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authorPablo Neira <pablo@netfilter.org>2014-11-25 19:54:47 +0100
committerDavid S. Miller <davem@davemloft.net>2014-11-25 14:14:51 -0500
commit43612d7c04f1a4f5e60104143918fcdf018b66ee (patch)
treecde0881345eea4c43ad76670e001f85271806604
parent814f7d115ec6348070b57e08851037fce486e16b (diff)
Revert "netfilter: conntrack: fix race in __nf_conntrack_confirm against get_next_corpse"
This reverts commit 5195c14c8b27cc0b18220ddbf0e5ad3328a04187. If the conntrack clashes with an existing one, it is left out of the unconfirmed list, thus, crashing when dropping the packet and releasing the conntrack since golden rule is that conntracks are always placed in any of the existing lists for traceability reasons. Reported-by: Daniel Borkmann <dborkman@redhat.com> Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=88841 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/netfilter/nf_conntrack_core.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 2c699757bccf..5016a6929085 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -611,16 +611,12 @@ __nf_conntrack_confirm(struct sk_buff *skb)
*/
NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
pr_debug("Confirming conntrack %p\n", ct);
-
- /* We have to check the DYING flag after unlink to prevent
- * a race against nf_ct_get_next_corpse() possibly called from
- * user context, else we insert an already 'dead' hash, blocking
- * further use of that particular connection -JM.
- */
- nf_ct_del_from_dying_or_unconfirmed_list(ct);
+ /* We have to check the DYING flag inside the lock to prevent
+ a race against nf_ct_get_next_corpse() possibly called from
+ user context, else we insert an already 'dead' hash, blocking
+ further use of that particular connection -JM */
if (unlikely(nf_ct_is_dying(ct))) {
- nf_ct_add_to_dying_list(ct);
nf_conntrack_double_unlock(hash, reply_hash);
local_bh_enable();
return NF_ACCEPT;
@@ -640,6 +636,8 @@ __nf_conntrack_confirm(struct sk_buff *skb)
zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
goto out;
+ nf_ct_del_from_dying_or_unconfirmed_list(ct);
+
/* Timer relative to confirmation time, not original
setting time, otherwise we'd get timer wrap in
weird delay cases. */