[PATCH ghak59 V2 3/6] audit: exclude user records from syscall context

From: Richard Guy Briggs
Date: Fri Jul 27 2018 - 15:51:56 EST


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 6cfe3c9..62ada1b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1054,7 +1054,8 @@ 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);
@@ -1064,7 +1065,7 @@ 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);
@@ -1072,6 +1073,11 @@ 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);
@@ -1338,7 +1344,7 @@ 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