From patchwork Fri Aug 20 07:02:53 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: 12448531 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 DBAE6C4338F for ; Fri, 20 Aug 2021 07:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C17036056C for ; Fri, 20 Aug 2021 07:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238725AbhHTHFg (ORCPT ); Fri, 20 Aug 2021 03:05:36 -0400 Received: from esa3.hgst.iphmx.com ([216.71.153.141]:20629 "EHLO esa3.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238427AbhHTHFa (ORCPT ); Fri, 20 Aug 2021 03:05:30 -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=1629443092; x=1660979092; h=from:to:subject:date:message-id:in-reply-to:references: mime-version:content-transfer-encoding; bh=1TkJ3vB1HtpkRnuxbMMe1MIpNKIlZkwUFRryFfPqUdA=; b=O+YatFVxfSKVk0HyKtR+2vhY+BIw2fa6bEsjSts7zHn2z79rs6LWRz7a UyYvSoFfYW5v4QkvwPGRQe+HmE0TPCJVoDDzsvLKjoso+l1rCpNZwH0NT SRIbkhJkGQPL9PiankFYCoag5dH6flNCJ8ZNiNGq0OLevu1Nt8BzBIkhr qraSghVMO1ibWczzok3LOfEJmrmRN/D1eoX6u9ILDIpx4rHDLBH7Ojafv LBulJ9g19KYl5I2gke/5LCjUvqk8YzrwbN+qLD0UuoxIfgpUnIsn6LL4/ 3Lej1UA+w6AMavT/bsWwfsAvJ1dwWt+u95MvfOrUA045jvjnzwSn6N9no Q==; X-IronPort-AV: E=Sophos;i="5.84,336,1620662400"; d="scan'208";a="182663595" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 20 Aug 2021 15:04:36 +0800 IronPort-SDR: MZZX2o/mpFEPfEbQNcjIAhRMLVUbB9WHqQvmpmG5rCQbJ0l9Ahgi+na1bLYn0UlPYrtNxc+CiO Vwpl6eW256SPU1osH10j1GTJ1idK3Pp9zpZAE3eLi7nAWKrSAbaW8LyM6mf3IdX4VZgQ6LuYoK fMZenG6mLt0oFdEY+robC02LUyeqaO7Q4ri9N9z1JS72bdrY5c6hJpzIZNRgIQ0H59i438Fz9H LQxKFFEB0Uccenbi0J0vXry8USl5seCV8Fnt5QAg/BXLiS/c0QQTTEidJ/57H8t9XbhCcLbqo8 KzZGXfgytSW4kArw44jHpDKM 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 23:39:57 -0700 IronPort-SDR: Z5y2fHy2N+KsiDkuZDXVs3MZ6jVVKqPu39+gccu0gc7lB4tVBIWCIZkfFoWbTFKLsPRWFXnYy0 lxngwohqSaak/tX4NSwMVNOZsH4rkOE81SbA/IkHJ81Gj85sxIrYsu1XCBhiPLPUe+fp0Ny8ab NkU/aIL4PsqsewuM3WIVnGQMDSsajIFTy+yRdVlwlXb9sAShIjsRNTanSrk/EPN2zz/g+giJLP HlqLIvXIt987nO8DIFKqhAcW9ZMbERAUyA9p/EMhcNZxLVOQydDdeSdmGOKt3XtlIsk1OKO1Ht N3k= WDCIronportException: Internal Received: from washi.fujisawa.hgst.com ([10.149.53.254]) by uls-op-cesaip02.wdc.com with ESMTP; 20 Aug 2021 00:04:37 -0700 From: Damien Le Moal To: linux-scsi@vger.kernel.org, "Martin K . Petersen" Subject: [PATCH v3 1/3] scsi: fix scsi_mode_sense() buffer length handling Date: Fri, 20 Aug 2021 16:02:53 +0900 Message-Id: <20210820070255.682775-2-damien.lemoal@wdc.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210820070255.682775-1-damien.lemoal@wdc.com> References: <20210820070255.682775-1-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];