1 files changed, 84 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/mpi/utils/identest.c b/security/nss/lib/freebl/mpi/utils/identest.c
new file mode 100644
index 000000000..321d2c2b0
--- /dev/null
+++ b/security/nss/lib/freebl/mpi/utils/identest.c
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "mpi.h"
+#include "mpprime.h"
+#include <sys/types.h>
+#include <time.h>
+
+#define MAX_PREC (4096 / MP_DIGIT_BIT)
+
+mp_err
+identity_test(void)
+{
+    mp_size preca, precb;
+    mp_err res;
+    mp_int a, b;
+    mp_int t1, t2, t3, t4, t5;
+
+    preca = (rand() % MAX_PREC) + 1;
+    precb = (rand() % MAX_PREC) + 1;
+
+    MP_DIGITS(&a) = 0;
+    MP_DIGITS(&b) = 0;
+    MP_DIGITS(&t1) = 0;
+    MP_DIGITS(&t2) = 0;
+    MP_DIGITS(&t3) = 0;
+    MP_DIGITS(&t4) = 0;
+    MP_DIGITS(&t5) = 0;
+
+    MP_CHECKOK(mp_init(&a));
+    MP_CHECKOK(mp_init(&b));
+    MP_CHECKOK(mp_init(&t1));
+    MP_CHECKOK(mp_init(&t2));
+    MP_CHECKOK(mp_init(&t3));
+    MP_CHECKOK(mp_init(&t4));
+    MP_CHECKOK(mp_init(&t5));
+
+    MP_CHECKOK(mpp_random_size(&a, preca));
+    MP_CHECKOK(mpp_random_size(&b, precb));
+
+    if (mp_cmp(&a, &b) < 0)
+        mp_exch(&a, &b);
+
+    MP_CHECKOK(mp_mod(&a, &b, &t1));       /* t1 = a%b */
+    MP_CHECKOK(mp_div(&a, &b, &t2, NULL)); /* t2 = a/b */
+    MP_CHECKOK(mp_mul(&b, &t2, &t3));      /* t3 = (a/b)*b */
+    MP_CHECKOK(mp_add(&t1, &t3, &t4));     /* t4 = a%b + (a/b)*b */
+    MP_CHECKOK(mp_sub(&t4, &a, &t5));      /* t5 = a%b + (a/b)*b - a */
+    if (mp_cmp_z(&t5) != 0) {
+        res = MP_UNDEF;
+        goto CLEANUP;
+    }
+
+CLEANUP:
+    mp_clear(&t5);
+    mp_clear(&t4);
+    mp_clear(&t3);
+    mp_clear(&t2);
+    mp_clear(&t1);
+    mp_clear(&b);
+    mp_clear(&a);
+    return res;
+}
+
+int
+main(void)
+{
+    unsigned int seed = (unsigned int)time(NULL);
+    unsigned long count = 0;
+    mp_err res;
+
+    srand(seed);
+
+    while (MP_OKAY == (res = identity_test())) {
+        if ((++count % 100) == 0)
+            fputc('.', stderr);
+    }
+
+    fprintf(stderr, "\ntest failed, err %d\n", res);
+    return res;
+}