/* packet-dcerpc-nt.c * Routines for DCERPC over SMB packet disassembly * Copyright 2001-2003, Tim Potter * * $Id: packet-dcerpc-nt.c,v 1.72 2003/04/27 21:48:46 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * 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. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include "packet-dcerpc.h" #include "packet-dcerpc-nt.h" #include "smb.h" #include "packet-smb-common.h" /* for dissect_smb_64bit_time() */ /* * This file contains helper routines that are used by the DCERPC over SMB * dissectors for ethereal. */ /* Parse some common RPC structures */ gint ett_nt_unicode_string = -1; /* FIXME: make static */ /* Dissect a counted string as a callback to dissect_ndr_pointer_cb() */ static int hf_nt_cs_len = -1; static int hf_nt_cs_size = -1; int dissect_ndr_counted_string_cb(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, char *drep, int hf_index, dcerpc_callback_fnct_t *callback, void *callback_args) { dcerpc_info *di = pinfo->private_data; guint16 len, size; /* Structure starts with short, but is aligned for longs */ ALIGN_TO_4_BYTES; if (di->conformant_run) return offset; /* struct { short len; short size; [size_is(size/2), length_is(len/2), ptr] unsigned short *string; } UNICODE_STRING; */ offset = dissect_ndr_uint16(tvb, offset, pinfo, tree, drep, hf_nt_cs_len, &len); offset = dissect_ndr_uint16(tvb, offset, pinfo, tree, drep, hf_nt_cs_size, &size); offset = dissect_ndr_pointer_cb(tvb, offset, pinfo, tree, drep, dissect_ndr_wchar_cvstring, NDR_POINTER_UNIQUE, "Character Array", hf_index, callback, callback_args); return offset; } static gint ett_nt_counted_string = -1; static int dissect_ndr_counted_string_helper(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, char *drep, int hf_index, int levels, gboolean add_subtree) { proto_item *item; proto_tree *subtree = tree; if (add_subtree) { item = proto_tree_add_text( tree, tvb, offset, 0, proto_registrar_get_name(hf_index)); subtree = proto_item_add_subtree(item, ett_nt_counted_string); } /* * Add 2 levels, so that the string gets attached to the * "Character Array" top-level item and to the top-level item * added above. */ return dissect_ndr_counted_string_cb( tvb, offset, pinfo, subtree, drep, hf_index, cb_wstr_postprocess, GINT_TO_POINTER(2 + levels)); } /* Dissect a counted string in-line. */ int dissect_ndr_counted_string(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, char *drep, int hf_index, int levels) { return dissect_ndr_counted_string_helper( tvb, offset, pinfo, tree, drep, hf_index, levels, TRUE); } /* Dissect a counted string as a callback to dissect_ndr_pointer(). This doesn't add a adds a proto item and subtreee for the string as the pointer dissection already creates one. */ int dissect_ndr_counted_string_ptr(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, char *drep) { dcerpc_info *di = pinfo->private_data; return dissect_ndr_counted_string_helper( tvb, offset, pinfo, tree, drep, di->hf_index, 0, FALSE); } /* Dissect a counted byte_array as a callback to dissect_ndr_pointer_cb() */ static gint ett_nt_counted_byte_array = -1; /* Dissect a counted byte array in-line. */ int dissect_ndr_counted_byte_array(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, char *drep, int hf_index) { dcerpc_info *di = pinfo->private_data; proto_item *item; proto_tree *subtree; guint16 len, size; /* Structure starts with short, but is aligned for longs */ ALIGN_TO_4_BYTES; if (di->conformant_run) return offset; item = proto_tree_add_text(tree, tvb, offset, 0, proto_registrar_get_name(hf_index)); subtree = proto_item_add_subtree(item, ett_nt_counted_byte_array); /* struct { short len; short size; [size_is(size), length_is(len), ptr] unsigned