static int dissect_gssapi_work(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean is_verifier) { proto_item *volatile item; proto_tree *volatile subtree; volatile int return_offset = 0; gssapi_conv_info_t *volatile gss_info; gssapi_oid_value *oidvalue; dissector_handle_t handle; conversation_t *conversation; tvbuff_t *oid_tvb; int len, start_offset, oid_start_offset; volatile int offset; gint8 appclass; gboolean pc, ind_field; gint32 tag; guint32 len1; const char *oid; fragment_data *fd_head=NULL; gssapi_frag_info_t *fi; tvbuff_t *volatile gss_tvb=NULL; asn1_ctx_t asn1_ctx; void *pd_save; start_offset=0; offset=0; asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo); /* * We don't know whether the data is encrypted, so say it's * not, for now. The subdissector must set gssapi_data_encrypted * if it is. */ pinfo->gssapi_data_encrypted = FALSE; /* * We need a conversation for later */ conversation = find_or_create_conversation(pinfo); gss_info = (gssapi_conv_info_t *)conversation_get_proto_data(conversation, proto_gssapi); if (!gss_info) { gss_info = se_new(gssapi_conv_info_t); gss_info->oid=NULL; gss_info->do_reassembly=FALSE; gss_info->frags=se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK, "gssapi_frags"); conversation_add_proto_data(conversation, proto_gssapi, gss_info); } item = proto_tree_add_item( tree, proto_gssapi, tvb, offset, -1, ENC_NA); subtree = proto_item_add_subtree(item, ett_gssapi); /* * Catch the ReportedBoundsError exception; the stuff we've been * handed doesn't necessarily run to the end of the packet, it's * an item inside a packet, so if it happens to be malformed (or * we, or a dissector we call, has a bug), so that an exception * is thrown, we want to report the error, but return and let * our caller dissect the rest of the packet. * * If it gets a BoundsError, we can stop, as there's nothing more * in the packet after our blob to see, so we just re-throw the * exception. */ pd_save = pinfo->private_data; TRY { gss_tvb=tvb; /* First of all, if it's the first time we see this packet * then check whether we are in the middle of reassembly or not */ if( (!pinfo->fd->flags.visited) && (gss_info->do_reassembly) && (gssapi_reassembly) ){ fi=(gssapi_frag_info_t *)se_tree_lookup32(gss_info->frags, gss_info->first_frame); if(!fi){ goto done; } se_tree_insert32(gss_info->frags, pinfo->fd->num, fi); fd_head=fragment_add(&gssapi_reassembly_table, tvb, 0, pinfo, fi->first_frame, NULL, gss_info->frag_offset, tvb_length(tvb), TRUE); gss_info->frag_offset+=tvb_length(tvb); /* we need more fragments */ if(!fd_head){ goto done; } /* this blob is now fully reassembled */ gss_info->do_reassembly=FALSE; fi->reassembled_in=pinfo->fd->num; gss_tvb=tvb_new_child_real_data(tvb, fd_head->data, fd_head->datalen, fd_head->datalen); add_new_data_source(pinfo, gss_tvb, "Reassembled GSSAPI"); } /* We have seen this packet before. * Is this blob part of reassembly or a normal blob ? */ if( (pinfo->fd->flags.visited) && (gssapi_reassembly) ){ fi=(gssapi_frag_info_t *)se_tree_lookup32(gss_info->frags, pinfo->fd->num); if(fi){ fd_head=fragment_get(&gssapi_reassembly_table, pinfo, fi->first_frame, NULL); if(fd_head && (fd_head->flags&FD_DEFRAGMENTED)){ if(pinfo->fd->num==fi->reassembled_in){ proto_item *frag_tree_item; gss_tvb=tvb_new_child_real_data(tvb, fd_head->data, fd_head->datalen, fd_head->datalen); add_new_data_source(pinfo, gss_tvb, "Reassembled GSSAPI"); show_fragment_tree(fd_head, &gssapi_frag_items, tree, pinfo, tvb, &frag_tree_item); } else { proto_item *it; it=proto_tree_add_uint(tree, hf_gssapi_reassembled_in, tvb, 0, 0, fi->reassembled_in); PROTO_ITEM_SET_GENERATED(it); goto done; } } } } /* Read header */ offset = get_ber_identifier(gss_tvb, offset, &appclass, &pc, &tag); offset = get_ber_length(gss_tvb, offset, &len1, &ind_field); if (!