mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-27 20:14:12 +08:00
ae83295915
This fixes a buffer over-read discovered by Bhargava Shastry. Add a test using the capture file supplied by the reporter(s), modified so the capture file won't be rejected as an invalid capture. Update another VTP test's .out file for this change. Don't treate a TLV type or length of 0 as invalid; a type of 0 should just be reported as illegal if that type isn't used, and the length is the length of the *value*, not the length of the entire TLV, so if it's zero there won't be an infinite loop. (It's still not *legal*, as the values of all the TLVs we handle are 1 16-bit word long; we added a check for that.) Update some comments while we're at it, to give a new URL for one Cisco page and a non-Cisco URL for another former Cisco page (Cisco's UniverCD pages don't seem to be available any more, and Cisco's robots.txt file didn't allow the Wayback Machine to archive it).
404 lines
14 KiB
C
404 lines
14 KiB
C
/*
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* Copyright (c) 1998-2007 The TCPDUMP project
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code
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* distributions retain the above copyright notice and this paragraph
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* in its entirety, and (2) distributions including binary code include
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* the above copyright notice and this paragraph in its entirety in
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* the documentation or other materials provided with the distribution.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND
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* WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
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* LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE.
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*
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* Reference documentation:
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* http://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html
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* http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
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*
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* Original code ode by Carles Kishimoto <carles.kishimoto@gmail.com>
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*/
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/* \summary: Cisco VLAN Trunking Protocol (VTP) printer */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <netdissect-stdinc.h>
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#include "netdissect.h"
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#include "addrtoname.h"
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#include "extract.h"
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#define VTP_HEADER_LEN 36
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#define VTP_DOMAIN_NAME_LEN 32
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#define VTP_MD5_DIGEST_LEN 16
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#define VTP_UPDATE_TIMESTAMP_LEN 12
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#define VTP_VLAN_INFO_FIXED_PART_LEN 12 /* length of VLAN info before VLAN name */
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#define VTP_SUMMARY_ADV 0x01
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#define VTP_SUBSET_ADV 0x02
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#define VTP_ADV_REQUEST 0x03
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#define VTP_JOIN_MESSAGE 0x04
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struct vtp_vlan_ {
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uint8_t len;
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uint8_t status;
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uint8_t type;
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uint8_t name_len;
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uint16_t vlanid;
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uint16_t mtu;
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uint32_t index;
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};
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static const struct tok vtp_message_type_values[] = {
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{ VTP_SUMMARY_ADV, "Summary advertisement"},
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{ VTP_SUBSET_ADV, "Subset advertisement"},
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{ VTP_ADV_REQUEST, "Advertisement request"},
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{ VTP_JOIN_MESSAGE, "Join message"},
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{ 0, NULL }
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};
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static const struct tok vtp_header_values[] = {
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{ 0x01, "Followers"}, /* On Summary advertisement, 3rd byte is Followers */
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{ 0x02, "Seq number"}, /* On Subset advertisement, 3rd byte is Sequence number */
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{ 0x03, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
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{ 0x04, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
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{ 0, NULL }
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};
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static const struct tok vtp_vlan_type_values[] = {
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{ 0x01, "Ethernet"},
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{ 0x02, "FDDI"},
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{ 0x03, "TrCRF"},
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{ 0x04, "FDDI-net"},
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{ 0x05, "TrBRF"},
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{ 0, NULL }
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};
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static const struct tok vtp_vlan_status[] = {
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{ 0x00, "Operational"},
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{ 0x01, "Suspended"},
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{ 0, NULL }
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};
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#define VTP_VLAN_SOURCE_ROUTING_RING_NUMBER 0x01
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#define VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER 0x02
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#define VTP_VLAN_STP_TYPE 0x03
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#define VTP_VLAN_PARENT_VLAN 0x04
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#define VTP_VLAN_TRANS_BRIDGED_VLAN 0x05
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#define VTP_VLAN_PRUNING 0x06
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#define VTP_VLAN_BRIDGE_TYPE 0x07
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#define VTP_VLAN_ARP_HOP_COUNT 0x08
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#define VTP_VLAN_STE_HOP_COUNT 0x09
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#define VTP_VLAN_BACKUP_CRF_MODE 0x0A
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static const struct tok vtp_vlan_tlv_values[] = {
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{ VTP_VLAN_SOURCE_ROUTING_RING_NUMBER, "Source-Routing Ring Number TLV"},
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{ VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER, "Source-Routing Bridge Number TLV"},
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{ VTP_VLAN_STP_TYPE, "STP type TLV"},
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{ VTP_VLAN_PARENT_VLAN, "Parent VLAN TLV"},
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{ VTP_VLAN_TRANS_BRIDGED_VLAN, "Translationally bridged VLANs TLV"},
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{ VTP_VLAN_PRUNING, "Pruning TLV"},
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{ VTP_VLAN_BRIDGE_TYPE, "Bridge Type TLV"},
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{ VTP_VLAN_ARP_HOP_COUNT, "Max ARP Hop Count TLV"},
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{ VTP_VLAN_STE_HOP_COUNT, "Max STE Hop Count TLV"},
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{ VTP_VLAN_BACKUP_CRF_MODE, "Backup CRF Mode TLV"},
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{ 0, NULL }
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};
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static const struct tok vtp_stp_type_values[] = {
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{ 1, "SRT"},
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{ 2, "SRB"},
