1 files changed, 184 insertions, 75 deletions

diff --git a/src/regress/lib/libcrypto/exp/exptest.c b/src/regress/lib/libcrypto/exp/exptest.c
index 5f9b663a26..45ca5ac5f5 100644
--- a/src/regress/lib/libcrypto/exp/exptest.c
+++ b/src/regress/lib/libcrypto/exp/exptest.c
@@ -5,21 +5,21 @@
  * 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:
@@ -34,10 +34,10 @@
  *     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 
+ * 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
@@ -49,7 +49,7 @@
  * 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
@@ -66,110 +66,213 @@
 
 #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, p, m;
+        BIGNUM r;
+        BN_ULONG one_word = 1;
+        BN_CTX *ctx = BN_CTX_new();
+        int ret = 1, failed = 0;
+
+        BN_init(&m);
+        BN_one(&m);
+
+        BN_init(&a);
+        BN_one(&a);
+
+        BN_init(&p);
+        BN_zero(&p);
+
+        BN_init(&r);
+
+        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_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_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[])
-        {
+{
         BN_CTX *ctx;
-        BIO *out=NULL;
-        int i,ret;
+        BIO *out = NULL;
+        int i, ret;
         unsigned char c;
-        BIGNUM *r_mont,*r_mont_const,*r_recp,*r_simple,*a,*b,*m;
+        BIGNUM *r_mont, *r_mont_const, *r_recp, *r_simple, *a, *b, *m;
 
         ERR_load_BN_strings();
 
-        ctx=BN_CTX_new();
-        if (ctx == NULL) exit(1);
-        r_mont=BN_new();
-        r_mont_const=BN_new();
-        r_recp=BN_new();
-        r_simple=BN_new();
-        a=BN_new();
-        b=BN_new();
-        m=BN_new();
-        if (    (r_mont == NULL) || (r_recp == NULL) ||
-                (a == NULL) || (b == NULL))
+        ctx = BN_CTX_new();
+        if (ctx == NULL)
+                exit(1);
+        r_mont = BN_new();
+        r_mont_const = BN_new();
+        r_recp = BN_new();
+        r_simple = BN_new();
+        a = BN_new();
+        b = BN_new();
+        m = BN_new();
+        if ((r_mont == NULL) || (r_recp == NULL) || (a == NULL) || (b == NULL))
                 goto err;
 
-        out=BIO_new(BIO_s_file());
+        out = BIO_new(BIO_s_file());
 
-        if (out == NULL) exit(1);
-        BIO_set_fp(out,stdout,BIO_NOCLOSE);
+        if (out == 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);
+        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(b, NUM_BITS + c, 0, 0);
 
-                arc4random_buf(&c,1);
-                c=(c%BN_BITS)-BN_BITS2;
-                BN_rand(m,NUM_BITS+c,0,1);
+                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);
+                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)
-                        {
+                ret = BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL);
+                if (ret <= 0) {
                         printf("BN_mod_exp_mont() problems\n");
                         ERR_print_errors(out);
                         exit(1);
-                        }
+                }
 
-                ret=BN_mod_exp_recp(r_recp,a,b,m,ctx);
-                if (ret <= 0)
-                        {
+                ret = BN_mod_exp_recp(r_recp, a, b, m, ctx);
+                if (ret <= 0) {
                         printf("BN_mod_exp_recp() problems\n");
                         ERR_print_errors(out);
                         exit(1);
-                        }
+                }
 
-                ret=BN_mod_exp_simple(r_simple,a,b,m,ctx);
-                if (ret <= 0)
-                        {
+                ret = BN_mod_exp_simple(r_simple, a, b, m, ctx);
+                if (ret <= 0) {
                         printf("BN_mod_exp_simple() problems\n");
                         ERR_print_errors(out);
                         exit(1);
-                        }
+                }
 
-                ret=BN_mod_exp_mont_consttime(r_mont_const,a,b,m,ctx,NULL);
-                if (ret <= 0)
-                        {
+                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");
                         ERR_print_errors(out);
                         exit(1);
-                        }
+                }
 
                 if (BN_cmp(r_simple, r_mont) == 0
-                    && BN_cmp(r_simple,r_recp) == 0
-                        && BN_cmp(r_simple,r_mont_const) == 0)
-                        {
+                        && BN_cmp(r_simple, r_recp) == 0
+                        && BN_cmp(r_simple, r_mont_const) == 0) {
                         printf(".");
                         fflush(stdout);
-                        }
-                else
-                        {
-                        if (BN_cmp(r_simple,r_mont) != 0)
+                } else {
+                        if (BN_cmp(r_simple, r_mont) != 0)
                                 printf("\nsimple and mont results differ\n");
-                        if (BN_cmp(r_simple,r_mont_const) != 0)
+                        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)
+                        if (BN_cmp(r_simple, r_recp) != 0)
                                 printf("\nsimple and recp 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("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_recp);
@@ -181,10 +284,16 @@ int main(int argc, char *argv[])
         ERR_remove_thread_state(NULL);
         CRYPTO_mem_leaks(out);
         BIO_free(out);
-        printf(" done\n");
-        exit(0);
-err:
+        printf("\n");
+
+        if (test_exp_mod_zero() != 0)
+                goto err;
+
+        printf("done\n");
+
+        return (0);
+ err:
         ERR_load_crypto_strings();
         ERR_print_errors(out);
-        exit(1);
-        }
+        return (1);
+}