char *string; } WHATEVER_THIS_IS_CALLED; */ offset = dissect_ndr_uint16(tvb, offset, pinfo, subtree, drep, hf_nt_cs_len, &len); offset = dissect_ndr_uint16(tvb, offset, pinfo, subtree, drep, hf_nt_cs_size, &size); offset = dissect_ndr_pointer(tvb, offset, pinfo, subtree, drep, dissect_ndr_char_cvstring, NDR_POINTER_UNIQUE, "Byte Array", hf_index); return offset; } /* This function is used to dissect a DCERPC encoded 64 bit time value. XXX it should be fixed both here and in dissect_smb_64bit_time so it can handle both BIG and LITTLE endian encodings */ int dissect_ndr_nt_NTTIME (tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, char *drep _U_, int hf_index) { dcerpc_info *di; di=pinfo->private_data; if(di->conformant_run){ /*just a run to handle conformant arrays, nothing to dissect */ return offset; } ALIGN_TO_4_BYTES; offset = dissect_smb_64bit_time(tvb, tree, offset, hf_index); return offset; } /* Define this symbol to display warnings about request/response and policy handle hash table collisions. This happens when a packet with the same conversation, smb fid and dcerpc call id occurs. I think this is due to a bug in the dcerpc/smb fragment reassembly code. */ #undef DEBUG_HASH_COLL /* * Policy handle hashing */ typedef struct { guint8 policy_hnd[20]; } pol_hash_key; typedef struct { guint32 open_frame, close_frame; /* Frame numbers for open/close */ char *name; /* Name of policy handle */ } pol_hash_value; #define POL_HASH_INIT_COUNT 100 static GHashTable *pol_hash; static GMemChunk *pol_hash_key_chunk; static GMemChunk *pol_hash_value_chunk; /* Hash function */ static guint pol_hash_fn(gconstpointer k) { const pol_hash_key *key = (const pol_hash_key *)k; /* Bytes 4-7 of the policy handle are a timestamp so should make a reasonable hash value */ return key->policy_hnd[4] + (key->policy_hnd[5] << 8) + (key->policy_hnd[6] << 16) + (key->policy_hnd[7] << 24); } /* Return true if a policy handle is all zeros */ static gboolean is_null_pol(e_ctx_hnd *policy_hnd) { static guint8 null_policy_hnd[20]; return memcmp(policy_hnd, null_policy_hnd, 20) == 0; } /* Hash compare function */ static gint pol_hash_compare(gconstpointer k1, gconstpointer k2) { const pol_hash_key *key1 = (const pol_hash_key *)k1; const pol_hash_key *key2 = (const pol_hash_key *)k2; return memcmp(key1->policy_hnd, key2->policy_hnd, sizeof(key1->policy_hnd)) == 0; } /* Store the open and close frame numbers of a policy handle */ void dcerpc_smb_store_pol_pkts(e_ctx_hnd *policy_hnd, guint32 open_frame, guint32 close_frame) { pol_hash_key *key; pol_hash_value *value; if (is_null_pol(policy_hnd) || (open_frame == 0 && close_frame == 0)) return; /* Look up existing value */ key = g_mem_chunk_alloc(pol_hash_key_chunk); memcpy(&key->policy_hnd, policy_hnd, sizeof(key->policy_hnd)); if ((value = g_hash_table_lookup(pol_hash, key))) { /* Update existing value */ if (open_frame) { #ifdef DEBUG_HASH_COLL if (value->open_frame != open_frame) g_warning("dcerpc_smb: pol_hash open frame collision %d/%d\n", value->open_frame, open_frame); #endif value->open_frame = open_frame; } if (close_frame) { #ifdef DEBUG_HASH_COLL if (value->close_frame != close_frame) g_warning("dcerpc_smb: pol_hash close frame collision %d/%d\n", value->close_frame, close_frame); #endif value->close_frame = close_frame; } return; } /* Create a new value */ value = g_mem_chunk_alloc(pol_hash_value_chunk); value->open_frame = open_frame; value->close_frame = close_frame; value->name = NULL; g_hash_table_insert(pol_hash, key, value); } /* Store a text string with a policy handle */ void dcerpc_smb_store_pol_name(e_ctx_hnd *policy_hnd, char *name) { pol_hash_key *key; pol_hash_value *value; if (is_null_pol(policy_hnd)) return; /* Look up existing value */ key = g_mem_chunk_alloc(pol_hash_key_chunk); memcpy(&key->policy_hnd, policy_hnd, sizeof(key->policy_hnd)); if ((value = g_hash_table_lookup(pol_hash, key))) { /* Update existing value */ if (value->name && name) { #ifdef DEBUG_HASH_COLL if (strcmp(value->name, name) != 0) g_warning("dcerpc_smb: pol_hash name collision %s/%s\n", value->name, name); #endif free(value->name); } value->name = strdup(name); return; } /* Create a new value */ value = g_mem_chunk_alloc(pol_hash_value_chunk); value->open_frame = 0; value->close_frame = 0; if (name) value->name = strdup(name); else value->name = strdup(""); g_hash_table_insert(pol_hash, key, value); } /* Retrieve a policy handle */ gboolean dcerpc_smb_fetch_pol(e_ctx_hnd *policy_hnd, char **name, guint32 *open_frame, guint32 *close_frame) { pol_hash_key key; pol_hash_value *value; /* Prevent uninitialised return vars */ if (name) *name = NULL; if (open_frame) *open_frame = 0; if (close_frame) *close_frame = 0; /* Look up existing value */ memcpy(&key.policy_hnd, policy_hnd, sizeof(key.policy_hnd)); value = g_hash_table_lookup(pol_hash, &key); /* Return name and frame numbers */ if (value) { if (name) *name = value->name; if (open_frame) *open_frame = value->open_frame; if (close_frame) *close_frame = value->close_frame; } return value != NULL; } /* Iterator to free a policy handle key/value pair */ static void free_pol_keyvalue(gpointer key _U_, gpointer value, gpointer user_data _U_) { pol_hash_value *pol_value = (pol_hash_value *)value; /* Free user data */ if (pol_value->name) { free(pol_value->name); pol_value->name = NULL; } } /* Initialise policy handle hash */ static void init_pol_hash(void) { /* Initialise memory chunks */ if (pol_hash_key_chunk) g_mem_chunk_destroy(pol_hash_key_chunk); pol_hash_key_chunk = g_mem_chunk_new( "Policy handle hash keys", sizeof(pol_hash_key), POL_HASH_INIT_COUNT * sizeof(pol_hash_key), G_ALLOC_ONLY); if (pol_hash_value_chunk) g_mem_chunk_destroy(pol_hash_value_chunk); pol_hash_value_chunk = g_mem_chunk_new( "Policy handle hash values", sizeof(pol_hash_value), POL_HASH_INIT_COUNT * sizeof(pol_hash_value), G_ALLOC_ONLY); /* Initialise hash table */ if (pol_hash) { g_hash_table_foreach(pol_hash, free_pol_keyvalue, NULL); g_hash_table_destroy(pol_hash); } pol_hash = g_hash_table_new(pol_hash_fn, pol_hash_compare); } /* Check if there is unparsed data remaining in a frame and display an error. I guess this could be made into an exception like the malformed frame exception. For the DCERPC over SMB dissectors a long frame indicates a bug in a dissector. */ void dcerpc_smb_check_long_frame(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { if (tvb_length_remaining(tvb, offset) != 0) { proto_tree_add_text( tree, tvb, offset, tvb_length_remaining(tvb, offset), "[Long frame (%d bytes): SPOOLSS]", tvb_length_remaining(tvb, offset)); if (check_col(pinfo->cinfo, COL_INFO)) col_append_fstr(pinfo->cinfo, COL_INFO, "[Long frame (%d bytes): SPOOLSS]", tvb_length_remaining(tvb, offset)); } } /* Dissect a NT status code */ int dissect_ntstatus(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree, char *drep, int hfindex, guint32 *pdata) { guint32 status; offset = dissect_ndr_uint32(tvb, offset, pinfo, tree, drep, hfindex, &status); if (status != 0 && check_col(pinfo->cinfo, COL_INFO)) col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", val_to_str(status, NT_errors, "Unknown error 0x%08x")); if (pdata) *pdata = status; return offset; } /* Dissect a DOS status code */ int dissect_doserror(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree, char *drep, int hfindex, guint32 *pdata) { guint32 status; offset = dissect_ndr_uint32(tvb, offset, pinfo, tree, drep, hfindex, &status); if (status != 0 && check_col(pinfo->cinfo, COL_INFO)) col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", val_to_str(status, DOS_errors, "Unknown error 0x%08x")); if (pdata) *pdata = status; return offset; } /* Dissect a NT policy handle */ static int hf_nt_policy_open_frame = -1; static int hf_nt_policy_close_frame = -1; static gint ett_nt_policy_hnd = -1; int dissect_nt_policy_hnd(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree, char *drep, int hfindex, e_ctx_hnd *pdata, gboolean is_open, gboolean is_close) { proto_item *item; proto_tree *subtree; e_ctx_hnd hnd; guint32 open_frame = 0, close_frame = 0; char *name; int old_offset = offset; /* Add to proto tree */ item = proto_tree_add_text(tree, tvb, offset, sizeof(e_ctx_hnd), "Policy Handle"); subtree = proto_item_add_subtree(item, ett_nt_policy_hnd); offset = dissect_ndr_ctx_hnd(tvb, offset, pinfo, subtree, drep, hfindex, &hnd); /* Store request/reply information */ dcerpc_smb_store_pol_pkts(&hnd, 0, is_close ? pinfo->fd->num : 0); dcerpc_smb_store_pol_pkts(&hnd, is_open ? pinfo->fd->num: 0, 0); /* Insert request/reply information if known */ if (dcerpc_smb_fetch_pol(&hnd, &name, &open_frame, &close_frame)) { if (open_frame) proto_tree_add_uint( subtree, hf_nt_policy_open_frame, tvb, old_offset, sizeof(e_ctx_hnd), open_frame); if (close_frame) proto_tree_add_uint( subtree, hf_nt_policy_close_frame, tvb, old_offset, sizeof(e_ctx_hnd), close_frame); if (name != NULL) proto_item_append_text(item, ": %s", name); } if (pdata) *pdata = hnd; return offset; } /* Some helper routines to dissect a range of uint8 characters. I don't think these are "official" NDR representations and are probably specific to NT so for the moment they're put here instead of in packet-dcerpc.c and packet-dcerpc-ndr.c. */ int dissect_dcerpc_uint8s(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_, proto_tree *tree, char *drep, int hfindex, int length, const guint8 **pdata) { const guint8 *data; data = (const guint8 *)tvb_get_ptr(tvb, offset, length); if (tree) { proto_tree_add_item (tree, hfindex, tvb, offset, length, (drep[0] & 0x10)); } if (pdata) *pdata = data; return offset + length; } int dissect_ndr_uint8s(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree, char *drep, int hfindex, int length, const guint8 **pdata) { dcerpc_info *di; di=pinfo->private_data; if(di->conformant_run){ /* just a run to handle conformant arrays, no scalars to dissect */ return offset; } /* no alignment needed */ return dissect_dcerpc_uint8s(tvb, offset, pinfo, tree, drep, hfindex, length, pdata); } int dissect_dcerpc_uint16s(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_, proto_tree *tree, char *drep, int hfindex, int length) { if (tree) { proto_tree_add_item (tree, hfindex, tvb, offset, length * 2, (drep[0] & 0x10)); } return offset + length * 2; } int dissect_ndr_uint16s(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree, char *drep, int hfindex, int length) { dcerpc_info *di; di=pinfo->private_data; if(di->conformant_run){ /* just a run to handle conformant arrays, no scalars to dissect */ return offset; } if (offset % 2) offset++; return dissect_dcerpc_uint16s(tvb, offset, pinfo, tree, drep, hfindex, length); } /* * Helper routines for dissecting NDR strings */ void cb_wstr_postprocess(packet_info *pinfo, proto_tree *tree _U_, proto_item *item, tvbuff_t *tvb, int start_offset, int end_offset, void *callback_args) { gint options = GPOINTER_TO_INT(callback_args); gint levels = CB_STR_ITEM_LEVELS(options); char *s; /* Align start_offset on 4-byte boundary. */ if (start_offset % 4) start_offset += 4 - (start_offset % 4); /* Get