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

Orabug: 22620626

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>
(cherry picked from commit 323c4a02c631d00851d8edc4213c4d184ef83647)
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 226d723894ca394bc7de04d20196fa53049fdde6..31b165b209508cc6018f87f1b8e01ae549157038 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -6485,6 +6485,9 @@ 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;
@@ -6502,9 +6505,15 @@ 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) ||