CVE-2017-12895 (Other, published 2017-09-14T06:29Z)
Description: value: The ICMP parser in tcpdump before 4.9.2 has a buffer over-read in print-icmp.c:icmp_print().
Severity: HIGH (CVSS v3 base score: 9.8)
Weakness: CWE-125 \u2014 Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
Repository: https://github.com/the-tcpdump-group/tcpdump
Files changed:
print-icmp.c
tests/TESTLIST
tests/icmp-cksum-oobr-1.out
tests/icmp-cksum-oobr-2.out
tests/icmp-cksum-oobr-3.out
tests/icmp-cksum-oobr-4.out
Commit message: CVE-2017-12895/ICMP: Check the availability of data before checksumming it.

This fixes a buffer over-read discovered by Forcepoint's security
researchers Otto Airamo & Antti Levomäki.

Add tests using the capture files supplied by the reporter(s).


Vulnerable code:
            if (!ext_dp->icmp_length) {
            vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
            vec[0].len = hlen;
            ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
                   EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
                   in_cksum(vec, 1) ? "in" : "",
                   hlen));

Fixed code:
            if (!ext_dp->icmp_length &&
                ND_TTEST2(ext_dp->icmp_ext_version_res, plen - ICMP_EXTD_MINLEN)) {
            if (ND_TTEST2(ext_dp->icmp_ext_version_res, hlen)) {
                vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
                vec[0].len = hlen;
                ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
                       EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
                       in_cksum(vec, 1) ? "in" : "",
                       hlen));
            }
icmp-cksum-oobr-1	icmp-cksum-oobr-1.pcap		icmp-cksum-oobr-1.out	-vvv -e
icmp-cksum-oobr-2	icmp-cksum-oobr-2.pcap		icmp-cksum-oobr-2.out	-vvv -e
icmp-cksum-oobr-3	icmp-cksum-oobr-3.pcap		icmp-cksum-oobr-3.out	-vvv -e
icmp-cksum-oobr-4	icmp-cksum-oobr-4.pcap		icmp-cksum-oobr-4.out	-vvv -e
Out 00:16:3e:27:78:a2 ethertype IPv4 (0x0800), length 204: truncated-ip - 13723 bytes missing! (tos 0x72,ECT(0), ttl 64, id 9472, offset 0, flags [none], proto ICMP (1), length 13911, bad cksum 67ea (->8c0c)!)
    62.220.31.247 > 62.225.245.115: ICMP 62.220.31.247 udp port 1027 unreachable, length 13891
	(tos 0xa0, ttl 114, id 30054, offset 0, flags [none], proto UDP (17), length 13728, bad cksum 3f1f (->a1f)!)
    62.225.245.115.9109 > 62.220.31.247.1027: [bad udp cksum 0xdfe7 -> 0xdb95!] UDP, length 132
	MPLS extension v0 packet not supported
IP (0x0021), length 244: truncated-ip - 32768 bytes missing! (tos 0x0, ttl 254, id 59168, offset 0, flags [DF], proto ICMP (1), length 33008, bad cksum 7ade (->fabd)!)
    10.4.0.34 > 12.4.4.4: ICMP time exceeded in-transit, length 32988
	(tos 0x0, ttl 1, id 42321, offset 0, flags [none], proto UDP (17), length 40)
    12.4.4.4.42315 > 12.1.1.1.33440: [bad udp cksum 0x1000 -> 0xbad0!] UDP, length 12
	MPLS extension v2
	  Extended Payload Object (2), Class-Type: 14, length 80
	    0x0000:  0000 000f 0001 0000 0a0a 0a0a 3f54 6869
	    0x0010:  732d 6973 2d74 6865 2d6e 616d 652d 6f66
	    0x0020:  2d74 6865 2d49 6e74 6572 6661 6365 2d74
	    0x0030:  6861 742d 7765 2d61 7265 2d6c 6f6f 6b69
	    0x0040:  6e67 2d66 6f72 2d5b 3a2d 295d[|icmp]
00:00:00:00:00:00 > 00:00:00:00:00:00, ethertype IPv4 (0x0800), length 337: truncated-ip - 4096 bytes missing! (tos 0x0, ttl 64, id 30662, offset 0, flags [DF], proto ICMP (1), length 4419, bad cksum cdf9 (->bdf9)!)
    97.242.24.11 > 97.242.24.11: ICMP 97.242.24.11 udp port 162 unreachable, length 4399
	(tos 0x0, ttl 128, id 30661, offset 0, flags [DF], proto UDP (17), length 295)
    97.242.24.11.60377 > 97.242.24.11.162: [udp sum ok]  { SNMPv1 C="trap" { Trap(251)  .1.3.6.1.4.1.3830.1.1.2.2.1 97.242.24.11 enterpriseSpecific s=52 61498489 .1.3.6.1.4.1.3830.1.1.2.1.1.1=3 .1.3.6.1.4.1.3830.1.1.2.1.1.2=2 .1.3.6.1.4.1.3830.1.1.2.1.1.3="%SMSA-E-POLLERR, Polling the SMSC was not successful." .1.3.6.1.4.1.3830.1.1.2.1.1.4="OPCOM" .1.3.6.1.4.1.3830.1.1.2.1.1.5="28-OCT-2010 20:42:14.67" .1.3.6.1.4.1.3830.1.1.2.1.1.6="SMRL51" } } 
	MPLS extension v0 packet not supported
IP (0x0021), length 172: truncated-ip - 8192 bytes missing! (tos 0xc0, ttl 251, id 5047, offset 0, flags [none], proto ICMP (1), length 8360, bad cksum 7edb (->5edb)!)
    10.0.12.2 > 10.0.12.1: ICMP time exceeded in-transit, length 8340
	(tos 0x0, ttl 1, id 2574, offset 0, flags [none], proto UDP (17), length 28)
    10.0.12.1.49215 > 10.255.255.4.33435: [udp sum ok] UDP, length 0
	MPLS extension v2
	  MPLS Stack Entry Object (1), Class-Type: 1, length 8
	    label 16, exp 0, [S], ttl 1[|icmp]