From: Linus Torvalds Date: Sat, 14 May 2016 18:11:44 +0000 (-0700) Subject: nf_conntrack: avoid kernel pointer value leak in slab name X-Git-Tag: v3.2.81~4 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=9f9aa476de1b6bd8fe179dfd9b204972c8c98791;ds=sidebyside nf_conntrack: avoid kernel pointer value leak in slab name 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 --- diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 7489bd301da5..c855673ceb23 100644 --- 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 net *net) 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;