The new upload in the -unapproved upload queue has been bumped by a
security update, and so, attaching a new debdiff rebased to the current
package in -updates and -security.
Mauricio, could you please sponsor the new debdiff?
I took the feedback on Description field formatting into account, should
be fixed on this debdiff.
** Patch added: "Debdiff for net-snmp for Focal V2"
https://bugs.launchpad.net/ubuntu/+source/net-snmp/+bug/1979933/+attachment/5606368/+files/lp1979933_focal_V2.debdiff
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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:
In Progress
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 0x7efd8d9f15b0 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 0x7efd8d9f817a 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 0x7efd8e74fe1b in netsnmp_mysql_init () from
/lib/x86_64-linux-gnu/libnetsnmptrapd.so.35
#4 0x555a8a9e3873 in main (argc=, argv=)
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
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:
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