regress/libcrypto: merge exp/ into bn/

Move exp/exptest.c to bn/bn_mod_exp.c. This is a BN test that mostly tests
a variety of BN_mod_exp*() API behavior and correctness.

Commit stolen from jsing

2 files changed, 361 insertions, 1 deletions

diff --git a/src/regress/lib/libcrypto/bn/Makefile b/src/regress/lib/libcrypto/bn/Makefile
index 971ace1c77..b5d146c71b 100644
--- a/src/regress/lib/libcrypto/bn/Makefile
+++ b/src/regress/lib/libcrypto/bn/Makefile
@@ -1,8 +1,9 @@
-#       $OpenBSD: Makefile,v 1.8 2022/12/01 20:50:10 tb Exp $
+#       $OpenBSD: Makefile,v 1.9 2022/12/01 21:21:51 tb Exp $
 
 PROGS +=        bn_add_sub
 PROGS +=        bn_cmp
 PROGS +=        bn_isqrt
+PROGS +=        bn_mod_exp
 PROGS +=        bn_mod_exp2_mont
 PROGS +=        bn_mod_sqrt
 PROGS +=        bn_mont
@@ -12,6 +13,7 @@ PROGS +=	bn_to_string
 PROGS +=        bn_unit
 
 STATIC_LINK +=  bn_isqrt
+STATIC_LINK +=  bn_mod_exp
 STATIC_LINK +=  bn_primes
 STATIC_LINK +=  bn_to_string
 STATIC_LINK +=  bn_rand_interval
diff --git a/src/regress/lib/libcrypto/bn/bn_mod_exp.c b/src/regress/lib/libcrypto/bn/bn_mod_exp.c
new file mode 100644
index 0000000000..337cbd1373
--- /dev/null
+++ b/src/regress/lib/libcrypto/bn/bn_mod_exp.c
@@ -0,0 +1,358 @@
+/*      $OpenBSD: bn_mod_exp.c,v 1.1 2022/12/01 21:21:51 tb Exp $       */
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.]
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/bio.h>
+#include <openssl/bn.h>
+#include <openssl/err.h>
+
+int BN_mod_exp_ct(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
+    const BIGNUM *m, BN_CTX *ctx);
+int BN_mod_exp_nonct(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
+    const BIGNUM *m, BN_CTX *ctx);
+int BN_mod_exp_mont_ct(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
+    const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
+int BN_mod_exp_mont_nonct(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
+    const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
+
+#define NUM_BITS        (BN_BITS*2)
+
+/*
+ * Test that r == 0 in test_exp_mod_zero(). Returns one on success,
+ * returns zero and prints debug output otherwise.
+ */
+static int
+a_is_zero_mod_one(const char *method, const BIGNUM *r, const BIGNUM *a)
+{
+        if (!BN_is_zero(r)) {
+                fprintf(stderr, "%s failed:\n", method);
+                fprintf(stderr, "a ** 0 mod 1 = r (should be 0)\n");
+                fprintf(stderr, "a = ");
+                BN_print_fp(stderr, a);
+                fprintf(stderr, "\nr = ");
+                BN_print_fp(stderr, r);
+                fprintf(stderr, "\n");
+                return 0;
+        }
+        return 1;
+}
+
+/*
+ * test_exp_mod_zero tests that x**0 mod 1 == 0. It returns zero on success.
+ */
+static int
+test_exp_mod_zero(void)
+{
+        BIGNUM *a = NULL, *p = NULL, *m = NULL, *r = NULL;
+        BN_ULONG one_word = 1;
+        BN_CTX *ctx;
+        int ret = 1, failed = 0;
+
+        if ((ctx = BN_CTX_new()) == NULL)
+                goto err;
+        if ((m = BN_new()) == NULL)
+                goto err;
+        if (!BN_one(m))
+                goto err;
+
+        if ((a = BN_new()) == NULL)
+                goto err;
+        if (!BN_one(a))
+                goto err;
+
+        if ((p = BN_new()) == NULL)
+                goto err;
+        BN_zero(p);
+
+        if ((r = BN_new()) == NULL)
+                goto err;
+
+        if (!BN_rand(a, 1024, 0, 0))
+                goto err;
+
+        if (!BN_mod_exp(r, a, p, m, ctx))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_ct(r, a, p, m, ctx))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp_ct", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_nonct(r, a, p, m, ctx))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp_nonct", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_recp(r, a, p, m, ctx))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp_recp", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_simple(r, a, p, m, ctx))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp_simple", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_mont(r, a, p, m, ctx, NULL))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp_mont", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_mont_ct(r, a, p, m, ctx, NULL))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp_mont_ct", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_mont_nonct(r, a, p, m, ctx, NULL))
+                goto err;
+
+        if (!a_is_zero_mod_one("BN_mod_exp_mont_nonct", r, a))
+                failed = 1;
+
+        if (!BN_mod_exp_mont_consttime(r, a, p, m, ctx, NULL)) {
+                goto err;
+        }
+
+        if (!a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a))
+                failed = 1;
+
+        /*
+         * A different codepath exists for single word multiplication
+         * in non-constant-time only.
+         */
+        if (!BN_mod_exp_mont_word(r, one_word, p, m, ctx, NULL))
+                goto err;
+
+        if (!BN_is_zero(r)) {
+                fprintf(stderr, "BN_mod_exp_mont_word failed:\n");
+                fprintf(stderr, "1 ** 0 mod 1 = r (should be 0)\n");
+                fprintf(stderr, "r = ");
+                BN_print_fp(stderr, r);
+                fprintf(stderr, "\n");
+                return 0;
+        }
+
+        ret = failed;
+
+ err:
+        BN_free(r);
