Mercurial > dropbear
view libtommath/bn_mp_expt_u32.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_EXPT_U32_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* calculate c = a**b using a square-multiply algorithm */ mp_err mp_expt_u32(const mp_int *a, uint32_t b, mp_int *c) { mp_err err; mp_int g; if ((err = mp_init_copy(&g, a)) != MP_OKAY) { return err; } /* set initial result */ mp_set(c, 1uL); while (b > 0u) { /* if the bit is set multiply */ if ((b & 1u) != 0u) { if ((err = mp_mul(c, &g, c)) != MP_OKAY) { goto LBL_ERR; } } /* square */ if (b > 1u) { if ((err = mp_sqr(&g, &g)) != MP_OKAY) { goto LBL_ERR; } } /* shift to next bit */ b >>= 1; } err = MP_OKAY; LBL_ERR: mp_clear(&g); return err; } #endif