tree 88838a074b48d84bea8765e8b1ee571fc30fbddb
parent 17510259cc05e19c01c5faf516bcc8568e73023b
author Greg Kaiser <gkaiser@google.com> 1518814896 -0800
committer Greg Kaiser <gkaiser@google.com> 1518823363 -0800

cryptfs: Use the crypt_mnt_ftr keysize

Our code has places where we were reading in the crypt_mnt_ftr
struct from disk, but then proceeding to use a hardcoded constant
for the keysize.  We plan to allow crypto with different sized
keys in the future, so we want to just trust the keysize we get
off of disk.

While doing this, we reject any crypt_mnt_ftr we read from disk
which has a keysize in excess of MAX_KEY_LEN.  This defends us
against buffer overflows in the case of corrupt disk data.

Bug: 73079191
Test: Compiled and tested in combination with other CLs.
Change-Id: Id6f192b905960e5508833e9cd3b4668d4754dc7e