Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755476AbaG3Mgc (ORCPT ); Wed, 30 Jul 2014 08:36:32 -0400 Received: from ip4-83-240-18-248.cust.nbox.cz ([83.240.18.248]:36705 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752864AbaG3MPb (ORCPT ); Wed, 30 Jul 2014 08:15:31 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Daniel Borkmann , "David S. Miller" , Jiri Slaby Subject: [PATCH 3.12 35/94] net: sctp: check proc_dointvec result in proc_sctp_do_auth Date: Wed, 30 Jul 2014 14:14:24 +0200 Message-Id: X-Mailer: git-send-email 2.0.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Daniel Borkmann 3.12-stable review patch. If anyone has any objections, please let me know. =============== [ Upstream commit 24599e61b7552673dd85971cf5a35369cd8c119e ] When writing to the sysctl field net.sctp.auth_enable, it can well be that the user buffer we handed over to proc_dointvec() via proc_sctp_do_auth() handler contains something other than integers. In that case, we would set an uninitialized 4-byte value from the stack to net->sctp.auth_enable that can be leaked back when reading the sysctl variable, and it can unintentionally turn auth_enable on/off based on the stack content since auth_enable is interpreted as a boolean. Fix it up by making sure proc_dointvec() returned sucessfully. Fixes: b14878ccb7fa ("net: sctp: cache auth_enable per endpoint") Reported-by: Florian Westphal Signed-off-by: Daniel Borkmann Acked-by: Neil Horman Acked-by: Vlad Yasevich Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby --- net/sctp/sysctl.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c index 976c89d5295b..968355f0de60 100644 --- a/net/sctp/sysctl.c +++ b/net/sctp/sysctl.c @@ -361,8 +361,7 @@ static int proc_sctp_do_auth(struct ctl_table *ctl, int write, tbl.data = &net->sctp.auth_enable; ret = proc_dointvec(&tbl, write, buffer, lenp, ppos); - - if (write) { + if (write && ret == 0) { struct sock *sk = net->sctp.ctl_sock; net->sctp.auth_enable = new_value; -- 2.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/