/*  $OpenBSD: sshbuf-getput-basic.c,v 1.13 2022/05/25 06:03:44 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.

 */

#define SSHBUF_INTERNAL

#include "includes.h"

#include <sys/types.h>

#include <stdarg.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <stdint.h>

#include "ssherr.h"

#include "sshbuf.h"

int

sshbuf_get(struct sshbuf *buf, void *v, size_t len)

{

  const u_char *p = sshbuf_ptr(buf);

  int r;

  if ((r = sshbuf_consume(buf, len)) < 0)

    return r;

  if (v != NULL && len != 0)

    memcpy(v, p, len);

  return 0;

}

int

sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp)

{

  const u_char *p = sshbuf_ptr(buf);

  int r;

  if ((r = sshbuf_consume(buf, 8)) < 0)

    return r;

  if (valp != NULL)

    *valp = PEEK_U64(p);

  return 0;

}

int

sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp)

{

  const u_char *p = sshbuf_ptr(buf);

  int r;

  if ((r = sshbuf_consume(buf, 4)) < 0)

    return r;

  if (valp != NULL)

    *valp = PEEK_U32(p);

  return 0;

}

int

sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp)

{

  const u_char *p = sshbuf_ptr(buf);

  int r;

  if ((r = sshbuf_consume(buf, 2)) < 0)

    return r;

  if (valp != NULL)

    *valp = PEEK_U16(p);

  return 0;

}

int

sshbuf_get_u8(struct sshbuf *buf, u_char *valp)

{

  const u_char *p = sshbuf_ptr(buf);

  int r;

  if ((r = sshbuf_consume(buf, 1)) < 0)

    return r;

  if (valp != NULL)

    *valp = (u_int8_t)*p;

  return 0;

}

static int

check_offset(const struct sshbuf *buf, int wr, size_t offset, size_t len)

{

  if (sshbuf_ptr(buf) == NULL) /* calls sshbuf_check_sanity() */

    return SSH_ERR_INTERNAL_ERROR;

  if (offset >= SIZE_MAX - len)

    return SSH_ERR_INVALID_ARGUMENT;

  if (offset + len > sshbuf_len(buf)) {

    return wr ?

        SSH_ERR_NO_BUFFER_SPACE : SSH_ERR_MESSAGE_INCOMPLETE;

  }

  return 0;

}

static int

check_roffset(const struct sshbuf *buf, size_t offset, size_t len,

    const u_char **p)

{

  int r;

  *p = NULL;

  if ((r = check_offset(buf, 0, offset, len)) != 0)

    return r;

  *p = sshbuf_ptr(buf) + offset;

  return 0;

}

int

sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, u_int64_t *valp)

{

  const u_char *p = NULL;

  int r;

  if (valp != NULL)

    *valp = 0;

  if ((r = check_roffset(buf, offset, 8, &p)) != 0)

    return r;

  if (valp != NULL)

    *valp = PEEK_U64(p);

  return 0;

}

int

sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, u_int32_t *valp)

{

  const u_char *p = NULL;

  int r;

  if (valp != NULL)

    *valp = 0;

  if ((r = check_roffset(buf, offset, 4, &p)) != 0)

    return r;

  if (valp != NULL)

    *valp = PEEK_U32(p);

  return 0;

}

int

sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, u_int16_t *valp)

{

  const u_char *p = NULL;

  int r;

  if (valp != NULL)

    *valp = 0;

  if ((r = check_roffset(buf, offset, 2, &p)) != 0)

    return r;

  if (valp != NULL)

    *valp = PEEK_U16(p);

  return 0;

}

int

sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, u_char *valp)

{

  const u_char *p = NULL;

  int r;

  if (valp != NULL)

    *valp = 0;

  if ((r = check_roffset(buf, offset, 1, &p)) != 0)

    return r;

  if (valp != NULL)

    *valp = *p;

  return 0;

}

int

sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp)

{

  const u_char *val;

  size_t len;

  int r;

  if (valp != NULL)

    *valp = NULL;

  if (lenp != NULL)

    *lenp = 0;

  if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0)

    return r;

  if (valp != NULL) {

    if ((*valp = malloc(len + 1)) == NULL) {

      SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));

      return SSH_ERR_ALLOC_FAIL;

    }

    if (len != 0)

      memcpy(*valp, val, len);

    (*valp)[len] = '\0';

  }

  if (lenp != NULL)

    *lenp = len;

  return 0;

}

int

sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp)

{

  size_t len;

  const u_char *p;

  int r;

  if (valp != NULL)

    *valp = NULL;

  if (lenp != NULL)

    *lenp = 0;

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

    return r;

  if (valp != NULL)

    *valp = p;

  if (lenp != NULL)

