Messages in this thread Patch in this message | | | From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 19/40] nf_conntrack: avoid kernel pointer value leak in slab name | Date | Wed, 25 May 2016 10:30:22 -0700 |
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3.19.8-ckt22 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Linus Torvalds <torvalds@linux-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@linux-foundation.org> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- 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 46d1b26..0ab748b 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1736,6 +1736,7 @@ void nf_conntrack_init_end(void) int nf_conntrack_init_net(struct net *net) { + static atomic64_t unique_id; int ret = -ENOMEM; int cpu; @@ -1759,7 +1760,8 @@ 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
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