The function, pkcs7_verify_one(), will be utilized to rework signature
verification logic aiming to support intermediate certificates in
"chain of trust."
To do that, its function interface is expanded, adding an extra argument
which is expected to return the last certificate in trusted chain.
Then, this last one must further be verified with signature database, db
and/or dbx.
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Imported from linux kernel v5.3:
pkcs7.asn1 without changes
pkcs7.h with changes marked as __UBOOT__
pkcs7_parser.h without changes
pkcs7_parser.c with changes marked as __UBOOT__
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>