    *lenp = len;

  if (sshbuf_consume(buf, len + 4) != 0) {

    /* Shouldn't happen */

    SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));

    SSHBUF_ABORT();

    return SSH_ERR_INTERNAL_ERROR;

  }

  return 0;

}

int

sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,

    size_t *lenp)

{

  u_int32_t len;

  const u_char *p = sshbuf_ptr(buf);

  if (valp != NULL)

    *valp = NULL;

  if (lenp != NULL)

    *lenp = 0;

  if (sshbuf_len(buf) < 4) {

    SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));

    return SSH_ERR_MESSAGE_INCOMPLETE;

  }

  len = PEEK_U32(p);

  if (len > SSHBUF_SIZE_MAX - 4) {

    SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE"));

    return SSH_ERR_STRING_TOO_LARGE;

  }

  if (sshbuf_len(buf) - 4 < len) {

    SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));

    return SSH_ERR_MESSAGE_INCOMPLETE;

  }

  if (valp != NULL)

    *valp = p + 4;

  if (lenp != NULL)

    *lenp = len;

  return 0;

}

int

sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp)

{

  size_t len;

  const u_char *p, *z;

  int r;

  if (valp != NULL)

    *valp = NULL;

  if (lenp != NULL)

    *lenp = 0;

  if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)

    return r;

  /* Allow a \0 only at the end of the string */

  if (len > 0 &&

      (z = memchr(p , '\0', len)) != NULL && z < p + len - 1) {

    SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT"));

    return SSH_ERR_INVALID_FORMAT;

  }

  if ((r = sshbuf_skip_string(buf)) != 0)

    return -1;

  if (valp != NULL) {

    if ((*valp = malloc(len + 1)) == NULL) {

      SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));

      return SSH_ERR_ALLOC_FAIL;

    }

    if (len != 0)

      memcpy(*valp, p, len);

    (*valp)[len] = '\0';

  }

  if (lenp != NULL)

    *lenp = (size_t)len;

  return 0;

}

int

sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v)

{

  u_int32_t len;

  u_char *p;

  int r;

  /*

   * Use sshbuf_peek_string_direct() to figure out if there is

   * a complete string in 'buf' and copy the string directly

   * into 'v'.

   */

  if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 ||

      (r = sshbuf_get_u32(buf, &len)) != 0 ||

      (r = sshbuf_reserve(v, len, &p)) != 0 ||

      (r = sshbuf_get(buf, p, len)) != 0)

    return r;

  return 0;

}

int

sshbuf_put(struct sshbuf *buf, const void *v, size_t len)

{

  u_char *p;

  int r;

  if ((r = sshbuf_reserve(buf, len, &p)) < 0)

    return r;

  if (len != 0)

    memcpy(p, v, len);

  return 0;

}

int

sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v)

{

  if (v == NULL)

    return 0;

  return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v));

}

int

sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)

{

  va_list ap;

  int r;

  va_start(ap, fmt);

  r = sshbuf_putfv(buf, fmt, ap);

  va_end(ap);

  return r;

}

int

sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap)

{

  va_list ap2;

  int r, len;

  u_char *p;

  VA_COPY(ap2, ap);

  if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) {

    r = SSH_ERR_INVALID_ARGUMENT;

    goto out;

  }

  if (len == 0) {

    r = 0;

    goto out; /* Nothing to do */

  }

  va_end(ap2);

  VA_COPY(ap2, ap);

  if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0)

    goto out;

  if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) {

    r = SSH_ERR_INTERNAL_ERROR;

    goto out; /* Shouldn't happen */

  }

  /* Consume terminating \0 */

  if ((r = sshbuf_consume_end(buf, 1)) != 0)

    goto out;

  r = 0;

 out:

  va_end(ap2);

  return r;

}

int

sshbuf_put_u64(struct sshbuf *buf, u_int64_t val)

{

  u_char *p;

  int r;

  if ((r = sshbuf_reserve(buf, 8, &p)) < 0)

    return r;

  POKE_U64(p, val);

  return 0;

}

int

sshbuf_put_u32(struct sshbuf *buf, u_int32_t val)

{

  u_char *p;

  int r;

  if ((r = sshbuf_reserve(buf, 4, &p)) < 0)

    return r;

  POKE_U32(p, val);

  return 0;

}

int

sshbuf_put_u16(struct sshbuf *buf, u_int16_t val)

{

  u_char *p;

  int r;

  if ((r = sshbuf_reserve(buf, 2, &p)) < 0)

    return r;

  POKE_U16(p, val);

  return 0;

}

int

sshbuf_put_u8(struct sshbuf *buf, u_char val)

