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=-8.1 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_SANE_1 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 B954FC7618B for ; Mon, 29 Jul 2019 11:51:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C5D5206BA for ; Mon, 29 Jul 2019 11:51:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="o3Tcex77" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387840AbfG2Lva (ORCPT ); Mon, 29 Jul 2019 07:51:30 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:38825 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387482AbfG2Lva (ORCPT ); Mon, 29 Jul 2019 07:51:30 -0400 Received: by mail-pl1-f195.google.com with SMTP id az7so27408357plb.5; Mon, 29 Jul 2019 04:51:29 -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=WqRMMRupBKE7/qZ1bepdmX1qSW8ae9qt5Rfev+leb0o=; b=o3Tcex775jyj393JOvhgfSQii40lor3lqmNDKnKYrp4RyejYNoFeZbb8c+8pHt4RUG mB6AxYPQvl7abU759YyuyhcmO5iL9CsftWKLqXLuZ+S+1GPKKB34WV/RuoFQFOEVbtCl ADt6brn5ZQXcjAG8WBkjUJ5DanrJmS8CEQ1YB5Kd2yIM6RdocFKPgm8hayCic59SN1NX sMca4fzw6Dy1UYzEsTTAOO5yFzj8bkDh902E2aNoZpDIoZA/4pw0hC+g6NH3cIyrEjCN CdaXtKIq5jL3Enwq94oGP4JwHwlboX/YjQMY1pDRMJvNLeOJaoDblYQy5h+WpCFcpYFu Ulcw== 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=WqRMMRupBKE7/qZ1bepdmX1qSW8ae9qt5Rfev+leb0o=; b=F0w+F5xlo06yYxujSZGfIi3Bn5zYNp7dagM6Xv6S4Hi8oiTnTU0F5GsPoM6fR8tdOv M8c8jS1XK31KYhnj5t2pBOANZ+L/BRMBmHq2+U1CIiZ8QvdzDQYPaOGNzZHweHn61gFF CxjIx07hXzzvZVaL1tJDRGtLEB7lDGsjPGU9c0JJbLwkOjI6BrT76N3/jHAd9/g2Mhwp 4LXB7edcxt7QTR32528NK7mdd2Q6v2r6Lc1Wap+Zv//Ua/S81VKkqWa+cRT7MobSe4ls jo3Cx/lJ2GLo7N+ZqRbGdmb2IIb+vAIWHZ19FUT5/vy5t/e3CE+/q2kUkh9VUOXS+TMD 7vgw== X-Gm-Message-State: APjAAAXvQ8TrmEqZErZpOJe4JmEullBLJA6Q1Iv2k6TBq/QBOpaKwH0F SWmUwPxrHGSD8uvorD8GL5ZRqu0AkMw= X-Google-Smtp-Source: APXvYqxoLosNXhTxkQU9yUOK5c7Ht5RUsb+YjkuU+pomYjU99vvynJxGwZxviUZ+S7Apez3HVTQGyw== X-Received: by 2002:a17:902:9349:: with SMTP id g9mr107924212plp.262.1564401089268; Mon, 29 Jul 2019 04:51:29 -0700 (PDT) Received: from ?IPv6:2402:f000:4:72:808::177e? ([2402:f000:4:72:808::177e]) by smtp.gmail.com with ESMTPSA id h11sm62244985pfn.120.2019.07.29.04.51.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 29 Jul 2019 04:51:28 -0700 (PDT) Subject: Re: [PATCH v2] usb: storage: sddr55: Fix a possible null-pointer dereference in sddr55_transport() To: stern@rowland.harvard.edu, gregkh@linuxfoundation.org, Oliver Neukum Cc: linux-usb@vger.kernel.org, usb-storage@lists.one-eyed-alien.net, linux-kernel@vger.kernel.org References: <20190729114936.6103-1-baijiaju1990@gmail.com> From: Jia-Ju Bai Message-ID: Date: Mon, 29 Jul 2019 19:51:29 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190729114936.6103-1-baijiaju1990@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sorry, I forgot to send to Oliver, so send it again. On 2019/7/29 19:49, Jia-Ju Bai wrote: > In sddr55_transport(), there is an if statement on line 836 to check > whether info->lba_to_pba is NULL: > if (info->lba_to_pba == NULL || ...) > > When info->lba_to_pba is NULL, it is used on line 948: > pba = info->lba_to_pba[lba]; > > Thus, a possible null-pointer dereference may occur. > > To fix this bug, info->lba_to_pba is checked before being used. > > This bug is found by a static analysis tool STCheck written by us. > > Signed-off-by: Jia-Ju Bai > --- > v2: > * Avoid uninitialized access of pba. > Thank Oliver for helpful advice. > > --- > drivers/usb/storage/sddr55.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/storage/sddr55.c b/drivers/usb/storage/sddr55.c > index b8527c55335b..d23aff16091e 100644 > --- a/drivers/usb/storage/sddr55.c > +++ b/drivers/usb/storage/sddr55.c > @@ -945,7 +945,7 @@ static int sddr55_transport(struct scsi_cmnd *srb, struct us_data *us) > return USB_STOR_TRANSPORT_FAILED; > } > > - pba = info->lba_to_pba[lba]; > + pba = info->lba_to_pba ? info->lba_to_pba[lba] : 0; > > if (srb->cmnd[0] == WRITE_10) { > usb_stor_dbg(us, "WRITE_10: write block %04X (LBA %04X) page %01X pages %d\n",