X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/49b23c5a9b0198bb382dcf43c458d46fcf2fa809..3d6e7bd1e42a7316fb2020348a8d3e86b1346b36:/print-vtp.c diff --git a/print-vtp.c b/print-vtp.c index 285beb96..d153cc19 100644 --- a/print-vtp.c +++ b/print-vtp.c @@ -13,9 +13,8 @@ * FOR A PARTICULAR PURPOSE. * * Reference documentation: - * http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52.shtml - * http://www.cisco.com/warp/public/473/21.html - * http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm + * http://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html + * http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm * * Original code ode by Carles Kishimoto */ @@ -36,7 +35,7 @@ #define VTP_DOMAIN_NAME_LEN 32 #define VTP_MD5_DIGEST_LEN 16 #define VTP_UPDATE_TIMESTAMP_LEN 12 -#define VTP_VLAN_INFO_OFFSET 12 +#define VTP_VLAN_INFO_FIXED_PART_LEN 12 /* length of VLAN info before VLAN name */ #define VTP_SUMMARY_ADV 0x01 #define VTP_SUBSET_ADV 0x02 @@ -223,6 +222,7 @@ vtp_print (netdissect_options *ndo, * */ + ND_TCHECK_32BITS(tptr); ND_PRINT((ndo, ", Config Rev %x", EXTRACT_32BITS(tptr))); /* @@ -243,6 +243,7 @@ vtp_print (netdissect_options *ndo, tptr += 4; while (tptr < (pptr+length)) { + ND_TCHECK_8BITS(tptr); len = *tptr; if (len == 0) break; @@ -250,6 +251,8 @@ vtp_print (netdissect_options *ndo, ND_TCHECK2(*tptr, len); vtp_vlan = (const struct vtp_vlan_*)tptr; + if (len < VTP_VLAN_INFO_FIXED_PART_LEN) + goto trunc; ND_TCHECK(*vtp_vlan); ND_PRINT((ndo, "\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ", tok2str(vtp_vlan_status,"Unknown",vtp_vlan->status), @@ -257,22 +260,33 @@ vtp_print (netdissect_options *ndo, EXTRACT_16BITS(&vtp_vlan->vlanid), EXTRACT_16BITS(&vtp_vlan->mtu), EXTRACT_32BITS(&vtp_vlan->index))); - fn_printzp(ndo, tptr + VTP_VLAN_INFO_OFFSET, vtp_vlan->name_len, NULL); - - /* - * Vlan names are aligned to 32-bit boundaries. - */ - len -= VTP_VLAN_INFO_OFFSET + 4*((vtp_vlan->name_len + 3)/4); - tptr += VTP_VLAN_INFO_OFFSET + 4*((vtp_vlan->name_len + 3)/4); + len -= VTP_VLAN_INFO_FIXED_PART_LEN; + tptr += VTP_VLAN_INFO_FIXED_PART_LEN; + if (len < 4*((vtp_vlan->name_len + 3)/4)) + goto trunc; + ND_TCHECK2(*tptr, vtp_vlan->name_len); + fn_printzp(ndo, tptr, vtp_vlan->name_len, NULL); + + /* + * Vlan names are aligned to 32-bit boundaries. + */ + len -= 4*((vtp_vlan->name_len + 3)/4); + tptr += 4*((vtp_vlan->name_len + 3)/4); /* TLV information follows */ while (len > 0) { /* - * Cisco specs says 2 bytes for type + 2 bytes for length, take only 1 - * See: http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm + * Cisco specs say 2 bytes for type + 2 bytes for length; + * see http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm + * However, actual packets on the wire appear to use 1 + * byte for the type and 1 byte for the length, so that's + * what we do. */ + if (len < 2) + goto trunc; + ND_TCHECK2(*tptr, 2); type = *tptr; tlv_len = *(tptr+1); @@ -280,59 +294,65 @@ vtp_print (netdissect_options *ndo, tok2str(vtp_vlan_tlv_values, "Unknown", type), type)); - /* - * infinite loop check - */ - if (type == 0 || tlv_len == 0) { + if (len < tlv_len * 2 + 2) { + ND_PRINT((ndo, " (TLV goes past the end of the packet)")); return; } - ND_TCHECK2(*tptr, tlv_len * 2 +2); - tlv_value = EXTRACT_16BITS(tptr+2); - - switch (type) { - case VTP_VLAN_STE_HOP_COUNT: - ND_PRINT((ndo, ", %u", tlv_value)); - break; - - case VTP_VLAN_PRUNING: - ND_PRINT((ndo, ", %s (%u)", - tlv_value == 1 ? "Enabled" : "Disabled", - tlv_value)); - break; - - case VTP_VLAN_STP_TYPE: - ND_PRINT((ndo, ", %s (%u)", - tok2str(vtp_stp_type_values, "Unknown", tlv_value), - tlv_value)); - break; - - case VTP_VLAN_BRIDGE_TYPE: - ND_PRINT((ndo, ", %s (%u)", - tlv_value == 1 ? "SRB" : "SRT", - tlv_value)); - break; - - case VTP_VLAN_BACKUP_CRF_MODE: - ND_PRINT((ndo, ", %s (%u)", - tlv_value == 1 ? "Backup" : "Not backup", - tlv_value)); - break; - - /* - * FIXME those are the defined TLVs that lack a decoder - * you are welcome to contribute code ;-) - */ - - case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER: - case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER: - case VTP_VLAN_PARENT_VLAN: - case VTP_VLAN_TRANS_BRIDGED_VLAN: - case VTP_VLAN_ARP_HOP_COUNT: - default: - print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2); - break; + /* + * We assume the value is a 2-byte integer; the length is + * in units of 16-bit words. + */ + if (tlv_len != 1) { + ND_PRINT((ndo, " (invalid TLV length %u != 1)", tlv_len)); + return; + } else { + tlv_value = EXTRACT_16BITS(tptr+2); + + switch (type) { + case VTP_VLAN_STE_HOP_COUNT: + ND_PRINT((ndo, ", %u", tlv_value)); + break; + + case VTP_VLAN_PRUNING: + ND_PRINT((ndo, ", %s (%u)", + tlv_value == 1 ? "Enabled" : "Disabled", + tlv_value)); + break; + + case VTP_VLAN_STP_TYPE: + ND_PRINT((ndo, ", %s (%u)", + tok2str(vtp_stp_type_values, "Unknown", tlv_value), + tlv_value)); + break; + + case VTP_VLAN_BRIDGE_TYPE: + ND_PRINT((ndo, ", %s (%u)", + tlv_value == 1 ? "SRB" : "SRT", + tlv_value)); + break; + + case VTP_VLAN_BACKUP_CRF_MODE: + ND_PRINT((ndo, ", %s (%u)", + tlv_value == 1 ? "Backup" : "Not backup", + tlv_value)); + break; + + /* + * FIXME those are the defined TLVs that lack a decoder + * you are welcome to contribute code ;-) + */ + + case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER: + case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER: + case VTP_VLAN_PARENT_VLAN: + case VTP_VLAN_TRANS_BRIDGED_VLAN: + case VTP_VLAN_ARP_HOP_COUNT: + default: + print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2); + break; + } } len -= 2 + tlv_len*2; tptr += 2 + tlv_len*2;