![Guy Harris](/assets/img/avatar_default.png)
tvb_get_string() - takes a tvbuff, an offset, and a length as arguments, allocates a buffer big enough to hold a string with the specified number of bytes plus an added null terminator (i.e., length+1), copies the specified number of bytes from the tvbuff, at the specified offset, to that buffer and puts in a null terminator, and returns a pointer to that buffer (or throws an exception before allocating the buffer if that many bytes aren't available in the tvbuff); tvb_get_stringz() - takes a tvbuff, an offset, and a pointer to a "gint" as arguments, gets the size of the null-terminated string starting at the specified offset in the tvbuff (throwing an exception if the null terminator isn't found), allocates a buffer big enough to hold that string, copies the string to that buffer, and returns a pointer to that buffer and stores the length of the string (including the terminating null) in the variable pointed to by the "gint" pointer. Replace many pieces of code allocating a buffer and copying a string with calls to "tvb_get_string()" (for one thing, "tvb_get_string()" doesn't require you to remember that the argument to "tvb_get_nstringz0()" is the size of the buffer into which you're copying the string, which might be the length of the string to be copied *plus 1*). Don't use fixed-length buffers for null-terminated strings (even if the code that generates those packets has a #define to limit the length of the string). Use "tvb_get_stringz()", instead. In some cases where a value is fetched but is only used to pass an argument to a "proto_tree_add_XXX" routine, use "proto_tree_add_item()" instead. svn path=/trunk/; revision=7859
475 lines
12 KiB
C
475 lines
12 KiB
C
/* packet-smb-common.c
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* Common routines for smb packet dissection
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* Copyright 2000, Jeffrey C. Foster <jfoste@woodward.com>
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*
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* $Id: packet-smb-common.c,v 1.18 2003/06/12 08:33:30 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* Copied from packet-pop.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "packet-smb-common.h"
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/*
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* Share type values - used in LANMAN and in SRVSVC.
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*
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* XXX - should we dissect share type values, at least in SRVSVC, as
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* a subtree with bitfields, as the 0x80000000 bit appears to be a
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* hidden bit, with some number of bits at the bottom being the share
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* type?
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*
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* Does LANMAN use that bit?
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*/
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const value_string share_type_vals[] = {
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{0, "Directory tree"},
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{1, "Printer queue"},
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{2, "Communications device"},
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{3, "IPC"},
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{0x80000000, "Hidden Directory tree"},
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{0x80000001, "Hidden Printer queue"},
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{0x80000002, "Hidden Communications device"},
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{0x80000003, "Hidden IPC"},
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{0, NULL}
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};
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int display_ms_string(tvbuff_t *tvb, proto_tree *tree, int offset, int hf_index, char **data)
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{
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char *str;
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gint len;
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/* display a string from the tree and return the new offset */
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str = tvb_get_stringz(tvb, offset, &len);
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proto_tree_add_string(tree, hf_index, tvb, offset, len, str);
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/* Return a copy of the string if requested */
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if (data)
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*data = str;
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else
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g_free(str);
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return offset+len;
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}
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int display_unicode_string(tvbuff_t *tvb, proto_tree *tree, int offset, int hf_index, char **data)
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{
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char *str, *p;
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int len;
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int charoffset;
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guint16 character;
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/* display a unicode string from the tree and return new offset */
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/*
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* Get the length of the string.
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* XXX - is it a bug or a feature that this will throw an exception
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* if we don't find the '\0'? I think it's a feature.
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*/
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len = 0;
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while ((character = tvb_get_letohs(tvb, offset + len)) != '\0')
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len += 2;
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len += 2; /* count the '\0' too */
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/*
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* Allocate a buffer for the string; "len" is the length in
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* bytes, not the length in characters.
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*/
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str = g_malloc(len/2);
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/*
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* XXX - this assumes the string is just ISO 8859-1; we need
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* to better handle multiple character sets in Ethereal,
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* including Unicode/ISO 10646, and multiple encodings of
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* that character set (UCS-2, UTF-8, etc.).
