[RFC PATCH ghak59 V1 3/6] audit: exclude user records from syscall context

[Richard Guy Briggs]

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
Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
---
 kernel/audit.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index e469234..c8c2efc 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1057,7 +1057,8 @@ 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);
@@ -1067,7 +1068,7 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
 		return;
 	}
 
-	*ab = audit_log_start(audit_context(), 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);
@@ -1075,6 +1076,11 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
 	audit_log_task_context(*ab);
 }
 
+static inline void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
+{
+	__audit_log_common_recv_msg(audit_context(), ab, msg_type);
+}
+
 int is_audit_feature_set(int i)
 {
 	return af.features & AUDIT_FEATURE_TO_MASK(i);
@@ -1341,7 +1347,7 @@ 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_common_recv_msg(NULL, &ab, msg_type);
 			if (msg_type != AUDIT_USER_TTY)
 				audit_log_format(ab, " msg='%.*s'",
 						 AUDIT_MESSAGE_TEXT_MAX,
-- 
1.8.3.1