Add a generic SubjectPublicKeyInfo decoder

Previously all the SubjectPublicKeyInfo decoders were specific to a key
type. We would iterate over all them until a match was found for the correct
key type. Each one would fully decode the key before then testing whether
it was a match or not - throwing it away if not. This was very inefficient.

Instead we introduce a generic SubjectPublicKeyInfo decoder which figures
out what type of key is contained within it, before subsequently passing on
the data to a key type specific SubjectPublicKeyInfo decoder.

Fixes #15646

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15662)

1 files changed, 2 insertions, 0 deletions

diff --git a/providers/implementations/encode_decode/endecoder_local.h b/providers/implementations/encode_decode/endecoder_local.h
index ab431b8086..96941e4d16 100644
--- a/providers/implementations/encode_decode/endecoder_local.h
+++ b/providers/implementations/encode_decode/endecoder_local.h
@@ -24,3 +24,5 @@ int ossl_prov_der_from_p8(unsigned char **new_der, long *new_der_len,
 void *ossl_prov_import_key(const OSSL_DISPATCH *fns, void *provctx,
                            int selection, const OSSL_PARAM params[]);
 void ossl_prov_free_key(const OSSL_DISPATCH *fns, void *key);
+int ossl_read_der(PROV_CTX *provctx, OSSL_CORE_BIO *cin,  unsigned char **data,
+                  long *len);