Remove p224-64 and p256-64 dead code for non-default generators.
This extends 9f1f04f31359330702451bc74ab98dca3abca602 to the other
implementations.
|EC_GFp_nistp224_method| and |EC_GFp_nistp256_method| are not marked
|OPENSSL_EXPORT|. |EC_GROUP_set_generator| doesn't allow the generator
to be changed for any |EC_GROUP| for built-in curves. Consequently,
there's no way (except some kind of terrible abuse) that this code
could be executed with a non-default generator.
Change-Id: I5d9b6be4e6f9d384159cb3d708390a8e3c69f23f
Reviewed-on: https://boringssl-review.googlesource.com/6489
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/ec/p256-64.c b/crypto/ec/p256-64.c
index 2adcd6b..74d0f84 100644
--- a/crypto/ec/p256-64.c
+++ b/crypto/ec/p256-64.c
@@ -1312,8 +1312,8 @@
*
* Tables for other points have table[i] = iG for i in 0 .. 16. */
-/* gmul is the table of precomputed base points */
-static const smallfelem gmul[2][16][3] = {
+/* g_pre_comp is the table of precomputed base points */
+static const smallfelem g_pre_comp[2][16][3] = {
{{{0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}},
{{0xf4a13945d898c296, 0x77037d812deb33a0, 0xf8bce6e563a440f2,
0x6b17d1f2e12c4247},
@@ -1505,8 +1505,7 @@
static void batch_mul(felem x_out, felem y_out, felem z_out,
const felem_bytearray scalars[],
const unsigned num_points, const u8 *g_scalar,
- const int mixed, const smallfelem pre_comp[][17][3],
- const smallfelem g_pre_comp[2][16][3]) {
+ const int mixed, const smallfelem pre_comp[][17][3]) {
int i, skip;
unsigned num, gen_mul = (g_scalar != NULL);
felem nq[3], ftmp;
@@ -1598,11 +1597,6 @@
felem_assign(z_out, nq[2]);
}
-/* Precomputation for the group generator. */
-typedef struct {
- smallfelem g_pre_comp[2][16][3];
-} NISTP256_PRE_COMP;
-
/******************************************************************************/
/*
* OPENSSL EC_METHOD FUNCTIONS
@@ -1724,12 +1718,9 @@
smallfelem *tmp_smallfelems = NULL;
felem_bytearray tmp;
unsigned i, num_bytes;
- int have_pre_comp = 0;
size_t num_points = num;
smallfelem x_in, y_in, z_in;
felem x_out, y_out, z_out;
- const smallfelem(*g_pre_comp)[16][3] = NULL;
- EC_POINT *generator = NULL;
const EC_POINT *p = NULL;
const BIGNUM *p_scalar = NULL;
@@ -1748,34 +1739,6 @@
goto err;
}
- if (scalar != NULL) {
- /* try to use the standard precomputation */
- g_pre_comp = &gmul[0];
- generator = EC_POINT_new(group);
- if (generator == NULL) {
- goto err;
- }
- /* get the generator from precomputation */
- if (!smallfelem_to_BN(x, g_pre_comp[0][1][0]) ||
- !smallfelem_to_BN(y, g_pre_comp[0][1][1]) ||
- !smallfelem_to_BN(z, g_pre_comp[0][1][2])) {
- OPENSSL_PUT_ERROR(EC, ERR_R_BN_LIB);
- goto err;
- }
- if (!ec_point_set_Jprojective_coordinates_GFp(group, generator, x, y, z,
- ctx)) {
- goto err;
- }
- if (0 == EC_POINT_cmp(group, generator, group->generator, ctx)) {
- /* precomputation matches generator */
- have_pre_comp = 1;
- } else {
- /* we don't have valid precomputation: treat the generator as a
- * random point. */
- num_points++;
- }
- }
-
if (num_points > 0) {
if (num_points >= 3) {
/* unless we precompute multiples for just one or two points,
@@ -1852,7 +1815,7 @@
}
/* the scalar for the generator */
- if (scalar != NULL && have_pre_comp) {
+ if (scalar != NULL) {
memset(g_secret, 0, sizeof(g_secret));
/* reduce scalar to 0 <= scalar < 2^256 */
if (BN_num_bits(scalar) > 256 || BN_is_negative(scalar)) {
@@ -1867,16 +1830,10 @@
num_bytes = BN_bn2bin(scalar, tmp);
}
flip_endian(g_secret, tmp, num_bytes);
- /* do the multiplication with generator precomputation */
- batch_mul(x_out, y_out, z_out, (const felem_bytearray(*))secrets,
- num_points, g_secret, mixed, (const smallfelem(*)[17][3])pre_comp,
- g_pre_comp);
- } else {
- /* do the multiplication without generator precomputation */
- batch_mul(x_out, y_out, z_out, (const felem_bytearray(*))secrets,
- num_points, NULL, mixed, (const smallfelem(*)[17][3])pre_comp,
- NULL);
}
+ batch_mul(x_out, y_out, z_out, (const felem_bytearray(*))secrets,
+ num_points, scalar != NULL ? g_secret : NULL, mixed,
+ (const smallfelem(*)[17][3])pre_comp);
/* reduce the output to its unique minimal representation */
felem_contract(x_in, x_out);
@@ -1892,7 +1849,6 @@
err:
BN_CTX_end(ctx);
- EC_POINT_free(generator);
BN_CTX_free(new_ctx);
OPENSSL_free(secrets);
OPENSSL_free(pre_comp);
