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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-14 11:11:44 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-06-15 21:28:14 +0100 |
| commit | 9f9aa476de1b6bd8fe179dfd9b204972c8c98791 (patch) | |
| tree | 5b389dc7417d6ac102ed4ef52ff0c09cd445f981 | |
| parent | d4203ded7550f38e69b18c37c1e0a67064fc02a8 (diff) | |
| download | lwn-9f9aa476de1b6bd8fe179dfd9b204972c8c98791.tar.gz lwn-9f9aa476de1b6bd8fe179dfd9b204972c8c98791.zip | |
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 <torvalds@linux-foundation.org>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | net/netfilter/nf_conntrack_core.c | 4 |
1 files changed, 3 insertions, 1 deletions
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; |