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{ 3, "Auto"},
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{ 0, NULL }
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};
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void
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vtp_print (netdissect_options *ndo,
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const u_char *pptr, u_int length)
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{
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int type, len, tlv_len, tlv_value, mgmtd_len;
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const u_char *tptr;
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const struct vtp_vlan_ *vtp_vlan;
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if (length < VTP_HEADER_LEN)
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goto trunc;
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tptr = pptr;
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ND_TCHECK2(*tptr, VTP_HEADER_LEN);
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type = *(tptr+1);
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ND_PRINT((ndo, "VTPv%u, Message %s (0x%02x), length %u",
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*tptr,
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tok2str(vtp_message_type_values,"Unknown message type", type),
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type,
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length));
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/* In non-verbose mode, just print version and message type */
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if (ndo->ndo_vflag < 1) {
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return;
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}
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/* verbose mode print all fields */
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ND_PRINT((ndo, "\n\tDomain name: "));
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mgmtd_len = *(tptr + 3);
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if (mgmtd_len < 1 || mgmtd_len > 32) {
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ND_PRINT((ndo, " [invalid MgmtD Len %d]", mgmtd_len));
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return;
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}
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fn_printzp(ndo, tptr + 4, mgmtd_len, NULL);
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ND_PRINT((ndo, ", %s: %u",
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tok2str(vtp_header_values, "Unknown", type),
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*(tptr+2)));
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tptr += VTP_HEADER_LEN;
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switch (type) {
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case VTP_SUMMARY_ADV:
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/*
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* SUMMARY ADVERTISEMENT
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*
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Version | Code | Followers | MgmtD Len |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Management Domain Name (zero-padded to 32 bytes) |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Configuration revision number |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Updater Identity IP address |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Update Timestamp (12 bytes) |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | MD5 digest (16 bytes) |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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*/
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ND_TCHECK2(*tptr, 8);
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ND_PRINT((ndo, "\n\t Config Rev %x, Updater %s",
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EXTRACT_32BITS(tptr),
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ipaddr_string(ndo, tptr+4)));
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tptr += 8;
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ND_TCHECK2(*tptr, VTP_UPDATE_TIMESTAMP_LEN);
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ND_PRINT((ndo, ", Timestamp 0x%08x 0x%08x 0x%08x",
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EXTRACT_32BITS(tptr),
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EXTRACT_32BITS(tptr + 4),
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EXTRACT_32BITS(tptr + 8)));
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tptr += VTP_UPDATE_TIMESTAMP_LEN;
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ND_TCHECK2(*tptr, VTP_MD5_DIGEST_LEN);
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ND_PRINT((ndo, ", MD5 digest: %08x%08x%08x%08x",
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EXTRACT_32BITS(tptr),
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EXTRACT_32BITS(tptr + 4),
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EXTRACT_32BITS(tptr + 8),
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EXTRACT_32BITS(tptr + 12)));
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tptr += VTP_MD5_DIGEST_LEN;
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break;
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case VTP_SUBSET_ADV:
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/*
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* SUBSET ADVERTISEMENT
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*
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Version | Code | Seq number | MgmtD Len |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Management Domain Name (zero-padded to 32 bytes) |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Configuration revision number |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | VLAN info field 1 |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | ................ |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | VLAN info field N |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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*/
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ND_TCHECK_32BITS(tptr);
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ND_PRINT((ndo, ", Config Rev %x", EXTRACT_32BITS(tptr)));
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/*
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* VLAN INFORMATION
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | V info len | Status | VLAN type | VLAN name len |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | ISL vlan id | MTU size |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | 802.10 index (SAID) |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | VLAN name |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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*/
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tptr += 4;
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while (tptr < (pptr+length)) {
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ND_TCHECK_8BITS(tptr);
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len = *tptr;
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if (len == 0)
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break;
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ND_TCHECK2(*tptr, len);
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vtp_vlan = (const struct vtp_vlan_*)tptr;
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if (len < VTP_VLAN_INFO_FIXED_PART_LEN)
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goto trunc;
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ND_TCHECK(*vtp_vlan);
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ND_PRINT((ndo, "\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ",
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tok2str(vtp_vlan_status,"Unknown",vtp_vlan->status),
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tok2str(vtp_vlan_type_values,"Unknown",vtp_vlan->type),
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EXTRACT_16BITS(&vtp_vlan->vlanid),
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EXTRACT_16BITS(&vtp_vlan->mtu),
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EXTRACT_32BITS(&vtp_vlan->index)));
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len -= VTP_VLAN_INFO_FIXED_PART_LEN;
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tptr += VTP_VLAN_INFO_FIXED_PART_LEN;
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if (len < 4*((vtp_vlan->name_len + 3)/4))
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goto trunc;
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ND_TCHECK2(*tptr, vtp_vlan->name_len);
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fn_printzp(ndo, tptr, vtp_vlan->name_len, NULL);
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/*
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* Vlan names are aligned to 32-bit boundaries.
