Commit 73a683b7 authored by Billy Brumley's avatar Billy Brumley Committed by Nicola Tuveri
Browse files

[test] ECC: check the bounds for auto computing cofactor 



Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
Reviewed-by: default avatarNicola Tuveri <nic.tuv@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/9821)

(cherry picked from commit 1d3cd983f56e0a580ee4216692ee3c9c7bf14de9)
parent 827eab4c

test/ectest.c

+91 −0
Original line number Diff line number Diff line
@@ -1827,6 +1827,96 @@ err: 
    return r;

}



/*-

 * random 256-bit explicit parameters curve, cofactor absent

 * order:    0x0c38d96a9f892b88772ec2e39614a82f4f (132 bit)

 * cofactor:   0x12bc94785251297abfafddf1565100da (125 bit)

 */

static const unsigned char params_cf_pass[] = {

    0x30, 0x81, 0xcd, 0x02, 0x01, 0x01, 0x30, 0x2c, 0x06, 0x07, 0x2a, 0x86,

    0x48, 0xce, 0x3d, 0x01, 0x01, 0x02, 0x21, 0x00, 0xe5, 0x00, 0x1f, 0xc5,

    0xca, 0x71, 0x9d, 0x8e, 0xf7, 0x07, 0x4b, 0x48, 0x37, 0xf9, 0x33, 0x2d,

    0x71, 0xbf, 0x79, 0xe7, 0xdc, 0x91, 0xc2, 0xff, 0xb6, 0x7b, 0xc3, 0x93,

    0x44, 0x88, 0xe6, 0x91, 0x30, 0x44, 0x04, 0x20, 0xe5, 0x00, 0x1f, 0xc5,

    0xca, 0x71, 0x9d, 0x8e, 0xf7, 0x07, 0x4b, 0x48, 0x37, 0xf9, 0x33, 0x2d,

    0x71, 0xbf, 0x79, 0xe7, 0xdc, 0x91, 0xc2, 0xff, 0xb6, 0x7b, 0xc3, 0x93,

    0x44, 0x88, 0xe6, 0x8e, 0x04, 0x20, 0x18, 0x8c, 0x59, 0x57, 0xc4, 0xbc,

    0x85, 0x57, 0xc3, 0x66, 0x9f, 0x89, 0xd5, 0x92, 0x0d, 0x7e, 0x42, 0x27,

    0x07, 0x64, 0xaa, 0x26, 0xed, 0x89, 0xc4, 0x09, 0x05, 0x4d, 0xc7, 0x23,

    0x47, 0xda, 0x04, 0x41, 0x04, 0x1b, 0x6b, 0x41, 0x0b, 0xf9, 0xfb, 0x77,

    0xfd, 0x50, 0xb7, 0x3e, 0x23, 0xa3, 0xec, 0x9a, 0x3b, 0x09, 0x31, 0x6b,

    0xfa, 0xf6, 0xce, 0x1f, 0xff, 0xeb, 0x57, 0x93, 0x24, 0x70, 0xf3, 0xf4,

    0xba, 0x7e, 0xfa, 0x86, 0x6e, 0x19, 0x89, 0xe3, 0x55, 0x6d, 0x5a, 0xe9,

    0xc0, 0x3d, 0xbc, 0xfb, 0xaf, 0xad, 0xd4, 0x7e, 0xa6, 0xe5, 0xfa, 0x1a,

    0x58, 0x07, 0x9e, 0x8f, 0x0d, 0x3b, 0xf7, 0x38, 0xca, 0x02, 0x11, 0x0c,

    0x38, 0xd9, 0x6a, 0x9f, 0x89, 0x2b, 0x88, 0x77, 0x2e, 0xc2, 0xe3, 0x96,

    0x14, 0xa8, 0x2f, 0x4f

};



/*-

 * random 256-bit explicit parameters curve, cofactor absent

 * order:    0x045a75c0c17228ebd9b169a10e34a22101 (131 bit)

 * cofactor:   0x2e134b4ede82649f67a2e559d361e5fe (126 bit)