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*/
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charoffset = offset;
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p = str;
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while ((character = tvb_get_letohs(tvb, charoffset)) != '\0') {
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*p++ = character;
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charoffset += 2;
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}
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*p = '\0';
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proto_tree_add_string(tree, hf_index, tvb, offset, len, str);
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if (data)
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*data = str;
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else
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g_free(str);
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return offset+len;
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}
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/* Max string length for displaying Unicode strings. */
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#define MAX_UNICODE_STR_LEN 256
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/* Turn a little-endian Unicode '\0'-terminated string into a string we
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can display.
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XXX - for now, we just handle the ISO 8859-1 characters.
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If exactlen==TRUE then us_lenp contains the exact len of the string in
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bytes. It might not be null terminated !
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bc specifies the number of bytes in the byte parameters; Windows 2000,
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at least, appears, in some cases, to put only 1 byte of 0 at the end
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of a Unicode string if the byte count
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*/
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static gchar *
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unicode_to_str(tvbuff_t *tvb, int offset, int *us_lenp, gboolean exactlen,
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guint16 bc)
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{
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static gchar str[3][MAX_UNICODE_STR_LEN+3+1];
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static gchar *cur;
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gchar *p;
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guint16 uchar;
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int len;
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int us_len;
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int overflow = 0;
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if (cur == &str[0][0]) {
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cur = &str[1][0];
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} else if (cur == &str[1][0]) {
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cur = &str[2][0];
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} else {
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cur = &str[0][0];
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}
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p = cur;
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len = MAX_UNICODE_STR_LEN;
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us_len = 0;
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for (;;) {
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if (bc == 0)
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break;
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if (bc == 1) {
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/* XXX - explain this */
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if (!exactlen)
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us_len += 1; /* this is a one-byte null terminator */
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break;
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}
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uchar = tvb_get_letohs(tvb, offset);
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if (uchar == 0) {
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us_len += 2; /* this is a two-byte null terminator */
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break;
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}
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if (len > 0) {
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if ((uchar & 0xFF00) == 0)
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*p++ = uchar; /* ISO 8859-1 */
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else
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*p++ = '?'; /* not 8859-1 */
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len--;
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} else
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overflow = 1;
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offset += 2;
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bc -= 2;
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us_len += 2;
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if(exactlen){
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if(us_len>= *us_lenp){
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break;
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}
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}
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}
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if (overflow) {
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/* Note that we're not showing the full string. */
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*p++ = '.';
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*p++ = '.';
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*p++ = '.';
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}
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*p = '\0';
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*us_lenp = us_len;
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return cur;
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}
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/* nopad == TRUE : Do not add any padding before this string
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* exactlen == TRUE : len contains the exact len of the string in bytes.
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* bc: pointer to variable with amount of data left in the byte parameters
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* region
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*/
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const gchar *
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get_unicode_or_ascii_string(tvbuff_t *tvb, int *offsetp,
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gboolean useunicode, int *len, gboolean nopad, gboolean exactlen,
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guint16 *bcp)
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{
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static gchar str[3][MAX_UNICODE_STR_LEN+3+1];
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static gchar *cur;
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const gchar *string;
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int string_len;
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unsigned int copylen;
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if (*bcp == 0) {
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/* Not enough data in buffer */
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return NULL;
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}
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if (useunicode) {
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if ((!nopad) && (*offsetp % 2)) {
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/*
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* XXX - this should be an offset relative to the beginning of the SMB,
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* not an offset relative to the beginning of the frame; if the stuff
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* before the SMB has an odd number of bytes, an offset relative to
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* the beginning of the frame will give the wrong answer.
