[kernel-hardening] Re: [PATCH v2 1/1] Add Trusted Path Execution as a stackable LSM

On Fri, 2017-06-09 at 09:18 -0400, Matt Brown wrote:

On 6/9/17 9:16 AM, Mimi Zohar wrote:

quoted

On Fri, 2017-06-09 at 05:55 -0700, Kees Cook wrote:

quoted

On Fri, Jun 9, 2017 at 3:18 AM, Mimi Zohar [off-list ref] wrote:

quoted

On Thu, 2017-06-08 at 23:50 -0400, Matt Brown wrote:

quoted

quoted

quoted

*  Issues:
   *  Can be bypassed by interpreted languages such as python. You can run
      malicious code by doing: python -c 'evil code'

What's the recommendation for people interested in using TPE but
having interpreters installed?

If you don't need a given interpreter installed, uninstall it. While
this is common sense system hardening it especially would make a
difference under the TPE threat model.

I don't have a knock down answer for this. Interpreters are a hard
problem for TPE.

You might be interested in the minor LSM named "shebang", that I
posted as a proof of concept back in January, which restricts the
python interactive prompt/interpreter, but allows the scripts
themselves to be executed.

https://patchwork.kernel.org/patch/9547405/

Maybe these could be merged and the interpreter string could be made
into a configurable list?

I updated shebang, but didn't bother to post it, as nobody seemed to
be interested at the time.  The updated version already has support
for the configurable list. Re-posting ...

That would be awesome. I think it's the perfect complement to TPE as it
protects a key hole in its current threat model.

Hm, I hadn't looked at it in since January. ?It still needs to be
cleaned up and expanded a bit. ?The original version used a pathname
for identifying the interpreter. ?This version converts the list of
pathnames to a set of inodes, which is better, but now requires a
method for updating the inode number after a software update.

Please feel free to expand on it or re-use whatever you like.

Mimi

--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html