Performing verification for Focal I install snmptrapd 5.8+dfsg-2ubuntu2.4 from updates, and edited /etc/snmp/snmptrapd.conf to have the following contents:
disableAuthorization yes traphandle default /usr/bin/logger sqlMaxQueue 1 sqlSaveInterval 9 I disabled all snmptrapd services: $ sudo systemctl stop snmptrapd.service $ sudo systemctl stop snmpd.service and then tried to start snmptrapd, but received a segmentation fault: $ sudo /usr/sbin/snmptrapd -LOw -f Segmentation fault >From syslog: Aug 4 00:47:45 focal-snmp kernel: [ 1615.972207] snmptrapd[5293]: segfault at 8 ip 00007f4879003680 sp 00007ffe914993f0 error 4 in libmysqlclient.so.21.2.30[7f4878f93000+130000] Aug 4 00:47:45 focal-snmp kernel: [ 1615.972229] Code: 5c 41 5d 41 5e 5d c3 e8 0e 17 f9 ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 55 48 89 e5 41 55 49 89 fd 41 54 53 48 83 ec 08 <4c> 8b 67 08 48 8b 47 10 4c 29 e0 48 83 f8 37 0f 86 cb 00 00 00 49 I then enabled -proposed and installed snmptrapd 5.8+dfsg-2ubuntu2.5. Again, I stopped the services: $ sudo systemctl stop snmptrapd.service $ sudo systemctl stop snmpd.service and tried to start snmptrapd: $ sudo /usr/sbin/snmptrapd -LOw -f mysql_real_connect() failed Error 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) This time we no longer segmentation fault, and snmptrapd keeps running. The package in -proposed fixes the issue, happy to mark verified. ** Tags removed: verification-needed verification-needed-focal ** Tags added: verification-done-focal -- You received this bug notification because you are a member of STS Sponsors, which is subscribed to the bug report. https://bugs.launchpad.net/bugs/1979933 Title: snmptrapd Segmentation Faults When Calling my_load_defaults() Status in net-snmp package in Ubuntu: Fix Released Status in net-snmp source package in Focal: Fix Committed Bug description: [Impact] When starting snmptrapd configured to connect to a mysql server, we segmentation fault when calling my_load_defaults(): $ sudo /usr/sbin/snmptrapd -LOw -f Segmentation fault (core dumped) (gdb) bt #0 0x00007efd8d9f15b0 in MEM_ROOT::Alloc (length=56, this=this@entry=0x0) at ./include/my_alloc.h:157 #1 init_default_directories (alloc=alloc@entry=0x0) at ./mysys/my_default.cc:1632 #2 0x00007efd8d9f817a in my_load_defaults (conf_file=0x7efd8e751f64 "my", groups=0x7efd8e7550c8, argc=0x7ffd8941b674, argv=0x7ffd8941b678, alloc=0x0, default_directories=0x555a8abccc00) at ./mysys/my_default.cc:692 #3 0x00007efd8e74fe1b in netsnmp_mysql_init () from /lib/x86_64-linux-gnu/libnetsnmptrapd.so.35 #4 0x0000555a8a9e3873 in main (argc=<optimized out>, argv=<optimized out>) at snmptrapd.c:1196 What happens is that we are calling my_load_defaults() even though we have mysql_options(), and the arguments we pass into my_load_defaults() are NULL, which eventually get de-referenced. The fix is to change the configure script to only call my_load_defaults() if we don't have mysql_options(). [Testcase] $ sudo apt update $ sudo apt install snmp snmpd snmptrapd snmp-mibs-downloader Edit /etc/snmp/snmptrapd.conf and add the following entries: disableAuthorization yes traphandle default /usr/bin/logger sqlMaxQueue 1 sqlSaveInterval 9 Save and exit. It is easier to reproduce if you stop and disable all services: $ sudo systemctl stop snmptrapd.service $ sudo systemctl stop snmpd.service Then try running: $ sudo /usr/sbin/snmptrapd -LOw -f Segmentation fault (core dumped) There is a test package available in the following ppa: https://launchpad.net/~mruffell/+archive/ubuntu/sf339433-test When running this test package, you will instead see: $ sudo /usr/sbin/snmptrapd -LOw -f mysql_real_connect() failed Error 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) (I don't have a mysql server configured, but we don't segfault anymore). [Where problems can occur] We are changing how snmptrapd initialises and begins connections to a mysql server, and if a regression were to occur, it would be limited to users of snmptrapd with the mysql backend. Other database backends would not be affected. Other binaries produced would also not be affected. [Other Info] The issue was fixed upstream by the following commit: commit 011342d8e453b9e0585bf77f659d80c648df8c9f Author: Bart Van Assche <bvanass...@acm.org> Date: Sat Aug 18 09:28:14 2018 -0700 Subject: snmptrapd: Let configure check for mysql_options() Link: https://github.com/net-snmp/net-snmp/commit/011342d8e453b9e0585bf77f659d80c648df8c9f To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/net-snmp/+bug/1979933/+subscriptions -- Mailing list: https://launchpad.net/~sts-sponsors Post to : sts-sponsors@lists.launchpad.net Unsubscribe : https://launchpad.net/~sts-sponsors More help : https://help.launchpad.net/ListHelp
