This test verifies behavior when a certificate has an unparseable/unsupported SPKI. It should be handled equivalently to a certificate with a failed signature verification: further processing should be shortcircuited. The certificate chain has 2 problems:

• leaf is expired
• intermediate has invalid SPKI

The verification should fail with only the SPKI parsing error, since further processing should be short-circuited.

Instructions for generating test certificate chain:

• cp ../expired-target/chain.pem .
• extract intermediate cert to int-pre.pem
• print_certificates --output=der2ascii int-pre.pem > int.derascii
• edit int.derascii to replace SPKI OID with something invalid
• extract the TBSCertificate part of the certificate to int.tbs.derascii ascii2der < int.tbs.derascii > int.tbs.der
• generate new signature: openssl pkeyutl -sign -rawin -in int.tbs.der -digest sha256 -inkey ../expired-target/keys/Root.key -out - | xxd -p -c 0
• replace the signature hex in int.derascii
• ascii2der < int.derascii > int.der
• print_certificates --output=openssl_text,pem int.der > int.pem
• replace the intermediate certificate in chain.pem with the contents of int.pem