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*/
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(*offsetp)++; /* Looks like a pad byte there sometimes */
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(*bcp)--;
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if (*bcp == 0) {
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/* Not enough data in buffer */
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return NULL;
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}
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}
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if(exactlen){
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string_len = *len;
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}
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string = unicode_to_str(tvb, *offsetp, &string_len, exactlen, *bcp);
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} else {
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if(exactlen){
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/*
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* The string we return must be null-terminated.
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*/
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if (cur == &str[0][0]) {
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cur = &str[1][0];
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} else if (cur == &str[1][0]) {
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cur = &str[2][0];
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} else {
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cur = &str[0][0];
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}
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copylen = *len;
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if (copylen > MAX_UNICODE_STR_LEN)
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copylen = MAX_UNICODE_STR_LEN;
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tvb_memcpy(tvb, (guint8 *)cur, *offsetp, copylen);
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cur[copylen] = '\0';
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if (copylen > MAX_UNICODE_STR_LEN)
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strcat(cur, "...");
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string_len = *len;
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string = cur;
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} else {
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string_len = tvb_strsize(tvb, *offsetp);
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string = tvb_get_ptr(tvb, *offsetp, string_len);
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}
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}
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*len = string_len;
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return string;
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}
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int
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dissect_smb_unknown(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, int offset)
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{
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/* display data as unknown */
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proto_tree_add_text(tree, tvb, offset, -1, "Data (%u bytes)",
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tvb_reported_length_remaining(tvb, offset));
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return offset+tvb_length_remaining(tvb, offset);
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}
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/* Dissect a NTLM response. This is documented at
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http://ubiqx.org/cifs/SMB.html#8, para 2.8.5.3 */
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static int hf_ntlmv2_response = -1;
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static int hf_ntlmv2_response_hmac = -1;
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static int hf_ntlmv2_response_header = -1;
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static int hf_ntlmv2_response_reserved = -1;
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static int hf_ntlmv2_response_time = -1;
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static int hf_ntlmv2_response_chal = -1;
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static int hf_ntlmv2_response_unknown = -1;
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static int hf_ntlmv2_response_name = -1;
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static int hf_ntlmv2_response_name_type = -1;
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static int hf_ntlmv2_response_name_len = -1;
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static gint ett_ntlmv2_response = -1;
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static gint ett_ntlmv2_response_name = -1;
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/* Name types */
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const value_string ntlm_name_types[] = {
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{ NTLM_NAME_END, "End of list" },
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{ NTLM_NAME_NB_HOST, "NetBIOS host name" },
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{ NTLM_NAME_NB_DOMAIN, "NetBIOS domain name" },
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{ NTLM_NAME_DNS_HOST, "DNS host name" },
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{ NTLM_NAME_DNS_DOMAIN, "DNS domain name" },
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{ 0, NULL }
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};
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int
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dissect_ntlmv2_response(tvbuff_t *tvb, proto_tree *tree, int offset, int len)
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{
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proto_item *ntlmv2_item = NULL;
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proto_tree *ntlmv2_tree = NULL;
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/* Dissect NTLMv2 bits&pieces */
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if (tree) {
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ntlmv2_item = proto_tree_add_item(
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tree, hf_ntlmv2_response, tvb,
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offset, len, TRUE);
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ntlmv2_tree = proto_item_add_subtree(
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ntlmv2_item, ett_ntlmv2_response);
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}
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proto_tree_add_item(
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ntlmv2_tree, hf_ntlmv2_response_hmac, tvb,
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offset, 16, TRUE);
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offset += 16;
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proto_tree_add_item(
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ntlmv2_tree, hf_ntlmv2_response_header, tvb,
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offset, 4, TRUE);
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offset += 4;
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proto_tree_add_item(
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ntlmv2_tree, hf_ntlmv2_response_reserved, tvb,
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offset, 4, TRUE);
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offset += 4;
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offset = dissect_smb_64bit_time(
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tvb, ntlmv2_tree, offset, hf_ntlmv2_response_time);
