Avoid hard-coded linkage of WNAF-based multiplication.
If the application is only using the P-256 implementation in p256-64.c,
then the WNAF code would all be dead code. The change reorganizes the
code so that all modern toolchains should be able to recognize that
fact and eliminate the WNAF-based code when it is unused.
Change-Id: I9f94bd934ca7d2292de4c29bb89e17c940c7cd2a
Reviewed-on: https://boringssl-review.googlesource.com/6173
Reviewed-by: Adam Langley <alangley@gmail.com>
diff --git a/crypto/ec/ec.c b/crypto/ec/ec.c
index f2d5167..4f614f2 100644
--- a/crypto/ec/ec.c
+++ b/crypto/ec/ec.c
@@ -569,12 +569,7 @@
}
int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx) {
- if (group->meth->mul == 0) {
- /* use default */
- return ec_wNAF_precompute_mult(group, ctx);
- }
-
- if (group->meth->precompute_mult != 0) {
+ if (group->meth->precompute_mult != NULL) {
return group->meth->precompute_mult(group, ctx);
}
@@ -582,16 +577,10 @@
}
int EC_GROUP_have_precompute_mult(const EC_GROUP *group) {
- if (group->meth->mul == 0) {
- /* use default */
- return ec_wNAF_have_precompute_mult(group);
+ if (group->pre_comp != NULL) {
+ return 1;
}
-
- if (group->meth->have_precompute_mult != 0) {
- return group->meth->have_precompute_mult(group);
- }
-
- return 0; /* cannot tell whether precomputation has been performed */
+ return 0;
}
EC_POINT *EC_POINT_new(const EC_GROUP *group) {
@@ -797,9 +786,15 @@
int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
size_t num, const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *ctx) {
- if (group->meth->mul == 0) {
- /* use default. Warning, not constant-time. */
- return ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);
+ size_t i;
+ for (i = 0; i < num; i++) {
+ if (points[i]->meth != r->meth) {
+ break;
+ }
+ }
+ if (i != num) {
+ OPENSSL_PUT_ERROR(EC, EC_R_INCOMPATIBLE_OBJECTS);
+ return 0;
}
return group->meth->mul(group, r, scalar, num, points, scalars, ctx);
diff --git a/crypto/ec/ec_montgomery.c b/crypto/ec/ec_montgomery.c
index fde9844..3715e0c 100644
--- a/crypto/ec/ec_montgomery.c
+++ b/crypto/ec/ec_montgomery.c
@@ -81,9 +81,8 @@
ec_GFp_mont_group_copy,
ec_GFp_mont_group_set_curve,
ec_GFp_simple_point_get_affine_coordinates,
- 0 /* mul */,
- 0 /* precompute_mult */,
- 0 /* have_precompute_mult */,
+ ec_wNAF_mul /* XXX: Not constant time. */,
+ ec_wNAF_precompute_mult,
ec_GFp_mont_field_mul,
ec_GFp_mont_field_sqr,
ec_GFp_mont_field_encode,
diff --git a/crypto/ec/internal.h b/crypto/ec/internal.h
index 836490a..6fdaf41 100644
--- a/crypto/ec/internal.h
+++ b/crypto/ec/internal.h
@@ -102,8 +102,6 @@
size_t num, const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *);
int (*precompute_mult)(EC_GROUP *group, BN_CTX *);
- int (*have_precompute_mult)(const EC_GROUP *group);
-
/* internal functions */
@@ -170,7 +168,6 @@
size_t num, const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *);
int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *);
-int ec_wNAF_have_precompute_mult(const EC_GROUP *group);
/* method functions in simple.c */
int ec_GFp_simple_group_init(EC_GROUP *);
diff --git a/crypto/ec/p224-64.c b/crypto/ec/p224-64.c
index 1958a90..e530c9f 100644
--- a/crypto/ec/p224-64.c
+++ b/crypto/ec/p224-64.c
@@ -1328,7 +1328,6 @@
ec_GFp_nistp224_point_get_affine_coordinates,
ec_GFp_nistp224_points_mul,
0 /* precompute_mult */,
- 0 /* have_precompute_mult */,
ec_GFp_simple_field_mul,
ec_GFp_simple_field_sqr,
0 /* field_encode */,
diff --git a/crypto/ec/p256-64.c b/crypto/ec/p256-64.c
index bc657cd..2adcd6b 100644
--- a/crypto/ec/p256-64.c
+++ b/crypto/ec/p256-64.c
@@ -1908,7 +1908,7 @@
ec_GFp_simple_group_copy, ec_GFp_nistp256_group_set_curve,
ec_GFp_nistp256_point_get_affine_coordinates,
ec_GFp_nistp256_points_mul,
- 0 /* precompute_mult */, 0 /* have_precompute_mult */,
+ 0 /* precompute_mult */,
ec_GFp_simple_field_mul, ec_GFp_simple_field_sqr,
0 /* field_encode */, 0 /* field_decode */, 0 /* field_set_to_one */
};
diff --git a/crypto/ec/simple.c b/crypto/ec/simple.c
index 9381028..2695fda 100644
--- a/crypto/ec/simple.c
+++ b/crypto/ec/simple.c
@@ -85,7 +85,6 @@
ec_GFp_simple_point_get_affine_coordinates,
0 /* mul */,
0 /* precompute_mult */,
- 0 /* have_precompute_mult */,
ec_GFp_simple_field_mul,
ec_GFp_simple_field_sqr,
0 /* field_encode */,
diff --git a/crypto/ec/wnaf.c b/crypto/ec/wnaf.c
index 7fa0e1b..4aaffd9 100644
--- a/crypto/ec/wnaf.c
+++ b/crypto/ec/wnaf.c
@@ -846,8 +846,3 @@
EC_POINT_free(base);
return ret;
}
-
-
-int ec_wNAF_have_precompute_mult(const EC_GROUP *group) {
- return group->pre_comp != NULL;
-}
