Mercurial > dropbear
view libtommath/bn_s_mp_add.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_S_MP_ADD_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* low level addition, based on HAC pp.594, Algorithm 14.7 */ mp_err s_mp_add(const mp_int *a, const mp_int *b, mp_int *c) { const mp_int *x; mp_err err; int olduse, min, max; /* find sizes, we let |a| <= |b| which means we have to sort * them. "x" will point to the input with the most digits */ if (a->used > b->used) { min = b->used; max = a->used; x = a; } else { min = a->used; max = b->used; x = b; } /* init result */ if (c->alloc < (max + 1)) { if ((err = mp_grow(c, max + 1)) != MP_OKAY) { return err; } } /* get old used digit count and set new one */ olduse = c->used; c->used = max + 1; { mp_digit u, *tmpa, *tmpb, *tmpc; int i; /* alias for digit pointers */ /* first input */ tmpa = a->dp; /* second input */ tmpb = b->dp; /* destination */ tmpc = c->dp; /* zero the carry */ u = 0; for (i = 0; i < min; i++) { /* Compute the sum at one digit, T[i] = A[i] + B[i] + U */ *tmpc = *tmpa++ + *tmpb++ + u; /* U = carry bit of T[i] */ u = *tmpc >> (mp_digit)MP_DIGIT_BIT; /* take away carry bit from T[i] */ *tmpc++ &= MP_MASK; } /* now copy higher words if any, that is in A+B * if A or B has more digits add those in */ if (min != max) { for (; i < max; i++) { /* T[i] = X[i] + U */ *tmpc = x->dp[i] + u; /* U = carry bit of T[i] */ u = *tmpc >> (mp_digit)MP_DIGIT_BIT; /* take away carry bit from T[i] */ *tmpc++ &= MP_MASK; } } /* add carry */ *tmpc++ = u; /* clear digits above oldused */ MP_ZERO_DIGITS(tmpc, olduse - c->used); } mp_clamp(c); return MP_OKAY; } #endif