From: tb <tb@openbsd.org>
Date: Thu, 19 Oct 2023 13:38:12 +0000 (+0000)
Subject: Add a few more test cases for mod_exp aliasing
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=24882d0aebd3074ff4e57dba8113fde1c67534b0;p=openbsd

Add a few more test cases for mod_exp aliasing
---

diff --git a/regress/lib/libcrypto/bn/bn_mod_exp.c b/regress/lib/libcrypto/bn/bn_mod_exp.c
index 61157385bfa..98b6a5d2efe 100644
--- a/regress/lib/libcrypto/bn/bn_mod_exp.c
+++ b/regress/lib/libcrypto/bn/bn_mod_exp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bn_mod_exp.c,v 1.39 2023/10/19 10:17:24 tb Exp $ */
+/*	$OpenBSD: bn_mod_exp.c,v 1.40 2023/10/19 13:38:12 tb Exp $ */
 
 /*
  * Copyright (c) 2022,2023 Theo Buehler <tb@openbsd.org>
@@ -561,6 +561,51 @@ test_bn_mod_exp2_mont_crash(void)
 	return failed;
 }
 
+const struct aliasing_test_case {
+	BN_ULONG a;
+	BN_ULONG p;
+	BN_ULONG m;
+} aliasing_test_cases[] = {
+	{
+		.a = 1031,
+		.p = 1033,
+		.m = 1039,
+	},
+	{
+		.a = 3,
+		.p = 4,
+		.m = 5,
+	},
+	{
+		.a = 97,
+		.p = 17,
+		.m = 11,
+	},
+	{
+		.a = 999961,
+		.p = 999979,
+		.m = 999983,
+	},
+};
+
+#define N_ALIASING_TEST_CASES \
+	(sizeof(aliasing_test_cases) / sizeof(aliasing_test_cases[0]))
+
+static void
+test_bn_mod_exp_aliasing_setup(BIGNUM *want, BIGNUM *a, BIGNUM *p, BIGNUM *m,
+    BN_CTX *ctx, const struct aliasing_test_case *tc)
+{
+	if (!BN_set_word(a, tc->a))
+		errx(1, "BN_set_word");
+	if (!BN_set_word(p, tc->p))
+		errx(1, "BN_set_word");
+	if (!BN_set_word(m, tc->m))
+		errx(1, "BN_set_word");
+
+	if (!BN_mod_exp_simple(want, a, p, m, ctx))
+		errx(1, "BN_mod_exp");
+}
+
 static int
 test_mod_exp_aliased(const char *alias, int want_ret, BIGNUM *got,
     const BIGNUM *want, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,
@@ -576,8 +621,10 @@ test_mod_exp_aliased(const char *alias, int want_ret, BIGNUM *got,
 	else
 		mod_exp_ret = test->mod_exp_mont_fn(got, a, p, m, ctx, NULL);
 
-	if (mod_exp_ret != want_ret)
-		errx(1, "%s() %s aliased with result failed", test->name, alias);
+	if (mod_exp_ret != want_ret) {
+		warnx("%s() %s aliased with result failed", test->name, alias);
+		goto err;
+	}
 
 	if (!mod_exp_ret)
 		goto done;
@@ -596,19 +643,34 @@ test_mod_exp_aliased(const char *alias, int want_ret, BIGNUM *got,
 	return ret;
 }
 
-static void
-test_bn_mod_exp_aliasing_setup(BIGNUM *want, BIGNUM *a, BIGNUM *p, BIGNUM *m,
-    BN_CTX *ctx)
+static int
+test_bn_mod_exp_aliasing_test(const struct mod_exp_test *test,
+    BIGNUM *a, BIGNUM *p, BIGNUM *m, BIGNUM *want, BIGNUM *got, BN_CTX *ctx)
 {
-	if (!BN_set_word(a, 1031))
-		errx(1, "BN_set_word");
-	if (!BN_set_word(p, 1033))
-		errx(1, "BN_set_word");
-	if (!BN_set_word(m, 1039))
-		errx(1, "BN_set_word");
+	int modulus_alias_works = test->mod_exp_fn != BN_mod_exp_simple;
+	size_t i;
+	int failed = 0;
 
-	if (!BN_mod_exp_simple(want, a, p, m, ctx))
-		errx(1, "BN_mod_exp");
+	for (i = 0; i < N_ALIASING_TEST_CASES; i++) {
+		const struct aliasing_test_case *tc = &aliasing_test_cases[i];
+
+		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx, tc);
+		if (!test_mod_exp_aliased("nothing", 1, got, want, a, p, m, ctx,
+		    test))
+			failed |= 1;
+		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx, tc);
+		if (!test_mod_exp_aliased("a", 1, a, want, a, p, m, ctx, test))
+			failed |= 1;
+		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx, tc);
+		if (!test_mod_exp_aliased("p", 1, p, want, a, p, m, ctx, test))
+			failed |= 1;
+		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx, tc);
+		if (!test_mod_exp_aliased("m", modulus_alias_works, m, want,
+		    a, p, m, ctx, test))
+			failed |= 1;
+	}
+
+	return failed;
 }
 
 static int
@@ -637,25 +699,8 @@ test_bn_mod_exp_aliasing(void)
 
 	for (i = 0; i < N_MOD_EXP_FN; i++) {
 		const struct mod_exp_test *test = &mod_exp_fn[i];
-		int aliasing_allowed = 1;
-
-		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx);
-		if (!test_mod_exp_aliased("nothing", 1, got, want, a, p, m, ctx,
-		    test))
-			failed |= 1;
-		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx);
-		if (!test_mod_exp_aliased("a", 1, a, want, a, p, m, ctx, test))
-			failed |= 1;
-		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx);
-		if (!test_mod_exp_aliased("p", 1, p, want, a, p, m, ctx, test))
-			failed |= 1;
-
-		if (test->mod_exp_fn == BN_mod_exp_simple)
-			aliasing_allowed = 0;
-		test_bn_mod_exp_aliasing_setup(want, a, p, m, ctx);
-		if (!test_mod_exp_aliased("m", aliasing_allowed, m, want,
-		    a, p, m, ctx, test))
-			failed |= 1;
+		failed |= test_bn_mod_exp_aliasing_test(test, a, p, m,
+		    want, got, ctx);
 	}
 
 	BN_CTX_end(ctx);