#include "includes.h"

#if DROPBEAR_SK_ED25519

#include "dbutil.h"

#include "buffer.h"

#include "curve25519.h"

#include "ed25519.h"

#include "ssh.h"

int buf_sk_ed25519_verify(buffer *buf, const dropbear_ed25519_key *key, const buffer *data_buf,

      const char* app, unsigned int applen,

      unsigned char sk_flags_mask) {

  int ret = DROPBEAR_FAILURE;

  unsigned char *s;

  unsigned long slen;

  hash_state hs;

  unsigned char hash[SHA256_HASH_SIZE];

  buffer *sk_buffer = NULL;

  unsigned char flags;

  unsigned int counter;

  TRACE(("enter buf_sk_ed25519_verify"))

  dropbear_assert(key != NULL);

  slen = buf_getint(buf);

  if (slen != 64 || buf->len - buf->pos < slen) {

    TRACE(("leave buf_sk_ed25519_verify: bad size"))

    goto out;

  }

  s = buf_getptr(buf, slen);

  buf_incrpos(buf, slen);

  flags = buf_getbyte (buf);

  counter = buf_getint (buf);

  /* create the message to be signed */

  sk_buffer = buf_new (2*SHA256_HASH_SIZE+5);

  sha256_init (&hs);

  sha256_process (&hs, app, applen);

  sha256_done (&hs, hash);

  buf_putbytes (sk_buffer, hash, sizeof (hash));

  buf_putbyte (sk_buffer, flags);

  buf_putint (sk_buffer, counter);

  sha256_init (&hs);

  sha256_process (&hs, data_buf->data, data_buf->len);

  sha256_done (&hs, hash);

  buf_putbytes (sk_buffer, hash, sizeof (hash));

  if (dropbear_ed25519_verify(sk_buffer->data, sk_buffer->len,

            s, slen, key->pub) == 0) {

    /* signature is valid */

    TRACE(("leave buf_sk_ed25519_verify: success!"))

    ret = DROPBEAR_SUCCESS;

  }

  if (~flags & sk_flags_mask & SSH_SK_USER_PRESENCE_REQD) {

    if (ret == DROPBEAR_SUCCESS) {

      dropbear_log(LOG_WARNING, "Rejecting, user-presence not set");

    }

    ret = DROPBEAR_FAILURE;

  }

  if (~flags & sk_flags_mask & SSH_SK_USER_VERIFICATION_REQD) {

    if (ret == DROPBEAR_SUCCESS) {

      dropbear_log(LOG_WARNING, "Rejecting, user-verification not set");

    }

    ret = DROPBEAR_FAILURE;

  }

out:

  buf_free(sk_buffer);

  TRACE(("leave buf_sk_ed25519_verify: ret %d", ret))

  return ret;

}

#endif /* DROPBEAR_SK_ED25519 */