Mercurial > dropbear
view libtommath/bn_mp_reduce_2k.c @ 1855:35d504d59c05
Implement server-side support for sk-ecdsa U2F-backed keys (#142)
* Implement server-side support for sk-ecdsa U2F-backed keys
* Fix out-of-bounds read on normal ecdsa-sha2-[identifier] keys
* Fix one more potential out-of-bounds read
* Check if nistp256 curve is used in sk-ecdsa-sha2- key
It's the only allowed curve per PROTOCOL.u2f specification
* Implement server-side support for sk-ed25519 FIDO2-backed keys
* Keys with type sk-* make no sense as host keys, so they should be
disabled
* fix typo
* Make sk-ecdsa call buf_ecdsa_verify
This reduces code duplication, the SK code just handles the
different message format.
* Reduce sk specific code
The application id can be stored in signkey, then we don't need
to call sk-specific functions from svr-authpubkey
* Remove debugging output, which causes compilation errors with DEBUG_TRACE disabled
* Proper cleanup of sk_app
Co-authored-by: Matt Johnston <[email protected]>
author | egor-duda <egor-duda@users.noreply.github.com> |
---|---|
date | Sat, 22 Jan 2022 16:53:04 +0300 |
parents | 1051e4eea25a |
children |
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#include "tommath_private.h" #ifdef BN_MP_REDUCE_2K_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* reduces a modulo n where n is of the form 2**p - d */ mp_err mp_reduce_2k(mp_int *a, const mp_int *n, mp_digit d) { mp_int q; mp_err err; int p; if ((err = mp_init(&q)) != MP_OKAY) { return err; } p = mp_count_bits(n); top: /* q = a/2**p, a = a mod 2**p */ if ((err = mp_div_2d(a, p, &q, a)) != MP_OKAY) { goto LBL_ERR; } if (d != 1u) { /* q = q * d */ if ((err = mp_mul_d(&q, d, &q)) != MP_OKAY) { goto LBL_ERR; } } /* a = a + q */ if ((err = s_mp_add(a, &q, a)) != MP_OKAY) { goto LBL_ERR; } if (mp_cmp_mag(a, n) != MP_LT) { if ((err = s_mp_sub(a, n, a)) != MP_OKAY) { goto LBL_ERR; } goto top; } LBL_ERR: mp_clear(&q); return err; } #endif