X-Git-Url: https://www.bearssl.org/gitweb//home/git/?p=BearSSL;a=blobdiff_plain;f=src%2Fec%2Fec_prime_i31.c;h=b205f367aebaec00048bec5a68fdc09999a58914;hp=0f2baa0f2e0d183eac34e6eabdc103079d0761d9;hb=b2ec2030e40acf5e9e4cd0f2669aacb27eadb540;hpb=44c79c1add4cd4a217b1dd77c8421c1d3a08dcef

diff --git a/src/ec/ec_prime_i31.c b/src/ec/ec_prime_i31.c
index 0f2baa0..b205f36 100644
--- a/src/ec/ec_prime_i31.c
+++ b/src/ec/ec_prime_i31.c
@@ -107,15 +107,16 @@ typedef struct {
 	const uint32_t *b;
 	const uint32_t *R2;
 	uint32_t p0i;
+	size_t point_len;
 } curve_params;
 
 static inline const curve_params *
 id_to_curve(int curve)
 {
 	static const curve_params pp[] = {
-		{ P256_P, P256_B, P256_R2, 0x00000001 },
-		{ P384_P, P384_B, P384_R2, 0x00000001 },
-		{ P521_P, P521_B, P521_R2, 0x00000001 }
+		{ P256_P, P256_B, P256_R2, 0x00000001,  65 },
+		{ P384_P, P384_B, P384_R2, 0x00000001,  97 },
+		{ P521_P, P521_B, P521_R2, 0x00000001, 133 }
 	};
 
 	return &pp[curve - BR_EC_secp256r1];
@@ -717,6 +718,14 @@ 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)
@@ -726,6 +735,9 @@ 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);
 	point_encode(G, &P, cc);
@@ -756,11 +768,14 @@ 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;
@@ -804,6 +819,7 @@ const br_ec_impl br_ec_prime_i31 = {
 	(uint32_t)0x03800000,
 	&api_generator,
 	&api_order,
+	&api_xoff,
 	&api_mul,
 	&api_mulgen,
 	&api_muladd