path: root/packet-smb-common.c

/* packet-smb-common.c
 * Common routines for smb packet dissection
 * Copyright 2000, Jeffrey C. Foster <jfoste@woodward.com>
 *
 * $Id: packet-smb-common.c,v 1.20 2004/04/03 03:50:44 guy Exp $
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * Copyright 1998 Gerald Combs
 *
 * Copied from packet-pop.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include "packet-smb-common.h"

/*
 * Share type values - used in LANMAN and in SRVSVC.
 *
 * XXX - should we dissect share type values, at least in SRVSVC, as
 * a subtree with bitfields, as the 0x80000000 bit appears to be a
 * hidden bit, with some number of bits at the bottom being the share
 * type?
 *
 * Does LANMAN use that bit?
 */
const value_string share_type_vals[] = {
	{0, "Directory tree"},
	{1, "Printer queue"},
	{2, "Communications device"},
	{3, "IPC"},
	{0x80000000, "Hidden Directory tree"},
	{0x80000001, "Hidden Printer queue"},
	{0x80000002, "Hidden Communications device"},
	{0x80000003, "Hidden IPC"},
	{0, NULL}
};

int display_ms_string(tvbuff_t *tvb, proto_tree *tree, int offset, int hf_index, char **data)
{
	char *str;
	gint len;

	/* display a string from the tree and return the new offset */

	str = tvb_get_stringz(tvb, offset, &len);
	proto_tree_add_string(tree, hf_index, tvb, offset, len, str);

	/* Return a copy of the string if requested */

	if (data)
		*data = str;
	else
		g_free(str);

	return 	offset+len;
}


int display_unicode_string(tvbuff_t *tvb, proto_tree *tree, int offset, int hf_index, char **data)
{
	char *str, *p;
	int len;
	int charoffset;
	guint16 character;

	/* display a unicode string from the tree and return new offset */

	/*
	 * Get the length of the string.
	 * XXX - is it a bug or a feature that this will throw an exception
	 * if we don't find the '\0'?  I think it's a feature.
	 */
	len = 0;
	while ((character = tvb_get_letohs(tvb, offset + len)) != '\0')
		len += 2;
	len += 2;	/* count the '\0' too */

	/*
	 * Allocate a buffer for the string; "len" is the length in
	 * bytes, not the length in characters.
	 */
	str = g_malloc(len/2);

	/*
	 * XXX - this assumes the string is just ISO 8859-1; we need
	 * to better handle multiple character sets in Ethereal,
	 * including Unicode/ISO 10646, and multiple encodings of
	 * that character set (UCS-2, UTF-8, etc.).
	 */
	charoffset = offset;
	p = str;
	while ((character = tvb_get_letohs(tvb, charoffset)) != '\0') {
		*p++ = (char) character;
		charoffset += 2;
	}
	*p = '\0';

	proto_tree_add_string(tree, hf_index, tvb, offset, len, str);

	if (data)
		*data = str;
	else
		g_free(str);

	return 	offset+len;
}

/* Max string length for displaying Unicode strings.  */
#define	MAX_UNICODE_STR_LEN	256

/* Turn a little-endian Unicode '\0'-terminated string into a string we
   can display.
   XXX - for now, we just handle the ISO 8859-1 characters.
   If exactlen==TRUE then us_lenp contains the exact len of the string in
   bytes. It might not be null terminated !
   bc specifies the number of bytes in the byte parameters; Windows 2000,
   at least, appears, in some cases, to put only 1 byte of 0 at the end
   of a Unicode string if the byte count
*/
static gchar *
unicode_to_str(tvbuff_t *tvb, int offset, int *us_lenp, gboolean exactlen,
		   guint16 bc)
{
  static gchar  str[3][MAX_UNICODE_STR_LEN+3+1];
  static gchar *cur;
  gchar        *p;
  guint16       uchar;
  int           len;
  int           us_len;
  gboolean      overflow = FALSE;

  if (cur == &str[0][0]) {
    cur = &str[1][0];
  } else if (cur == &str[1][0]) {
    cur = &str[2][0];
  } else {
    cur = &str[0][0];
  }
  p = cur;
  len = MAX_UNICODE_STR_LEN;
  us_len = 0;
  for (;;) {
    if (bc == 0)
      break;
    if (bc == 1) {
      /* XXX - explain this */
      if (!exactlen)
        us_len += 1;	/* this is a one-byte null terminator */
      break;
    }
    uchar = tvb_get_letohs(tvb, offset);
    if (uchar == 0) {
      us_len += 2;	/* this is a two-byte null terminator */
      break;
    }
    if (len > 0) {
      if ((uchar & 0xFF00) == 0)
        *p++ = (gchar) uchar;	/* ISO 8859-1 */
      else
        *p++ = '?';	/* not 8859-1 */
      len--;
    } else
      overflow = TRUE;
    offset += 2;
    bc -= 2;
    us_len += 2;
    if(exactlen){
      if(us_len>= *us_lenp){
        break;
      }
    }
  }
  if (overflow) {
    /* Note that we're not showing the full string.  */
    *p++ = '.';
    *p++ = '.';
    *p++ = '.';
  }
  *p = '\0';
  *us_lenp = us_len;
  return cur;
}

