REDHAT-BUG-1414429: Medium severity MySQL mysqld_safe vulnerability

It was discovered that the mysqldsafe could read ledir value - which specifies the directory where mysqld is stored - from configuration file. This could allow a user with privileges to write to some mysql configuration file - either mysql OS user, or any local OS user able to write to the config via some other way, e.g. by exploiting CVE-2016-6662 - to escalate their privileges to root if mysqldsafe was run with root privileges.

This problem is related to this change applied as part of the CVE-2016-6662 fix:

https://github.com/mysql/mysql-server/commit/684a165f28b3718160a3e4c5ebd18a465d85e97c#diff-144aa2f11374843c969d96b7b84247eaR211

It introduced restriction that mysqld and mysqldversion options can only be specified on the command line and can not be defined in a configuration file. However, such restriction was trivial to bypass while ledir was not restricted in a similar way.

Restriction for ledir was added in MySQL versions 5.5.54, 5.6.35, and 5.7.17. The following related entry can be found in the release notes:

The --ledir option now is accepted only on the command line, not in option files.

http://dev.mysql.com/doc/relnotes/mysql/5.5/en/news-5-5-54.html http://dev.mysql.com/doc/relnotes/mysql/5.6/en/news-5-6-35.html http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-17.html

MySQL upstream commit:

https://github.com/mysql/mysql-server/commit/53230ba274a37fa13d65e802c6ef3766cd0c6d91#diff-144aa2f11374843c969d96b7b84247ea

The CVE was made public via Oracle CPU January 2017:

http://www.oracle.com/technetwork/security-advisory/cpujan2017-2881727.html#AppendixMSQL