[PATCH v2 1/2] scsi: scsi_ioctl: Validate command size

From: Tadeusz Struk <tadeusz.struk@linaro.org>
To: Bart Van Assche <bvanassche@acm.org>, linux-scsi@vger.kernel.org
Cc: Tadeusz Struk <tadeusz.struk@linaro.org>,
	Christoph Hellwig <hch@lst.de>,
	"James E . J . Bottomley" <jejb@linux.ibm.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: [PATCH v2 1/2] scsi: scsi_ioctl: Validate command size
Date: Wed,  3 Nov 2021 10:06:58 -0700	[thread overview]
Message-ID: <20211103170659.22151-1-tadeusz.struk@linaro.org> (raw)

Need to make sure the command size is valid before copying
the command from user.

Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: <linux-scsi@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Cc: <stable@vger.kernel.org> # 5.15, 5.14, 5.10
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
---
Changes in v2:
- removed check for upper len limit as it is handled in sg_io()
---
 drivers/scsi/scsi_ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
index 6ff2207bd45a..a06c61f22742 100644
--- a/drivers/scsi/scsi_ioctl.c
+++ b/drivers/scsi/scsi_ioctl.c
@@ -347,6 +347,8 @@ static int scsi_fill_sghdr_rq(struct scsi_device *sdev, struct request *rq,
 {
 	struct scsi_request *req = scsi_req(rq);
 
+	if (hdr->cmd_len < 6)
+		return -EMSGSIZE;
 	if (copy_from_user(req->cmd, hdr->cmdp, hdr->cmd_len))
 		return -EFAULT;
 	if (!scsi_cmd_allowed(req->cmd, mode))
-- 
2.33.1