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*/
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len -= 4*((vtp_vlan->name_len + 3)/4);
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tptr += 4*((vtp_vlan->name_len + 3)/4);
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/* TLV information follows */
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while (len > 0) {
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/*
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* Cisco specs say 2 bytes for type + 2 bytes for length;
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* see http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
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* However, actual packets on the wire appear to use 1
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* byte for the type and 1 byte for the length, so that's
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* what we do.
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*/
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if (len < 2)
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goto trunc;
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ND_TCHECK2(*tptr, 2);
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type = *tptr;
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tlv_len = *(tptr+1);
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ND_PRINT((ndo, "\n\t\t%s (0x%04x) TLV",
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tok2str(vtp_vlan_tlv_values, "Unknown", type),
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type));
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if (len < tlv_len * 2 + 2) {
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ND_PRINT((ndo, " (TLV goes past the end of the packet)"));
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return;
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}
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ND_TCHECK2(*tptr, tlv_len * 2 +2);
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/*
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* We assume the value is a 2-byte integer; the length is
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* in units of 16-bit words.
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*/
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if (tlv_len != 1) {
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ND_PRINT((ndo, " (invalid TLV length %u != 1)", tlv_len));
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return;
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} else {
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tlv_value = EXTRACT_16BITS(tptr+2);
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switch (type) {
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case VTP_VLAN_STE_HOP_COUNT:
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ND_PRINT((ndo, ", %u", tlv_value));
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break;
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case VTP_VLAN_PRUNING:
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ND_PRINT((ndo, ", %s (%u)",
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tlv_value == 1 ? "Enabled" : "Disabled",
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tlv_value));
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break;
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case VTP_VLAN_STP_TYPE:
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ND_PRINT((ndo, ", %s (%u)",
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tok2str(vtp_stp_type_values, "Unknown", tlv_value),
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tlv_value));
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break;
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case VTP_VLAN_BRIDGE_TYPE:
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ND_PRINT((ndo, ", %s (%u)",
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tlv_value == 1 ? "SRB" : "SRT",
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tlv_value));
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break;
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case VTP_VLAN_BACKUP_CRF_MODE:
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ND_PRINT((ndo, ", %s (%u)",
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tlv_value == 1 ? "Backup" : "Not backup",
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tlv_value));
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break;
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/*
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* FIXME those are the defined TLVs that lack a decoder
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* you are welcome to contribute code ;-)
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*/
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case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER:
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case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER:
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case VTP_VLAN_PARENT_VLAN:
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case VTP_VLAN_TRANS_BRIDGED_VLAN:
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case VTP_VLAN_ARP_HOP_COUNT:
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default:
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print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2);
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break;
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}
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}
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len -= 2 + tlv_len*2;
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tptr += 2 + tlv_len*2;
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}
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}
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break;
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case VTP_ADV_REQUEST:
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/*
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* ADVERTISEMENT REQUEST
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*
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Version | Code | Reserved | MgmtD Len |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Management Domain Name (zero-padded to 32 bytes) |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Start value |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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*/
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ND_TCHECK2(*tptr, 4);
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ND_PRINT((ndo, "\n\tStart value: %u", EXTRACT_32BITS(tptr)));
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break;
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case VTP_JOIN_MESSAGE:
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/* FIXME - Could not find message format */
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break;
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default:
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break;
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}
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return;
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trunc:
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ND_PRINT((ndo, "[|vtp]"));
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}
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/*
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* Local Variables:
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* c-style: whitesmith
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* c-basic-offset: 4
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* End:
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*/
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