From adf652436a42a5132e708f8003b7621647f0a404 Mon Sep 17 00:00:00 2001 From: Matt Caswell Date: Thu, 24 May 2018 16:13:43 +0100 Subject: [PATCH] Test that a ^ 0 mod -1 is always 0 Check all functions that do this. Reviewed-by: Rich Salz (Merged from https://github.com/openssl/openssl/pull/6355) --- test/bntest.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/test/bntest.c b/test/bntest.c index 629707ad16..35587780f3 100644 --- a/test/bntest.c +++ b/test/bntest.c @@ -2063,6 +2063,53 @@ err: return st; } +static int test_expmodone(void) +{ + int ret = 0, i; + BIGNUM *r = BN_new(); + BIGNUM *a = BN_new(); + BIGNUM *p = BN_new(); + BIGNUM *m = BN_new(); + + if (!TEST_ptr(r) + || !TEST_ptr(a) + || !TEST_ptr(p) + || !TEST_ptr(p) + || !TEST_ptr(m) + || !TEST_true(BN_set_word(a, 1)) + || !TEST_true(BN_set_word(p, 0)) + || !TEST_true(BN_set_word(m, 1))) + goto err; + + /* Calculate r = 1 ^ 0 mod 1, and check the result is always 0 */ + for (i = 0; i < 2; i++) { + if (!TEST_true(BN_mod_exp(r, a, p, m, NULL)) + || !TEST_BN_eq_zero(r) + || !TEST_true(BN_mod_exp_mont(r, a, p, m, NULL, NULL)) + || !TEST_BN_eq_zero(r) + || !TEST_true(BN_mod_exp_mont_consttime(r, a, p, m, NULL, NULL)) + || !TEST_BN_eq_zero(r) + || !TEST_true(BN_mod_exp_mont_word(r, 1, p, m, NULL, NULL)) + || !TEST_BN_eq_zero(r) + || !TEST_true(BN_mod_exp_simple(r, a, p, m, NULL)) + || !TEST_BN_eq_zero(r) + || !TEST_true(BN_mod_exp_recp(r, a, p, m, NULL)) + || !TEST_BN_eq_zero(r)) + goto err; + /* Repeat for r = 1 ^ 0 mod -1 */ + if (i == 0) + BN_set_negative(m, 1); + } + + ret = 1; +err: + BN_free(r); + BN_free(a); + BN_free(p); + BN_free(m); + return ret; +} + static int test_smallprime(void) { static const int kBits = 10; @@ -2189,6 +2236,7 @@ int setup_tests(void) ADD_TEST(test_negzero); ADD_TEST(test_badmod); ADD_TEST(test_expmodzero); + ADD_TEST(test_expmodone); ADD_TEST(test_smallprime); ADD_TEST(test_swap); #ifndef OPENSSL_NO_EC2M -- 2.25.1