From 31b0b385f69d8d5491a4bca288e25e63f1d945d0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 14 May 2016 11:11:44 -0700 Subject: [PATCH] nf_conntrack: avoid kernel pointer value leak in slab name 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 --- 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 895d11dced3c..e27fd17c6743 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1778,6 +1778,7 @@ void nf_conntrack_init_end(void) int nf_conntrack_init_net(struct net *net) { + static atomic64_t unique_id; int ret = -ENOMEM; int cpu; @@ -1800,7 +1801,8 @@ 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; -- 2.20.1