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Store EC field and orders in minimal form.

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The order (and later the field) are used to size stack-allocated fixed
width word arrays. They're also entirely public, so this is fine.

Bug: 232
Change-Id: Ie98869cdbbdfea92dcad64a300f7e0b47bef6bf2
Reviewed-on: https://boringssl-review.googlesource.com/25256
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
David Benjamin 2018-01-22 09:28:13 -05:00 committed by CQ bot account: commit-bot@chromium.org
parent 226b4b51b5
commit cb4e300f17
3 changed files with 29 additions and 2 deletions
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2
crypto/fipsmodule/ec/ec.c
View File

@ -387,6 +387,8 @@ int EC_GROUP_set_generator(EC_GROUP *group, const EC_POINT *generator,
EC_POINT_free(copy);
return 0;
}
// Store the order in minimal form, so it can be used with |BN_ULONG| arrays.
bn_correct_top(&group->order);
BN_MONT_CTX_free(group->order_mont);
group->order_mont = BN_MONT_CTX_new_for_modulus(&group->order, NULL);

23
crypto/fipsmodule/ec/ec_test.cc
View File

@ -304,6 +304,29 @@ TEST(ECTest, ArbitraryCurve) {
order.get(), BN_value_one()));
EXPECT_NE(0, EC_GROUP_cmp(group.get(), group3.get(), NULL));
#if !defined(BORINGSSL_SHARED_LIBRARY)
// group4 has non-minimal components that do not fit in |EC_SCALAR| and the
// future |EC_FELEM|.
ASSERT_TRUE(bn_resize_words(p.get(), 32));
ASSERT_TRUE(bn_resize_words(a.get(), 32));
ASSERT_TRUE(bn_resize_words(b.get(), 32));
ASSERT_TRUE(bn_resize_words(gx.get(), 32));
ASSERT_TRUE(bn_resize_words(gy.get(), 32));
ASSERT_TRUE(bn_resize_words(order.get(), 32));
bssl::UniquePtr<EC_GROUP> group4(
EC_GROUP_new_curve_GFp(p.get(), a.get(), b.get(), ctx.get()));
ASSERT_TRUE(group4);
bssl::UniquePtr<EC_POINT> generator4(EC_POINT_new(group4.get()));
ASSERT_TRUE(generator4);
ASSERT_TRUE(EC_POINT_set_affine_coordinates_GFp(
group4.get(), generator4.get(), gx.get(), gy.get(), ctx.get()));
ASSERT_TRUE(EC_GROUP_set_generator(group4.get(), generator4.get(),
order.get(), BN_value_one()));
EXPECT_EQ(0, EC_GROUP_cmp(group.get(), group4.get(), NULL));
#endif
}
TEST(ECTest, SetKeyWithoutGroup) {

6
crypto/fipsmodule/ec/simple.c
View File

@ -135,9 +135,11 @@ int ec_GFp_simple_group_set_curve(EC_GROUP *group, const BIGNUM *p,
goto err;
}
BN_set_negative(&group->field, 0);
// Store the field in minimal form, so it can be used with |BN_ULONG| arrays.
bn_correct_top(&group->field);
// group->a
if (!BN_nnmod(tmp_a, a, p, ctx)) {
if (!BN_nnmod(tmp_a, a, &group->field, ctx)) {
goto err;
}
if (group->meth->field_encode) {
@ -149,7 +151,7 @@ int ec_GFp_simple_group_set_curve(EC_GROUP *group, const BIGNUM *p,
}
// group->b
if (!BN_nnmod(&group->b, b, p, ctx)) {
if (!BN_nnmod(&group->b, b, &group->field, ctx)) {
goto err;
}
if (group->meth->field_encode &&