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From: Tyler Hicks <tyhicks@canonical.com>
To: James Morris <jmorris@namei.org>
Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org
Subject: [PATCH RESEND 2/2] net: Use ns_capable_noaudit() when determining net sysctl permissions
Date: Thu,  2 Jun 2016 23:43:22 -0500	[thread overview]
Message-ID: <1464929002-6624-3-git-send-email-tyhicks@canonical.com> (raw)
In-Reply-To: <1464929002-6624-1-git-send-email-tyhicks@canonical.com>

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@canonical.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
---
 net/sysctl_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sysctl_net.c b/net/sysctl_net.c
index ed98c1f..46a71c7 100644
--- a/net/sysctl_net.c
+++ b/net/sysctl_net.c
@@ -46,7 +46,7 @@ static int net_ctl_permissions(struct ctl_table_header *head,
 	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;
-- 
2.7.4

  parent reply	other threads:[~2016-06-03  4:43 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-03  4:43 [PATCH RESEND 0/2] Quiet noisy LSM denial when accessing net sysctl Tyler Hicks
2016-06-03  4:43 ` [PATCH RESEND 1/2] kernel: Add noaudit variant of ns_capable() Tyler Hicks
2016-06-03  4:43 ` Tyler Hicks [this message]
2016-06-06  9:51   ` [PATCH RESEND 2/2] net: Use ns_capable_noaudit() when determining net sysctl permissions James Morris

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