(appclass == BER_CLASS_APP && pc && tag == 0)) { /* It could be NTLMSSP, with no OID. This can happen for anything that microsoft calls 'Negotiate' or GSS-SPNEGO */ if ((tvb_length_remaining(gss_tvb, start_offset)>7) && (tvb_strneql(gss_tvb, start_offset, "NTLMSSP", 7) == 0)) { return_offset = call_dissector(ntlmssp_handle, tvb_new_subset_remaining(gss_tvb, start_offset), pinfo, subtree); goto done; } /* Maybe it's new NTLMSSP payload */ if ((tvb_length_remaining(gss_tvb, start_offset)>16) && ((tvb_memeql(gss_tvb, start_offset, "\x01\x00\x00\x00", 4) == 0))) { return_offset = call_dissector(ntlmssp_payload_handle, tvb_new_subset_remaining(gss_tvb, start_offset), pinfo, subtree); pinfo->gssapi_data_encrypted = TRUE; goto done; } if ((tvb_length_remaining(gss_tvb, start_offset)==16) && ((tvb_memeql(gss_tvb, start_offset, "\x01\x00\x00\x00", 4) == 0))) { if( is_verifier ) { return_offset = call_dissector(ntlmssp_verf_handle, tvb_new_subset_remaining(gss_tvb, start_offset), pinfo, subtree); } else if( pinfo->gssapi_encrypted_tvb ) { return_offset = call_dissector(ntlmssp_data_only_handle, tvb_new_subset_remaining(pinfo->gssapi_encrypted_tvb, 0), pinfo, subtree); pinfo->gssapi_data_encrypted = TRUE; } goto done; } /* Maybe it's new GSSKRB5 CFX Wrapping */ if ((tvb_length_remaining(gss_tvb, start_offset)>2) && ((tvb_memeql(gss_tvb, start_offset, "\04\x04", 2) == 0) || (tvb_memeql(gss_tvb, start_offset, "\05\x04", 2) == 0))) { return_offset = call_dissector(spnego_krb5_wrap_handle, tvb_new_subset_remaining(gss_tvb, start_offset), pinfo, subtree); goto done; } /* * If we do not recognise an Application class, * then we are probably dealing with an inner context * token or a wrap token, and we should retrieve the * gssapi_oid_value pointer from the per-frame data or, * if there is no per-frame data (as would be the case * the first time we dissect this frame), from the * conversation that exists or that we created from * pinfo (and then make it per-frame data). * We need to make it per-frame data as there can be * more than one GSS-API negotiation in a conversation. * * Note! We "cheat". Since we only need the pointer, * we store that as the data. (That's not really * "cheating" - the per-frame data and per-conversation * data code doesn't care what you supply as a data * pointer; it just treats it as an opaque pointer, it * doesn't dereference it or free what it points to.) */ oidvalue = (gssapi_oid_value *)p_get_proto_data(pinfo->fd, proto_gssapi, 0); if (!oidvalue && !pinfo->fd->flags.visited) { /* No handle attached to this frame, but it's the first */ /* pass, so it'd be attached to the conversation. */ oidvalue = gss_info->oid; if (gss_info->oid) p_add_proto_data(pinfo->fd, proto_gssapi, 0, gss_info->oid); } if (!oidvalue) { proto_tree_add_text(subtree, gss_tvb, start_offset, 0, "Unknown header (class=%d, pc=%d, tag=%d)", appclass, pc, tag); return_offset = tvb_length(gss_tvb); goto done; } else { tvbuff_t *oid_tvb_local; oid_tvb_local = tvb_new_subset_remaining(gss_tvb, start_offset); if (is_verifier) handle = oidvalue->wrap_handle; else handle = oidvalue->handle; len = call_dissector(handle, oid_tvb_local, pinfo, subtree); if (len == 0) return_offset = tvb_length(gss_tvb); else return_offset = start_offset + len; goto done; /* We are finished here */ } } /* Read oid */ oid_start_offset=offset; offset=dissect_ber_object_identifier_str(FALSE, &asn1_ctx, subtree, gss_tvb, offset, hf_gssapi_oid, &oid); oidvalue = gssapi_lookup_oid_str(oid); /* Check if we need reassembly of this blob. * Only try reassembly for OIDs we recognize * and when we have the entire tvb * * SMB will sometimes split one large