ED25519 Power-on Self Test / CAST / KAT (#1834)

### Description of changes: 
Per IG guidance:
>Note10: the ECDSA signature generation and deterministic ECDSA
signature generation methods shall
each have their own CAST if both are implemented in the approved mode.
• for the EdDSA algorithm,
o if the module implements digital signature generation, the module
shall have an EdDSA digital
signature generation CAST. If a KAT is used, the EdDSA digital signature
shall be pre-
computed, generate an EdDSA digital signature using known data and keys,
and then compare
the result to the pre-computed value;
o if the module implements digital signature verification, the module
shall have an EdDSA digital
signature verification CAST. If a KAT is used, the EdDSA digital
signature shall be pre-
computed (which could be the output of the EdDSA digital signature
generate test), and using a
known key, verify the signature as specified in section 7.7 of FIPS
186-5.

This KAT was sourced from the ACVP vectors for SigGen that were
validated with the NIST demo server.

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license and the ISC license.

crypto/fipsmodule/self_check/self_check.c

@@ -21,6 +21,7 @@
 #include <openssl/aes.h>
 #include <openssl/bn.h>
 #include <openssl/ctrdrbg.h>
+#include <openssl/curve25519.h>
 #include <openssl/dh.h>
 #include <openssl/digest.h>
 #include <openssl/ec.h>
@@ -1246,6 +1247,52 @@ static int boringssl_self_test_fast(void) {
     goto err;
   }
 
+  const uint8_t kEd25519PrivateKey[ED25519_PRIVATE_KEY_SEED_LEN] = {
+      0xb3, 0x99, 0x05, 0xbf, 0x43, 0x0b, 0x2a, 0xd2, 0x1d, 0xb6, 0x5d,
+      0x49, 0xa6, 0xab, 0x03, 0xc1, 0x7d, 0xdb, 0x72, 0xe7, 0xa9, 0x8e,
+      0xb9, 0x8f, 0xae, 0x59, 0x91, 0x7a, 0xe2, 0x5f, 0x92, 0x14};
+  const uint8_t kEd25519PublicKey[ED25519_PUBLIC_KEY_LEN] = {
+      0xe7, 0x75, 0xcf, 0x0e, 0x33, 0x48, 0x52, 0xa7, 0xe6, 0x99, 0xbe,
+      0xba, 0x13, 0xbc, 0x24, 0xf8, 0x32, 0xf3, 0xc2, 0xa3, 0xa0, 0x3d,
+      0xc9, 0x3c, 0x42, 0xb5, 0x92, 0x76, 0x15, 0xa5, 0x46, 0xba};
+  const uint8_t kEd25519Signature[ED25519_SIGNATURE_LEN] = {
+      0x30, 0x1a, 0x4c, 0x56, 0xe0, 0x37, 0x0b, 0x57, 0x2f, 0x7d, 0x8c,
+      0x75, 0x1b, 0x5c, 0xfa, 0xb6, 0xc3, 0x98, 0x7c, 0x6f, 0x5d, 0xe8,
+      0x7c, 0xac, 0x4d, 0x71, 0x16, 0x73, 0xda, 0x8c, 0xb2, 0x19, 0x86,
+      0x03, 0xcd, 0x91, 0x82, 0x73, 0xa5, 0x34, 0x24, 0x93, 0xf1, 0xc1,
+      0xad, 0x0e, 0x8a, 0x78, 0x45, 0x15, 0xa7, 0xfe, 0xc8, 0xc9, 0xbe,
+      0xa2, 0xa3, 0xf1, 0xcf, 0x7b, 0x3a, 0x89, 0x10, 0x0f};
+  const uint8_t kEd25519Message[128] = {
+      0x13, 0x1d, 0x2a, 0xa9, 0x8f, 0x46, 0xfd, 0x5a, 0xca, 0xef, 0x8e, 0x92,
+      0xfa, 0x8c, 0x50, 0xd4, 0x8b, 0xda, 0xdf, 0xfe, 0x13, 0xd7, 0x9c, 0xc7,
+      0x1b, 0x95, 0x85, 0x5f, 0xaf, 0xa4, 0x84, 0x66, 0x50, 0x2a, 0x1c, 0x61,
+      0x4d, 0xb7, 0x85, 0xfc, 0xc9, 0x4c, 0x50, 0x61, 0x65, 0x23, 0x93, 0x42,
+      0xcb, 0x9b, 0x3e, 0xe6, 0x3b, 0x35, 0xdc, 0x2f, 0x7e, 0x78, 0x61, 0x15,
+      0x42, 0xc7, 0xa6, 0x1b, 0x50, 0xf3, 0xb6, 0x8e, 0xcf, 0x1b, 0x70, 0xca,
+      0xc0, 0x1b, 0x34, 0xef, 0x06, 0x1b, 0x3f, 0x7c, 0xaa, 0xc8, 0x26, 0x56,
+      0xbf, 0xd5, 0x5a, 0x06, 0xb8, 0xeb, 0x7d, 0xbe, 0x82, 0x45, 0x17, 0xfe,
+      0x3c, 0x56, 0x7d, 0xa5, 0xa0, 0x3e, 0x0b, 0xf2, 0xf1, 0xfe, 0xbb, 0x96,
+      0x3c, 0x94, 0x1a, 0xfc, 0x36, 0xe4, 0x5a, 0x5a, 0xc5, 0xe2, 0x71, 0xcd,
+      0x99, 0x56, 0xcc, 0xda, 0x0d, 0x62, 0xc8, 0x7c};
+  uint8_t ed25519_private_key[ED25519_PRIVATE_KEY_LEN] = {0};
+  OPENSSL_memcpy(ed25519_private_key, kEd25519PrivateKey,
+                 ED25519_PRIVATE_KEY_SEED_LEN);
+  OPENSSL_memcpy(ed25519_private_key + ED25519_PRIVATE_KEY_SEED_LEN,
+                 kEd25519PublicKey, ED25519_PUBLIC_KEY_LEN);
+  uint8_t ed25519_out_sig[ED25519_SIGNATURE_LEN] = {0};
+  if (!ED25519_sign(&ed25519_out_sig[0], &kEd25519Message[0],
+                    sizeof(kEd25519Message), ed25519_private_key) ||
+      !check_test(&kEd25519Signature[0], &ed25519_out_sig[0],
+                  ED25519_SIGNATURE_LEN, "ED25519 sign")) {
+    fprintf(stderr, "ED25519 sign failed.\n");
+    goto err;
+  }
+  if (!ED25519_verify(&kEd25519Message[0], sizeof(kEd25519Message),
+                      ed25519_out_sig, kEd25519PublicKey)) {
+    fprintf(stderr, "ED25519 verify failed.\n");
+    goto err;
+  }
+
   ret = 1;
 
 err: