Small improvement to tolerate PEM files missing the terminating newline in the brssl...

[BearSSL] / src / ec / ecdsa_i31_sign_raw.c

diff --git a/src/ec/ecdsa_i31_sign_raw.c b/src/ec/ecdsa_i31_sign_raw.c
index 3849545..1df98fe 100644 (file)
--- a/src/ec/ecdsa_i31_sign_raw.c
+++ b/src/ec/ecdsa_i31_sign_raw.c
@@ -50,6 +50,13 @@ br_ecdsa_i31_sign_raw(const br_ec_impl *impl,
        uint32_t n0i, ctl;
        br_hmac_drbg_context drbg;
 
+       /*
+        * If the curve is not supported, then exit with an error.
+        */
+       if (((impl->supported_curves >> sk->curve) & 1) == 0) {
+               return 0;
+       }
+
        /*
         * Get the curve parameters (generator and order).
         */
@@ -125,18 +132,8 @@ br_ecdsa_i31_sign_raw(const br_ec_impl *impl,
         * prime order, that reduction is only a matter of computing
         * a subtraction.
         */
-       ulen = cd->generator_len;
-       memcpy(eU, cd->generator, ulen);
        br_i31_encode(tt, nlen, k);
-       if (!impl->mul(eU, ulen, tt, nlen, sk->curve)) {
-               /*
-                * Point multiplication may fail here only if the
-                * EC implementation does not support the curve, or the
-                * private key is incorrect (x is a multiple of the curve
-                * order).
-                */
-               return 0;
-       }
+       ulen = impl->mulgen(eU, tt, nlen, sk->curve);
        br_i31_zero(r, n[0]);
        br_i31_decode(r, &eU[1], ulen >> 1);
        r[0] = n[0];