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Create mutable EC_GROUP API for OpenSSL compatability
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@samuel40791765
samuel40791765 committed Sep 18, 2024
1 parent 9d21f38 commit 04adba6
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Showing 5 changed files with 294 additions and 72 deletions.
146 changes: 119 additions & 27 deletions crypto/fipsmodule/ec/ec.c
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Original file line number Diff line number Diff line change
Expand Up @@ -144,6 +144,8 @@ DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_p224) {
ec_group_set_a_minus3(out);
out->has_order = 1;
out->field_greater_than_order = 1;
out->conv_form = POINT_CONVERSION_UNCOMPRESSED;
out->mutable_ec_group = 0;
}

DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_p256) {
Expand Down Expand Up @@ -176,6 +178,8 @@ DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_p256) {
ec_group_set_a_minus3(out);
out->has_order = 1;
out->field_greater_than_order = 1;
out->conv_form = POINT_CONVERSION_UNCOMPRESSED;
out->mutable_ec_group = 0;
}

DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_p384) {
Expand Down Expand Up @@ -206,6 +210,8 @@ DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_p384) {
ec_group_set_a_minus3(out);
out->has_order = 1;
out->field_greater_than_order = 1;
out->conv_form = POINT_CONVERSION_UNCOMPRESSED;
out->mutable_ec_group = 0;
}

DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_p521) {
Expand Down Expand Up @@ -240,6 +246,8 @@ DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_p521) {
ec_group_set_a_minus3(out);
out->has_order = 1;
out->field_greater_than_order = 1;
out->conv_form = POINT_CONVERSION_UNCOMPRESSED;
out->mutable_ec_group = 0;
}

DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_secp256k1) {
Expand All @@ -266,6 +274,8 @@ DEFINE_METHOD_FUNCTION(EC_GROUP, EC_group_secp256k1) {
ec_group_set_a_zero(out);
out->has_order = 1;
out->field_greater_than_order = 1;
out->conv_form = POINT_CONVERSION_UNCOMPRESSED;
out->mutable_ec_group = 0;
}

EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
Expand Down Expand Up @@ -300,6 +310,12 @@ EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
return NULL;
}
ret->references = 1;
// TODO: Treat custom curves as "immutable" for now. There's the possibility
// that we'll need dynamically allocated custom curve |EC_GROUP|s. But there
// are additional complexities around untangling the expectations already set
// for |EC_GROUP_new_curve_GFp| and |EC_GROUP_set_generator|.
// Note: See commit cb16f17b36d9ee9528a06d2e520374a4f177af4d.
ret->mutable_ec_group = 0;
ret->meth = EC_GFp_mont_method();
bn_mont_ctx_init(&ret->field);
bn_mont_ctx_init(&ret->order);
Expand Down Expand Up @@ -391,59 +407,126 @@ EC_GROUP *EC_GROUP_new_by_curve_name(int nid) {
}
}

EC_GROUP *EC_GROUP_new_by_curve_name_mutable(int nid) {
EC_GROUP *ret = NULL;
switch (nid) {
case NID_secp224r1:
ret = (EC_GROUP *)OPENSSL_memdup(EC_group_p224(), sizeof(EC_GROUP));
break;
case NID_X9_62_prime256v1:
ret = (EC_GROUP *)OPENSSL_memdup(EC_group_p256(), sizeof(EC_GROUP));
break;
case NID_secp384r1:
ret = (EC_GROUP *)OPENSSL_memdup(EC_group_p384(), sizeof(EC_GROUP));
break;
case NID_secp521r1:
ret = (EC_GROUP *)OPENSSL_memdup(EC_group_p521(), sizeof(EC_GROUP));
break;
case NID_secp256k1:
ret = (EC_GROUP *)OPENSSL_memdup(EC_group_secp256k1(), sizeof(EC_GROUP));
break;
default:
OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
return NULL;
}
ret->mutable_ec_group = 1;
return ret;
}

void EC_GROUP_free(EC_GROUP *group) {
if (group == NULL ||
// Built-in curves are static.
group->curve_name != NID_undef ||
!CRYPTO_refcount_dec_and_test_zero(&group->references)) {
if (group == NULL) {
return;
}

if (!group->mutable_ec_group) {
if (group->curve_name != NID_undef ||
!CRYPTO_refcount_dec_and_test_zero(&group->references)) {
// Built-in curves are static.
return;
}
}

bn_mont_ctx_cleanup(&group->order);
bn_mont_ctx_cleanup(&group->field);
OPENSSL_free(group);
}

EC_GROUP *EC_GROUP_dup(const EC_GROUP *a) {
if (a == NULL ||
// Built-in curves are static.
a->curve_name != NID_undef) {
if (a == NULL) {
return (EC_GROUP *)a;
}

