Mercurial > dropbear
view libtommath/bn_mp_sqrt.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_SQRT_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* this function is less generic than mp_n_root, simpler and faster */ mp_err mp_sqrt(const mp_int *arg, mp_int *ret) { mp_err err; mp_int t1, t2; /* must be positive */ if (arg->sign == MP_NEG) { return MP_VAL; } /* easy out */ if (MP_IS_ZERO(arg)) { mp_zero(ret); return MP_OKAY; } if ((err = mp_init_copy(&t1, arg)) != MP_OKAY) { return err; } if ((err = mp_init(&t2)) != MP_OKAY) { goto E2; } /* First approx. (not very bad for large arg) */ mp_rshd(&t1, t1.used/2); /* t1 > 0 */ if ((err = mp_div(arg, &t1, &t2, NULL)) != MP_OKAY) { goto E1; } if ((err = mp_add(&t1, &t2, &t1)) != MP_OKAY) { goto E1; } if ((err = mp_div_2(&t1, &t1)) != MP_OKAY) { goto E1; } /* And now t1 > sqrt(arg) */ do { if ((err = mp_div(arg, &t1, &t2, NULL)) != MP_OKAY) { goto E1; } if ((err = mp_add(&t1, &t2, &t1)) != MP_OKAY) { goto E1; } if ((err = mp_div_2(&t1, &t1)) != MP_OKAY) { goto E1; } /* t1 >= sqrt(arg) >= t2 at this point */ } while (mp_cmp_mag(&t1, &t2) == MP_GT); mp_exch(&t1, ret); E1: mp_clear(&t2); E2: mp_clear(&t1); return err; } #endif