GSSAPI blob * across multiple SMB/SessionSetup commands. * While we should look at the uid returned in the response * to the first SessionSetup and use that as a key * instead for simplicity we assume there will not be several * such authentication at once on a single tcp session */ if( (!pinfo->fd->flags.visited) && (oidvalue) && (tvb_length(gss_tvb)==tvb_reported_length(gss_tvb)) && (len1>(guint32)tvb_length_remaining(gss_tvb, oid_start_offset)) && (gssapi_reassembly) ){ fi=se_new(gssapi_frag_info_t); fi->first_frame=pinfo->fd->num; fi->reassembled_in=0; se_tree_insert32(gss_info->frags, pinfo->fd->num, fi); fragment_add(&gssapi_reassembly_table, gss_tvb, 0, pinfo, pinfo->fd->num, NULL, 0, tvb_length(gss_tvb), TRUE); fragment_set_tot_len(&gssapi_reassembly_table, pinfo, pinfo->fd->num, NULL, len1+oid_start_offset); gss_info->do_reassembly=TRUE; gss_info->first_frame=pinfo->fd->num; gss_info->frag_offset=tvb_length(gss_tvb); goto done; } /* * Hand off to subdissector. */ if ((oidvalue == NULL) || !proto_is_protocol_enabled(oidvalue->proto)) { /* No dissector for this oid */ proto_tree_add_text(subtree, gss_tvb, oid_start_offset, -1, "Token object"); return_offset = tvb_length(gss_tvb); goto done; } /* Save a pointer to the data for the OID for the * GSSAPI protocol for this conversation. */ /* * Now add the proto data ... * but only if it is not already there. */ if(!gss_info->oid){ gss_info->oid=oidvalue; } if (is_verifier) { handle = oidvalue->wrap_handle; if (handle != NULL) { oid_tvb = tvb_new_subset_remaining(gss_tvb, offset); len = call_dissector(handle, oid_tvb, pinfo, subtree); if (len == 0) return_offset = tvb_length(gss_tvb); else return_offset = offset + len; } else { proto_tree_add_text(subtree, gss_tvb, offset, -1, "Authentication verifier"); return_offset = tvb_length(gss_tvb); } } else { handle = oidvalue->handle; if (handle != NULL) { oid_tvb = tvb_new_subset_remaining(gss_tvb, offset); len = call_dissector(handle, oid_tvb, pinfo, subtree); if (len == 0) return_offset = tvb_length(gss_tvb); else return_offset = offset + len; } else { proto_tree_add_text(subtree, gss_tvb, offset, -1, "Authentication credentials"); return_offset = tvb_length(gss_tvb); } } done: ; } CATCH_NONFATAL_ERRORS { /* * Somebody threw an exception that means that there * was a problem dissecting the payload; that means * that a dissector was found, so we don't need to * dissect the payload as data or update the protocol * or info columns. * * Just show the exception and then drive on to show * the trailer, after noting that a dissector was found * and restoring the protocol value that was in effect * before we called the subdissector. * * Restore the private_data structure in case one of the * called dissectors modified it (and, due to the exception, * was unable to restore it). */ pinfo->private_data = pd_save; show_exception(gss_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE); } ENDTRY; proto_item_set_len(item, return_offset); return return_offset; }
static void dissect_btobex(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_item *ti; proto_tree *st; fragment_data *frag_msg = NULL; gboolean save_fragmented, complete; tvbuff_t* new_tvb = NULL; tvbuff_t* next_tvb = NULL; guint32 no_of_segments = 0; int offset = 0; save_fragmented = pinfo->fragmented; complete = FALSE; if (fragment_get(pinfo, pinfo->p2p_dir, fragment_table)) { /* not the first fragment */ frag_msg = fragment_add_seq_next(tvb, 0, pinfo, pinfo->p2p_dir, fragment_table, reassembled_table, tvb_length(tvb), TRUE); new_tvb = process_reassembled_data(tvb, 0, pinfo, "Reassembled Obex packet", frag_msg, &btobex_frag_items, NULL, tree); pinfo->fragmented = TRUE; } else { if (tvb_length(tvb) < tvb_get_ntohs(tvb, offset+1)) { /* first