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https://issues.apache.org/jira/browse/YARN-7197?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16241479#comment-16241479
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Eric Yang commented on YARN-7197:
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I am starting to doubt the feasibility of blacklist approach to prevent
jailbreak or leak information at the cost of creating many bind mounted
location. The permutation is too costly, and the solution is difficult to use
for developer and system admin cross examine every files and symlinks/hard
links in the system. We should accept the fact that privileged container is
equal to root power on the host system, hence only trusted users can be given
access to spawn privileged containers. We only govern the system by checking
sudo privileges to spawn privileged container, and honor file system ACL.
Although the rules may sound like a good idea, but computation of directory
depth * number of black listed item * user defined mounts * symlink permutation
* hardlink permutation can be a challenge. All bind mount path should not
exceed the run command buffer. I think this solution does not scale in real
life. Hence, I propose that we shift focus toward YARN-7221, YARN-7446 and
YARN-7430. If group is enforced properly, and sudoers check are verified, then
there is much less risk to expose host information into container container or
let unauthorized user to take control of the host system. If the community
agree with this analysis, I will close this as won't fix.
> Add support for a volume blacklist for docker containers
> --------------------------------------------------------
>
> Key: YARN-7197
> URL: https://issues.apache.org/jira/browse/YARN-7197
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: yarn
> Reporter: Shane Kumpf
> Assignee: Eric Yang
> Attachments: YARN-7197.001.patch, YARN-7197.002.patch,
> YARN-7197.003.patch, YARN-7197.004.patch, YARN-7197.005.patch
>
>
> Docker supports bind mounting host directories into containers. Work is
> underway to allow admins to configure a whilelist of volume mounts. While
> this is a much needed and useful feature, it opens the door for
> misconfiguration that may lead to users being able to compromise or crash the
> system.
> One example would be allowing users to mount /run from a host running
> systemd, and then running systemd in that container, rendering the host
> mostly unusable.
> This issue is to add support for a default blacklist. The default blacklist
> would be where we put files and directories that if mounted into a container,
> are likely to have negative consequences. Users are encouraged not to remove
> items from the default blacklist, but may do so if necessary.
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