X-Git-Url: https://www.bearssl.org/gitweb//home/git/?p=BearSSL;a=blobdiff_plain;f=src%2Fec%2Fec_prime_i15.c;h=f86dbe6ff0dbc036af470e369048c4ae02d33337;hp=bf1d00271a6aee68804e01dc2a747f9e88936f43;hb=HEAD;hpb=44c79c1add4cd4a217b1dd77c8421c1d3a08dcef

diff --git a/src/ec/ec_prime_i15.c b/src/ec/ec_prime_i15.c
index bf1d002..f86dbe6 100644
--- a/src/ec/ec_prime_i15.c
+++ b/src/ec/ec_prime_i15.c
@@ -716,6 +716,14 @@ api_order(int curve, size_t *len)
 	return cd->order;
 }
 
+static size_t
+api_xoff(int curve, size_t *len)
+{
+	api_generator(curve, len);
+	*len >>= 1;
+	return 1;
+}
+
 static uint32_t
 api_mul(unsigned char *G, size_t Glen,
 	const unsigned char *x, size_t xlen, int curve)
@@ -725,11 +733,12 @@ api_mul(unsigned char *G, size_t Glen,
 	jacobian P;
 
 	cc = id_to_curve(curve);
+	if (Glen != cc->point_len) {
+		return 0;
+	}
 	r = point_decode(&P, G, Glen, cc);
 	point_mul(&P, x, xlen, cc);
-	if (Glen == cc->point_len) {
-		point_encode(G, &P, cc);
-	}
+	point_encode(G, &P, cc);
 	return r;
 }
 
@@ -757,11 +766,14 @@ api_muladd(unsigned char *A, const unsigned char *B, size_t len,
 
 	/*
 	 * TODO: see about merging the two ladders. Right now, we do
-	 * two independant point multiplications, which is a bit
+	 * two independent point multiplications, which is a bit
 	 * wasteful of CPU resources (but yields short code).
 	 */
 
 	cc = id_to_curve(curve);
+	if (len != cc->point_len) {
+		return 0;
+	}
 	r = point_decode(&P, A, len, cc);
 	if (B == NULL) {
 		size_t Glen;
@@ -805,6 +817,7 @@ const br_ec_impl br_ec_prime_i15 = {
 	(uint32_t)0x03800000,
 	&api_generator,
 	&api_order,
+	&api_xoff,
 	&api_mul,
 	&api_mulgen,
 	&api_muladd