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proto_tree_add_item(
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ntlmv2_tree, hf_ntlmv2_response_chal, tvb,
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offset, 8, TRUE);
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offset += 8;
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proto_tree_add_item(
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ntlmv2_tree, hf_ntlmv2_response_unknown, tvb,
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offset, 4, TRUE);
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offset += 4;
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/* Variable length list of names */
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while(1) {
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guint16 name_type = tvb_get_letohs(tvb, offset);
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guint16 name_len = tvb_get_letohs(tvb, offset + 2);
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proto_tree *name_tree = NULL;
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proto_item *name_item = NULL;
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char *name = NULL;
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if (ntlmv2_tree) {
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name_item = proto_tree_add_item(
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ntlmv2_tree, hf_ntlmv2_response_name,
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tvb, offset, 0, TRUE);
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name_tree = proto_item_add_subtree(
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name_item, ett_ntlmv2_response_name);
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}
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/* Dissect name header */
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proto_tree_add_item(
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name_tree, hf_ntlmv2_response_name_type, tvb,
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offset, 2, TRUE);
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offset += 2;
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proto_tree_add_item(
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name_tree, hf_ntlmv2_response_name_len, tvb,
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offset, 2, TRUE);
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offset += 2;
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/* Dissect name */
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if (name_len > 0) {
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name = tvb_fake_unicode(
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tvb, offset, name_len / 2, TRUE);
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proto_tree_add_text(
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name_tree, tvb, offset, name_len,
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"Name: %s", name);
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} else
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name = g_strdup("NULL");
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if (name_type == 0)
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proto_item_append_text(
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name_item, "%s",
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val_to_str(name_type, ntlm_name_types,
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"Unknown"));
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else
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proto_item_append_text(
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name_item, "%s, %s",
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val_to_str(name_type, ntlm_name_types,
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"Unknown"), name);
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g_free(name);
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offset += name_len;
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proto_item_set_len(name_item, name_len + 4);
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if (name_type == 0) /* End of list */
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break;
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};
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return offset;
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}
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void register_smb_common(int proto_smb)
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{
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static hf_register_info hf[] = {
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{ &hf_ntlmv2_response,
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{ "NTLMv2 Response", "smb.ntlmv2response", FT_BYTES,
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BASE_HEX, NULL, 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_hmac,
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{ "HMAC", "smb.ntlmv2response.hmac", FT_BYTES, BASE_HEX,
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NULL, 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_header,
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{ "Header", "smb.ntlmv2response.header", FT_UINT32,
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BASE_HEX, NULL, 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_reserved,
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{ "Reserved", "smb.ntlmv2response.reserved", FT_UINT32,
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BASE_HEX, NULL, 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_time,
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{ "Time", "smb.ntlmv2response.time", FT_ABSOLUTE_TIME,
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BASE_NONE, NULL, 0, "", HFILL }},
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{ &hf_ntlmv2_response_chal,
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{ "Client challenge", "smb.ntlmv2response.chal", FT_BYTES,
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BASE_HEX, NULL, 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_unknown,
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{ "Unknown", "smb.ntlmv2response.unknown", FT_UINT32,
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BASE_HEX, NULL, 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_name,
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{ "Name", "smb.ntlmv2response.name", FT_STRING, BASE_NONE,
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NULL, 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_name_type,
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{ "Name type", "smb.ntlmv2response.name.type", FT_UINT32,
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BASE_DEC, VALS(ntlm_name_types), 0x0, "", HFILL }},
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{ &hf_ntlmv2_response_name_len,
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{ "Name len", "smb.ntlmv2response.name.len", FT_UINT32,
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BASE_DEC, NULL, 0x0, "", HFILL }}
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};
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static gint *ett[] = {
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&ett_ntlmv2_response,
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&ett_ntlmv2_response_name
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};
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proto_register_subtree_array(ett, array_length(ett));
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proto_register_field_array(proto_smb, hf, array_length(hf));
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}
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