Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756155AbaBEVA3 (ORCPT ); Wed, 5 Feb 2014 16:00:29 -0500 Received: from mail.windriver.com ([147.11.1.11]:54686 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754346AbaBEUFV (ORCPT ); Wed, 5 Feb 2014 15:05:21 -0500 From: Paul Gortmaker To: , CC: Mathias Krause , "David S. Miller" , Paul Gortmaker Subject: [v2.6.34-stable 071/213] xfrm_user: return error pointer instead of NULL Date: Wed, 5 Feb 2014 15:00:26 -0500 Message-ID: <1391630568-49251-72-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.8.5.2 In-Reply-To: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> References: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mathias Krause ------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. ------------------- commit 864745d291b5ba80ea0bd0edcbe67273de368836 upstream. When dump_one_state() returns an error, e.g. because of a too small buffer to dump the whole xfrm state, xfrm_state_netlink() returns NULL instead of an error pointer. But its callers expect an error pointer and therefore continue to operate on a NULL skbuff. This could lead to a privilege escalation (execution of user code in kernel context) if the attacker has CAP_NET_ADMIN and is able to map address 0. Signed-off-by: Mathias Krause Acked-by: Steffen Klassert Signed-off-by: David S. Miller Signed-off-by: Paul Gortmaker --- net/xfrm/xfrm_user.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 44d18db58cbb..bbc09e0c1ae7 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -765,6 +765,7 @@ static struct sk_buff *xfrm_state_netlink(struct sk_buff *in_skb, { struct xfrm_dump_info info; struct sk_buff *skb; + int err; skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); if (!skb) @@ -775,9 +776,10 @@ static struct sk_buff *xfrm_state_netlink(struct sk_buff *in_skb, info.nlmsg_seq = seq; info.nlmsg_flags = 0; - if (dump_one_state(x, 0, &info)) { + err = dump_one_state(x, 0, &info); + if (err) { kfree_skb(skb); - return NULL; + return ERR_PTR(err); } return skb; -- 1.8.5.2 -- 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/