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=unavailable 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 A057EC433DF for ; Thu, 11 Jun 2020 02:41:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D7FE2074B for ; Thu, 11 Jun 2020 02:41:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mLJu4gXz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726312AbgFKClF (ORCPT ); Wed, 10 Jun 2020 22:41:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726279AbgFKClF (ORCPT ); Wed, 10 Jun 2020 22:41:05 -0400 Received: from mail-qt1-x843.google.com (mail-qt1-x843.google.com [IPv6:2607:f8b0:4864:20::843]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11BF8C08C5C1; Wed, 10 Jun 2020 19:41:05 -0700 (PDT) Received: by mail-qt1-x843.google.com with SMTP id w9so3557998qtv.3; Wed, 10 Jun 2020 19:41:04 -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=wTiC49GnZ5ZEBNWsG/S2XbISpIYn0F/SWZwBLcW/d2A=; b=mLJu4gXzzMsz/IBbFLkr4QLmm3M3YXOfBvk576ubygCcnlm8I9VMZUgkm2nTfQ9ZSD ONnGYD4+rO7gGeX7gzYNjf9AJlKUREeRHxupmKvL6xy8G2MJo5+MSg2AJJvHm7PBeNzz IeQeL7DREZbwLWShJNRz7GZPUGTpCxrGwKej+sZXZXbZzUOIMtY6mPW47SP4TqXFc+4C L6YgVDRl4nKgQw+VztXXtmdyrCv/RRaLDrzANJNs4rx5/Pj2skxlQfTUAX+QTCXmC2IT YOf1XhQG2bPB6GmnYDQ6WwVJ/hLFCD2lVJykV0mYtGmjUNfZY24OwGBVQ2l1DwmoeUr5 bdCw== 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=wTiC49GnZ5ZEBNWsG/S2XbISpIYn0F/SWZwBLcW/d2A=; b=Z1xtnRsdWiiBf7OnZQAuOtZEZK1qWFtGoqDm4x63aXQwvEKd26Ns8ODyu4qOLJth5E Shm8Wx2as5F5pWTugdRsd63u8dVJJ9msmQLFbR2mYkFIq23avKG/iY1LYU22y/phgDXb wzhD32MvmYUkRJXddhnqN8bgUSK18fY3mRVjggNAn175JFlMMM7Ep5FT124+rayc89hv a/NGI3Rq2pNvVRmFndk3rzfbe7ZGNK83OycSj0mJEvWCyGmd2d+dIEkFa/+JQNkc8rml o0mQOg3n9Qto83FkrLuwitKQHkRGxMDAUIiIoXqcS0qzGv88gZF2UNhb0fWxiT8uPYWa lcuQ== X-Gm-Message-State: AOAM530IkyxBMbJSkMhG6VKnd7918D8N8bY8Jitoa5mMnoM/cxdNnu4p b+ylcyWliFrXaa/mWZ+2C3StGxsMjw5YtQ== X-Google-Smtp-Source: ABdhPJwkRdDdS5KBsTGSggDXQTHMfO9ECWm+ZUkwd4fu9vppbYNA0a5kdhFJ44GPc6tARd98iiOkiw== X-Received: by 2002:ac8:6bc6:: with SMTP id b6mr6537003qtt.101.1591843264037; Wed, 10 Jun 2020 19:41:04 -0700 (PDT) Received: from linux.home ([2604:2000:1344:41d:61ac:316c:1207:3fa6]) by smtp.googlemail.com with ESMTPSA id z194sm1265023qkb.73.2020.06.10.19.41.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Jun 2020 19:41:03 -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: Wed, 10 Jun 2020 22:40:36 -0400 Message-Id: <20200611024053.10429-1-gaurav1086@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 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. Signed-off-by: Gaurav Singh --- 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