 */

static const unsigned char params_cf_fail[] = {

    0x30, 0x81, 0xcd, 0x02, 0x01, 0x01, 0x30, 0x2c, 0x06, 0x07, 0x2a, 0x86,

    0x48, 0xce, 0x3d, 0x01, 0x01, 0x02, 0x21, 0x00, 0xc8, 0x95, 0x27, 0x37,

    0xe8, 0xe1, 0xfd, 0xcc, 0xf9, 0x6e, 0x0c, 0xa6, 0x21, 0xc1, 0x7d, 0x6b,

    0x9d, 0x44, 0x42, 0xea, 0x73, 0x4e, 0x04, 0xb6, 0xac, 0x62, 0x50, 0xd0,

    0x33, 0xc2, 0xea, 0x13, 0x30, 0x44, 0x04, 0x20, 0xc8, 0x95, 0x27, 0x37,

    0xe8, 0xe1, 0xfd, 0xcc, 0xf9, 0x6e, 0x0c, 0xa6, 0x21, 0xc1, 0x7d, 0x6b,

    0x9d, 0x44, 0x42, 0xea, 0x73, 0x4e, 0x04, 0xb6, 0xac, 0x62, 0x50, 0xd0,

    0x33, 0xc2, 0xea, 0x10, 0x04, 0x20, 0xbf, 0xa6, 0xa8, 0x05, 0x1d, 0x09,

    0xac, 0x70, 0x39, 0xbb, 0x4d, 0xb2, 0x90, 0x8a, 0x15, 0x41, 0x14, 0x1d,

    0x11, 0x86, 0x9f, 0x13, 0xa2, 0x63, 0x1a, 0xda, 0x95, 0x22, 0x4d, 0x02,

    0x15, 0x0a, 0x04, 0x41, 0x04, 0xaf, 0x16, 0x71, 0xf9, 0xc4, 0xc8, 0x59,

    0x1d, 0xa3, 0x6f, 0xe7, 0xc3, 0x57, 0xa1, 0xfa, 0x9f, 0x49, 0x7c, 0x11,

    0x27, 0x05, 0xa0, 0x7f, 0xff, 0xf9, 0xe0, 0xe7, 0x92, 0xdd, 0x9c, 0x24,

    0x8e, 0xc7, 0xb9, 0x52, 0x71, 0x3f, 0xbc, 0x7f, 0x6a, 0x9f, 0x35, 0x70,

    0xe1, 0x27, 0xd5, 0x35, 0x8a, 0x13, 0xfa, 0xa8, 0x33, 0x3e, 0xd4, 0x73,

    0x1c, 0x14, 0x58, 0x9e, 0xc7, 0x0a, 0x87, 0x65, 0x8d, 0x02, 0x11, 0x04,

    0x5a, 0x75, 0xc0, 0xc1, 0x72, 0x28, 0xeb, 0xd9, 0xb1, 0x69, 0xa1, 0x0e,

    0x34, 0xa2, 0x21, 0x01

};



/*-

 * Test two random 256-bit explicit parameters curves with absent cofactor.

 * The two curves are chosen to roughly straddle the bounds at which the lib

 * can compute the cofactor automatically, roughly 4*sqrt(p). So test that:

 *

 * - params_cf_pass: order is sufficiently close to p to compute cofactor

 * - params_cf_fail: order is too far away from p to compute cofactor

 *

 * For standards-compliant curves, cofactor is chosen as small as possible.

 * So you can see neither of these curves are fit for cryptographic use.

 *

 * Some standards even mandate an upper bound on the cofactor, e.g. SECG1 v2:

 * h <= 2**(t/8) where t is the security level of the curve, for which the lib

 * will always succeed in computing the cofactor. Neither of these curves

 * conform to that -- this is just robustness testing.

 */

static int cofactor_range_test(void)

{

    EC_GROUP *group = NULL;

    BIGNUM *cf = NULL;

    int ret = 0;

    const unsigned char *b1 = (const unsigned char *)params_cf_fail;

    const unsigned char *b2 = (const unsigned char *)params_cf_pass;



    if (!TEST_ptr(group = d2i_ECPKParameters(NULL, &b1, sizeof(params_cf_fail)))

        || !TEST_BN_eq_zero(EC_GROUP_get0_cofactor(group))

        || !TEST_ptr(group = d2i_ECPKParameters(&group, &b2,

                                                sizeof(params_cf_pass)))

        || !TEST_int_gt(BN_hex2bn(&cf, "12bc94785251297abfafddf1565100da"), 0)

        || !TEST_BN_eq(cf, EC_GROUP_get0_cofactor(group)))

        goto err;

    ret = 1;

 err:

    BN_free(cf);

    EC_GROUP_free(group);

    return ret;

}



/*-

 * For named curves, test that:

 * - the lib correctly computes the cofactor if passed a NULL or zero cofactor
@@ -1920,6 +2010,7 @@ int setup_tests(void) 
        return 0;



    ADD_TEST(parameter_test);

    ADD_TEST(cofactor_range_test);

    ADD_ALL_TESTS(cardinality_test, crv_len);

    ADD_TEST(prime_field_tests);

# ifndef OPENSSL_NO_EC2M