Mercurial > dropbear
view libtommath/bn_mp_rshd.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_RSHD_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* shift right a certain amount of digits */ void mp_rshd(mp_int *a, int b) { int x; mp_digit *bottom, *top; /* if b <= 0 then ignore it */ if (b <= 0) { return; } /* if b > used then simply zero it and return */ if (a->used <= b) { mp_zero(a); return; } /* shift the digits down */ /* bottom */ bottom = a->dp; /* top [offset into digits] */ top = a->dp + b; /* this is implemented as a sliding window where * the window is b-digits long and digits from * the top of the window are copied to the bottom * * e.g. b-2 | b-1 | b0 | b1 | b2 | ... | bb | ----> /\ | ----> \-------------------/ ----> */ for (x = 0; x < (a->used - b); x++) { *bottom++ = *top++; } /* zero the top digits */ MP_ZERO_DIGITS(bottom, a->used - x); /* remove excess digits */ a->used -= b; } #endif