{

  u_char *p;

  int r;

  if ((r = sshbuf_reserve(buf, 1, &p)) < 0)

    return r;

  p[0] = val;

  return 0;

}

static int

check_woffset(struct sshbuf *buf, size_t offset, size_t len, u_char **p)

{

  int r;

  *p = NULL;

  if ((r = check_offset(buf, 1, offset, len)) != 0)

    return r;

  if (sshbuf_mutable_ptr(buf) == NULL)

    return SSH_ERR_BUFFER_READ_ONLY;

  *p = sshbuf_mutable_ptr(buf) + offset;

  return 0;

}

int

sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val)

{

  u_char *p = NULL;

  int r;

  if ((r = check_woffset(buf, offset, 8, &p)) != 0)

    return r;

  POKE_U64(p, val);

  return 0;

}

int

sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val)

{

  u_char *p = NULL;

  int r;

  if ((r = check_woffset(buf, offset, 4, &p)) != 0)

    return r;

  POKE_U32(p, val);

  return 0;

}

int

sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val)

{

  u_char *p = NULL;

  int r;

  if ((r = check_woffset(buf, offset, 2, &p)) != 0)

    return r;

  POKE_U16(p, val);

  return 0;

}

int

sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val)

{

  u_char *p = NULL;

  int r;

  if ((r = check_woffset(buf, offset, 1, &p)) != 0)

    return r;

  *p = val;

  return 0;

}

int

sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len)

{

  u_char *p = NULL;

  int r;

  if ((r = check_woffset(buf, offset, len, &p)) != 0)

    return r;

  memcpy(p, v, len);

  return 0;

}

int

sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len)

{

  u_char *d;

  int r;

  if (len > SSHBUF_SIZE_MAX - 4) {

    SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));

    return SSH_ERR_NO_BUFFER_SPACE;

  }

  if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0)

    return r;

  POKE_U32(d, len);

  if (len != 0)

    memcpy(d + 4, v, len);

  return 0;

}

int

sshbuf_put_cstring(struct sshbuf *buf, const char *v)

{

  return sshbuf_put_string(buf, v, v == NULL ? 0 : strlen(v));

}

int

sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v)

{

  if (v == NULL)

    return sshbuf_put_string(buf, NULL, 0);

  return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v));

}

int

sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp)

{

  const u_char *p;

  size_t len;

  struct sshbuf *ret;

  int r;

  if (buf == NULL || bufp == NULL)

    return SSH_ERR_INVALID_ARGUMENT;

  *bufp = NULL;

  if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)

    return r;

  if ((ret = sshbuf_from(p, len)) == NULL)

    return SSH_ERR_ALLOC_FAIL;

  if ((r = sshbuf_consume(buf, len + 4)) != 0 ||  /* Shouldn't happen */

      (r = sshbuf_set_parent(ret, buf)) != 0) {

    sshbuf_free(ret);

    return r;

  }

  *bufp = ret;

  return 0;

}

int

sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)

{

  u_char *d;

  const u_char *s = (const u_char *)v;

  int r, prepend;

  if (len > SSHBUF_SIZE_MAX - 5) {

    SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));

    return SSH_ERR_NO_BUFFER_SPACE;

  }

  /* Skip leading zero bytes */

  for (; len > 0 && *s == 0; len--, s++)

    ;

  /*

   * If most significant bit is set then prepend a zero byte to

   * avoid interpretation as a negative number.

   */

  prepend = len > 0 && (s[0] & 0x80) != 0;

  if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0)

    return r;

  POKE_U32(d, len + prepend);

  if (prepend)

    d[4] = 0;

  if (len != 0)

    memcpy(d + 4 + prepend, s, len);

  return 0;

}

int

sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,

    const u_char **valp, size_t *lenp)

{

  const u_char *d;

  size_t len, olen;

  int r;

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

    return r;

  len = olen;

  /* Refuse negative (MSB set) bignums */

  if ((len != 0 && (*d & 0x80) != 0))

    return SSH_ERR_BIGNUM_IS_NEGATIVE;

  /* Refuse overlong bignums, allow prepended \0 to avoid MSB set */

  if (len > SSHBUF_MAX_BIGNUM + 1 ||

      (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))

    return SSH_ERR_BIGNUM_TOO_LARGE;

  /* Trim leading zeros */

  while (len > 0 && *d == 0x00) {

    d++;

    len--;

  }

  if (valp != NULL)

    *valp = d;

  if (lenp != NULL)

    *lenp = len;

  if (sshbuf_consume(buf, olen + 4) != 0) {

    /* Shouldn't happen */

    SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));

    SSHBUF_ABORT();

    return SSH_ERR_INTERNAL_ERROR;

  }

  return 0;

}