/*  $OpenBSD: sshbuf-misc.c,v 1.18 2022/01/22 00:43:43 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 <sys/socket.h>

#include <netinet/in.h>

#include <errno.h>

#include <stdlib.h>

#ifdef HAVE_STDINT_H

# include <stdint.h>

#endif

#include <stdio.h>

#include <limits.h>

#include <string.h>

#include <resolv.h>

#include <ctype.h>

#include <unistd.h>

#include "ssherr.h"

#define SSHBUF_INTERNAL

#include "sshbuf.h"

void

sshbuf_dump_data(const void *s, size_t len, FILE *f)

{

  size_t i, j;

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

  for (i = 0; i < len; i += 16) {

    fprintf(f, "%.4zu: ", i);

    for (j = i; j < i + 16; j++) {

      if (j < len)

        fprintf(f, "%02x ", p[j]);

      else

        fprintf(f, "   ");

    }

    fprintf(f, " ");

    for (j = i; j < i + 16; j++) {

      if (j < len) {

        if  (isascii(p[j]) && isprint(p[j]))

          fprintf(f, "%c", p[j]);

        else

          fprintf(f, ".");

      }

    }

    fprintf(f, "\n");

  }

}

void

sshbuf_dump(const struct sshbuf *buf, FILE *f)

{

  fprintf(f, "buffer len = %zu\n", sshbuf_len(buf));

  sshbuf_dump_data(sshbuf_ptr(buf), sshbuf_len(buf), f);

}

char *

sshbuf_dtob16(struct sshbuf *buf)

{

  size_t i, j, len = sshbuf_len(buf);

  const u_char *p = sshbuf_ptr(buf);

  char *ret;

  const char hex[] = "0123456789abcdef";

  if (len == 0)

    return strdup("");

  if (SIZE_MAX / 2 <= len || (ret = malloc(len * 2 + 1)) == NULL)

    return NULL;

  for (i = j = 0; i < len; i++) {

    ret[j++] = hex[(p[i] >> 4) & 0xf];

    ret[j++] = hex[p[i] & 0xf];

  }

  ret[j] = '\0';

  return ret;

}

int

sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap)

{

  size_t i, slen = 0;

  char *s = NULL;

  int r;

  if (d == NULL || b64 == NULL || sshbuf_len(d) >= SIZE_MAX / 2)

    return SSH_ERR_INVALID_ARGUMENT;

  if (sshbuf_len(d) == 0)

    return 0;

  slen = ((sshbuf_len(d) + 2) / 3) * 4 + 1;

  if ((s = malloc(slen)) == NULL)

    return SSH_ERR_ALLOC_FAIL;

  if (b64_ntop(sshbuf_ptr(d), sshbuf_len(d), s, slen) == -1) {

    r = SSH_ERR_INTERNAL_ERROR;

    goto fail;

  }

  if (wrap) {

    for (i = 0; s[i] != '\0'; i++) {

      if ((r = sshbuf_put_u8(b64, s[i])) != 0)

        goto fail;

      if (i % 70 == 69 && (r = sshbuf_put_u8(b64, '\n')) != 0)

        goto fail;

    }

    if ((i - 1) % 70 != 69 && (r = sshbuf_put_u8(b64, '\n')) != 0)

      goto fail;

  } else {

    if ((r = sshbuf_put(b64, s, strlen(s))) != 0)

      goto fail;

  }

  /* Success */

  r = 0;

 fail:

  freezero(s, slen);

  return r;

}

char *

sshbuf_dtob64_string(const struct sshbuf *buf, int wrap)

{

  struct sshbuf *tmp;

  char *ret;

  if ((tmp = sshbuf_new()) == NULL)

    return NULL;

  if (sshbuf_dtob64(buf, tmp, wrap) != 0) {

    sshbuf_free(tmp);

    return NULL;

  }

  ret = sshbuf_dup_string(tmp);

  sshbuf_free(tmp);

  return ret;

}

int

sshbuf_b64tod(struct sshbuf *buf, const char *b64)

{

  size_t plen = strlen(b64);

  int nlen, r;

  u_char *p;

  if (plen == 0)

    return 0;

  if ((p = malloc(plen)) == NULL)

    return SSH_ERR_ALLOC_FAIL;

  if ((nlen = b64_pton(b64, p, plen)) < 0) {

    freezero(p, plen);

    return SSH_ERR_INVALID_FORMAT;

  }

  if ((r = sshbuf_put(buf, p, nlen)) < 0) {

    freezero(p, plen);

    return r;

  }

  freezero(p, plen);

  return 0;

}

int

sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap)