/* nopad == TRUE : Do not add any padding before this string
 * exactlen == TRUE : len contains the exact len of the string in bytes.
 * bc: pointer to variable with amount of data left in the byte parameters
 *   region
 */
const gchar *
get_unicode_or_ascii_string(tvbuff_t *tvb, int *offsetp,
    gboolean useunicode, int *len, gboolean nopad, gboolean exactlen,
    guint16 *bcp)
{
  static gchar  str[3][MAX_UNICODE_STR_LEN+3+1];
  static gchar *cur;
  const gchar *string;
  int string_len;
  int copylen;
  gboolean overflow = FALSE;

  if (*bcp == 0) {
    /* Not enough data in buffer */
    return NULL;
  }
  if (useunicode) {
    if ((!nopad) && (*offsetp % 2)) {
      /*
       * XXX - this should be an offset relative to the beginning of the SMB,
       * not an offset relative to the beginning of the frame; if the stuff
       * before the SMB has an odd number of bytes, an offset relative to
       * the beginning of the frame will give the wrong answer.
       */
      (*offsetp)++;   /* Looks like a pad byte there sometimes */
      (*bcp)--;
      if (*bcp == 0) {
        /* Not enough data in buffer */
        return NULL;
      }
    }
    if(exactlen){
      string_len = *len;
      if (string_len < 0) {
        /* This probably means it's a very large unsigned number; just set
           it to the largest signed number, so that we throw the appropriate
           exception. */
        string_len = INT_MAX;
      }
    }
    string = unicode_to_str(tvb, *offsetp, &string_len, exactlen, *bcp);
  } else {
    if(exactlen){
      /*
       * The string we return must be null-terminated.
       */
      if (cur == &str[0][0]) {
        cur = &str[1][0];
      } else if (cur == &str[1][0]) {
        cur = &str[2][0];
      } else {
        cur = &str[0][0];
      }
      copylen = *len;
      if (copylen < 0) {
        /* This probably means it's a very large unsigned number; just set
           it to the largest signed number, so that we throw the appropriate
           exception. */
        copylen = INT_MAX;
      }
      tvb_ensure_bytes_exist(tvb, *offsetp, copylen);
      if (copylen > MAX_UNICODE_STR_LEN) {
        copylen = MAX_UNICODE_STR_LEN;
        overflow = TRUE;
      }
      tvb_memcpy(tvb, (guint8 *)cur, *offsetp, copylen);
      cur[copylen] = '\0';
      if (overflow)
        strcat(cur, "...");
      string_len = *len;
      string = cur;
    } else {
      string_len = tvb_strsize(tvb, *offsetp);
      string = tvb_get_ptr(tvb, *offsetp, string_len);
    }
  }
  *len = string_len;
  return string;
}

int
dissect_smb_unknown(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, int offset)
{
	/* display data as unknown */

	proto_tree_add_text(tree, tvb, offset, -1, "Data (%u bytes)",
	    tvb_reported_length_remaining(tvb, offset));

	return offset+tvb_length_remaining(tvb, offset);
}

/* Dissect a NTLM response. This is documented at
   http://ubiqx.org/cifs/SMB.html#8, para 2.8.5.3 */

static int hf_ntlmv2_response = -1;
static int hf_ntlmv2_response_hmac = -1;
static int hf_ntlmv2_response_header = -1;
static int hf_ntlmv2_response_reserved = -1;
static int hf_ntlmv2_response_time = -1;
static int hf_ntlmv2_response_chal = -1;
static int hf_ntlmv2_response_unknown = -1;
static int hf_ntlmv2_response_name = -1;
static int hf_ntlmv2_response_name_type = -1;
static int hf_ntlmv2_response_name_len = -1;

static gint ett_ntlmv2_response = -1;
static gint ett_ntlmv2_response_name = -1;

/* Name types */

const value_string ntlm_name_types[] = {
	{ NTLM_NAME_END, "End of list" },
	{ NTLM_NAME_NB_HOST, "NetBIOS host name" },
	{ NTLM_NAME_NB_DOMAIN, "NetBIOS domain name" },
	{ NTLM_NAME_DNS_HOST, "DNS host name" },
	{ NTLM_NAME_DNS_DOMAIN, "DNS domain name" },
	{ 0, NULL }
};

int
dissect_ntlmv2_response(tvbuff_t *tvb, proto_tree *tree, int offset, int len)
{
	proto_item *ntlmv2_item = NULL;
	proto_tree *ntlmv2_tree = NULL;

