Segmentation fault

[SteveClement]

Dear,

I am having a similar issue to Issue #113

I have done your suggestions and it looks a little like this:

~/node_modules/pcap   master ●  sudo ~/node_modules/pcap/examples/simple_capture en6 ""
libpcap version 1.6.2
Key: addr
address: fe80::384d:550d:e25d:702d
Key: netmask
address: ffff:ffff:ffff:ffff::
Key: broadaddr
Key: dstaddr
address: (null)

My ifconfig can be seen here: https://gist.github.com/SteveClement/d5664765b2a22660fbd5

I also compiled it with that latest libpcap (thought that might fix it) but it really looks like it cannot handle one of the devices it tries to enumerate.

cheers.

[coffeegist]

Same issue here. Here is an ifconfig. Can't figure out exactly why this is happening.

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
    options=3<RXCSUM,TXCSUM>
    inet6 ::1 prefixlen 128 
    inet 127.0.0.1 netmask 0xff000000 
    inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
    nd6 options=1<PERFORMNUD>
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    options=10b<RXCSUM,TXCSUM,VLAN_HWTAGGING,AV>
    ether 0c:4d:e9:c0:ef:ec 
    inet6 fe80::e4d:e9ff:fec0:efec%en0 prefixlen 64 scopeid 0x4 
    inet 192.168.1.123 netmask 0xffff0000 broadcast 192.168.255.255
    nd6 options=1<PERFORMNUD>
    media: autoselect (1000baseT <full-duplex,flow-control,energy-efficient-ethernet>)
    status: active
en1: flags=8823<UP,BROADCAST,SMART,SIMPLEX,MULTICAST> mtu 1500
    ether 88:63:df:a8:03:87 
    nd6 options=1<PERFORMNUD>
    media: autoselect (<unknown type>)
    status: inactive
en2: flags=963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX> mtu 1500
    options=60<TSO4,TSO6>
    ether 32:00:1c:36:00:00 
    media: autoselect <full-duplex>
    status: inactive
en3: flags=963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX> mtu 1500
    options=60<TSO4,TSO6>
    ether 32:00:1c:36:00:01 
    media: autoselect <full-duplex>
    status: inactive
p2p0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 2304
    ether 0a:63:df:a8:03:87 
    media: autoselect
    status: inactive
awdl0: flags=8902<BROADCAST,PROMISC,SIMPLEX,MULTICAST> mtu 1484
    ether 06:f2:77:ef:74:95 
    nd6 options=1<PERFORMNUD>
    media: autoselect
    status: inactive
bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    options=63<RXCSUM,TXCSUM,TSO4,TSO6>
    ether 0e:4d:e9:0c:12:00 
    Configuration:
        id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
        maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
        root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
        ipfilter disabled flags 0x2
    member: en2 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 6 priority 0 path cost 0
    member: en3 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 7 priority 0 path cost 0
    nd6 options=1<PERFORMNUD>
    media: <unknown type>
    status: inactive
utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
    inet6 fe80::df5e:d57c:c09f:637%utun0 prefixlen 64 scopeid 0xb 
    nd6 options=1<PERFORMNUD>

[coffeegist]

From what I see, it is failing on the utun0 device. More specifically, with the inet_ntop return value. I noticed that @SteveClement also has a device with the same name.

Edit: Upon further inspection, when processing utun0, the cur_dev->dstaddr is a non-null pointer, where as for the rest of the devices, cur_dev->dstaddr is just equal to 0.

[SteveClement]

Haven't followed up on this one. Have you tried to destroy utun0 and launch again?

[coffeegist]

I haven't done that. However, modifying the pcap_binding.cc at line 32 fixes the issue.

Original Way

const char* address = inet_ntop(addr->sa_family, src, dst_addr, size);
Address->Set(Nan::New(key).ToLocalChecked(), Nan::New(address).ToLocalChecked());

Modified Way

const char* address = inet_ntop(addr->sa_family, src, dst_addr, size);
if (address) {
    Address->Set(Nan::New(key).ToLocalChecked(), Nan::New(address).ToLocalChecked());
}

src is coming in as an empty string. When you pass an empty string to inet_ntop, it's return value is null, and it doesn't change dst_addr. I'm going to create a pull request with this fix unless someone thinks I'm missing something.

EDIT: utun0 is created by "Back To My Mac" in OS X. You can turn this service off to bring the interface down if you want.