view libtommath/bn_mp_clamp.c @ 1861:2b3a8026a6ce

Add re-exec for server This allows ASLR to re-randomize the address space for every connection, preventing some vulnerabilities from being exploitable by repeated probing. Overhead (memory and time) is yet to be confirmed. At present this is only enabled on Linux. Other BSD platforms with fexecve() would probably also work though have not been tested.
author Matt Johnston <matt@ucc.asn.au>
date Sun, 30 Jan 2022 10:14:56 +0800
parents 1051e4eea25a
children
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#include "tommath_private.h"
#ifdef BN_MP_CLAMP_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */

/* trim unused digits
 *
 * This is used to ensure that leading zero digits are
 * trimed and the leading "used" digit will be non-zero
 * Typically very fast.  Also fixes the sign if there
 * are no more leading digits
 */
void mp_clamp(mp_int *a)
{
   /* decrease used while the most significant digit is
    * zero.
    */
   while ((a->used > 0) && (a->dp[a->used - 1] == 0u)) {
      --(a->used);
   }

   /* reset the sign flag if used == 0 */
   if (a->used == 0) {
      a->sign = MP_ZPOS;
   }
}
#endif