	/* Dissect NTLMv2 bits&pieces */

	if (tree) {
		ntlmv2_item = proto_tree_add_item(
			tree, hf_ntlmv2_response, tvb, 
			offset, len, TRUE);
		ntlmv2_tree = proto_item_add_subtree(
			ntlmv2_item, ett_ntlmv2_response);
	}

	proto_tree_add_item(
		ntlmv2_tree, hf_ntlmv2_response_hmac, tvb,
		offset, 16, TRUE);

	offset += 16;

	proto_tree_add_item(
		ntlmv2_tree, hf_ntlmv2_response_header, tvb,
		offset, 4, TRUE);

	offset += 4;

	proto_tree_add_item(
		ntlmv2_tree, hf_ntlmv2_response_reserved, tvb,
		offset, 4, TRUE);

	offset += 4;

	offset = dissect_smb_64bit_time(
		tvb, ntlmv2_tree, offset, hf_ntlmv2_response_time);

	proto_tree_add_item(
		ntlmv2_tree, hf_ntlmv2_response_chal, tvb,
		offset, 8, TRUE);

	offset += 8;

	proto_tree_add_item(
		ntlmv2_tree, hf_ntlmv2_response_unknown, tvb,
		offset, 4, TRUE);

	offset += 4;

	/* Variable length list of names */

	while(1) {
		guint16 name_type = tvb_get_letohs(tvb, offset);
		guint16 name_len = tvb_get_letohs(tvb, offset + 2);
		proto_tree *name_tree = NULL;
		proto_item *name_item = NULL;
		char *name = NULL;

		if (ntlmv2_tree) {
			name_item = proto_tree_add_item(
				ntlmv2_tree, hf_ntlmv2_response_name, 
				tvb, offset, 0, TRUE);
			name_tree = proto_item_add_subtree(
				name_item, ett_ntlmv2_response_name);
		}

		/* Dissect name header */

		proto_tree_add_item(
			name_tree, hf_ntlmv2_response_name_type, tvb,
			offset, 2, TRUE);

		offset += 2;

		proto_tree_add_item(
			name_tree, hf_ntlmv2_response_name_len, tvb,
			offset, 2, TRUE);

		offset += 2;

		/* Dissect name */

		if (name_len > 0) {
			name = tvb_fake_unicode(
				tvb, offset, name_len / 2, TRUE);

			proto_tree_add_text(
				name_tree, tvb, offset, name_len, 
				"Name: %s", name);
		} else
			name = g_strdup("NULL");

		if (name_type == 0)
			proto_item_append_text(
				name_item, "%s", 
				val_to_str(name_type, ntlm_name_types,
					   "Unknown"));
		else
			proto_item_append_text(
				name_item, "%s, %s",
				val_to_str(name_type, ntlm_name_types,
					   "Unknown"), name);

		g_free(name);

		offset += name_len;

		proto_item_set_len(name_item, name_len + 4);

		if (name_type == 0) /* End of list */
			break;
	};

	return offset;
}

void register_smb_common(int proto_smb)
{
	static hf_register_info hf[] = {

		{ &hf_ntlmv2_response,
		  { "NTLMv2 Response", "smb.ntlmv2response", FT_BYTES, 
		    BASE_HEX, NULL, 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_hmac,
		  { "HMAC", "smb.ntlmv2response.hmac", FT_BYTES, BASE_HEX, 
		    NULL, 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_header,
		  { "Header", "smb.ntlmv2response.header", FT_UINT32, 
		    BASE_HEX, NULL, 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_reserved,
		  { "Reserved", "smb.ntlmv2response.reserved", FT_UINT32, 
		    BASE_HEX, NULL, 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_time,
		  { "Time", "smb.ntlmv2response.time", FT_ABSOLUTE_TIME, 
		    BASE_NONE, NULL, 0, "", HFILL }},

		{ &hf_ntlmv2_response_chal,
		  { "Client challenge", "smb.ntlmv2response.chal", FT_BYTES, 
		    BASE_HEX, NULL, 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_unknown,
		  { "Unknown", "smb.ntlmv2response.unknown", FT_UINT32, 
		    BASE_HEX, NULL, 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_name,
		  { "Name", "smb.ntlmv2response.name", FT_STRING, BASE_NONE, 
		    NULL, 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_name_type,
		  { "Name type", "smb.ntlmv2response.name.type", FT_UINT32, 
		    BASE_DEC, VALS(ntlm_name_types), 0x0, "", HFILL }},

		{ &hf_ntlmv2_response_name_len,
		  { "Name len", "smb.ntlmv2response.name.len", FT_UINT32, 
		    BASE_DEC, NULL, 0x0, "", HFILL }}
	};

	static gint *ett[] = {
		&ett_ntlmv2_response,
		&ett_ntlmv2_response_name
	};

	proto_register_subtree_array(ett, array_length(ett));
	proto_register_field_array(proto_smb, hf, array_length(hf));
}