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]>

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */
#include "tomcrypt.h"

/**
  @file crypt_cipher_is_valid.c
  Determine if cipher is valid, Tom St Denis
*/

/*
   Test if a cipher index is valid
   @param idx   The index of the cipher to search for
   @return CRYPT_OK if valid
*/
int cipher_is_valid(int idx)
{
   LTC_MUTEX_LOCK(&ltc_cipher_mutex);
   if (idx < 0 || idx >= TAB_SIZE || cipher_descriptor[idx].name == NULL) {
      LTC_MUTEX_UNLOCK(&ltc_cipher_mutex);
      return CRYPT_INVALID_CIPHER;
   }
   LTC_MUTEX_UNLOCK(&ltc_cipher_mutex);
   return CRYPT_OK;
}

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