Verify the signature on a self-signed TA cert against it's own pubkey

X509_verify_cert() doesn't check the purported root certificate itself
unless X509_V_FLAG_CHECK_SS_SIGNATURE is set.

The pubkey was compared against the TAL, so check that the signature is
right as required by RFC 6487, section 7, additional condition 1,
applied to self-issued certs.

The error check looks weird, but OpenSSL 3 broke yet another API.

With help from Theo Buehler and Claudio Jeker

diff --git a/src/object/certificate.c b/src/object/certificate.c
index 876eb8354df58e31353739137d1574d64fcd43b3..b302898713efb1bc03882474502f94d3c8ca4d5f 100644 (file)
--- a/src/object/certificate.c
+++ b/src/object/certificate.c
@@ -467,6 +467,7 @@ static int
 validate_public_key(X509 *cert, enum cert_type type)
 {
        X509_PUBKEY *pubkey;
+       EVP_PKEY *evppkey;
        X509_ALGOR *pa;
        int ok;
        int error;
@@ -507,6 +508,10 @@ validate_public_key(X509 *cert, enum cert_type type)
                error = validate_spki(pubkey);
                if (error)
                        return error;
+               if ((evppkey = X509_get0_pubkey(cert)) == NULL)
+                       return val_crypto_err("X509_get0_pubkey() returned NULL");
+               if (X509_verify(cert, evppkey) != 1)
+                       return -EINVAL;
        }
 
        return 0;