Support all five EdDSA instances from RFC 8032

Fixes #6277

Description:
Make each of the five EdDSA instances defined in RFC 8032 -- Ed25519,
Ed25519ctx, Ed25519ph, Ed448, Ed448ph -- available via the EVP APIs.

The desired EdDSA instance is specified via an OSSL_PARAM.

All instances, except for Ed25519, allow context strings as input.
Context strings are passed via an OSSL_PARAM.  For Ed25519ctx, the
context string must be nonempty.

Ed25519, Ed25519ctx, Ed448 are PureEdDSA instances, which means that
the full message (not a digest) must be passed to sign and verify
operations.

Ed25519ph, Ed448ph are HashEdDSA instances, which means that the input
message is hashed before sign and verify.

Testing:
All 21 test vectors from RFC 8032 have been added to evppkey_ecx.txt
(thanks to Shane Lontis for showing how to do that).  Those 21 test
vectors are exercised by evp_test.c and cover all five instances.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/19705)

2 files changed, 14 insertions, 47 deletions

diff --git a/crypto/ec/curve448/curve448_local.h b/crypto/ec/curve448/curve448_local.h
index 3410f091a6..f118d851ee 100644
--- a/crypto/ec/curve448/curve448_local.h
+++ b/crypto/ec/curve448/curve448_local.h
@@ -10,15 +10,4 @@
 # define OSSL_CRYPTO_EC_CURVE448_LOCAL_H
 # include "curve448utils.h"
 
-int
-ossl_ed448ph_sign(OSSL_LIB_CTX *ctx, uint8_t *out_sig, const uint8_t hash[64],
-                  const uint8_t public_key[57], const uint8_t private_key[57],
-                  const uint8_t *context, size_t context_len, const char *propq);
-
-int
-ossl_ed448ph_verify(OSSL_LIB_CTX *ctx, const uint8_t hash[64],
-                    const uint8_t signature[114], const uint8_t public_key[57],
-                    const uint8_t *context, size_t context_len,
-                    const char *propq);
-
 #endif              /* OSSL_CRYPTO_EC_CURVE448_LOCAL_H */
diff --git a/crypto/ec/curve448/eddsa.c b/crypto/ec/curve448/eddsa.c
index 6648692ff3..cbef27d9bb 100644
--- a/crypto/ec/curve448/eddsa.c
+++ b/crypto/ec/curve448/eddsa.c
@@ -61,12 +61,8 @@ static c448_error_t hash_init_with_dom(OSSL_LIB_CTX *ctx, EVP_MD_CTX *hashctx,
                                        size_t context_len,
                                        const char *propq)
 {
-#ifdef CHARSET_EBCDIC
-    const char dom_s[] = {0x53, 0x69, 0x67, 0x45,
-                          0x64, 0x34, 0x34, 0x38, 0x00};
-#else
-    const char dom_s[] = "SigEd448";
-#endif
+    /* ASCII: "SigEd448", in hex for EBCDIC compatibility */
+    const char dom_s[] = "\x53\x69\x67\x45\x64\x34\x34\x38";
     uint8_t dom[2];
     EVP_MD *shake256 = NULL;
 
@@ -82,7 +78,7 @@ static c448_error_t hash_init_with_dom(OSSL_LIB_CTX *ctx, EVP_MD_CTX *hashctx,
         return C448_FAILURE;
 
     if (!EVP_DigestInit_ex(hashctx, shake256, NULL)
-            || !EVP_DigestUpdate(hashctx, dom_s, strlen(dom_s))
+            || !EVP_DigestUpdate(hashctx, dom_s, sizeof(dom_s)-1)
             || !EVP_DigestUpdate(hashctx, dom, sizeof(dom))
             || !EVP_DigestUpdate(hashctx, context, context_len)) {
         EVP_MD_free(shake256);
@@ -373,48 +369,30 @@ ossl_c448_ed448_verify_prehash(
 }
 
 int
-ossl_ed448_sign(OSSL_LIB_CTX *ctx, uint8_t *out_sig, const uint8_t *message,
-                size_t message_len, const uint8_t public_key[57],
-                const uint8_t private_key[57], const uint8_t *context,
-                size_t context_len, const char *propq)
+ossl_ed448_sign(OSSL_LIB_CTX *ctx, uint8_t *out_sig,
+                const uint8_t *message, size_t message_len,
+                const uint8_t public_key[57], const uint8_t private_key[57],
+                const uint8_t *context, size_t context_len,
+                const uint8_t phflag, const char *propq)
 {
     return ossl_c448_ed448_sign(ctx, out_sig, private_key, public_key, message,
-                                message_len, 0, context, context_len,
+                                message_len, phflag, context, context_len,
                                 propq) == C448_SUCCESS;
 }
 
 int
-ossl_ed448_verify(OSSL_LIB_CTX *ctx, const uint8_t *message, size_t message_len,
+ossl_ed448_verify(OSSL_LIB_CTX *ctx,
+                  const uint8_t *message, size_t message_len,
                   const uint8_t signature[114], const uint8_t public_key[57],
-                  const uint8_t *context, size_t context_len, const char *propq)
+                  const uint8_t *context, size_t context_len,
+                  const uint8_t phflag, const char *propq)
 {
     return ossl_c448_ed448_verify(ctx, signature, public_key, message,
-                                  message_len, 0, context, (uint8_t)context_len,
+                                  message_len, phflag, context, (uint8_t)context_len,
                                   propq) == C448_SUCCESS;
 }
 
 int
-ossl_ed448ph_sign(OSSL_LIB_CTX *ctx, uint8_t *out_sig, const uint8_t hash[64],
-                  const uint8_t public_key[57], const uint8_t private_key[57],
-                  const uint8_t *context, size_t context_len, const char *propq)
-{
-    return ossl_c448_ed448_sign_prehash(ctx, out_sig, private_key, public_key,
-                                        hash, context, context_len,
-                                        propq) == C448_SUCCESS;
-}
-
-int
-ossl_ed448ph_verify(OSSL_LIB_CTX *ctx, const uint8_t hash[64],
-                    const uint8_t signature[114], const uint8_t public_key[57],
-                    const uint8_t *context, size_t context_len,
-                    const char *propq)
-{
-    return ossl_c448_ed448_verify_prehash(ctx, signature, public_key, hash,
-                                          context, (uint8_t)context_len,
-                                          propq) == C448_SUCCESS;
-}
-
-int
 ossl_ed448_public_from_private(OSSL_LIB_CTX *ctx, uint8_t out_public_key[57],
                                const uint8_t private_key[57], const char *propq)
 {