Mercurial > dropbear
view libtommath/bn_mp_cnt_lsb.c @ 1885:5d8dbb6fdab7
Fix SSH_PUBKEYINFO, limit characters, add tests
We fix a bad_bufptr() failure from a previous commit. We now limit
the allowed characters to those that will definitely be safe
in a shell. Some scripts/programs may use arbitrary environment
variables without escaping correctly - that could be a problem
in a restricted environment.
The current allowed set is a-z A-Z 0-9 .,_-+@
This also adds a test for SSH_PUBKEYINFO, by default it only runs
under github actions (or "act -j build").
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Wed, 16 Mar 2022 17:17:23 +0800 |
parents | 1051e4eea25a |
children |
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#include "tommath_private.h" #ifdef BN_MP_CNT_LSB_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ static const int lnz[16] = { 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 }; /* Counts the number of lsbs which are zero before the first zero bit */ int mp_cnt_lsb(const mp_int *a) { int x; mp_digit q, qq; /* easy out */ if (MP_IS_ZERO(a)) { return 0; } /* scan lower digits until non-zero */ for (x = 0; (x < a->used) && (a->dp[x] == 0u); x++) {} q = a->dp[x]; x *= MP_DIGIT_BIT; /* now scan this digit until a 1 is found */ if ((q & 1u) == 0u) { do { qq = q & 15u; x += lnz[qq]; q >>= 4; } while (qq == 0u); } return x; } #endif