Nmap Development mailing list archives
Fwd: Sean Rivera Progress report 13/17
From: sean rivera <sean.au.rivera () gmail com>
Date: Tue, 24 Jul 2012 11:19:06 -0600
---------- Forwarded message ---------- From: Sean Rivera <rivera.shadowoftruth () gmail com> Date: Tue, Jul 24, 2012 at 11:05 AM Subject: Re: Sean Rivera Progress report 13/17 To: David Fifield <david () bamsoftware com> On 07/23/2012 09:52 PM, David Fifield wrote:
On Mon, Jul 23, 2012 at 09:23:38PM -0600, sean rivera wrote:Priorities, Finish fixing the race condition here from this todo race condition. [NPING] At least on my (Fyodor) system, I get errors like "READ-PCAP killed: Resource temporarily unavailable" with some commands. Example: # nping --tcp -p80 -c1 scanme.nmap.org I've currently found that it exists for tcp, udp, and icmp, and isolated it down to a couple of lines. I hope to fix this soon.Can you briefly summarize what the problem is and the lines you've isolated it to? David Fifield ______________________________**_________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/**mailman/listinfo/nmap-dev<http://cgi.insecure.org/mailman/listinfo/nmap-dev> Archived at http://seclists.org/nmap-dev/
Hey David, Sorry for the delay in getting back to you. I crashed somewhat early yesterday. The problem is somewhere in lines 398-410 (Or 448-460 for icmp and arp packets).
From my testing I've noticed that the error does not show up with the -N
flag (So it needs the scheduled packet read) and it only works on a single packet sent (-c1). I've also found that setting the delay can change the error message or eliminate it all together. By running a simple shell script that caught stderr and tossed into a file --delay flag value I've found some interesting results for single packet sends. Results: Delay = 2 Always prints two nping_event_handler(): READ-PCAP killed: Resource temporarily unavailable nping_event_handler(): READ-PCAP killed: Resource temporarily unavailable Which I believe comes from nsock_pcap_read_packet(nsp, pcap_nsi, nping_event_handler, o.getDelay(), NULL); Delay =1 Race condition exists here which makes sense, as delay=1 is the default value Delay <1 and delay is greater then .1 Same deal with the race conditions. Delay <=.1 I've tried running this hundreds of times and I cannot get the nping_event_handler(): TIMER killed: Resource temporarily unavailable.
From my testing so far I think the race condition is a combo of the
"nsock_pcap_read_packet(nsp, pcap_nsi, nping_event_handler, o.getDelay(), NULL);" scheduled event and the "nsock_timer_create(nsp, nping_event_handler, 1, &pkts2send[pc]);" that is called only on the first time. I am also pretty sure that it is because of that hard coded 1 for time out. (Every other time it is o.getDelay() but I'll need to test that. Other thoughts/suggestions? -- ~Sean Rivera _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Archived at http://seclists.org/nmap-dev/
Current thread:
- Sean Rivera Progress report 13/17 sean rivera (Jul 23)
- Re: Sean Rivera Progress report 13/17 David Fifield (Jul 23)
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- Fwd: Sean Rivera Progress report 13/17 sean rivera (Jul 24)
- Re: Fwd: Sean Rivera Progress report 13/17 David Fifield (Jul 24)
- Re: Fwd: Sean Rivera Progress report 13/17 sean rivera (Jul 24)
- Re: Fwd: Sean Rivera Progress report 13/17 Luis MartinGarcia (Jul 24)
- Re: Fwd: Sean Rivera Progress report 13/17 David Fifield (Jul 24)
- Re: Fwd: Sean Rivera Progress report 13/17 sean rivera (Jul 24)
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- Re: Sean Rivera Progress report 13/17 David Fifield (Jul 23)