						 AUDIT_MESSAGE_TEXT_MAX,
@@ -1361,7 +1368,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
 			return -EINVAL;
 		if (audit_enabled == AUDIT_LOCKED) {
-			audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+			audit_log_common_recv_msg(audit_context(), &ab,
+						  AUDIT_CONFIG_CHANGE);
 			audit_log_format(ab, " op=%s audit_enabled=%d res=0",
 					 msg_type == AUDIT_ADD_RULE ?
 						"add_rule" : "remove_rule",
@@ -1376,7 +1384,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		break;
 	case AUDIT_TRIM:
 		audit_trim_trees();
-		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
 		audit_log_format(ab, " op=trim res=1");
 		audit_log_end(ab);
 		break;
@@ -1406,8 +1415,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		/* OK, here comes... */
 		err = audit_tag_tree(old, new);
 
-		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
-
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
 		audit_log_format(ab, " op=make_equiv old=");
 		audit_log_untrustedstring(ab, old);
 		audit_log_format(ab, " new=");
@@ -1474,7 +1483,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		old.enabled = t & AUDIT_TTY_ENABLE;
 		old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
 
-		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
 		audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
 				 " old-log_passwd=%d new-log_passwd=%d res=%d",
 				 old.enabled, s.enabled, old.log_passwd,