sts-sponsors team mailing list archive

[Mauricio Faria de Oliveira <1979933@xxxxxxxxxxxxxxxxxx>]

Hi Matthew,

Thanks for the debdiff; sponsored to focal!

I just fixed the Description: field in the patch DEP3 headers,
which isn't as free-form as Subject: line + unstructured text.
(Please see sample in DEP-3 [1] and multiline fields/paragraph
separators in Debian Policy [2] for details, if you'd like it.)

Everything else looks excellent, and I'll just document checks.

cheers,
Mauricio

- Built successfully on all architectures with focal-proposed [0].

- Upstream source code remains the same as with this change,
as of commit 4d43fbd64a07 ("Makefile.in: Only build the fuzzing tests in regular mode").

- Focal's MySQL source code, of course, defines the relied upon
function mysql_options():

    int STDCALL mysql_options(MYSQL *mysql, enum mysql_option option,
                              const void *arg);

- Supported releases after Focal already have the fix:

	$ git describe --contains 011342d8e453b9e0585bf77f659d80c648df8c9f
	v5.8.1.pre1~91

	$ rmadison --arch=source net-snmp
	...
	 net-snmp | 5.8+dfsg-2ubuntu2       | focal           | source
	 net-snmp | 5.8+dfsg-2ubuntu2.3     | focal-security  | source
	 net-snmp | 5.8+dfsg-2ubuntu2.3     | focal-updates   | source
	 net-snmp | 5.9.1+dfsg-1ubuntu2     | jammy           | source
	 net-snmp | 5.9.1+dfsg-1ubuntu2.1   | jammy-updates   | source
	 net-snmp | 5.9.1+dfsg-4ubuntu1     | kinetic         | source

- The backport delta (thanks for noting it in DEP-3's Origin:)
is 2 context lines:

	- /* Define to 1 if you have the <my_global.h> header file. */
	- #undef HAVE_MY_GLOBAL_H
	+ /* Define if MY_INIT() is availabe in libmysqlclient */
	+ #undef HAVE_MY_INIT

- The patch seems to no longer accept command line arguments to
specify connection parameters to MySQL, but it looks like that
was never the purpose (just some flexibility, I guess) per:

* the original code commit

* the comment "load .my.cnf values" in the failing / now disabled calls:

	    /** load .my.cnf values */
	#if HAVE_MY_LOAD_DEFAULTS
	    my_load_defaults ("my", _sql.groups, &not_argc, &not_argv, 0);
	#elif defined(HAVE_LOAD_DEFAULTS)
	    load_defaults ("my", _sql.groups, &not_argc, &not_argv);

* the usage of mysql_options(MYSQL_READ_DEFAULT_GROUP) [3]:

          MYSQL_READ_DEFAULT_GROUP (argument type: char *)

          Read options from the named group from my.cnf or the file
specified with MYSQL_READ_DEFAULT_FILE.

* Most importantly, the project's README.sql file:

	net-snmp-5.8+dfsg$ head -n15 README.sql
	snmptrapd MySQL Logging
	-----------------------

	A trap handler for logging traps to a MySQL database was added
	in release 5.5.0.

	The MySQL database location and password must be configured in
	/root/.my.cnf:

		[snmptrapd]
		host=localhost
		password=sql

        User may also be configured, if using a MySQL user besides root.


[0] https://launchpad.net/~mfo/+archive/ubuntu/lp1979933
[1] https://dep-team.pages.debian.net/deps/dep3/
[2] https://www.debian.org/doc/debian-policy/ch-controlfields.html#syntax-of-control-files
[3] https://dev.mysql.com/doc/c-api/8.0/en/mysql-options.html

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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  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 <bvanassche@xxxxxxx>
  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

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