tcp wrappers and mysqld

Hello

We found a problem with MySQL that can cause serious problems when
receiving connections from disallowed hosts. On our systems we can
produce the problem by following the following steps:
1. Configure tcpwrappers to deny connections from everywhere to mysqld
2. Configure MySQL to accept connections from the network.
3. Start/Restart MySQL
4. Connect from a disallowed host.
5. Whilst the above is still "blocking" connect to MySQL on the machine
itself. It should block until 4 has finished.

And number 5 is excactly the problem. You would expect 4 to terminate
almost immediately due to access denied or something and then to start
authenticating 5. Instead, it locks up.

J Kroon

--
MySQL Bugs Mailing List
For list archives: http://lists.mysql.com/bugs
To unsubscribe: http://lists.mysql.com/bugs?unsub=gcdmb-bugs@m.gmane.org

Re: tcp wrappers and mysqld

Dear Jaco,

I need to ask more about your configuration of tcp wrappers

On Wed, 19 Nov 2003, Jaco Kroon wrote:
> We found a problem with MySQL that can cause serious problems when
> receiving connections from disallowed hosts. On our systems we can
> produce the problem by following the following steps:
> 1. Configure tcpwrappers to deny connections from everywhere to mysqld
> 2. Configure MySQL to accept connections from the network.
> 3. Start/Restart MySQL
> 4. Connect from a disallowed host.
> 5. Whilst the above is still "blocking" connect to MySQL on the machine
> itself. It should block until 4 has finished.

Could you please provide the exact version of tcp wrappers and what OS you
are using. Could you also show the exact commands used. The details are
very important because I tried this on two machines and did not experience
any problem it worked exactly as tcp wrappers has always worked and I
experience not problems with MySQL.


> And number 5 is excactly the problem. You would expect 4 to terminate
> almost immediately due to access denied or something and then to start
> authenticating 5. Instead, it locks up.


Thanks for the report but I have been unable to duplicate your problem.

Sincerly,

--
Boyd Gerber, Software Engineeer & Support Specialist
MySQL AB, www.mysql.com

Are you MySQL certified? www.mysql.com/certification


--
MySQL Bugs Mailing List
For list archives: http://lists.mysql.com/bugs
To unsubscribe: http://lists.mysql.com/bugs?unsub=gcdmb-bugs@m.gmane.org

Re: tcp wrappers and mysqld

On Wed, 19 Nov 2003, Boyd Gerber wrote:
> I need to ask more about your configuration of tcp wrappers
> On Wed, 19 Nov 2003, Jaco Kroon wrote:
> > We found a problem with MySQL that can cause serious problems when
> > receiving connections from disallowed hosts. On our systems we can
> > produce the problem by following the following steps:
> > 1. Configure tcpwrappers to deny connections from everywhere to mysqld
> > 2. Configure MySQL to accept connections from the network.
> > 3. Start/Restart MySQL
> > 4. Connect from a disallowed host.
> > 5. Whilst the above is still "blocking" connect to MySQL on the machine
> > itself. It should block until 4 has finished.
>
> Could you please provide the exact version of tcp wrappers and what OS you
> are using. Could you also show the exact commands used. The details are
> very important because I tried this on two machines and did not experience
> any problem it worked exactly as tcp wrappers has always worked and I
> experience not problems with MySQL.
>
>
> > And number 5 is excactly the problem. You would expect 4 to terminate
> > almost immediately due to access denied or something and then to start
> > authenticating 5. Instead, it locks up.
>
>
> Thanks for the report but I have been unable to duplicate your problem.


Thanks for the information you provided. I wish I chould be of more help.
I have checked with serveral people that use gentoo Linux and none of them
are having this problem. I would check your configure options.

I heard from them that unsafe compiler optimization or various libraries
can cause problems. I also heard that sometimes mixing f77 or forcing the
use of the asm may lead to problems. Other than your configure
options the gentoo linux users I talked with did not have the problem.
Their remarks were you are using options that they do not. They did
mention what was different. Sorry for not being of more help.

Sincerely,

--
Boyd Gerber, Software Engineer & Support Specialist
MySQL AB, www.mysql.com

Are you MySQL certified? www.mysql.com/certification


--
MySQL Bugs Mailing List
For list archives: http://lists.mysql.com/bugs
To unsubscribe: http://lists.mysql.com/bugs?unsub=gcdmb-bugs@m.gmane.org