linux-kernel - [PATCH 3.12 054/116] megaraid_sas : SMAP restriction--do not access user memory from IOCTL code

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Date:	Fri,  4 Mar 2016 10:01:39 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org,
	"sumit.saxena@...gotech.com" <sumit.saxena@...gotech.com>,
	Kashyap Desai <kashyap.desai@...gotech.com>,
	"Martin K . Petersen" <martin.petersen@...cle.com>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 054/116] megaraid_sas : SMAP restriction--do not access user memory from IOCTL code

From: "sumit.saxena@...gotech.com" <sumit.saxena@...gotech.com>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 323c4a02c631d00851d8edc4213c4d184ef83647 upstream.

This is an issue on SMAP enabled CPUs and 32 bit apps running on 64 bit
OS. Do not access user memory from kernel code. The SMAP bit restricts
accessing user memory from kernel code.

Signed-off-by: Sumit Saxena <sumit.saxena@...gotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai@...gotech.com>
Reviewed-by: Tomas Henzl <thenzl@...hat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 drivers/scsi/megaraid/megaraid_sas_base.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 884c33d46874..6811a9b37053 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -5284,6 +5284,9 @@ static int megasas_mgmt_compat_ioctl_fw(struct file *file, unsigned long arg)
 	int i;
 	int error = 0;
 	compat_uptr_t ptr;
+	unsigned long local_raw_ptr;
+	u32 local_sense_off;
+	u32 local_sense_len;
 
 	if (clear_user(ioc, sizeof(*ioc)))
 		return -EFAULT;
@@ -5301,9 +5304,15 @@ static int megasas_mgmt_compat_ioctl_fw(struct file *file, unsigned long arg)
 	 * sense_len is not null, so prepare the 64bit value under
 	 * the same condition.
 	 */
-	if (ioc->sense_len) {
+	if (get_user(local_raw_ptr, ioc->frame.raw) ||
+		get_user(local_sense_off, &ioc->sense_off) ||
+		get_user(local_sense_len, &ioc->sense_len))
+		return -EFAULT;
+
+
+	if (local_sense_len) {
 		void __user **sense_ioc_ptr =
-			(void __user **)(ioc->frame.raw + ioc->sense_off);
+			(void __user **)((u8*)local_raw_ptr + local_sense_off);
 		compat_uptr_t *sense_cioc_ptr =
 			(compat_uptr_t *)(cioc->frame.raw + cioc->sense_off);
 		if (get_user(ptr, sense_cioc_ptr) ||
-- 
2.7.2