/*  $OpenBSD: sshbuf-getput-crypto.c,v 1.12 2024/08/15 00:51:51 djm Exp $ */

/*

 * Copyright (c) 2011 Damien Miller

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include "includes.h"

#include <sys/types.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#ifdef WITH_OPENSSL

#include <openssl/bn.h>

#include <openssl/ec.h>

#include "ssherr.h"

#define SSHBUF_INTERNAL

#include "sshbuf.h"

int

sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp)

{

  BIGNUM *v;

  const u_char *d;

  size_t len;

  int r;

  if (valp != NULL)

    *valp = NULL;

  if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0)

    return r;

  if (valp != NULL) {

    if ((v = BN_new()) == NULL ||

        BN_bin2bn(d, len, v) == NULL) {

      BN_clear_free(v);

      return SSH_ERR_ALLOC_FAIL;

    }

    *valp = v;

  }

  return 0;

}

static int

get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g)

{

  /* Refuse overlong bignums */

  if (len == 0 || len > SSHBUF_MAX_ECPOINT)

    return SSH_ERR_ECPOINT_TOO_LARGE;

  /* Only handle uncompressed points */

  if (*d != POINT_CONVERSION_UNCOMPRESSED)

    return SSH_ERR_INVALID_FORMAT;

  if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1)

    return SSH_ERR_INVALID_FORMAT; /* XXX assumption */

  return 0;

}

int

sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)

{

  const u_char *d;

  size_t len;

  int r;

  if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)

    return r;

  if ((r = get_ec(d, len, v, g)) != 0)

    return r;

  /* Skip string */

  if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {

    /* Shouldn't happen */

    SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));

    SSHBUF_ABORT();

    return SSH_ERR_INTERNAL_ERROR;

  }

  return 0;

}

int

sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)

{

  EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v));

  int r;

  const u_char *d;

  size_t len;

  if (pt == NULL) {

    SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));

    return SSH_ERR_ALLOC_FAIL;

  }

  if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {

    EC_POINT_free(pt);

    return r;

  }

  if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) {

    EC_POINT_free(pt);

    return r;

  }

  if (EC_KEY_set_public_key(v, pt) != 1) {

    EC_POINT_free(pt);

    return SSH_ERR_ALLOC_FAIL; /* XXX assumption */

  }

  EC_POINT_free(pt);

  /* Skip string */

  if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {

    /* Shouldn't happen */

    SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));

    SSHBUF_ABORT();

    return SSH_ERR_INTERNAL_ERROR;

  }

  return 0;

}

int

sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v)

{

  u_char d[SSHBUF_MAX_BIGNUM + 1];

  int len = BN_num_bytes(v), prepend = 0, r;

  if (len < 0 || len > SSHBUF_MAX_BIGNUM)

    return SSH_ERR_INVALID_ARGUMENT;

  *d = '\0';

  if (BN_bn2bin(v, d + 1) != len)

    return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */

  /* If MSB is set, prepend a \0 */

  if (len > 0 && (d[1] & 0x80) != 0)

    prepend = 1;

  if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) {

    explicit_bzero(d, sizeof(d));

    return r;

  }

  explicit_bzero(d, sizeof(d));

  return 0;

}

int

sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)

{

  u_char d[SSHBUF_MAX_ECPOINT];

  size_t len;

  int ret;

  if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,

      NULL, 0, NULL)) > SSHBUF_MAX_ECPOINT) {

    return SSH_ERR_INVALID_ARGUMENT;

  }

  if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,

      d, len, NULL) != len) {

    return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */

  }

  ret = sshbuf_put_string(buf, d, len);

  explicit_bzero(d, len);

  return ret;

}

int

sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v)

{

  return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v),

      EC_KEY_get0_group(v));

}

int

sshbuf_put_ec_pkey(struct sshbuf *buf, EVP_PKEY *pkey)

{

  const EC_KEY *ec;

  if ((ec = EVP_PKEY_get0_EC_KEY(pkey)) == NULL)

    return SSH_ERR_LIBCRYPTO_ERROR;

  return sshbuf_put_eckey(buf, ec);

}

#endif /* WITH_OPENSSL */