Mercurial > dropbear
view libtommath/bn_s_mp_mul_high_digs.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_MUL_HIGH_DIGS_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* multiplies |a| * |b| and does not compute the lower digs digits * [meant to get the higher part of the product] */ mp_err s_mp_mul_high_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs) { mp_int t; int pa, pb, ix, iy; mp_err err; mp_digit u; mp_word r; mp_digit tmpx, *tmpt, *tmpy; /* can we use the fast multiplier? */ if (MP_HAS(S_MP_MUL_HIGH_DIGS_FAST) && ((a->used + b->used + 1) < MP_WARRAY) && (MP_MIN(a->used, b->used) < MP_MAXFAST)) { return s_mp_mul_high_digs_fast(a, b, c, digs); } if ((err = mp_init_size(&t, a->used + b->used + 1)) != MP_OKAY) { return err; } t.used = a->used + b->used + 1; pa = a->used; pb = b->used; for (ix = 0; ix < pa; ix++) { /* clear the carry */ u = 0; /* left hand side of A[ix] * B[iy] */ tmpx = a->dp[ix]; /* alias to the address of where the digits will be stored */ tmpt = &(t.dp[digs]); /* alias for where to read the right hand side from */ tmpy = b->dp + (digs - ix); for (iy = digs - ix; iy < pb; iy++) { /* calculate the double precision result */ r = (mp_word)*tmpt + ((mp_word)tmpx * (mp_word)*tmpy++) + (mp_word)u; /* get the lower part */ *tmpt++ = (mp_digit)(r & (mp_word)MP_MASK); /* carry the carry */ u = (mp_digit)(r >> (mp_word)MP_DIGIT_BIT); } *tmpt = u; } mp_clamp(&t); mp_exch(&t, c); mp_clear(&t); return MP_OKAY; } #endif