From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754952AbcEXR4I (ORCPT ); Tue, 24 May 2016 13:56:08 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:37927 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965017AbcEXR4B (ORCPT ); Tue, 24 May 2016 13:56:01 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Linus Torvalds , "David S . Miller" , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 26/53] nf_conntrack: avoid kernel pointer value leak in slab name Date: Tue, 24 May 2016 10:54:56 -0700 Message-Id: <1464112523-3701-27-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1464112523-3701-1-git-send-email-kamal@canonical.com> References: <1464112523-3701-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt11 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Linus Torvalds commit 31b0b385f69d8d5491a4bca288e25e63f1d945d0 upstream. 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 Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- 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 0625a42..affc51e 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1756,6 +1756,7 @@ void nf_conntrack_init_end(void) int nf_conntrack_init_net(struct net *net) { + static atomic64_t unique_id; int ret = -ENOMEM; int cpu; @@ -1778,7 +1779,8 @@ 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; -- 2.7.4