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=-13.1 required=3.0 tests=BAYES_00,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,URIBL_BLOCKED,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 A38B4C433E4 for ; Tue, 14 Jul 2020 18:10:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8605E20825 for ; Tue, 14 Jul 2020 18:10:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="WsiJGXVq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729003AbgGNSK2 (ORCPT ); Tue, 14 Jul 2020 14:10:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728301AbgGNSK2 (ORCPT ); Tue, 14 Jul 2020 14:10:28 -0400 Received: from mail-qt1-x841.google.com (mail-qt1-x841.google.com [IPv6:2607:f8b0:4864:20::841]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E26A9C061755; Tue, 14 Jul 2020 11:10:27 -0700 (PDT) Received: by mail-qt1-x841.google.com with SMTP id u12so13508019qth.12; Tue, 14 Jul 2020 11:10:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ZX4l9y/mb02MIUOaKSz1lj12ECx0wlEAm51QAfF6o/8=; b=WsiJGXVqDNs9WargJT52mvIz/gaCVCuxb52bFJeFukAYzSUEIh2fdlkQeVqeuWbB0D Bzbqn0r0doaRe/L6ZZIb3zStjHYGZ8RF2beyf9yjYgP8agdHAl0PAiSbAO4euheDv12l 8btObml9Y9hX6nYx8w01Xl2cH7DSo25hPOO4FJFsbXHDRP0OEfMtN0dqr2T/CmkEn3QC pOonLTv9BirBHzAunpzAGUXm4OHH4ctLfxxq13swaSMV/LTuMoEKHkYbwWJA0nb4jEM7 7Ke2VPeIG86ZGrJ4GX1h39LqB8Ud3pcWPrGhbq8RY+MWZ+rPqXoJNibnsLvzBSqf90bk QeSw== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=ZX4l9y/mb02MIUOaKSz1lj12ECx0wlEAm51QAfF6o/8=; b=WK71pxN91y9WAgxJ1Gm/yHPuW91KAmwbGJnGDseTNRa445SVDVBhAkkW8sVHRLEuPd SqHZ6F97P7CCk6BtDSbH0NQf04eR3vgRUIbOywAa4pXh1KlQTjkqVGgTpDQbL47RKlvS 9RzOi9xVrEuuTtKMQPDlK2j0IXWhn3jId1uOA/im9vxzPpCgEbdBn9EyQ2PVSM0NYpFM e1NDWJVwCouTeWhVbSUOmnx2YFIrBb5U34ntq4uUa8HThl/zddlkzNBSY7zf+cDPwT4e me+k/BLRReO0VbQwlO/VC41qwiRLj2XJFDD1r4a70o8mL8JeMs+DDQ4kMCLIjSJpspk4 JCww== X-Gm-Message-State: AOAM530SlVMg0pF7ewMbMJLxRkYDhfv+nxzPBG+E1DMbXlbzwSW5RVCB v9i7lTg3ntGGtIix6rhL4w== X-Google-Smtp-Source: ABdhPJzIfX8uNaGelEtus3hlnEHUAzJCj9p6MTHvuiHUjgC4AFO0/AIzEJVEUS+Rr3I8EFtZYkxMRQ== X-Received: by 2002:ac8:3028:: with SMTP id f37mr5775930qte.351.1594750226967; Tue, 14 Jul 2020 11:10:26 -0700 (PDT) Received: from localhost.localdomain ([209.94.141.207]) by smtp.gmail.com with ESMTPSA id n64sm22663726qke.77.2020.07.14.11.10.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jul 2020 11:10:26 -0700 (PDT) From: Peilin Ye To: Andrii Nakryiko , Alexei Starovoitov Cc: Peilin Ye , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Greg Kroah-Hartman , netdev@vger.kernel.org, bpf@vger.kernel.org, syzkaller-bugs@googlegroups.com, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [Linux-kernel-mentees] [PATCH v3] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() Date: Tue, 14 Jul 2020 14:09:04 -0400 Message-Id: <20200714180904.277512-1-yepeilin.cs@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux` as NULL. This patch fixes the following syzbot bug: https://syzkaller.appspot.com/bug?id=f823224ada908fa5c207902a5a62065e53ca0fcc Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com Signed-off-by: Peilin Ye --- Sorry, I got the link wrong. Thank you for pointing that out. Change in v3: - Fix incorrect syzbot dashboard link. Change in v2: - Split NULL and IS_ERR cases. kernel/bpf/btf.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 30721f2c2d10..092116a311f4 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4088,6 +4088,11 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn, const char *tname, *sym; u32 btf_id, i; + if (!btf_vmlinux) { + bpf_log(log, "btf_vmlinux doesn't exist\n"); + return -EINVAL; + } + if (IS_ERR(btf_vmlinux)) { bpf_log(log, "btf_vmlinux is malformed\n"); return -EINVAL; -- 2.25.1