From: Guy Harris Date: Wed, 22 Mar 2017 18:48:06 +0000 (-0700) Subject: CVE-2017-13029/PPP: Fix a bounds check, and clean up other bounds checks. X-Git-Tag: tcpdump-4.9.2~47 X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/35591264d7e5fa727fbed3b20ef427e1b648c1a2?ds=sidebyside CVE-2017-13029/PPP: Fix a bounds check, and clean up other bounds checks. For configuration protocol options, use ND_TCHECK() and ND_TCHECK_nBITS() macros, passing them the appropriate pointer argument. This fixes one case where the ND_TCHECK2() call they replace was not checking enough bytes. This fixes a buffer over-read discovered by Bhargava Shastry, SecT/TU Berlin. 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. --- diff --git a/print-ppp.c b/print-ppp.c index 13438920..d07763cb 100644 --- a/print-ppp.c +++ b/print-ppp.c @@ -611,7 +611,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be >= 6)")); return len; } - ND_TCHECK2(*(p + 2), 3); + ND_TCHECK_24BITS(p + 2); ND_PRINT((ndo, ": Vendor: %s (%u)", tok2str(oui_values,"Unknown",EXTRACT_24BITS(p+2)), EXTRACT_24BITS(p + 2))); @@ -630,7 +630,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be = 4)")); return len; } - ND_TCHECK2(*(p + 2), 2); + ND_TCHECK_16BITS(p + 2); ND_PRINT((ndo, ": %u", EXTRACT_16BITS(p + 2))); break; case LCPOPT_ACCM: @@ -638,7 +638,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be = 6)")); return len; } - ND_TCHECK2(*(p + 2), 4); + ND_TCHECK_32BITS(p + 2); ND_PRINT((ndo, ": 0x%08x", EXTRACT_32BITS(p + 2))); break; case LCPOPT_AP: @@ -646,7 +646,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be >= 4)")); return len; } - ND_TCHECK2(*(p + 2), 2); + ND_TCHECK_16BITS(p + 2); ND_PRINT((ndo, ": %s", tok2str(ppptype2str, "Unknown Auth Proto (0x04x)", EXTRACT_16BITS(p + 2)))); switch (EXTRACT_16BITS(p+2)) { @@ -668,7 +668,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be >= 4)")); return 0; } - ND_TCHECK2(*(p + 2), 2); + ND_TCHECK_16BITS(p+2); if (EXTRACT_16BITS(p+2) == PPP_LQM) ND_PRINT((ndo, ": LQR")); else @@ -679,7 +679,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be = 6)")); return 0; } - ND_TCHECK2(*(p + 2), 4); + ND_TCHECK_32BITS(p + 2); ND_PRINT((ndo, ": 0x%08x", EXTRACT_32BITS(p + 2))); break; case LCPOPT_PFC: @@ -691,7 +691,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be = 4)")); return 0; } - ND_TCHECK2(*(p + 2), 2); + ND_TCHECK_16BITS(p + 2); ND_PRINT((ndo, ": 0x%04x", EXTRACT_16BITS(p + 2))); break; case LCPOPT_CBACK: @@ -710,7 +710,7 @@ print_lcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be = 4)")); return 0; } - ND_TCHECK2(*(p + 2), 2); + ND_TCHECK_16BITS(p + 2); ND_PRINT((ndo, ": %u", EXTRACT_16BITS(p + 2))); break; case LCPOPT_MLED: @@ -1055,7 +1055,7 @@ print_ipcp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be >= 4)")); return 0; } - ND_TCHECK2(*(p + 2), 2); + ND_TCHECK_16BITS(p+2); compproto = EXTRACT_16BITS(p+2); ND_PRINT((ndo, ": %s (0x%02x):", @@ -1241,7 +1241,7 @@ print_ccp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be >= 3)")); return len; } - ND_TCHECK2(*(p + 2), 1); + ND_TCHECK(p[2]); ND_PRINT((ndo, ": Version: %u, Dictionary Bits: %u", p[2] >> 5, p[2] & 0x1f)); break; @@ -1250,7 +1250,7 @@ print_ccp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be >= 4)")); return len; } - ND_TCHECK2(*(p + 2), 1); + ND_TCHECK(p[3]); ND_PRINT((ndo, ": Features: %u, PxP: %s, History: %u, #CTX-ID: %u", (p[2] & 0xc0) >> 6, (p[2] & 0x20) ? "Enabled" : "Disabled", @@ -1261,7 +1261,7 @@ print_ccp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be >= 4)")); return len; } - ND_TCHECK2(*(p + 2), 1); + ND_TCHECK(p[3]); ND_PRINT((ndo, ": Window: %uK, Method: %s (0x%x), MBZ: %u, CHK: %u", (p[2] & 0xf0) >> 4, ((p[2] & 0x0f) == 8) ? "zlib" : "unknown", @@ -1336,7 +1336,7 @@ print_bacp_config_options(netdissect_options *ndo, ND_PRINT((ndo, " (length bogus, should be = 6)")); return len; } - ND_TCHECK2(*(p + 2), 4); + ND_TCHECK_32BITS(p + 2); ND_PRINT((ndo, ": Magic-Num 0x%08x", EXTRACT_32BITS(p + 2))); break; default: diff --git a/tests/TESTLIST b/tests/TESTLIST index 1437348c..f5d14dd2 100644 --- a/tests/TESTLIST +++ b/tests/TESTLIST @@ -531,6 +531,7 @@ isis_stlv_asan-3 isis_stlv_asan-3.pcap isis_stlv_asan-3.out -v isis_stlv_asan-4 isis_stlv_asan-4.pcap isis_stlv_asan-4.out -v lldp_mgmt_addr_tlv_asan lldp_mgmt_addr_tlv_asan.pcap lldp_mgmt_addr_tlv_asan.out -v bootp_asan bootp_asan.pcap bootp_asan.out -v +ppp_ccp_config_deflate_option_asan ppp_ccp_config_deflate_option_asan.pcap ppp_ccp_config_deflate_option_asan.out -v # RTP tests # fuzzed pcap diff --git a/tests/ppp_ccp_config_deflate_option_asan.out b/tests/ppp_ccp_config_deflate_option_asan.out new file mode 100644 index 00000000..423ef050 --- /dev/null +++ b/tests/ppp_ccp_config_deflate_option_asan.out @@ -0,0 +1,3 @@ +: CCP, Conf-Request (0x01), id 223, length 125685 + encoded length 15 (=Option(s) length 11) + MVRCA Option (0x18), length 5[|ccp] diff --git a/tests/ppp_ccp_config_deflate_option_asan.pcap b/tests/ppp_ccp_config_deflate_option_asan.pcap new file mode 100644 index 00000000..e3be3ee4 Binary files /dev/null and b/tests/ppp_ccp_config_deflate_option_asan.pcap differ