utils: Use chunk_equals_const() for all cryptographic purposes

src/libstrongswan/plugins/openssl/openssl_pkcs7.c

@@ -305,7 +305,7 @@ static bool verify_digest(CMS_ContentInfo *cms, CMS_SignerInfo *si, int hash_oid
 	}
 	hasher->destroy(hasher);
 
-	if (!chunk_equals(digest, hash))
+	if (!chunk_equals_const(digest, hash))
 	{
 		free(hash.ptr);
 		DBG1(DBG_LIB, "invalid messageDigest");

src/libstrongswan/plugins/openssl/openssl_rsa_public_key.c

@@ -74,7 +74,7 @@ static bool verify_emsa_pkcs1_signature(private_openssl_rsa_public_key_t *this,
 								 RSA_PKCS1_PADDING);
 		if (len != -1)
 		{
-			valid = chunk_equals(data, chunk_create(buf, len));
+			valid = chunk_equals_const(data, chunk_create(buf, len));
 		}
 		free(buf);
 	}

src/libstrongswan/plugins/pkcs12/pkcs12_decode.c

@@ -356,7 +356,7 @@ static bool verify_mac(hash_algorithm_t hash, chunk_t salt,
 		{
 			break;
 		}
-		if (chunk_equals(mac, calculated))
+		if (chunk_equals_const(mac, calculated))
 		{
 			success = TRUE;
 			break;

src/libstrongswan/plugins/pkcs7/pkcs7_signed_data.c

@@ -269,7 +269,7 @@ METHOD(enumerator_t, enumerate, bool,
 		hasher->destroy(hasher);
 		DBG3(DBG_LIB, "hash: %B", &hash);
 
-		valid = chunk_equals(chunk, hash);
+		valid = chunk_equals_const(chunk, hash);
 		free(hash.ptr);
 		if (!valid)
 		{