[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <201702101200.00422@pali>
Date: Fri, 10 Feb 2017 11:59:59 +0100
From: pali@...n.org
To: oss-security@...ts.openwall.com
Subject: Re: Use after free in libmysqlclient.so
Hello, are you going to assign CVE for this particular defect?
On Friday 27 January 2017 23:53:29 pali@...n.org wrote:
> Hello, I would like to report problem related to MySQL/MariaDB and
> possibly asking for assigning CVE if this list is the right place.
>
> C client library for MySQL (libmysqlclient.so) has use-after-free
> defect which can cause crash of applications using that MySQL
> client.
>
> Defect occurs by calling mysql_close() function from
> libmysqlclient.so. If mysql_close() is called before calling all
> mysql_stmt_close() (for all allocated stmts), then following
> mysql_stmt_close() call try to write to already released memory.
> mysql_close() let dangling pointer exist for prepared statements.
> Real problem is in function
> mysql_prune_stmt_list() which incorrectly iterate over elements.
> Function list_add() overwrite ->next pointer of current element which
> overwrite next element for iteration.
>
> Basically it is just wrong usage of linked list structure.
>
> Languages in which is not guaranteed order of executing destructor of
> created objects have a big problem as such writing to memory pointed
> by dangling can cause crash of whole application.
>
> E.g. libmysqlclient.so used by perl DBD::mysql driver cause crash of
> whole perl process with simple script:
>
> perl -MDBI -e '
> $dbh = DBI->connect("dbi:mysql:", "root", undef,
> {RaiseError => 1, mysql_server_prepare => 1});
> $sth1 = $dbh->prepare("SELECT 1");
> $sth2 = $dbh->prepare("USE mysql");
> $dbh->disconnect;
> $dbh = undef;
> '
> Segmentation fault
>
> Tested on amd64 Ubuntu 12.04 LTS with perl 5.14.2. To reproduce
> change username, password and host where is running mysql server.
> Valgrind can prove that memory corruption really occurs.
>
> This defect was fixed in MySQL 5.6.21 and MySQL 5.7.5 releases. But
> is present in all MySQL 5.5 versions (and also older) and
> appropriate older 5.6 and 5.7 versions. MySQL 5.5 is still used,
> supported and included in lot of linux distributions.
>
> Moreover this defect is present also in MariaDB releases. I tested
> all last major versions 10.2.3, 10.1.21, 10.0.29, 5.5.54 and all
> those are affected.
>
> MySQL and MariaDB provides also standalone package with only C client
> library libmysqlclient.so (without server) under name "Connector/C"
> and so appropriate versions of it are affected too.
>
> I found that this defected was fixed in MySQL git repository by
> commit:
> https://github.com/mysql/mysql-server/commit/4797ea0b772d5f4c5889bc5
> 52424132806f46e93
>
> That commit can be easily applied to last MySQL 5.5.54 version and
> fixes this defect.
>
> Looks like problem was already reported and is publically available
> in MySQL bug tracker, see more details on links:
> https://bugs.mysql.com/bug.php?id=70429
> https://bugs.mysql.com/bug.php?id=63363
> (tickets are closed despite fact that MySQL 5.5 and older are not
> fixed)
>
> ---
>
> I reported this problem to Oracle secalert_us@...cle.com two months
> ago, but they did absolutely nothing for fixing it in MySQL 5.5.
> Instead they started resending this problem to some random people
> with @cpan.org address for unknown reason. And told me to not
> disclose information about this defect. Resending does not look like
> normal handling of security related problem! Therefore I suggest
> other people to not wasting time reporting problems to Oracle for
> open source applications.
>
> As two months is really long time to fix such problem which was
> already fixed in new versions; it is already publically disclosed in
> MySQL bug tracker; fix available in public git; problem is in major
> MariaDB versions; fix is small; and this is open source product
> included in many linux distributions I decided to send information
> to oss-security.
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
