drivers/staging/bcm: Integer overflow

The checking condition in 'validateFlash2xReadWrite()' is not
sufficient. A large number invalid would cause an integer overflow and
pass the condition, which could cause further integer overflows in
'Bcmchar.c:bcm_char_ioctl()'.
Signed-off-by: Wenliang Fan <fanwlexca@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/bcm/nvm.c

@@ -3944,6 +3944,15 @@ int validateFlash2xReadWrite(struct bcm_mini_adapter *Adapter, struct bcm_flash2
 
 	BCM_DEBUG_PRINT(Adapter, DBG_TYPE_OTHERS, NVM_RW, DBG_LVL_ALL, "End offset :%x\n", uiSectEndOffset);
 
+	/* psFlash2xReadWrite->offset and uiNumOfBytes are user controlled and can lead to integer overflows */
+	if (psFlash2xReadWrite->offset > uiSectEndOffset) {
+		BCM_DEBUG_PRINT(Adapter, DBG_TYPE_PRINTK, 0, 0, "Invalid Request....");
+		return false;
+	}
+	if (uiNumOfBytes > uiSectEndOffset) {
+		BCM_DEBUG_PRINT(Adapter, DBG_TYPE_PRINTK, 0, 0, "Invalid Request....");
+		return false;
+	}
 	/* Checking the boundary condition */
 	if ((uiSectStartOffset + psFlash2xReadWrite->offset + uiNumOfBytes) <= uiSectEndOffset)
 		return TRUE;