Re: segfault in stream5

[snort user <snort.user () gmail com>]

Brett,

Also, could you post your http inspect and unified2 configurations. It
may be possible to work around this bug by tweaking the config
options. Just a thought.

cheers.



On Wed, Oct 5, 2011 at 12:11 AM, snort user <snort.user () gmail com> wrote:
> Brett,
>
> It looks like there is a bug and as Joel had suggested you may want to
> file a bug via the proper channel.
>
> In short, GetHttpGzipData is expecting Packet * as the first argument,
> where as it is being passed ssnptr as the first argument.
>
> Details -
>
> > When the function crashes the ssnptr is invalid. In a different frame you will notice the correct ssnptr (0xf3e97f0)
>
> Specifically, focus on GetHttpGzipData. Here is how it gets called -
>
> GetHttpGzipData (data=0x5ea000005ea, buf=0x5, len=0x7fffd61d95e8,
> type=0x7fffd61d95ec)
>
> and here is the actual function signature -
>
> int GetHttpGzipData(void *data, uint8_t **buf, uint32_t *len, uint32_t *type)
>
>
> Notice how "ssnptr" is passed to GetHttpGzipData as first argument
> when it is being used as Packet *.
>
>
> void AlertExtraData(void *ssnptr, void *data, LogFunction *log_funcs,
> uint16_t log_func_count, uint32_t event_id, uint32_t event_second)
> {
> <snip>
>
>    for(i=0; i< log_func_count; i++)
>    {
>        if((*(log_funcs[i]))(ssnptr, &write_buffer,&len,&type))
> <snip>
>
>
>
> int GetHttpGzipData(void *data, uint8_t **buf, uint32_t *len, uint32_t *type)
> {
>    if(!IsGzipData((Packet *)data))
>
>
>
>
> cheers. I hope that was helpful.
>
>
>
> On Tue, Oct 4, 2011 at 10:51 AM, Brett Edgar <brett.edgar () gmail com> wrote:
> > I did a grep.  That function is not called (by that name) anywhere
> > else in the code.
> >
> > Here's the backtrace:
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > Stream5GetApplicationData (ssnptr=0x5ea000005ea, protocol=5) at
> > spp_stream5.c:1368
> > 1368    spp_stream5.c: No such file or directory.
> >        in spp_stream5.c
> > (gdb) bt
> > #0  Stream5GetApplicationData (ssnptr=0x5ea000005ea, protocol=5) at
> > spp_stream5.c:1368
> > #1  0x000000000046c4d5 in GetHttpSessionData (p=<value optimized out>)
> > at ./snort_httpinspect.h:163
> > #2  IsGzipData (p=<value optimized out>) at snort_httpinspect.c:3846
> > #3  0x000000000046c51a in GetHttpGzipData (data=0x5ea000005ea,
> > buf=0x5, len=0x7fffd61d95e8, type=0x7fffd61d95ec)
> >    at snort_httpinspect.c:3859
> > #4  0x0000000000449bc2 in AlertExtraData (ssnptr=0xf3e97f0,
> > data=<value optimized out>, log_funcs=<value optimized out>,
> >    log_func_count=<value optimized out>, event_id=2707977984,
> > event_second=4294967295) at spo_unified2.c:777
> > #5  0x0000000000491adf in purge_alerts (tcpssn=<value optimized out>,
> > talker=0x7fb5873e3160, listener=<value optimized out>,
> >    tdb=<value optimized out>, p=0x7fffd61d99f0) at snort_stream5_tcp.c:3211
> > #6  purge_to_seq (tcpssn=<value optimized out>, talker=0x7fb5873e3160,
> > listener=<value optimized out>,
> >    tdb=<value optimized out>, p=0x7fffd61d99f0) at snort_stream5_tcp.c:3304
> > #7  CheckFlushPolicyOnAck (tcpssn=<value optimized out>,
> > talker=0x7fb5873e3160, listener=<value optimized out>,
> >    tdb=<value optimized out>, p=0x7fffd61d99f0) at snort_stream5_tcp.c:9106
> > #8  0x000000000049598b in ProcessTcp (lwssn=0xf3e97f0,
> > p=0x7fffd61d99f0, tdb=<value optimized out>,
> > s5TcpPolicy=0x7fb57aaf3010)
> >    at snort_stream5_tcp.c:8684
> > #9  0x0000000000496178 in Stream5ProcessTcp (p=0x7fffd61d99f0,
> > lwssn=0xf3e97f0, s5TcpPolicy=0x7fb57aaf3010, skey=0x7fffd61d9920)
> >    at snort_stream5_tcp.c:5132
> > #10 0x000000000047a369 in Stream5Process (p=0x7fffd61d99f0,
> > context=<value optimized out>) at spp_stream5.c:1213
> > #11 0x0000000000431b85 in Preprocess (p=0x7fffd61d99f0) at detect.c:170
> > #12 0x0000000000426dee in ProcessPacket (user=<value optimized out>,
> > pkthdr=0x7fffd61da760, pkt=<value optimized out>, ft=0x0)
> >    at snort.c:1490
> > #13 0x000000000042adfa in PacketCallback (user=0x0,
