CVE-2017-13024/IPv6 mobility: Add a bounds check before fetching data

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 cause 'tcpdump: pcap_loop: truncated dump file'

diff --git a/print-mobility.c b/print-mobility.c
index 64497b36e86ee7c4bf3533c33b3a67a6958db8c5..21a0fbade4894450e7063c95ada17bd7d49dcf71 100644 (file)
--- a/print-mobility.c
+++ b/print-mobility.c
@@ -166,6 +166,8 @@ mobility_opt_print(netdissect_options *ndo,
                                ND_PRINT((ndo, "(ni: trunc)"));
                                goto trunc;
                        }
+                       ND_TCHECK_16BITS(&bp[i+2]);
+                       ND_TCHECK_16BITS(&bp[i+4]);
                        ND_PRINT((ndo, "(ni: ho=0x%04x co=0x%04x)",
                                EXTRACT_16BITS(&bp[i+2]),
                                EXTRACT_16BITS(&bp[i+4])));

diff --git a/tests/TESTLIST b/tests/TESTLIST
index 3e215960d7b4ec5a2793ba182e8537bbb3c642e7..e0caaa34b51b6aea21ed4f2592e7cceab5c82b35 100644 (file)
--- a/tests/TESTLIST
+++ b/tests/TESTLIST
@@ -525,6 +525,7 @@ vtp_asan            vtp_asan.pcap                   vtp_asan.out    -v
 icmp6_mobileprefix_asan        icmp6_mobileprefix_asan.pcap    icmp6_mobileprefix_asan.out     -v
 ip_printroute_asan     ip_printroute_asan.pcap         ip_printroute_asan.out  -v
 mobility_opt_asan      mobility_opt_asan.pcap          mobility_opt_asan.out   -v
+mobility_opt_asan_2    mobility_opt_asan_2.pcap        mobility_opt_asan_2.out -v
 
 # RTP tests
 # fuzzed pcap

diff --git a/tests/mobility_opt_asan_2.out b/tests/mobility_opt_asan_2.out
new file mode 100644 (file)
index 0000000..403926e
--- /dev/null
+++ b/tests/mobility_opt_asan_2.out
@@ -0,0 +1 @@
+IP6 (class 0x50, flowlabel 0x0002c, hlim 0, next-header Mobile IP (old) (62) payload length: 7168) ff:7f0f:40:0:ee00:0:b658:5203 > 205:20:1:b00:0:2200:af01:e000: mobility: BRR(type-0x06: len=0)[|MOBILITY]

diff --git a/tests/mobility_opt_asan_2.pcap b/tests/mobility_opt_asan_2.pcap
new file mode 100644 (file)
index 0000000..7fadc58
Binary files /dev/null and b/tests/mobility_opt_asan_2.pcap differ