tree e26cbe6607da8407709277b5d4808bb759e501cb
parent 2165a3ecf9d2d4385c7ef7a473b1c4f3501b92ca
author Antonio Nino Diaz <antonio.ninodiaz@arm.com> 1484315612 +0000
committer Antonio Nino Diaz <antonio.ninodiaz@arm.com> 1485268933 +0000

tbbr: Use constant-time bcmp() to compare hashes

To avoid timing side-channel attacks, it is needed to use a constant
time memory comparison function when comparing hashes. The affected
code only cheks for equality so it isn't needed to use any variant of
memcmp(), bcmp() is enough.

Also, timingsafe_bcmp() is as fast as memcmp() when the two compared
regions are equal, so this change incurrs no performance hit in said
case. In case they are unequal, the boot sequence wouldn't continue as
normal, so performance is not an issue.

Change-Id: I1c7c70ddfa4438e6031c8814411fef79fd3bb4df
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>