From 1d3cd983f56e0a580ee4216692ee3c9c7bf14de9 Mon Sep 17 00:00:00 2001 From: Billy Brumley Date: Mon, 9 Sep 2019 11:29:09 +0300 Subject: [PATCH] [test] ECC: check the bounds for auto computing cofactor Reviewed-by: Matt Caswell Reviewed-by: Nicola Tuveri (Merged from https://github.com/openssl/openssl/pull/9821) --- test/ectest.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) diff --git a/test/ectest.c b/test/ectest.c index 4f3bfb7569..58836339af 100644 --- a/test/ectest.c +++ b/test/ectest.c @@ -2121,6 +2121,96 @@ 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 @@ -2269,6 +2359,7 @@ 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 -- 2.25.1