Fix curve25519 in case sha512 is not available

Before this patch it silently didn't work, now it errors out.

Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>

Author: sjaeckel

src/pk/ec25519/tweetnacl.c

@@ -312,6 +312,7 @@ int tweetnacl_crypto_sk_to_pk(u8 *pk, const u8 *sk)
 {
   u8 d[64];
   gf p[4];
+  if (find_hash("sha512") == -1) return CRYPT_INVALID_HASH;
   tweetnacl_crypto_hash(d, sk, 32);
   d[0] &= 248;
   d[31] &= 127;
@@ -387,6 +388,8 @@ int tweetnacl_crypto_sign(u8 *sm,u64 *smlen,const u8 *m,u64 mlen,const u8 *sk,co
   i64 i,j,x[64];
   gf p[4];
 
+  if (find_hash("sha512") == -1) return CRYPT_INVALID_HASH;
+
   tweetnacl_crypto_hash(d, sk, 32);
   d[0] &= 248;
   d[31] &= 127;
@@ -456,6 +459,7 @@ int tweetnacl_crypto_sign_open(int *stat, u8 *m,u64 *mlen,const u8 *sm,u64 smlen
   gf p[4],q[4];
 
   *stat = 0;
+  if (find_hash("sha512") == -1) return CRYPT_INVALID_HASH;
   if (*mlen < smlen) return CRYPT_BUFFER_OVERFLOW;
   *mlen = -1;
   if (smlen < 64) return CRYPT_INVALID_ARG;

src/pk/ed25519/ed25519_sign.c

@@ -23,6 +23,7 @@ static int s_ed25519_sign(const unsigned char  *msg, unsigned long  msglen,
    LTC_ARGCHK(siglen      != NULL);
    LTC_ARGCHK(private_key != NULL);
 
+   if (find_hash("sha512") == -1) return CRYPT_INVALID_HASH;
    if (private_key->pka != LTC_PKA_ED25519) return CRYPT_PK_INVALID_TYPE;
    if (private_key->type != PK_PRIVATE) return CRYPT_PK_INVALID_TYPE;
 

src/pk/ed25519/ed25519_verify.c

@@ -26,6 +26,7 @@ static int s_ed25519_verify(const  unsigned char *msg, unsigned long msglen,
 
    *stat = 0;
 
+   if (find_hash("sha512") == -1) return CRYPT_INVALID_HASH;
    if (siglen != 64uL) return CRYPT_INVALID_ARG;
    if (public_key->pka != LTC_PKA_ED25519) return CRYPT_PK_INVALID_TYPE;