From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Ricardo Leitner Subject: Re: [PATCH net v3] sctp: asconf's process should verify address parameter is in the beginning Date: Wed, 26 Aug 2015 17:59:25 -0300 Message-ID: <20150826205925.GL1873@localhost.localdomain> References: <55DE24AD.5090507@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Xin Long , network dev , davem@davemloft.net To: Vlad Yasevich Return-path: Received: from mx1.redhat.com ([209.132.183.28]:33846 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750832AbbHZU71 (ORCPT ); Wed, 26 Aug 2015 16:59:27 -0400 Content-Disposition: inline In-Reply-To: <55DE24AD.5090507@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Aug 26, 2015 at 04:42:21PM -0400, Vlad Yasevich wrote: > On 08/26/2015 04:35 PM, Xin Long wrote: > > in sctp_process_asconf(), we get address parameter from the beginning of > > the addip params. but we never check if it's really there. if the addr > > param is not there, it still can pass sctp_verify_asconf(), then to be > > handled by sctp_process_asconf(), it will not be safe. > > > > so add a code in sctp_verify_asconf() to check the address parameter is in > > the beginning, or return false to send abort. > > > > v2->v3: > > * put the check in the loop, add the check for multiple address parameters. > > > Please split the multiple address detection from first address detection. > They are 2 different bugs and each one deserves a separate commit and > changelog. See below, thx. > > Thanks > -vlad > > > v1->v2: > > * put the check behind the params' length verify. > > > > Signed-off-by: Xin Long > > Signed-off-by: Vlad Yasevich > > --- > > net/sctp/sm_make_chunk.c | 14 ++++++++++++-- > > 1 file changed, 12 insertions(+), 2 deletions(-) > > > > diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c > > index 06320c8..4068fe1 100644 > > --- a/net/sctp/sm_make_chunk.c > > +++ b/net/sctp/sm_make_chunk.c > > @@ -3130,14 +3130,24 @@ bool sctp_verify_asconf(const struct sctp_association *asoc, > > case SCTP_PARAM_ERR_CAUSE: > > break; > > case SCTP_PARAM_IPV4_ADDRESS: > > + if (addr_param_seen) { > > + /* peer placed multiple address parameters into > > + * the same asconf. reject it. > > + */ > > + return false; > > + } > > if (length != sizeof(sctp_ipv4addr_param_t)) > > return false; > > - addr_param_seen = true; > > + if (param.v == addip->addip_hdr.params) > > + addr_param_seen = true; > > break; I know I had suggested using addr_param_seen to check for multiple occurrences, but now realized we can simplify this with something like: + if (param.v != addip->addip_hdr.params) + return false; addr_param_seen = true; Then the check against addr_param_seen is not needed and do both checks at once. Thanks, Marcelo > > case SCTP_PARAM_IPV6_ADDRESS: > > + if (addr_param_seen) > > + return false; > > if (length != sizeof(sctp_ipv6addr_param_t)) > > return false; > > - addr_param_seen = true; > > + if (param.v == addip->addip_hdr.params) > > + addr_param_seen = true; > > break; > > case SCTP_PARAM_ADD_IP: > > case SCTP_PARAM_DEL_IP: > > >