return KEY_ED25519;
}
+/* L = 2^252+27742317777372353535851937790883648493 in little-endian form */
+static chunk_t curve25519_order = chunk_from_chars(
+ 0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58,
+ 0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9, 0xde, 0x14,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10);
+
METHOD(public_key_t, verify, bool,
private_curve25519_public_key_t *this, signature_scheme_t scheme,
void *params, chunk_t data, chunk_t signature)
{
return FALSE;
}
+ /* make sure 0 <= s < L, as per RFC 8032, section 5.1.7 to prevent signature
+ * malleability. Due to the three-bit check above (forces s < 2^253) there
+ * is not that much room, but adding L once works with most signatures */
+ for (i = 31; ; i--)
+ {
+ if (sig[i+32] < curve25519_order.ptr[i])
+ {
+ break;
+ }
+ else if (sig[i+32] > curve25519_order.ptr[i] || i == 0)
+ {
+ return FALSE;
+ }
+ }
hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA512);
if (!hasher)
};
/**
- * Ed25519 Test Vectors from draft-irtf-cfrg-eddsa
+ * Ed25519 Test Vectors from RFC 8032
*/
static sig_test_t sig_tests[] = {
/* Test 1 */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00);
+/* sig_tests[0].sig with s+L */
+static chunk_t malleable_sig = chunk_from_chars(
+ 0xe5, 0x56, 0x43, 0x00, 0xc3, 0x60, 0xac, 0x72, 0x90, 0x86,
+ 0xe2, 0xcc, 0x80, 0x6e, 0x82, 0x8a, 0x84, 0x87, 0x7f, 0x1e,
+ 0xb8, 0xe5, 0xd9, 0x74, 0xd8, 0x73, 0xe0, 0x65, 0x22, 0x49,
+ 0x01, 0x55, 0x4c, 0x8c, 0x78, 0x72, 0xaa, 0x06, 0x4e, 0x04,
+ 0x9d, 0xbb, 0x30, 0x13, 0xfb, 0xf2, 0x93, 0x80, 0xd2, 0x5b,
+ 0xf5, 0xf0, 0x59, 0x5b, 0xbe, 0x24, 0x65, 0x51, 0x41, 0x43,
+ 0x8e, 0x7a, 0x10, 0x1b);
+
START_TEST(test_ed25519_fail)
{
private_key_t *key;
ck_assert(!pubkey->verify(pubkey, SIGN_ED25519, NULL, chunk_empty,
chunk_empty));
+ /* RFC 8032, section 5.1.7 requires that 0 <= s < L to prevent signature
+ * malleability. Only a warning because Botan and OpenSSL are both
+ * vulnerable to this. */
+ if (pubkey->verify(pubkey, SIGN_ED25519, NULL, sig_tests[0].msg,
+ malleable_sig))
+ {
+ warn("Ed25519 signature verification is vulnerable to malleable "
+ "signatures");
+ }
+
/* malformed signature */
sig = chunk_create(sig1, 64);
memcpy(sig1, sig_tests[0].sig.ptr, 64);