From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49618 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755897AbdERKxY (ORCPT ); Thu, 18 May 2017 06:53:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoph Hellwig , "Martin K. Petersen" , Tejun Heo Subject: [PATCH 4.11 106/114] libata: reject passthrough WRITE SAME requests Date: Thu, 18 May 2017 12:46:56 +0200 Message-Id: <20170518103620.727581878@linuxfoundation.org> In-Reply-To: <20170518103604.736737251@linuxfoundation.org> References: <20170518103604.736737251@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christoph Hellwig commit c6ade20f5e50e188d20b711a618b20dd1d50457e upstream. The WRITE SAME to TRIM translation rewrites the DATA OUT buffer. While the SCSI code accomodates for this by passing a read-writable buffer userspace applications don't cater for this behavior. In fact it can be used to rewrite e.g. a readonly file through mmap and should be considered as a security fix. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- drivers/ata/libata-scsi.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -3462,6 +3462,14 @@ static unsigned int ata_scsi_write_same_ if (unlikely(!dev->dma_mode)) goto invalid_opcode; + /* + * We only allow sending this command through the block layer, + * as it modifies the DATA OUT buffer, which would corrupt user + * memory for SG_IO commands. + */ + if (unlikely(blk_rq_is_passthrough(scmd->request))) + goto invalid_opcode; + if (unlikely(scmd->cmd_len < 16)) { fp = 15; goto invalid_fld;