> > pkthdr=0x7fffd61da760, pkt=0x7fb563769042 "") at snort.c:1404
> > #14 0x00007fb56a9045f3 in ?? () from /usr/lib/daq/daq_afpacket.so
> > #15 0x00000000004411f4 in DAQ_Acquire (max=<value optimized out>,
> > callback=0x7fffd61d95ec, user=0x7fb5a1687700 "") at sfdaq.c:464
> > #16 0x000000000042af8c in PacketLoop () at snort.c:2800
> > #17 0x000000000042c09f in SnortMain (argc=<value optimized out>,
> > argv=<value optimized out>) at snort.c:733
> > #18 0x000000000042c0e5 in main (argc=1514, argv=0x5) at snort.c:665
> >
> >
> > I'll work on getting a core dump and PCAP.  I do get full packet
> > capture, but I have yet to be able to reproduce the problem when
> > replaying the traffic...
> >
> > -Brett
> >
> > On Mon, Oct 3, 2011 at 9:59 PM, snort user <snort.user () gmail com> wrote:
> > > Hi Brett,
> > >
> > > Stream5GetApplicationData is called whenever an application needs to
> > > retrieve any information that it saved/piggybacked onto the session
> > > structure. You would see it in any of the preprocessors like dcerpc2
> > > or smtp. I am assuming that you would have done a grep by now to
> > > figure this out already.
> > >
> > > More importantly, would it be possible to provide
> > >
> > > 1. a stack trace ?
> > > 2. the core file ?
> > > 3. can you replicate the issue and if so can you capture the related
> > > pcap when the issue occur ?
> > >
> > > These would be a great start to debug the issue and the list,
> > > including me, would be able to help you out as well.
> > >
> > >
> > > cheers
> > >
> > >
> > >
> > >
> > >
> > > On Mon, Oct 3, 2011 at 10:46 PM, Brett Edgar <brett.edgar () gmail com> wrote:
> > > > I am getting segfaults in spp_stream5.c on line 1368 and it's
> > > > happening on multiple systems that have completely disjoint network
> > > > traffic.  Somehow, the ssn pointer being passed into stream5 is not
> > > > NULL (otherwise the if(ssnptr) would prevent the crash) but also not
> > > > valid (since I'm getting a segfault).
> > > >
> > > > The systems that are exhibiting the problem are Gentoo systems.  Some
> > > > are x86 and some are amd64.  The stream5 configurations are very
> > > > similar between the systems.  Here is the stream5 configuration on one
> > > > of the systems:
> > > >
> > > > preprocessor stream5_global: track_tcp yes, \
> > > >   track_udp yes, \
> > > >   track_icmp no, \
> > > >   max_tcp 262144, \
> > > >   max_udp 131072
> > > > preprocessor stream5_tcp: policy windows, require_3whs 180, \
> > > >   overlap_limit 10, small_segments 3 bytes 150, timeout 180, \
> > > >    ports client 21 22 23 25 42 53 79 109 110 111 113 119 135 136 137 139 143 \
> > > >        161 445 513 514 587 593 691 1433 1521 2100 3306 6070 6665 6666
> > > > 6667 6668 6669 \
> > > >        7000 8181 32770 32771 32772 32773 32774 32775 32776 32777 32778 32779, \
> > > >    ports both 80 81 110 143 311 443 465 563 591 593 636 901 989 992
> > > > 993 994 995 1220 1414 1830 2301 2381 2809 3128 3702 4343 5250 7907
> > > > 7001 7145 7510 7802 7777 7779 \
> > > >        7801 7900 7901 7902 7903 7904 7905 7906 7908 7909 7910 7911
> > > > 7912 7913 7914 7915 7916 \
> > > >        7917 7918 7919 7920 8000 8008 8014 8028 8080 8088 8118 8123
> > > > 8180 8243 8280 8800 8888 8899 9080 9090 9091 9443 9999 11371 55555
> > > > preprocessor stream5_udp: timeout 180
> > > >
> > > > That's very close, if not identical to, the snort.conf  in the VRT
> > > > tarballs (except for the active response configuration statements in
> > > > stream5_global that are not enabled because I didn't compile snort
> > > > with that configuration option).
> > > >
> > > > I am a fairly competent C programmer, but I'm asking for suggestions
> > > > on where to look in this mailing list since I am not familiar with the
> > > > Snort code.  I'm hoping someone knows when Stream5GetApplicationData
> > > > (the function that contains the segfault) gets called so I can narrow
> > > > down my search more quickly...
> > > >
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