Re: pkg/49860: DoS against snmpd on netbsd routers

[6bone%6bone.informatik.uni-leipzig.de@localhost]

The following reply was made to PR pkg/49860; it has been noted by GNATS.

From: 6bone%6bone.informatik.uni-leipzig.de@localhost
To: gnats-bugs%NetBSD.org@localhost
Cc: pkg-manager%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, pkgsrc-bugs%netbsd.org@localhost
Subject: Re: pkg/49860: DoS against snmpd on netbsd routers
Date: Mon, 27 Apr 2015 15:16:11 +0200 (CEST)

 On Sun, 26 Apr 2015, Joerg Sonnenberger wrote:
 
 > Can you ktrace it to see what it is doing? Does sockstat work fine? The
 > problem with net-snmp is that it is extremely messy code and quite a few
 > things are using kmem when they don't have to, so it is easy to hit race
 > conditions and the like.
 
 I've never worked with ktrace. I have tested ktruss -p <pid snmpd>
 
 The output at 100% CPU was as follows:
 
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 ....
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    mmap(0, 0x100000, 0x3, 0x14001002, 0xffffffff, 0, 0) 
 = 0x7f7feeb00000
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 ...
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    mmap(0, 0x100000, 0x3, 0x14001002, 0xffffffff, 0, 0) 
 = 0x7f7fee300000
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 ...
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    mmap(0, 0x100000, 0x3, 0x14001002, 0xffffffff, 0, 0) 
 = 0x7f7fee200000
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 ...
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    mmap(0, 0x100000, 0x3, 0x14001002, 0xffffffff, 0, 0) 
 = 0x7f7fedf00000
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 10754      1 snmpd    __clock_gettime50(0x3, 0x7f7fffffd930) = 0
 ...
 
 Does that help?
 
 Regards
 Uwe