diff -r 000000000000 -r 6474c204b198 security/nss/lib/freebl/mpi/utils/fact.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/security/nss/lib/freebl/mpi/utils/fact.c	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,82 @@
+/*
+ * fact.c
+ *
+ * Compute factorial of input integer
+ *
+ * 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 <string.h>
+
+#include "mpi.h"
+
+mp_err mp_fact(mp_int *a, mp_int *b);
+
+int main(int argc, char *argv[])
+{
+  mp_int  a;
+  mp_err  res;
+
+  if(argc < 2) {
+    fprintf(stderr, "Usage: %s <number>\n", argv[0]);
+    return 1;
+  }
+
+  mp_init(&a);
+  mp_read_radix(&a, argv[1], 10);
+
+  if((res = mp_fact(&a, &a)) != MP_OKAY) {
+    fprintf(stderr, "%s: error: %s\n", argv[0],
+	    mp_strerror(res));
+    mp_clear(&a);
+    return 1;
+  }
+
+  {
+    char  *buf;
+    int    len;
+
+    len = mp_radix_size(&a, 10);
+    buf = malloc(len);
+    mp_todecimal(&a, buf);
+
+    puts(buf);
+
+    free(buf);
+  }
+
+  mp_clear(&a);
+  return 0;
+}
+
+mp_err mp_fact(mp_int *a, mp_int *b)
+{
+  mp_int    ix, s;
+  mp_err    res = MP_OKAY;
+
+  if(mp_cmp_z(a) < 0)
+    return MP_UNDEF;
+
+  mp_init(&s);
+  mp_add_d(&s, 1, &s);   /* s = 1  */
+  mp_init(&ix);
+  mp_add_d(&ix, 1, &ix); /* ix = 1 */
+
+  for(/*  */; mp_cmp(&ix, a) <= 0; mp_add_d(&ix, 1, &ix)) {
+    if((res = mp_mul(&s, &ix, &s)) != MP_OKAY)
+      break;
+  }
+
+  mp_clear(&ix);
+
+  /* Copy out results if we got them */
+  if(res == MP_OKAY)
+    mp_copy(&s, b);
+
+  mp_clear(&s);
+
+  return res;
+}