fail2ban/server
Yaroslav Halchenko 8d25e83f5d BF: race condition -- file should not be read unless it is not empty
Previous code would store md5sum of an empty line as the one
identifying the monitored file.  That file then was read and possibly
failures were found.  Upon next "container.open()", md5 digest of now
present first line was compared against previous digest of an empty
line, which was different, thus file was assumed to be rotated and all
the log lines were read once again.

The History
-----------
In rare cases various tests failed somewhat consistently.  Below you
can find one case in test_move_file where such failure really made no
sense -- we should have not had 4 failures by that point.

Fail2ban 0.8.10.dev test suite. Python 2.4.6 (#2, Sep 25 2009, 22:22:06) [GCC 4.3.4]. Please wait...
I: Skipping gamin backend testing. Got exception 'No module named gamin'
I: Skipping pyinotify backend testing. Got exception 'No module named pyinotify'
D: fn=/home/yoh/test/monitorfailures_FilterPoll9nUKoCfail2ban-0 hashes=d41d8cd98f00b204e9800998ecf8427e/d41d8cd98f00b204e9800998ecf8427e inos=5398862/5398862 pos=0 rotate=False
D: Adding a ticket for ('193.168.0.128', 1124013599.0, ['Aug 14 11:59:59 [sshd] error: PAM: Authentication failure for kevin from 193.168.0.128\n'])
D: Adding a ticket for ('193.168.0.128', 1124013599.0, ['Aug 14 11:59:59 [sshd] error: PAM: Authentication failure for kevin from 193.168.0.128\n'])
D: Closed <closed file '/home/yoh/test/monitorfailures_FilterPoll9nUKoCfail2ban-0', mode 'r' at 0x7f472b2efdc8> with pos 1231
D: fn=/home/yoh/test/monitorfailures_FilterPoll9nUKoCfail2ban-0 hashes=d41d8cd98f00b204e9800998ecf8427e/aeb4e73e6922a746d027eb365ece2149 inos=5398862/5398862 pos=1231 rotate=True
D: Adding a ticket for ('193.168.0.128', 1124013599.0, ['Aug 14 11:59:59 [sshd] error: PAM: Authentication failure for kevin from 193.168.0.128\n'])
D: Adding a ticket for ('193.168.0.128', 1124013599.0, ['Aug 14 11:59:59 [sshd] error: PAM: Authentication failure for kevin from 193.168.0.128\n'])
D: Closed <closed file '/home/yoh/test/monitorfailures_FilterPoll9nUKoCfail2ban-0', mode 'r' at 0x7f472b2ef558> with pos 1231
F
======================================================================
FAIL: test_move_file (testcases.filtertestcase.MonitorFailures<FilterPoll>(/home/yoh/test/monitorfailures_FilterPoll9nUKoCfail2ban))
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/yoh/deb/gits/fail2ban/testcases/filtertestcase.py", line 451, in test_move_file
    "Queue must be empty but it is not: %s."
AssertionError: Queue must be empty but it is not: server.ticket.FailTicket: ip=193.168.0.128 time=1124013599.0 #attempts=4.

----------------------------------------------------------------------

N.B.1 I preserved here and in the code corresponding additional debug
print statements, which are commented out by default. sensible md5
digest was generated by using hexdigest() instead of current a bit
faster digest().  Running tests with all the debug output simply
breaks the race loose and failure doesn't trigger.

N.B.2 d41d8cd98f00b204e9800998ecf8427e is an md5sum of an empty
string, and aeb4e73e6922a746d027eb365ece2149 of the first line in that
file.
2013-07-02 23:37:23 -04:00
..
__init__.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00
action.py Merge branch 'master' of git://github.com/fail2ban/fail2ban 2013-05-02 23:28:18 -04:00
actions.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00
asyncserver.py ENH: consistent operation of formatExceptionInfo + unittest for it 2013-05-09 22:46:59 -04:00
banmanager.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00
datedetector.py Merge branch PR #193 ASSP SMTP Proxy support (with some manual squashing) 2013-05-03 00:57:49 -04:00
datetemplate.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00
faildata.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00
failmanager.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00
failregex.py ENH: "is None" instead of "== None" + tune ups in headers 2013-05-02 23:25:43 -04:00
filter.py BF: race condition -- file should not be read unless it is not empty 2013-07-02 23:37:23 -04:00
filtergamin.py FD_CLOEXEC support 2013-04-02 19:11:59 +02:00
filterpoll.py ENH(+possibly BF): for FilterPoll rely not only on mtime but also ino and size to assess if file was modified 2013-07-02 20:43:51 -04:00
filterpyinotify.py ENH: strengthen detection of working pyinotify 2013-05-10 11:40:12 -04:00
iso8601.py ENH: modelines for emacs and vim to assure consistent indentation scheme (tabs) 2011-10-07 15:49:38 -04:00
jail.py ENH: issue a warning if jail name is longer than 19 symbols (Close #222) 2013-05-12 22:19:50 -04:00
jails.py RF: move exceptions used by both client and server into common/exceptions.py 2013-01-28 09:46:50 -05:00
jailthread.py BF: setSleepTime -- would barf since value is not str (wasn't used/tested) 2013-07-02 17:11:24 -04:00
mytime.py ENH: "is None" instead of "== None" + tune ups in headers 2013-05-02 23:25:43 -04:00
server.py ENH: now we know that logging handlers closing was still buggy in 2.6.2 2013-05-12 22:55:02 -04:00
ticket.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00
transmitter.py DOC: purge of svn tags 2013-05-03 16:03:38 +10:00