From patchwork Fri Aug 20 03:28:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 12448331 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 7BF16C4320A for ; Fri, 20 Aug 2021 03:30:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6469A610F9 for ; Fri, 20 Aug 2021 03:30:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238342AbhHTDam (ORCPT ); Thu, 19 Aug 2021 23:30:42 -0400 Received: from esa3.hgst.iphmx.com ([216.71.153.141]:4898 "EHLO esa3.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238210AbhHTDal (ORCPT ); Thu, 19 Aug 2021 23:30:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1629430202; x=1660966202; h=from:to:subject:date:message-id:in-reply-to:references: mime-version:content-transfer-encoding; bh=1TkJ3vB1HtpkRnuxbMMe1MIpNKIlZkwUFRryFfPqUdA=; b=aCHlKt3usPvjS033+66h8UWDy2vNHu1U5idxOMr3dI4mrZAuTDjomsPC Pd9+mgWB91a2WMzpuqN5a8K4ezP0Z1aU+A78iGE7EMBVxGZrEAihnvdVf EGV+a92nZvAtzgRGI26BeUY9enJddpYovmNWhDfWWE4B+3/gfYVV3NCA+ Ht7Xz7H98jWS/GgRkqKBOiTDf2PVz/VxKw75u00Rr9rjDmpisVU+n2O1c qLQb4ZWYgXxGqJkEagkGPUkQ9QbaYVVX24jBW+ug5xO2FwjXS/HPDeq9L OIY09eq7DUNdPpADIPLJw2vFoclX2nlagSMYWVUUvv15R0Cy5PEZTKBY7 w==; X-IronPort-AV: E=Sophos;i="5.84,336,1620662400"; d="scan'208";a="182646445" Received: from h199-255-45-15.hgst.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 20 Aug 2021 11:30:01 +0800 IronPort-SDR: GpnjGQ/NQXkCwtvyocQ7MJCikbqV47qpa5GCeIEJUkkt4I2ZXK/ENIUUQnvnYX0K40HkBeDrJK 1nvHdHY2yDOkdT4ZZX8je8AytmqOhSIQkds7235iTc5QPtsMKyKZ53agPVKDa1z3C5LX7h6aRc jJSfpmiAB/+pF4pbGIa1z/sN5t4u5FzG/4nzf+GUlaie1gcYOqo8ytf7Wc8aJm7ZaDKyNLXP2j A6HuaT1xxu0mdCmX9UwSLRK6ZNyt9TSaO/N8InO/L0zac4snwdqIIfx1YqNW3/YCkWryThptR4 3NcK2rOPYMNU8i71ppxA5sEn Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Aug 2021 20:05:23 -0700 IronPort-SDR: W7KegB0CKiaZ92/5JDOsTKfvJ7KW32Qce4+i2lR4zcdjNvTaSv2iV6T0XXgdyuOZQekoSBYLi2 bLYlzSTlRXP7CSEbMaXfkVqq6d9Z6m57xFTKTJWappjKrdzbFvOPGn2CRb1W4gIsskqg/CVH6Y X+w92GTFCUyNIliSG4UeNAOoJI3r0trcGyzVOOTtNrXQfF9dHG1ais+su7SufXZnqUYD5Fhr2I 3DqXnUhfyWEDVOnEs+j20snvE6PnzFhp9KA4XVJzA3n+ZqnFrokUmyZfHNbvrXIjto08DBlAAY VNQ= WDCIronportException: Internal Received: from washi.fujisawa.hgst.com ([10.149.53.254]) by uls-op-cesaip02.wdc.com with ESMTP; 19 Aug 2021 20:30:02 -0700 From: Damien Le Moal To: linux-scsi@vger.kernel.org, "Martin K . Petersen" Subject: [PATCH v2 1/2] scsi: fix scsi_mode_sense() buffer length handling Date: Fri, 20 Aug 2021 12:28:12 +0900 Message-Id: <20210820032813.575032-2-damien.lemoal@wdc.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210820032813.575032-1-damien.lemoal@wdc.com> References: <20210820032813.575032-1-damien.lemoal@wdc.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Several problems exist with scsi_mode_sense() buffer length handling: 1) The allocation length field of the MODE SENSE 10 command is 16-bits, occupying bytes 7 and 8 of the CDB. With this command, access to mode pages larger than 255 bytes is thus possible. However, the CDB allocation length field is set by assigning len to byte 8 only, thus truncating buffer length larger than 255. 2) If scsi_mode_sense() is called with len smaller than 8 with sdev->use_10_for_ms set, or smaller than 4 otherwise, the buffer length is increased to 8 and 4 respectively, and the buffer is zero filled with these increased values, thus corrupting the memory following the buffer. Fix these 2 problems by using put_unaligned_be16() to set the allocation length field of MODE SENSE 10 CDB and by returning an error when len is too small. Furthermore, if len is larger than 255B, always try MODE SENSE 10 first, even if the device driver did not set sdev->use_10_for_ms. In case of invalid opcode error for MODE SENSE 10, access to mode pages larger than 255 bytes are not retried using MODE SENSE (6). To avoid buffer length overflows for the MODE_SENSE 10 case, check that len is smaller than 65535 bytes While at it, also fix the folowing: * use get_unaligned_be16() to retrieve the mode data length and block descriptor length fields of the mode sense reply header instead of using an open coded calculation. * Fix the kdoc dbd argument explanation: the DBD bit stands for Disable Block Descriptor, which is the opposite of what the dbd argument description was. Signed-off-by: Damien Le Moal --- drivers/scsi/scsi_lib.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 572673873ddf..327ea74a5e31 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2075,7 +2075,7 @@ EXPORT_SYMBOL_GPL(scsi_mode_select); /** * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. * @sdev: SCSI device to be queried - * @dbd: set if mode sense will allow block descriptors to be returned + * @dbd: set to prevent mode sense from returning block descriptors * @modepage: mode page being requested * @buffer: request buffer (may not be smaller than eight bytes) * @len: length of request buffer. @@ -2110,18 +2110,18 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, sshdr = &my_sshdr; retry: - use_10_for_ms = sdev->use_10_for_ms; + use_10_for_ms = sdev->use_10_for_ms || len > 255; if (use_10_for_ms) { - if (len < 8) - len = 8; + if (len < 8 || len > 65535) + return -EINVAL; cmd[0] = MODE_SENSE_10; - cmd[8] = len; + put_unaligned_be16(len, &cmd[7]); header_length = 8; } else { if (len < 4) - len = 4; + return -EINVAL; cmd[0] = MODE_SENSE; cmd[4] = len; @@ -2145,9 +2145,15 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, if ((sshdr->sense_key == ILLEGAL_REQUEST) && (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { /* - * Invalid command operation code + * Invalid command operation code: retry using + * MODE SENSE (6) if this was a MODE SENSE 10 + * request, except if the request mode page is + * too large for MODE SENSE single byte + * allocation length field. */ if (use_10_for_ms) { + if (len > 255) + return -EIO; sdev->use_10_for_ms = 0; goto retry; } @@ -2171,12 +2177,11 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, data->longlba = 0; data->block_descriptor_length = 0; } else if (use_10_for_ms) { - data->length = buffer[0]*256 + buffer[1] + 2; + data->length = get_unaligned_be16(&buffer[0]) + 2; data->medium_type = buffer[2]; data->device_specific = buffer[3]; data->longlba = buffer[4] & 0x01; - data->block_descriptor_length = buffer[6]*256 - + buffer[7]; + data->block_descriptor_length = get_unaligned_be16(&buffer[6]); } else { data->length = buffer[0] + 1; data->medium_type = buffer[1];