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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 7C60FC433E0 for ; Tue, 16 Jun 2020 16:29:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5E3FC2067B for ; Tue, 16 Jun 2020 16:29:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GJwhOaQi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730772AbgFPQ3d (ORCPT ); Tue, 16 Jun 2020 12:29:33 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:20480 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729167AbgFPQ3c (ORCPT ); Tue, 16 Jun 2020 12:29:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592324971; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=ERS+2jm6G8eP/qULDs3m7N2SVMVdN3wgBEZ1bGF0bCo=; b=GJwhOaQikhXtysH/NS7mbXP9OfTntFuj1SJnUQRfI4GDpXUxFW8wMghEkv/mtyEXMbnkW6 XQHY2uBiYm1NgD4YpTjR6giU8bP//agf6gouM9YjV0kggyqLi8RFOSpkSFTJy70jTJzGMK YyQssgs5enAo+J2EPi3v4z6l+6d2K8Y= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-248-zNuL0vdFNUqbkyb_V-IyEA-1; Tue, 16 Jun 2020 12:29:28 -0400 X-MC-Unique: zNuL0vdFNUqbkyb_V-IyEA-1 Received: by mail-qk1-f199.google.com with SMTP id a6so17229786qka.9 for ; Tue, 16 Jun 2020 09:29:28 -0700 (PDT) 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; bh=ERS+2jm6G8eP/qULDs3m7N2SVMVdN3wgBEZ1bGF0bCo=; b=Ht1updz+t5OkFY3Wg7VvZGvBpL25TU4uF1KQZnz+9t61ujY5v7rFVVc6X9OmisJ2qd KPQHcU0Z/5NA3yjVs+0AIs+56qkDxvOm4isOzAxS7qL0XhU/IbPWGluggd8As9ehhmmT 74w62XOZTElnRNzm7FN4AdxUPAsfSXqDa0LcVdRAtWmErW3Mll5r34eqKag31IrDsMG3 4tLDaVDs8W00NHfO6ZtCcmJ5apXK6mpfLlGqw/8dOrV1dyPCzZr2jDo0WOdd/WfvHKxZ uvqL46usTgTNHV93y/qbgNH/tEecUDPijTvbklg66TSWvVNJoIJHB/2aW7R4VsLdIIQE 2DKA== X-Gm-Message-State: AOAM533lkGrqzHf7seZHvkbQ+Zlj0LwMXcs+41ZtUhhXXI7doTrL/Mp0 Si/bgdchkovYeicoYU+DXnbsmDJEKKjMlZd7YVMbO4HdstTkDpGWVW1DsNyr9yvuky7zlCoUMa9 l0BkZe9z6EdQJZ3DWT7DDfPCp X-Received: by 2002:a0c:8d46:: with SMTP id s6mr3143588qvb.241.1592324968288; Tue, 16 Jun 2020 09:29:28 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwPiCjs+KhSMorb/vjtXy68V8lc6ZAVuWB3rMp3H4SFEqGWmHFi/pfLbhMXeynTHXZQduXSUA== X-Received: by 2002:a0c:8d46:: with SMTP id s6mr3143579qvb.241.1592324968089; Tue, 16 Jun 2020 09:29:28 -0700 (PDT) Received: from trix.remote.csb (075-142-250-213.res.spectrum.com. [75.142.250.213]) by smtp.gmail.com with ESMTPSA id s42sm16386942qtk.14.2020.06.16.09.29.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jun 2020 09:29:27 -0700 (PDT) From: trix@redhat.com To: hirofumi@mail.parknet.co.jp Cc: linux-kernel@vger.kernel.org, Tom Rix Subject: [PATCH] fat: add a check to fat_add_new_entries Date: Tue, 16 Jun 2020 09:29:22 -0700 Message-Id: <20200616162922.26168-1-trix@redhat.com> X-Mailer: git-send-email 2.18.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tom Rix Clang static analysis reports a possible null pointer dereference fs/fat/dir.c:1255:9: warning: Dereference of undefined pointer value [core.NullDereference] memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy); ^~~~~~~~~~~~~~ This is because setting of bhs[n] depends on the inner loop executing. So add a check that the inner loop will be executed. Signed-off-by: Tom Rix --- fs/fat/dir.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/fat/dir.c b/fs/fat/dir.c index b4ddf48fa444..3eea540486cb 100644 --- a/fs/fat/dir.c +++ b/fs/fat/dir.c @@ -1228,6 +1228,13 @@ static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots, do { start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]); last_blknr = start_blknr + sbi->sec_per_clus; + + /* overflow */ + if (unlikely(last_blknr <= start_blknr)) { + err = -ENOMEM; + goto error_nomem; + } + while (blknr < last_blknr) { bhs[n] = sb_getblk(sb, blknr); if (!bhs[n]) { -- 2.18.1