From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82032C43381 for ; Tue, 2 Apr 2019 01:09:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52F1B206B6 for ; Tue, 2 Apr 2019 01:09:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728657AbfDBBJR (ORCPT ); Mon, 1 Apr 2019 21:09:17 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:41014 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726072AbfDBBJR (ORCPT ); Mon, 1 Apr 2019 21:09:17 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id E4740133E975F; Mon, 1 Apr 2019 18:09:16 -0700 (PDT) Date: Mon, 01 Apr 2019 18:09:16 -0700 (PDT) Message-Id: <20190401.180916.964654086564122108.davem@davemloft.net> To: lucien.xin@gmail.com Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org, marcelo.leitner@gmail.com, nhorman@tuxdriver.com, syzkaller@googlegroups.com Subject: Re: [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 01 Apr 2019 18:09:17 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Xin Long Date: Sun, 31 Mar 2019 16:58:15 +0800 > Syzbot report a kernel-infoleak: > > BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32 > Call Trace: > _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32 > copy_to_user include/linux/uaccess.h:174 [inline] > sctp_getsockopt_peer_addrs net/sctp/socket.c:5911 [inline] > sctp_getsockopt+0x1668e/0x17f70 net/sctp/socket.c:7562 > ... > Uninit was stored to memory at: > sctp_transport_init net/sctp/transport.c:61 [inline] > sctp_transport_new+0x16d/0x9a0 net/sctp/transport.c:115 > sctp_assoc_add_peer+0x532/0x1f70 net/sctp/associola.c:637 > sctp_process_param net/sctp/sm_make_chunk.c:2548 [inline] > sctp_process_init+0x1a1b/0x3ed0 net/sctp/sm_make_chunk.c:2361 > ... > Bytes 8-15 of 16 are uninitialized > > It was caused by that th _pad field (the 8-15 bytes) of a v4 addr (saved in > struct sockaddr_in) wasn't initialized, but directly copied to user memory > in sctp_getsockopt_peer_addrs(). > > So fix it by calling memset(addr->v4.sin_zero, 0, 8) to initialize _pad of > sockaddr_in before copying it to user memory in sctp_v4_addr_to_user(), as > sctp_v6_addr_to_user() does. > > Reported-by: syzbot+86b5c7c236a22616a72f@syzkaller.appspotmail.com > Signed-off-by: Xin Long Applied and queued up for -stable, thanks Xin!