From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [PATCH net] net: sctp: fix sctp_connectx abi for ia32 emulation/compat mode Date: Mon, 17 Feb 2014 10:52:20 -0500 Message-ID: <53023034.3090700@gmail.com> References: <1392635471-31528-1-git-send-email-dborkman@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org To: Daniel Borkmann , davem@davemloft.net Return-path: Received: from mail-qc0-f182.google.com ([209.85.216.182]:35913 "EHLO mail-qc0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753688AbaBQPwX (ORCPT ); Mon, 17 Feb 2014 10:52:23 -0500 In-Reply-To: <1392635471-31528-1-git-send-email-dborkman@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On 02/17/2014 06:11 AM, Daniel Borkmann wrote: > SCTP's sctp_connectx() abi breaks for 64bit kernels compiled with 32bit > emulation (e.g. ia32 emulation or x86_x32). Due to internal usage of > 'struct sctp_getaddrs_old' which includes a struct sockaddr pointer, > sizeof(param) check will always fail in kernel as the structure in > 64bit kernel space is 4bytes larger than for user binaries compiled > in 32bit mode. Thus, applications making use of sctp_connectx() won't > be able to run under such circumstances. > > Introduce a compat interface in the kernel to deal with such > situations by using a 'struct compat_sctp_getaddrs_old' structure > where user data is copied into it, and then sucessively transformed > into a 'struct sctp_getaddrs_old' structure with the help of > compat_ptr(). That fixes sctp_connectx() abi without any changes > needed in user space, and lets the SCTP test suite pass when compiled > in 32bit and run on 64bit kernels. > > Fixes: f9c67811ebc0 ("sctp: Fix regression introduced by new sctp_connectx api") > Signed-off-by: Daniel Borkmann Acked-by: Vlad Yasevich -vlad