Under the current implementation, all the signatures, if any, in
a signed image must be verified before loading it.
Meanwhile, UEFI specification v2.8b section 32.5.3.3 says,
Multiple signatures are allowed to exist in the binary’s certificate
table (as per PE/COFF Section “Attribute Certificate Table”). Only
one hash or signature is required to be present in db in order to pass
validation, so long as neither the SHA-256 hash of the binary nor any
present signature is reflected in dbx.
This patch makes the semantics of signature verification compliant with
the specification mentioned above.
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
52956e535e