megaraid_sas : SMAP restriction--do not access user memory from IOCTL code

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.

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>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 071ea1cad41c3c4ba6fa301e6c65735f60a11fc3..cc953725d9be8e28cc70d7831190e6cb00dcfda1 100644 (file)
--- 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) ||