+        BN_free(a);
+        BN_free(p);
+        BN_free(m);
+        BN_CTX_free(ctx);
+
+        return ret;
+}
+
+int
+main(int argc, char *argv[])
+{
+        BIGNUM *r_mont, *r_mont_const, *r_recp, *r_simple;
+        BIGNUM *r_mont_ct, *r_mont_nonct, *a, *b, *m;
+        BN_CTX *ctx;
+        BIO *out = NULL;
+        unsigned char c;
+        int i, ret;
+
+        ERR_load_BN_strings();
+
+        if ((ctx = BN_CTX_new()) == NULL)
+                goto err;
+        if ((r_mont = BN_new()) == NULL)
+                goto err;
+        if ((r_mont_const = BN_new()) == NULL)
+                goto err;
+        if ((r_mont_ct = BN_new()) == NULL)
+                goto err;
+        if ((r_mont_nonct = BN_new()) == NULL)
+                goto err;
+        if ((r_recp = BN_new()) == NULL)
+                goto err;
+        if ((r_simple = BN_new()) == NULL)
+                goto err;
+        if ((a = BN_new()) == NULL)
+                goto err;
+        if ((b = BN_new()) == NULL)
+                goto err;
+        if ((m = BN_new()) == NULL)
+                goto err;
+
+        if ((out = BIO_new(BIO_s_file())) == NULL)
+                exit(1);
+        BIO_set_fp(out, stdout, BIO_NOCLOSE);
+
+        for (i = 0; i < 200; i++) {
+                arc4random_buf(&c, 1);
+                c = (c % BN_BITS) - BN_BITS2;
+                BN_rand(a, NUM_BITS + c, 0, 0);
+
+                arc4random_buf(&c, 1);
+                c = (c % BN_BITS) - BN_BITS2;
+                BN_rand(b, NUM_BITS + c, 0, 0);
+
+                arc4random_buf(&c, 1);
+                c = (c % BN_BITS) - BN_BITS2;
+                BN_rand(m, NUM_BITS + c, 0, 1);
+
+                BN_mod(a, a, m, ctx);
+                BN_mod(b, b, m, ctx);
+
+                ret = BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL);
+                if (ret <= 0) {
+                        printf("BN_mod_exp_mont() problems\n");
+                        goto err;
+                }
+
+                ret = BN_mod_exp_mont_ct(r_mont_ct, a, b, m, ctx, NULL);
+                if (ret <= 0) {
+                        printf("BN_mod_exp_mont_ct() problems\n");
+                        goto err;
+                }
+
+                ret = BN_mod_exp_mont_nonct(r_mont_nonct, a, b, m, ctx, NULL);
+                if (ret <= 0) {
+                        printf("BN_mod_exp_mont_nonct() problems\n");
+                        goto err;
+                }
+
+                ret = BN_mod_exp_recp(r_recp, a, b, m, ctx);
+                if (ret <= 0) {
+                        printf("BN_mod_exp_recp() problems\n");
+                        goto err;
+                }
+
+                ret = BN_mod_exp_simple(r_simple, a, b, m, ctx);
+                if (ret <= 0) {
+                        printf("BN_mod_exp_simple() problems\n");
+                        goto err;
+                }
+
+                ret = BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL);
+                if (ret <= 0) {
+                        printf("BN_mod_exp_mont_consttime() problems\n");
+                        goto err;
+                }
+
+                if (BN_cmp(r_simple, r_mont) != 0 ||
+                    BN_cmp(r_simple, r_recp) != 0 ||
+                    BN_cmp(r_simple, r_mont_const) != 0) {
+                        if (BN_cmp(r_simple, r_mont) != 0)
+                                printf("\nsimple and mont results differ\n");
+                        if (BN_cmp(r_simple, r_mont_const) != 0)
+                                printf("\nsimple and mont const time results differ\n");
+                        if (BN_cmp(r_simple, r_recp) != 0)
+                                printf("\nsimple and recp results differ\n");
+                        if (BN_cmp(r_mont, r_mont_ct) != 0)
+                                printf("\nmont_ct and mont results differ\n");
+                        if (BN_cmp(r_mont_ct, r_mont_nonct) != 0)
+                                printf("\nmont_ct and mont_nonct results differ\n");
+
+                        printf("a (%3d) = ", BN_num_bits(a));
+                        BN_print(out, a);
+                        printf("\nb (%3d) = ", BN_num_bits(b));
+                        BN_print(out, b);
+                        printf("\nm (%3d) = ", BN_num_bits(m));
+                        BN_print(out, m);
+                        printf("\nsimple   =");
+                        BN_print(out, r_simple);
+                        printf("\nrecp   =");
+                        BN_print(out, r_recp);
+                        printf("\nmont   =");
+                        BN_print(out, r_mont);
+                        printf("\nmont_ct  =");
+                        BN_print(out, r_mont_const);
+                        printf("\n");
+                        exit(1);
+                }
+        }
+        BN_free(r_mont);
+        BN_free(r_mont_const);
+        BN_free(r_mont_ct);
+        BN_free(r_mont_nonct);
+        BN_free(r_recp);
+        BN_free(r_simple);
+        BN_free(a);
+        BN_free(b);
+        BN_free(m);
+        BN_CTX_free(ctx);
+        ERR_remove_thread_state(NULL);
+        CRYPTO_mem_leaks(out);
+        BIO_free(out);
+
+        if (test_exp_mod_zero() != 0)
+                goto err;
+
+        return (0);
+
+ err:
+        ERR_load_crypto_strings();
+        ERR_print_errors(out);
+        return (1);
+}