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Date: Mon, 16 May 2016 18:21:46 -0700 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Linus Torvalds <torvalds@...ux-foundation.org>, Eric Dumazet <eric.dumazet@...il.com>, "David S. Miller" <davem@...emloft.net> Subject: [PATCH 4.5 101/101] nf_conntrack: avoid kernel pointer value leak in slab name 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds <torvalds@...ux-foundation.org> 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 <torvalds@...ux-foundation.org> Acked-by: Eric Dumazet <eric.dumazet@...il.com> Signed-off-by: David S. Miller <davem@...emloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- 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 @@ -1780,6 +1780,7 @@ void nf_conntrack_init_end(void) int nf_conntrack_init_net(struct net *net) { + static atomic64_t unique_id; int ret = -ENOMEM; int cpu; @@ -1802,7 +1803,8 @@ int nf_conntrack_init_net(struct net *ne 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;
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