Add a few more test cases for mod_exp aliasing

1 files changed, 78 insertions, 33 deletions

diff --git a/src/regress/lib/libcrypto/bn/bn_mod_exp.c b/src/regress/lib/libcrypto/bn/bn_mod_exp.c
index 61157385bf..98b6a5d2ef 100644
--- a/src/regress/lib/libcrypto/bn/bn_mod_exp.c
+++ b/src/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);