{

  int r = SSH_ERR_INTERNAL_ERROR;

  u_char *p;

  struct sshbuf *b = NULL;

  size_t i, l;

  if ((b = sshbuf_new()) == NULL)

    return SSH_ERR_ALLOC_FAIL;

  /* Encode using regular base64; we'll transform it once done */

  if ((r = sshbuf_dtob64(d, b, wrap)) != 0)

    goto out;

  /* remove padding from end of encoded string*/

  for (;;) {

    l = sshbuf_len(b);

    if (l <= 1 || sshbuf_ptr(b) == NULL) {

      r = SSH_ERR_INTERNAL_ERROR;

      goto out;

    }

    if (sshbuf_ptr(b)[l - 1] != '=')

      break;

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

      goto out;

  }

  /* Replace characters with rfc4648 equivalents */

  l = sshbuf_len(b);

  if ((p = sshbuf_mutable_ptr(b)) == NULL) {

    r = SSH_ERR_INTERNAL_ERROR;

    goto out;

  }

  for (i = 0; i < l; i++) {

    if (p[i] == '+')

      p[i] = '-';

    else if (p[i] == '/')

      p[i] = '_';

  }

  r = sshbuf_putb(b64, b);

 out:

  sshbuf_free(b);

  return r;

}

char *

sshbuf_dup_string(struct sshbuf *buf)

{

  const u_char *p = NULL, *s = sshbuf_ptr(buf);

  size_t l = sshbuf_len(buf);

  char *r;

  if (s == NULL || l > SIZE_MAX)

    return NULL;

  /* accept a nul only as the last character in the buffer */

  if (l > 0 && (p = memchr(s, '\0', l)) != NULL) {

    if (p != s + l - 1)

      return NULL;

    l--; /* the nul is put back below */

  }

  if ((r = malloc(l + 1)) == NULL)

    return NULL;

  if (l > 0)

    memcpy(r, s, l);

  r[l] = '\0';

  return r;

}

int

sshbuf_cmp(const struct sshbuf *b, size_t offset,

    const void *s, size_t len)

{

  if (sshbuf_ptr(b) == NULL)

    return SSH_ERR_INTERNAL_ERROR;

  if (offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)

    return SSH_ERR_INVALID_ARGUMENT;

  if (offset + len > sshbuf_len(b))

    return SSH_ERR_MESSAGE_INCOMPLETE;

  if (timingsafe_bcmp(sshbuf_ptr(b) + offset, s, len) != 0)

    return SSH_ERR_INVALID_FORMAT;

  return 0;

}

int

sshbuf_find(const struct sshbuf *b, size_t start_offset,

    const void *s, size_t len, size_t *offsetp)

{

  void *p;

  if (offsetp != NULL)

    *offsetp = 0;

  if (sshbuf_ptr(b) == NULL)

    return SSH_ERR_INTERNAL_ERROR;

  if (start_offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)

    return SSH_ERR_INVALID_ARGUMENT;

  if (start_offset > sshbuf_len(b) || start_offset + len > sshbuf_len(b))

    return SSH_ERR_MESSAGE_INCOMPLETE;

  if ((p = memmem(sshbuf_ptr(b) + start_offset,

      sshbuf_len(b) - start_offset, s, len)) == NULL)

    return SSH_ERR_INVALID_FORMAT;

  if (offsetp != NULL)

    *offsetp = (const u_char *)p - sshbuf_ptr(b);

  return 0;

}

int

sshbuf_read(int fd, struct sshbuf *buf, size_t maxlen, size_t *rlen)

{

  int r, oerrno;

  size_t adjust;

  ssize_t rr;

  u_char *d;

  if (rlen != NULL)

    *rlen = 0;

  if ((r = sshbuf_reserve(buf, maxlen, &d)) != 0)

    return r;

  rr = read(fd, d, maxlen);

  oerrno = errno;

  /* Adjust the buffer to include only what was actually read */

  if ((adjust = maxlen - (rr > 0 ? rr : 0)) != 0) {

    if ((r = sshbuf_consume_end(buf, adjust)) != 0) {

      /* avoid returning uninitialised data to caller */

      memset(d + rr, '\0', adjust);

      return SSH_ERR_INTERNAL_ERROR; /* shouldn't happen */

    }

  }

  if (rr < 0) {

    errno = oerrno;

    return SSH_ERR_SYSTEM_ERROR;

  } else if (rr == 0) {

    errno = EPIPE;

    return SSH_ERR_SYSTEM_ERROR;

  }

  /* success */

  if (rlen != NULL) {

    *rlen = (size_t)rr;

  }

  return 0;

}