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=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 7739DC433DF for ; Thu, 23 Jul 2020 00:57:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60DD520825 for ; Thu, 23 Jul 2020 00:57:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387424AbgGWA5R (ORCPT ); Wed, 22 Jul 2020 20:57:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728607AbgGWA5Q (ORCPT ); Wed, 22 Jul 2020 20:57:16 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82323C0619DC; Wed, 22 Jul 2020 17:57:16 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (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 DDCEB126ABE80; Wed, 22 Jul 2020 17:40:29 -0700 (PDT) Date: Wed, 22 Jul 2020 17:57:14 -0700 (PDT) Message-Id: <20200722.175714.1713497446730685740.davem@davemloft.net> To: yepeilin.cs@gmail.com Cc: jreuter@yaina.de, ralf@linux-mips.org, gregkh@linuxfoundation.org, syzkaller-bugs@googlegroups.com, linux-kernel-mentees@lists.linuxfoundation.org, kuba@kernel.org, linux-hams@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [Linux-kernel-mentees] [PATCH net] AX.25: Fix out-of-bounds read in ax25_connect() From: David Miller In-Reply-To: <20200722151901.350003-1-yepeilin.cs@gmail.com> References: <20200722151901.350003-1-yepeilin.cs@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.3 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]); Wed, 22 Jul 2020 17:40:30 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Peilin Ye Date: Wed, 22 Jul 2020 11:19:01 -0400 > Checks on `addr_len` and `fsa->fsa_ax25.sax25_ndigis` are insufficient. > ax25_connect() can go out of bounds when `fsa->fsa_ax25.sax25_ndigis` > equals to 7 or 8. Fix it. > > This issue has been reported as a KMSAN uninit-value bug, because in such > a case, ax25_connect() reaches into the uninitialized portion of the > `struct sockaddr_storage` statically allocated in __sys_connect(). > > It is safe to remove `fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS` because > `addr_len` is guaranteed to be less than or equal to > `sizeof(struct full_sockaddr_ax25)`. > > Reported-by: syzbot+c82752228ed975b0a623@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?id=55ef9d629f3b3d7d70b69558015b63b48d01af66 > Signed-off-by: Peilin Ye Applied and queued up for -stable, thanks.