From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:17377 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753971AbcESEV4 (ORCPT ); Thu, 19 May 2016 00:21:56 -0400 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Linus Torvalds , "David S. Miller" , Sasha Levin Subject: [added to the 4.1 stable tree] nf_conntrack: avoid kernel pointer value leak in slab name Date: Thu, 19 May 2016 00:20:06 -0400 Message-Id: <1463631606-32540-67-git-send-email-sasha.levin@oracle.com> In-Reply-To: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> References: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> Sender: stable-owner@vger.kernel.org List-ID: From: Linus Torvalds This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit 31b0b385f69d8d5491a4bca288e25e63f1d945d0 ] The slab name ends up being visible in the directory structure under /sys, and even if you don't have access rights to the file you can see the filenames. Just use a 64-bit counter instead of the pointer to the 'net' structure to generate a unique name. This code will go away in 4.7 when the conntrack code moves to a single kmemcache, but this is the backportable simple solution to avoiding leaking kernel pointers to user space. Fixes: 5b3501faa874 ("netfilter: nf_conntrack: per netns nf_conntrack_cachep") Signed-off-by: Linus Torvalds Acked-by: Eric Dumazet Cc: stable@vger.kernel.org Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/netfilter/nf_conntrack_core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 13fad86..bc3f791 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1735,6 +1735,7 @@ void nf_conntrack_init_end(void) int nf_conntrack_init_net(struct net *net) { + static atomic64_t unique_id; int ret = -ENOMEM; int cpu; @@ -1758,7 +1759,8 @@ int nf_conntrack_init_net(struct net *net) if (!net->ct.stat) goto err_pcpu_lists; - net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); + net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%llu", + (u64)atomic64_inc_return(&unique_id)); if (!net->ct.slabname) goto err_slabname; -- 2.5.0