security/intel/txt: Avoid shifting by a negative value

Coverity detects an integer handling issue with BAD_SHIFT. The inline
function log2_ceil(u32 x) { return (x == 0) ? -1 : log2(x * 2 - 1); }
could return -1, which causes shifting by a negative amount value and
has undefined behavior. Add sanity check for the acm_header->size to
avoid shifting negative value.

Found-by: Coverity CID 1431124
TEST=None

Signed-off-by: John Zhao <john.zhao@intel.com>
Change-Id: Ic687349b14917e39d2a8186968037ca2521c7cdc
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44186
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

0 files changed, 0 insertions, 0 deletions