linux-kernel - [PATCH 4.7 04/59] net: Use ns_capable_noaudit() when determining net sysctl permissions

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Message-Id: <20160912152128.937299474@linuxfoundation.org>
Date:   Mon, 12 Sep 2016 17:29:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Tyler Hicks <tyhicks@...onical.com>,
        "Serge E. Hallyn" <serge.hallyn@...ntu.com>,
        James Morris <james.l.morris@...cle.com>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.7 04/59] net: Use ns_capable_noaudit() when determining net sysctl permissions

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

------------------

From: Tyler Hicks <tyhicks@...onical.com>

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@...onical.com>
Acked-by: Serge E. Hallyn <serge.hallyn@...ntu.com>
Signed-off-by: James Morris <james.l.morris@...cle.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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;