vboot2: Allocate more buffer for kernel verification

The low-level verification functions' *_WORKBUF_BYTES constants assume
the work buffer is already aligned to VB2_WORKBUF_ALIGN.  But malloc()
may return a less-aligned pointer, in which case vb2_workbuf_init()
aligns it (and loses a bit of space in the process).  This can cause an
error "vb2_rsa_verify_digest: ERROR - vboot2 work buffer too small!".

High-level functions should be using the *_WORKBUF_RECOMMENDED_SIZE
constants for allocation, which have enough padding to compensate for
alignment problems.

BUG=chrome-os-partner:59306
BRANCH=none
TEST=make runtests; boot a recovery image on reef

Change-Id: I1055fa56072b3fe1cd07c5c090293635c42c77a2
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/406526
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2 files changed