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https://github.com/the-tcpdump-group/tcpdump.git
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0db4dcafe5
In that function the "length" parameter means off-the-wire length, that is, the length declared inside the outer header. The "caplen" parameter means the amount of bytes actually available in the captured packet. gre_print_0() and the functions modelled after it passed the value of "length" instead of the value of "caplen", this could make ether_print() access beyond the memory allocated for the captured packet. Brian Carpenter had demonstrated this for the OTV case. Fix the involved functions that call ether_print() to pass the correct value and leave a comment to dismiss "caplen" later as its value can be reliably derived from the other ether_print() parameters.
114 lines
3.5 KiB
C
114 lines
3.5 KiB
C
/* Copyright (c) 2015, bugyo
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* All rights reserved.
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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 the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* \summary: Generic Protocol Extension for VXLAN (VXLAN GPE) printer */
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/* specification: draft-ietf-nvo3-vxlan-gpe-01 */
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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 "extract.h"
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static const char tstr[] = " [|VXLAN-GPE]";
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static const struct tok vxlan_gpe_flags [] = {
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{ 0x08, "I" },
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{ 0x04, "P" },
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{ 0x01, "O" },
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{ 0, NULL }
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};
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#define VXLAN_GPE_HDR_LEN 8
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/*
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* VXLAN GPE header, draft-ietf-nvo3-vxlan-gpe-01
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* Generic Protocol Extension for VXLAN
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*
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* 0 1 2 3
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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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* |R|R|Ver|I|P|R|O| Reserved |Next Protocol |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | VXLAN Network Identifier (VNI) | Reserved |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*/
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void
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vxlan_gpe_print(netdissect_options *ndo, const u_char *bp, u_int len)
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{
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uint8_t flags;
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uint8_t next_protocol;
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uint32_t vni;
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if (len < VXLAN_GPE_HDR_LEN)
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goto trunc;
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ND_TCHECK2(*bp, VXLAN_GPE_HDR_LEN);
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flags = *bp;
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bp += 3;
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next_protocol = *bp;
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bp += 1;
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vni = EXTRACT_24BITS(bp);
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bp += 4;
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ND_PRINT((ndo, "VXLAN-GPE, "));
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ND_PRINT((ndo, "flags [%s], ",
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bittok2str_nosep(vxlan_gpe_flags, "none", flags)));
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ND_PRINT((ndo, "vni %u", vni));
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ND_PRINT((ndo, ndo->ndo_vflag ? "\n " : ": "));
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switch (next_protocol) {
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case 0x1:
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ip_print(ndo, bp, len - 8);
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break;
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case 0x2:
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ip6_print(ndo, bp, len - 8);
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break;
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case 0x3:
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ether_print(ndo, bp, len - 8, ndo->ndo_snapend - bp, NULL, NULL);
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break;
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case 0x4:
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nsh_print(ndo, bp, len - 8);
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break;
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case 0x5:
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mpls_print(ndo, bp, len - 8);
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break;
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default:
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ND_PRINT((ndo, "ERROR: unknown-next-protocol"));
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return;
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}
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return;
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trunc:
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ND_PRINT((ndo, "%s", tstr));
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}
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