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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,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 E155CC2D0E4 for ; Fri, 20 Nov 2020 18:06:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6A9FC2245A for ; Fri, 20 Nov 2020 18:06:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="KYlbryWp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729625AbgKTSGP (ORCPT ); Fri, 20 Nov 2020 13:06:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:41418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728988AbgKTSGO (ORCPT ); Fri, 20 Nov 2020 13:06:14 -0500 Received: from kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com (unknown [163.114.132.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 866A22240B; Fri, 20 Nov 2020 18:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605895574; bh=5QsJhiNlDYF6e5+XXwRtT9R/LRbCv501uDAH0fgcN0Q=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=KYlbryWpufKcNB1iYssy8CcD1+/3Gqqh2EdgFmZ9rTm6f4AXmNUy1gjQvi6APx9PN r1AmcaO7XP5Y1fOxjaLen/tWVjpFkEzsN+vCD9HbgGQJ5gIbMizYt3/SxLds3QVXjh 6sY9n3QbkPvlEyGj3Ok3Z22jd+4VvnGPpHqfme3w= Date: Fri, 20 Nov 2020 10:06:12 -0800 From: Jakub Kicinski To: Anmol Karn Cc: ralf@linux-mips.org, davem@davemloft.net, saeed@kernel.org, gregkh@linuxfoundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hams@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, syzkaller-bugs@googlegroups.com, syzbot+a1c743815982d9496393@syzkaller.appspotmail.com Subject: Re: [Linux-kernel-mentees] [PATCH v5 net] rose: Fix Null pointer dereference in rose_send_frame() Message-ID: <20201120100612.62d9d770@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20201119191043.28813-1-anmol.karan123@gmail.com> References: <20201115114448.GA40574@Thinkpad> <20201119191043.28813-1-anmol.karan123@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Nov 2020 00:40:43 +0530 Anmol Karn wrote: > rose_send_frame() dereferences `neigh->dev` when called from > rose_transmit_clear_request(), and the first occurrence of the > `neigh` is in rose_loopback_timer() as `rose_loopback_neigh`, > and it is initialized in rose_add_loopback_neigh() as NULL. > i.e when `rose_loopback_neigh` used in rose_loopback_timer() > its `->dev` was still NULL and rose_loopback_timer() was calling > rose_rx_call_request() without checking for NULL. > > - net/rose/rose_link.c > This bug seems to get triggered in this line: > > rose_call = (ax25_address *)neigh->dev->dev_addr; > > Fix it by adding NULL checking for `rose_loopback_neigh->dev` > in rose_loopback_timer(). > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Suggested-by: Jakub Kicinski > Reported-by: syzbot+a1c743815982d9496393@syzkaller.appspotmail.com > Tested-by: syzbot+a1c743815982d9496393@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?id=9d2a7ca8c7f2e4b682c97578dfa3f236258300b3 > Signed-off-by: Anmol Karn Applied to net, thanks!