From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David S. Miller" , "Eric Dumazet" , "Linus Torvalds" Date: Sun, 12 Jun 2016 22:34:42 +0100 Message-ID: Subject: [PATCH 3.2 43/46] nf_conntrack: avoid kernel pointer value leak in slab name In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.81-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- net/netfilter/nf_conntrack_core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1493,6 +1493,7 @@ err_proto: static int nf_conntrack_init_net(struct net *net) { + static atomic64_t unique_id; int ret; atomic_set(&net->ct.count, 0); @@ -1504,7 +1505,8 @@ static int nf_conntrack_init_net(struct goto err_stat; } - 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) { ret = -ENOMEM; goto err_slabname;