stack smashing

[LordGaav]

We ran into a stack smashing error on ns3, the relevant daemon.log entries are:

May 29 11:15:46 ns3 dnssnarf: started.
May 29 11:21:14 ns3 dnssnarf: *** stack smashing detected ***: /usr/bin/dnssnarf terminated

With some google skill and shitty C skills I think it's because we have a buffer overflow somewhere.

[sierag]

Would be cool if we could solve this issue!

[LordGaav]

whoa, I left my terminal open and this happened:

*** stack smashing detected ***: /usr/bin/dnssnarf terminated
======= Backtrace: =========
/lib/libc.so.6(__fortify_fail+0x37)[0x7f09f0a637e7]
/lib/libc.so.6(__fortify_fail+0x0)[0x7f09f0a637b0]
/usr/bin/dnssnarf[0x401ee1]
/usr/bin/dnssnarf[0x401ff0]
/usr/lib/libpcap.so.0.8(+0x530f)[0x7f09f0cec30f]
/usr/lib/libpcap.so.0.8(pcap_loop+0x59)[0x7f09f0cf0559]
/usr/bin/dnssnarf[0x4018b3]
/lib/libc.so.6(__libc_start_main+0xfd)[0x7f09f0982c4d]
/usr/bin/dnssnarf[0x400e79]
======= Memory map: ========
00400000-00403000 r-xp 00000000 08:01 134798                             /usr/bin/dnssnarf
00602000-00603000 r--p 00002000 08:01 134798                             /usr/bin/dnssnarf
00603000-00604000 rw-p 00003000 08:01 134798                             /usr/bin/dnssnarf
0243b000-0245c000 rw-p 00000000 00:00 0                                  [heap]
7f09f0355000-7f09f036b000 r-xp 00000000 08:01 3698                       /lib/libgcc_s.so.1
7f09f036b000-7f09f056a000 ---p 00016000 08:01 3698                       /lib/libgcc_s.so.1
7f09f056a000-7f09f056b000 r--p 00015000 08:01 3698                       /lib/libgcc_s.so.1
7f09f056b000-7f09f056c000 rw-p 00016000 08:01 3698                       /lib/libgcc_s.so.1
7f09f056c000-7f09f0964000 rw-s 00000000 00:06 62756281                   socket:[62756281]
7f09f0964000-7f09f0ade000 r-xp 00000000 08:01 3222                       /lib/libc-2.11.1.so
7f09f0ade000-7f09f0cdd000 ---p 0017a000 08:01 3222                       /lib/libc-2.11.1.so
7f09f0cdd000-7f09f0ce1000 r--p 00179000 08:01 3222                       /lib/libc-2.11.1.so
7f09f0ce1000-7f09f0ce2000 rw-p 0017d000 08:01 3222                       /lib/libc-2.11.1.so
7f09f0ce2000-7f09f0ce7000 rw-p 00000000 00:00 0 
7f09f0ce7000-7f09f0d17000 r-xp 00000000 08:01 149748                     /usr/lib/libpcap.so.1.0.0
7f09f0d17000-7f09f0f17000 ---p 00030000 08:01 149748                     /usr/lib/libpcap.so.1.0.0
7f09f0f17000-7f09f0f18000 r--p 00030000 08:01 149748                     /usr/lib/libpcap.so.1.0.0
7f09f0f18000-7f09f0f19000 rw-p 00031000 08:01 149748                     /usr/lib/libpcap.so.1.0.0
7f09f0f19000-7f09f0f1a000 rw-p 00000000 00:00 0 
7f09f0f1a000-7f09f0f3a000 r-xp 00000000 08:01 3202                       /lib/ld-2.11.1.so
7f09f0fb9000-7f09f1004000 r--s 00000000 00:05 1386                       /dev/usbmon1
7f09f1004000-7f09f104f000 r--s 00000000 00:05 1449                       /dev/usbmon2
7f09f104f000-7f09f109a000 r--s 00000000 00:05 1456                       /dev/usbmon3
7f09f109a000-7f09f10e5000 r--s 00000000 00:05 1462                       /dev/usbmon4
7f09f10e5000-7f09f1130000 r--s 00000000 00:05 1468                       /dev/usbmon5
7f09f1130000-7f09f1133000 rw-p 00000000 00:00 0 
7f09f1136000-7f09f1137000 rw-s 00000000 00:04 0                          /SYSV0000162e (deleted)
7f09f1137000-7f09f1139000 rw-p 00000000 00:00 0 
7f09f1139000-7f09f113a000 r--p 0001f000 08:01 3202                       /lib/ld-2.11.1.so
7f09f113a000-7f09f113b000 rw-p 00020000 08:01 3202                       /lib/ld-2.11.1.so
7f09f113b000-7f09f113c000 rw-p 00000000 00:00 0 
7fffe6cde000-7fffe6cf3000 rw-p 00000000 00:00 0                          [stack]
7fffe6dff000-7fffe6e00000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]

More info supplied.

[blasty]

Yikes, will investigate.