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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 BBA6AC433E0 for ; Wed, 10 Jun 2020 03:43:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 910B5207ED for ; Wed, 10 Jun 2020 03:43:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bpUMlBXZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726166AbgFJDna (ORCPT ); Tue, 9 Jun 2020 23:43:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725988AbgFJDn2 (ORCPT ); Tue, 9 Jun 2020 23:43:28 -0400 Received: from mail-qv1-xf44.google.com (mail-qv1-xf44.google.com [IPv6:2607:f8b0:4864:20::f44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BE5BC05BD1E; Tue, 9 Jun 2020 20:43:27 -0700 (PDT) Received: by mail-qv1-xf44.google.com with SMTP id dp10so419660qvb.10; Tue, 09 Jun 2020 20:43:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id; bh=qm+oX+JQzV56QUtwpMbMoKGf+j/HM4yHTB8cqsstqTg=; b=bpUMlBXZEXALee+IT7Ke3lzVjM9eFpSHKJPQ7jWtW1ZCSh9fYvzftShwYgAZMP4+gm 72QVGyOnorRDtEdS2pC6xNakGk4m/D1H73P8jO8cJKQslHxveHNTxoqEdaY2E81TTbNF MdB2DWbL/Xctu4oLqLLHa4gjPJT/01rh3q24cPTZuzh5mRamlh9Mmkvn/QewFY1MYRjS PgA2Yk31L5u6bW6HniD3sLa+UE1FnkYNrnLJVFYZ2gq+mOaAXsjbnwvDF71CwSY70hzl Bx0o9ZGqFMVqpNrM6PskLgIh5uDZ5I6UJW2+ZF4DEP8uXqUMK3P7mqz/efZEufNPteWJ Rsdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id; bh=qm+oX+JQzV56QUtwpMbMoKGf+j/HM4yHTB8cqsstqTg=; b=DWcrOFVmYggAjr3h96i6lUX6auT7aTUaiVmfAxj3xQ07+dTwcSC9wuUxRgxXFNNjdM vHLwFjcTP0483cCQ93Q4nTZdDXs15RXkEk37Q8YnSQdMH+hT43QrEav4RQWokEyV8B1q gusFAQMf0KuKXAve03TJSD16f0FyQQS7+XK7nC9PCRCXbSj5He8sDrhsDGq4mNuUWJLE O6G4U17qlG1e2rfJ/Bal4RVLLXhHJ4znLfw2SlNr1V+Gwj9AQTZHqJV/kx4xfPiXxqOJ FqGiKP+Y71w12rexf58Ee9x/miieyvOcGSnJAwoZj1/CPq/sVl/w2wLuN9qsYpHAtB+I fizQ== X-Gm-Message-State: AOAM532VtRLaLwxZLBsl5RK03+/70WatKS5WiBfu8X3lqiYqLLQSC7x+ oDdpo3jTekiXIYDBGUo1NWQ= X-Google-Smtp-Source: ABdhPJxTJl/mAPYn1Zj+USIzItK0bT9+uv/88xJzEVVK2p+GeSYUecA0nOyh7z47J+f44eSXz1U2GA== X-Received: by 2002:ad4:4725:: with SMTP id l5mr1394050qvz.120.1591760605788; Tue, 09 Jun 2020 20:43:25 -0700 (PDT) Received: from linux.home ([2604:2000:1344:41d:29ac:7979:1e2e:c67b]) by smtp.googlemail.com with ESMTPSA id p13sm11195403qke.135.2020.06.09.20.43.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Jun 2020 20:43:25 -0700 (PDT) From: Gaurav Singh To: gaurav1086@gmail.com, Jeff Dike , Richard Weinberger , Anton Ivanov , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , John Fastabend , KP Singh , Alex Dewar , linux-um@lists.infradead.org (open list:USER-MODE LINUX (UML)), linux-kernel@vger.kernel.org (open list), netdev@vger.kernel.org (open list:BPF (Safe dynamic programs and tools)), bpf@vger.kernel.org (open list:BPF (Safe dynamic programs and tools)) Subject: [PATCH] Fix null pointer dereference in vector_user_bpf Date: Tue, 9 Jun 2020 23:43:00 -0400 Message-Id: <20200610034314.9290-1-gaurav1086@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Gaurav Singh The bpf_prog is being checked for !NULL after uml_kmalloc but later its used directly for example: bpf_prog->filter = bpf and is also later returned upon success. Fix this, do a NULL check and return right away. --- arch/um/drivers/vector_user.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c index aa28e9eecb7b..71d043ae306f 100644 --- a/arch/um/drivers/vector_user.c +++ b/arch/um/drivers/vector_user.c @@ -730,10 +730,12 @@ void *uml_vector_user_bpf(char *filename) return false; } bpf_prog = uml_kmalloc(sizeof(struct sock_fprog), UM_GFP_KERNEL); - if (bpf_prog != NULL) { - bpf_prog->len = statbuf.st_size / sizeof(struct sock_filter); - bpf_prog->filter = NULL; + if (bpf_prog == NULL) { + printk(KERN_ERR "Failed to allocate bpf prog buffer"); + return NULL; } + bpf_prog->len = statbuf.st_size / sizeof(struct sock_filter); + bpf_prog->filter = NULL; ffd = os_open_file(filename, of_read(OPENFLAGS()), 0); if (ffd < 0) { printk(KERN_ERR "Error %d opening bpf file", -errno); -- 2.17.1