sde-drm: Fix potential buffer overflow

Initializing the string stream with blob data pointer directly may
cause buffer overflow, if the blob data pointer is not terminated with
NULL character. So copy the blob data into character array and
explicitly terminate with null character before initializing the
stringstream to avoid buffer overflow.

Change-Id: I75fca3b4ecfbf3bc5b8865afdb4ab51b25aff22c
3 files changed