From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Moore Subject: Re: [PATCH 1/1] net: fix cipso packet validation when !NETLABEL Date: Sat, 12 Oct 2013 07:57:27 -0400 Message-ID: <2291823.ee0I8c00DA@olly> References: <0DB595A2CB707F458400BE9663B6A72269C0047793@SC-VEXCH2.marvell.com> <11516872.z0JUlZSHlI@sifl> <0DB595A2CB707F458400BE9663B6A72269C0047841@SC-VEXCH2.marvell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: "davem@davemloft.net" , "netdev@vger.kernel.org" , "thomas.petazzoni@free-electrons.com" , Dmitri Epshtein To: Seif Mazareeb Return-path: Received: from mail-qe0-f52.google.com ([209.85.128.52]:50418 "EHLO mail-qe0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752189Ab3JLL5a (ORCPT ); Sat, 12 Oct 2013 07:57:30 -0400 Received: by mail-qe0-f52.google.com with SMTP id w7so4092951qeb.11 for ; Sat, 12 Oct 2013 04:57:29 -0700 (PDT) In-Reply-To: <0DB595A2CB707F458400BE9663B6A72269C0047841@SC-VEXCH2.marvell.com> Sender: netdev-owner@vger.kernel.org List-ID: On Friday, October 11, 2013 2:04:10 PM Seif Mazareeb wrote: > When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could > loop forever in the main loop if opt[opt_iter +1] == 0, this will causing a > kernel crash in an SMP system, since the CPU executing this function will > stall /not respond to IPIs. > > This problem can be reproduced by running the IP Stack Integrity Checker > (http://isic.sourceforge.net) using the following command on a Linux machine > connected to DUT: > > "icmpsic -s rand -d -r 123456" > wait (1-2 min) > > Signed-off-by: Seif Mazareeb > --- > include/net/cipso_ipv4.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h > index a7a683e..286b7da 100644 > --- a/include/net/cipso_ipv4.h > +++ b/include/net/cipso_ipv4.h > @@ -290,6 +290,7 @@ static inline int cipso_v4_validate(const struct sk_buff > *skb, unsigned char err_offset = 0; > u8 opt_len = opt[1]; > u8 opt_iter; > + u8 tag_len; > > if (opt_len < 8) { > err_offset = 1; > @@ -302,7 +303,8 @@ static inline int cipso_v4_validate(const struct sk_buff > *skb, } > > for (opt_iter = 6; opt_iter < opt_len;) { > - if (opt[opt_iter + 1] > (opt_len - opt_iter)) { > + tag_len = opt[opt_iter + 1]; > + if ((tag_len == 0) || (opt[opt_iter + 1] > (opt_len - > opt_iter))) { err_offset = opt_iter + 1; > goto out; > } You should also use 'tag_len' inside the for-loop, and after the if-block, where we increment 'opt_iter'. See my original reply for an example. -- paul moore www.paul-moore.com