From patchwork Thu Nov 5 15:56:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anmol Karn X-Patchwork-Id: 1395079 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=CwLJVzbY; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CRp6R0Q4fz9sTL for ; Fri, 6 Nov 2020 02:56:31 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731299AbgKEP42 (ORCPT ); Thu, 5 Nov 2020 10:56:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730973AbgKEP42 (ORCPT ); Thu, 5 Nov 2020 10:56:28 -0500 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12DCDC0613CF; Thu, 5 Nov 2020 07:56:28 -0800 (PST) Received: by mail-pj1-x1044.google.com with SMTP id gi3so289551pjb.3; Thu, 05 Nov 2020 07:56:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=0TyRW4uWJJtZcAW80DlztYPoMgVPukL6fuFYNjjkzDE=; b=CwLJVzbYeqMzwKr8N4c0irQdu/f97dx0RKkTorEdzvvTffs+0V8F7lfwdH4jpz7v0V 4hY8MG81Xn4RgMBDNj5Icl/qMMibAXHmp1sdvvMX4IYVBQ32MFzzbGwAkT/mJhdHZy3L eHToAsxrCiRFUC15wNY0WrGDOavL5b3+xW5jaORefVxjMmZOk9Hka9w8tzBeeuas/jAT htExxA1jMPlWsGImkT25mD8uMsWLarf5hglLSBrLETRPtJiBpRSAZV49spj9nX1XcyUF QDrnaYexaB3zFCCVfGwFS4xNDa47SImXc8JBORQhIHNcQ6BaqZAopm5n30JhAaKZ1F9d 1t3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=0TyRW4uWJJtZcAW80DlztYPoMgVPukL6fuFYNjjkzDE=; b=TRMaNNtxtoxG53Dgj5Qag6eZHZxvF76rFFcZN6jzUWIGos03bN7RyA+FpSgyr5wGAd FqEkvEgxjOHKR+sJSHU4IdQtIQmxVqPfiAR5edx6rT9e5DT1YYHG1i08SoQ30TQmv6xM CUuyvUbtvPdraLCORhMh+KTX2aoUiip3mXDZHsAKAS7m4F7N/HMJrXXszbNyyWEK7R70 llt5mUOJO4RQ0fI3KXWCQJx5poYksV2iGhC32gO5N8q9pOjwzWJm4sf4IxZTjImAFSLa VnKcVtozv7V/9MsQ7zGLAClU4rrwIbzucbneNqYBwOOe6adrzdIMiTX54kkpJ9vlhqC7 nb9Q== X-Gm-Message-State: AOAM5335FtiLpjzoldfRNQ6VLgCgBLJojrV+kAA24hYc36EmK/YPGBt5 OF8qjhJsqm1AbRG2beDRFxisb94gTfuljpNM X-Google-Smtp-Source: ABdhPJwUYkZrB2yh0Ep+0HNwhtXh6FsGHYcWVuYvcSY3LanQmju6FwFNaW+0fMaSheXxulRl4zNhOw== X-Received: by 2002:a17:90a:62c1:: with SMTP id k1mr3093670pjs.135.1604591787299; Thu, 05 Nov 2020 07:56:27 -0800 (PST) Received: from localhost.localdomain ([45.118.167.194]) by smtp.googlemail.com with ESMTPSA id nv5sm2600029pjb.54.2020.11.05.07.56.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2020 07:56:26 -0800 (PST) From: Anmol Karn To: ralf@linux-mips.org, davem@davemloft.net, kuba@kernel.org Cc: 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, anmol.karan123@gmail.com, syzbot+a1c743815982d9496393@syzkaller.appspotmail.com Subject: [Linux-kernel-mentees] [PATCH v2 net] rose: Fix Null pointer dereference in rose_send_frame() Date: Thu, 5 Nov 2020 21:26:00 +0530 Message-Id: <20201105155600.9711-1-anmol.karan123@gmail.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org rose_send_frame() dereferences `neigh->dev` when called from rose_transmit_clear_request(), and the first occurance 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(). Reported-and-tested-by: syzbot+a1c743815982d9496393@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=9d2a7ca8c7f2e4b682c97578dfa3f236258300b3 Signed-off-by: Anmol Karn --- net/rose/rose_loopback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/rose/rose_loopback.c b/net/rose/rose_loopback.c index 7b094275ea8b..cd7774cb1d07 100644 --- a/net/rose/rose_loopback.c +++ b/net/rose/rose_loopback.c @@ -96,7 +96,7 @@ static void rose_loopback_timer(struct timer_list *unused) } if (frametype == ROSE_CALL_REQUEST) { - if ((dev = rose_dev_get(dest)) != NULL) { + if (rose_loopback_neigh->dev && (dev = rose_dev_get(dest)) != NULL) { if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) kfree_skb(skb); } else {