fragment in a sequence */ no_of_segments = tvb_get_ntohs(tvb, offset+1)/tvb_length(tvb); if (tvb_get_ntohs(tvb, offset+1) > (no_of_segments * tvb_length(tvb))) no_of_segments++; frag_msg = fragment_add_seq_next(tvb, 0, pinfo, pinfo->p2p_dir, fragment_table, reassembled_table, tvb_length(tvb), TRUE); fragment_set_tot_len(pinfo, pinfo->p2p_dir, fragment_table, no_of_segments-1); new_tvb = process_reassembled_data(tvb, 0, pinfo, "Reassembled Obex packet", frag_msg, &btobex_frag_items, NULL, tree); pinfo->fragmented = TRUE; } else if (tvb_length(tvb) == tvb_get_ntohs(tvb, offset+1)) { /* non-fragmented */ complete = TRUE; pinfo->fragmented = FALSE; } } if (new_tvb) { /* take it all */ next_tvb = new_tvb; complete = TRUE; } else { /* make a new subset */ next_tvb = tvb_new_subset_remaining(tvb, offset); } if (complete) { guint8 code, final_flag; /* fully dissectable packet ready */ col_set_str(pinfo->cinfo, COL_PROTOCOL, "OBEX"); ti = proto_tree_add_item(tree, proto_btobex, next_tvb, 0, -1, ENC_NA); st = proto_item_add_subtree(ti, ett_btobex); /* op/response code */ code = tvb_get_guint8(next_tvb, offset) & BTOBEX_CODE_VALS_MASK; final_flag = tvb_get_guint8(next_tvb, offset) & 0x80; switch (pinfo->p2p_dir) { case P2P_DIR_SENT: col_add_fstr(pinfo->cinfo, COL_INFO, "Sent "); break; case P2P_DIR_RECV: col_add_fstr(pinfo->cinfo, COL_INFO, "Rcvd "); break; case P2P_DIR_UNKNOWN: break; default: col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown direction %d ", pinfo->p2p_dir); break; } col_append_fstr(pinfo->cinfo, COL_INFO, "%s", val_to_str_ext_const(code, &code_vals_ext, "Unknown")); if ((code < BTOBEX_CODE_VALS_CONTINUE) || (code == BTOBEX_CODE_VALS_ABORT)) { proto_tree_add_item(st, hf_opcode, next_tvb, offset, 1, ENC_BIG_ENDIAN); if (pinfo->p2p_dir == P2P_DIR_SENT || pinfo->p2p_dir == P2P_DIR_RECV) { last_opcode[pinfo->p2p_dir] = code; } } else { proto_tree_add_item(st, hf_response_code, next_tvb, offset, 1, ENC_BIG_ENDIAN); } proto_tree_add_item(st, hf_final_flag, next_tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* length */ proto_tree_add_item(st, hf_length, next_tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2; switch(code) { case BTOBEX_CODE_VALS_CONNECT: proto_tree_add_item(st, hf_version, next_tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(st, hf_flags, next_tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(st, hf_max_pkt_len, next_tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2; break; case BTOBEX_CODE_VALS_PUT: case BTOBEX_CODE_VALS_GET: col_append_fstr(pinfo->cinfo, COL_INFO, " %s", (final_flag == 0x80) ? "final" : "continue"); break; case BTOBEX_CODE_VALS_SET_PATH: proto_tree_add_item(st, hf_flags, next_tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(st, hf_set_path_flags_0, next_tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(st, hf_set_path_flags_1, next_tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(st, hf_constants, next_tvb, offset, 1, ENC_BIG_ENDIAN); offset++; break; case BTOBEX_CODE_VALS_DISCONNECT: case BTOBEX_CODE_VALS_ABORT: break; default: { guint8 response_opcode = last_opcode[(pinfo->p2p_dir + 1) & 0x01]; if (response_opcode == BTOBEX_CODE_VALS_CONNECT) { proto_tree_add_item(st, hf_version, next_tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(st, hf_flags, next_tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(st, hf_max_pkt_len, next_tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2; } } break; } dissect_headers(st, next_tvb, offset, pinfo); } else { /* packet fragment */ col_add_fstr(pinfo->cinfo, COL_INFO, "%s Obex fragment", (pinfo->p2p_dir==P2P_DIR_SENT) ? "Sent" : "Rcvd"); call_dissector(data_handle, next_tvb, pinfo, tree); } pinfo->fragmented = save_fragmented; }