[Snort-devel] segfault in stream5

snort user snort.user at ...2499...
Wed Oct 5 00:35:27 EDT 2011


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 at ...2499...> 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 at ...2499...> 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 at ...2499...> 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 at ...2499...> 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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>>>
>>
>




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