[PATCH 4.4 145/192] net: Use ns_capable_noaudit() when determining net sysctl permissions

From: Greg Kroah-Hartman
Date: Mon Sep 12 2016 - 13:21:20 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>

commit d6e0d306449bcb5fa3c80e7a3edf11d45abf9ae9 upstream.

The capability check should not be audited since it is only being used
to determine the inode permissions. A failed check does not indicate a
violation of security policy but, when an LSM is enabled, a denial audit
message was being generated.

The denial audit message caused confusion for some application authors
because root-running Go applications always triggered the denial. To
prevent this confusion, the capability check in net_ctl_permissions() is
switched to the noaudit variant.

BugLink: https://launchpad.net/bugs/1465724

Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>
Acked-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxx>
Signed-off-by: James Morris <james.l.morris@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

net/sysctl_net.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sysctl_net.c
+++ b/net/sysctl_net.c
@@ -46,7 +46,7 @@ static int net_ctl_permissions(struct ct
kgid_t root_gid = make_kgid(net->user_ns, 0);

/* Allow network administrator to have same access as root. */
- if (ns_capable(net->user_ns, CAP_NET_ADMIN) ||
+ if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN) ||
uid_eq(root_uid, current_euid())) {
int mode = (table->mode >> 6) & 7;
return (mode << 6) | (mode << 3) | mode;