[PATCH 10/12] megaraid_sas : SMAP restriction-do not access user memory from IOCTL code

[PATCH 10/12] megaraid_sas : SMAP restriction-do not access user memory from IOCTL code

[sumit.saxena]

This is an issue on SMAP enabled CPUs and 32 bit apps running on 64 bit OS. Donot access user memory from kernel code.
SMAP bit restricts to access user memory from kernel code. Corresponding Redhat Bugzilla id for this is:[Bug 1267911].

Cc: <stable@vger.kernel.org>
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
---
 drivers/scsi/megaraid/megaraid_sas_base.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index c74d7c5..f8d5455 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -6470,6 +6470,9 @@ 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;
@@ -6487,9 +6490,15 @@ 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) ||
-- 
1.7.1

Re: [PATCH 10/12] megaraid_sas : SMAP restriction-do not access user memory from IOCTL code

[Tomas Henzl]

On 15.10.2015 10:10, sumit.saxena@avagotech.com wrote:
> This is an issue on SMAP enabled CPUs and 32 bit apps running on 64 bit OS. Donot access user memory from kernel code.
> SMAP bit restricts to access user memory from kernel code. Corresponding Redhat Bugzilla id for this is:[Bug 1267911].
>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>

Reviewed-by: Tomas Henzl <thenzl@redhat.com>

Tomas