string value */ if ((end_offset - start_offset) <= 12) return; /* XXX: Use unistr2 dissector instead? */ s = tvb_fake_unicode( tvb, start_offset + 12, (end_offset - start_offset - 12) / 2, TRUE); /* Append string to COL_INFO */ if (options & CB_STR_COL_INFO) { if (check_col(pinfo->cinfo, COL_INFO)) col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", s); } /* Append string to upper-level proto_items */ if (levels > 0 && item && s && s[0]) { proto_item_append_text(item, ": %s", s); item = item->parent; levels--; if (levels > 0) { proto_item_append_text(item, ": %s", s); item = item->parent; levels--; while (levels > 0) { proto_item_append_text(item, " %s", s); item = item->parent; levels--; } } } /* Save string to dcv->private_data */ if (options & CB_STR_SAVE) { dcerpc_info *di = (dcerpc_info *)pinfo->private_data; dcerpc_call_value *dcv = (dcerpc_call_value *)di->call_data; dcv->private_data = g_strdup(s); } g_free(s); } void cb_str_postprocess(packet_info *pinfo, proto_tree *tree _U_, proto_item *item, tvbuff_t *tvb, int start_offset, int end_offset, void *callback_args) { gint options = GPOINTER_TO_INT(callback_args); gint levels = CB_STR_ITEM_LEVELS(options); char *s; /* Align start_offset on 4-byte boundary. */ if (start_offset % 4) start_offset += 4 - (start_offset % 4); /* Get string value */ if ((end_offset - start_offset) <= 12) return; /* XXX: Use unistr2 dissector instead? */ s = tvb_format_text(tvb, start_offset + 12, (end_offset - start_offset - 12) ); /* Append string to COL_INFO */ if (options & CB_STR_COL_INFO) { if (check_col(pinfo->cinfo, COL_INFO)) col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", s); } /* Append string to upper-level proto_items */ if (levels > 0 && item && s && s[0]) { proto_item_append_text(item, ": %s", s); item = item->parent; levels--; if (levels > 0) { proto_item_append_text(item, ": %s", s); item = item->parent; levels--; while (levels > 0) { proto_item_append_text(item, " %s", s); item = item->parent; levels--; } } } /* Save string to dcv->private_data */ if (options & CB_STR_SAVE) { dcerpc_info *di = (dcerpc_info *)pinfo->private_data; dcerpc_call_value *dcv = (dcerpc_call_value *)di->call_data; dcv->private_data = g_strdup(s); } g_free(s); } /* Dissect a pointer to a NDR string and append the string value to the proto_item. */ int dissect_ndr_str_pointer_item(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree, char *drep, int type, char *text, int hf_index, int levels) { return dissect_ndr_pointer_cb( tvb, offset, pinfo, tree, drep, dissect_ndr_wchar_cvstring, type, text, hf_index, cb_wstr_postprocess, GINT_TO_POINTER(levels + 1)); } /* * Register ett/hf values and perform DCERPC over SMB specific * initialisation. */ void dcerpc_smb_init(int proto_dcerpc) { static hf_register_info hf[] = { /* String handling */ { &hf_nt_cs_size, { "Size", "nt.str.size", FT_UINT16, BASE_DEC, NULL, 0x0, "Size of string in short integers", HFILL }}, { &hf_nt_cs_len, { "Length", "nt.str.len", FT_UINT16, BASE_DEC, NULL, 0x0, "Length of string in short integers", HFILL }}, /* Policy handles */ { &hf_nt_policy_open_frame, { "Frame handle opened", "dcerpc.nt.open_frame", FT_FRAMENUM, BASE_NONE, NULL, 0x0, "Frame handle opened", HFILL }}, { &hf_nt_policy_close_frame, { "Frame handle closed", "dcerpc.nt.close_frame", FT_FRAMENUM, BASE_NONE, NULL, 0x0, "Frame handle closed", HFILL }}, }; static gint *ett[] = { &ett_nt_unicode_string, &ett_nt_counted_string, &ett_nt_counted_byte_array, &ett_nt_policy_hnd, }; /* Register ett's and hf's */ proto_register_subtree_array(ett, array_length(ett)); proto_register_field_array(proto_dcerpc, hf, array_length(hf)); /* Initialise policy handle hash */ init_pol_hash(); }