You have been subscribed to a public bug by Mauricio Faria de Oliveira (mfo):
[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 <[email protected]> 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 ** Affects: net-snmp (Ubuntu) Importance: Undecided Status: Fix Released ** Affects: net-snmp (Ubuntu Focal) Importance: Medium Assignee: Matthew Ruffell (mruffell) Status: In Progress ** Tags: focal sts sts-sponsor-mfo -- snmptrapd Segmentation Faults When Calling my_load_defaults() https://bugs.launchpad.net/bugs/1979933 You received this bug notification because you are a member of STS Sponsors, which is subscribed to the bug report. -- Mailing list: https://launchpad.net/~sts-sponsors Post to : [email protected] Unsubscribe : https://launchpad.net/~sts-sponsors More help : https://help.launchpad.net/ListHelp
