Should be cc'ed to netfilter-devel; now done.
---------- Forwarded message ----------
Date: Sun, 2 Dec 2012 08:21:08
From: Feng Gao <FGao@xxxxxxxxxxxxxxx>
To: laforge, jengelh
Subject: One issue in the xt_hashlimit.c
Hi Harald & Jan,
I am a programmer in China. I read the codes of netfilter recently, and find
one potent issue in the funciton "hashlimit_mt", file "xt_hashlimit.c".
The following codes are from function "hashlimit_mt".
dh = dsthash_find(hinfo, &dst);
if (dh == NULL) {
dh = dsthash_alloc_init(hinfo, &dst);
When two or more threads invoke dsthash_find(hinfo, &dst) at the same time
and fail to find the dh, then all of them will enter the dsthash_alloc_init
to create one new node.
As a result, it will casue that these multiple threads create multle nodes
with same IP. It is not expected behavior.
we should add the check in the fucntion "dsthash_alloc_init" to if the node
has been already created in the function to fix it.
The attachment is my fix.
Best Regards
Feng
Attachment:
xt_hashlimit.diff
Description: xt_hashlimit.diff