// Groups are logically immutable (but for |EC_GROUP_set_generator| which must
// be called early on), so we simply take a reference.
EC_GROUP *group = (EC_GROUP *)a;
CRYPTO_refcount_inc(&group->references);
return group;
}
if (!a->mutable_ec_group) {
if (a->curve_name != NID_undef) {
// Built-in curves are static.
return (EC_GROUP *)a;
}

int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ignored) {
// Note this function returns 0 if equal and non-zero otherwise.
if (a == b) {
return 0;
// Groups are logically immutable (but for |EC_GROUP_set_generator| which must be called early on), so we simply take a reference.
EC_GROUP *group = (EC_GROUP *)a;
CRYPTO_refcount_inc(&group->references);
return group;
}
if (a->curve_name != b->curve_name) {
return 1;

// Do a deep copy of |EC_GROUP| if it was dynamically allocated.
EC_GROUP *ret = OPENSSL_zalloc(sizeof(EC_GROUP));
if (ret == NULL) {
return NULL;
}
if (a->curve_name != NID_undef) {
// Built-in curves may be compared by curve name alone.
return 0;
ret->has_order = a->has_order;
ret->a_is_minus3 = a->a_is_minus3;
ret->curve_name = a->curve_name;
ret->conv_form = a->conv_form;
ret->field_greater_than_order = a->field_greater_than_order;

ret->generator.group = ret;
OPENSSL_memcpy(ret->generator.raw.X.words, a->generator.raw.X.words,
sizeof(EC_FELEM));
OPENSSL_memcpy(ret->generator.raw.Y.words, a->generator.raw.Y.words,
sizeof(EC_FELEM));
OPENSSL_memcpy(ret->generator.raw.Z.words, a->generator.raw.Z.words,
sizeof(EC_FELEM));
OPENSSL_memcpy(ret->a.words, a->a.words, sizeof(EC_FELEM));
OPENSSL_memcpy(ret->b.words, a->b.words, sizeof(EC_FELEM));

ret->mutable_ec_group = a->mutable_ec_group;
ret->meth = a->meth;
bn_mont_ctx_init(&ret->field);
bn_mont_ctx_init(&ret->order);
if (!BN_MONT_CTX_copy(&ret->field, &a->field) ||
!BN_MONT_CTX_copy(&ret->order, &a->order)) {
EC_GROUP_free(ret);
ret = NULL;
}
return ret;
}

int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ignored) {
if (!a->mutable_ec_group) {
// Note this function returns 0 if equal and non-zero otherwise.
if (a == b) {
return 0;
}
if (a->curve_name != b->curve_name) {
return 1;
}
if (a->curve_name != NID_undef) {
// Built-in curves may be compared by curve name alone.
return 0;
}
}
// |a| and |b| are both custom curves. We compare the entire curve
// structure. If |a| or |b| is incomplete (due to legacy OpenSSL mistakes,
// custom curve construction is sadly done in two parts) but otherwise not the
// same object, we consider them always unequal.
return a->meth != b->meth || //
// custom curve construction is sadly done in two parts) but otherwise not the same object, we consider them always unequal.
return a->curve_name != b->curve_name || a->meth != b->meth ||
!a->has_order || !b->has_order ||
BN_cmp(&a->order.N, &b->order.N) != 0 ||
BN_cmp(&a->field.N, &b->field.N) != 0 ||
!ec_felem_equal(a, &a->a, &b->a) || //
!ec_felem_equal(a, &a->b, &b->b) ||
!ec_felem_equal(a, &a->a, &b->a) || !ec_felem_equal(a, &a->b, &b->b) ||
!ec_GFp_simple_points_equal(a, &a->generator.raw, &b->generator.raw);
}


const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group) {
return group->has_order ? &group->generator : NULL;
}
Expand Down Expand Up @@ -1095,6 +1178,15 @@ void EC_GROUP_set_point_conversion_form(EC_GROUP *group,
form != POINT_CONVERSION_COMPRESSED) {
abort();
}
// Only dynamically allocated groups are mutable.
if(group->mutable_ec_group) {
group->conv_form = form;
}
}

point_conversion_form_t EC_GROUP_get_point_conversion_form(const EC_GROUP
*group) {
return group->conv_form;
}

size_t EC_GROUP_set_seed(EC_GROUP *group, const unsigned char *seed,
Expand Down
3 changes: 3 additions & 0 deletions crypto/fipsmodule/ec/ec_key.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -280,6 +280,9 @@ point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {

void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
key->conv_form = cform;
if (key->group->mutable_ec_group) {
key->group->conv_form = cform;
}
}

int EC_KEY_check_key(const EC_KEY *eckey) {
Expand Down
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