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=-14.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 9759CC432BE for ; Mon, 9 Aug 2021 11:50:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7413560EFF for ; Mon, 9 Aug 2021 11:50:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234546AbhHILvE (ORCPT ); Mon, 9 Aug 2021 07:51:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234295AbhHILvC (ORCPT ); Mon, 9 Aug 2021 07:51:02 -0400 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBC24C0613D3; Mon, 9 Aug 2021 04:50:41 -0700 (PDT) Received: by mail-pj1-x1031.google.com with SMTP id s22-20020a17090a1c16b0290177caeba067so34110367pjs.0; Mon, 09 Aug 2021 04:50:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=lEzRqawbCO3Oz7zqhJzZDzxmM9xxyvbKbGJKK51n77s=; b=CGGbHiQxQHOtVwEfubzZ9ceQPWqmETo95FQMcSqJ0TCV2NzJ9F0fuC3wm/RCnSVZRG Z5wfMX20T4zAnugcvmObELxDMvAfiA9i05R3D86KdMluIyMeW7LNQ7qDLkiZGME09a+n /qspJvkO+BTbNWqmzQqscmIVX799p/dhOPaHU9sg4Ev+7YK54vf4byFGi7Idl0ioojXN +c3GokUwZvjCMXT4CFAFbtPnB6Hak/lmGqHob1fNDdTCHPN1n6Y9rAcDfX4xy3k+eV1J tkXE1oibwbxSXIyroWAAjsNdKB0kvGXA4l2ghjQisC/7svtWGQSnq7O97HsqM+P3aNba ovxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=lEzRqawbCO3Oz7zqhJzZDzxmM9xxyvbKbGJKK51n77s=; b=A97jSCOkVTzJB3GNNsADe4xz+yuX/nmKbigmMzHf909KxQdnuJus0AHSzM3/61bWmv O5Aa0wxCQuOF7r2m1gVMWs4xDIHtP3jTOLfepLZs+NG4N+ssB5f7Gi1iy1r/vVqAXc69 uKn+/hSHni0nqKaI5QjE1VPa9OdPujhmyHdnrYeumO8D5K8pVIwdusbjglapT2VDBDvq K/2cQSqPabn/gOrX8/2Wg80YJHuO8Ilw4jYuOVTz/BcckCXT0Eh+jglPfWHZhPtI1gYX ZSJaRDy4Q9zvE0X9qw779Cqzi6EjVjnv3xi0N6sV9Kt7zXhk+jdKVVYmm6Av95QoIf7H iMMQ== X-Gm-Message-State: AOAM533/mHWAHH0uRzB90rbjosJ8cDt51kYcTbGBv+7yzAgISvvn0qbh Alyr0G1zB8AWkamDI17hMiY= X-Google-Smtp-Source: ABdhPJxJrRwYquMEhsP80YPY2COvRlMDmLJN3BmTl+5y3TJFofzDG7vEJ3GquXp8SItJi85ZD/nmGw== X-Received: by 2002:a17:902:c641:b029:12c:ef04:fa86 with SMTP id s1-20020a170902c641b029012cef04fa86mr9762891pls.40.1628509841418; Mon, 09 Aug 2021 04:50:41 -0700 (PDT) Received: from [10.177.0.134] ([85.203.23.214]) by smtp.gmail.com with ESMTPSA id z16sm22469492pgu.21.2021.08.09.04.50.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Aug 2021 04:50:41 -0700 (PDT) Subject: Re: [PATCH] scsi: target: pscsi: Fix possible null-pointer dereference in pscsi_complete_cmd() To: Bodo Stroesser Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com, TOTE Robot , martin.petersen@oracle.com References: <20210807134651.245436-1-islituo@gmail.com> From: Tuo Li Message-ID: <7c6622d0-2f28-27a7-250e-9a8fd79691a8@gmail.com> Date: Mon, 9 Aug 2021 19:50:37 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thanks for your feedback. We will prepare a V2 patch and put the transport_kunmap_data_sg() into the else-branch of the if (!buf). Best wishes, Tuo Li On 2021/8/9 18:36, Bodo Stroesser wrote: > On 07.08.21 15:46, Tuo Li wrote: >> The return value of transport_kmap_data_sg() is assigned to the variable >> buf: >>    buf = transport_kmap_data_sg(cmd); >> >> And then it is checked: >>    if (!buf) { >> >> This indicates that buf can be NULL. However, it is dereferenced in the >> following statements: >>    if (!(buf[3] & 0x80)) >>      buf[3] |= 0x80; >>    if (!(buf[2] & 0x80)) >>     buf[2] |= 0x80; >> >> To fix these possible null-pointer dereferences, dereference buf only >> when >> it is not NULL. >> >> Reported-by: TOTE Robot >> Signed-off-by: Tuo Li >> --- >>   drivers/target/target_core_pscsi.c | 14 +++++++------- >>   1 file changed, 7 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/target/target_core_pscsi.c >> b/drivers/target/target_core_pscsi.c >> index 2629d2ef3970..560815729182 100644 >> --- a/drivers/target/target_core_pscsi.c >> +++ b/drivers/target/target_core_pscsi.c >> @@ -620,14 +620,14 @@ static void pscsi_complete_cmd(struct se_cmd >> *cmd, u8 scsi_status, >>               buf = transport_kmap_data_sg(cmd); >>               if (!buf) { >>                   ; /* XXX: TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE */ >> -            } >> - >> -            if (cdb[0] == MODE_SENSE_10) { >> -                if (!(buf[3] & 0x80)) >> -                    buf[3] |= 0x80; >>               } else { >> -                if (!(buf[2] & 0x80)) >> -                    buf[2] |= 0x80; >> +                if (cdb[0] == MODE_SENSE_10) { >> +                    if (!(buf[3] & 0x80)) >> +                        buf[3] |= 0x80; >> +                } else { >> +                    if (!(buf[2] & 0x80)) >> +                        buf[2] |= 0x80; >> +                } >>               } >>                 transport_kunmap_data_sg(cmd); >> > > I'm wondering whether we should better put the > transport_kunmap_data_sg into the else-branch of the if (!buf)? > AFAICS, calling it after transport_kmap_data_sg failed does not > cause problems, but I feel it would be cleaner. > > Otherwise it looks good to me.