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]>

/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/*
   Current values evaluated on an AMD A8-6600K (64-bit).
   Type "make tune" to optimize them for your machine but
   be aware that it may take a long time. It took 2:30 minutes
   on the aforementioned machine for example.
 */

#define MP_DEFAULT_KARATSUBA_MUL_CUTOFF 80
#define MP_DEFAULT_KARATSUBA_SQR_CUTOFF 120
#define MP_DEFAULT_TOOM_MUL_CUTOFF      350
#define MP_DEFAULT_TOOM_SQR_CUTOFF      400