Review Request 126203: Disable ptrace for kcheckpass and the greeter

[Tobias Berner]

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I think FreeBSD 10 introduced a similar interface in r277322
https://svnweb.freebsd.org/base?view=revision&revision=277322
Though it is explicitely stated to not be a "security feature".

According to the man page of progctl 
https://www.freebsd.org/cgi/man.cgi?query=procctl&apropos=0&sektion=2&manpath=FreeBSD+10.2-RELEASE&arch=default&format=html
this would be PROC_TRACE_CTL with data PROC_TRACE_CTL_DISABLE.


I will have to ask someone more familiar with that.

- Tobias Berner


On Nov. 30, 2015, 9:01 vorm., Martin Gräßlin wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/126203/
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> 
> (Updated Nov. 30, 2015, 9:01 vorm.)
> 
> 
> Review request for Plasma and Tobias Berner.
> 
> 
> Repository: kscreenlocker
> 
> 
> Description
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> 
> Setting the PR_SET_DUMPABLE flag to 0 for the security relevant
> command kcheckpass and kscreenlocker_greet. If one wants to gdb into
> the running command it will result in:
> 
> ptrace: Operation not permitted.
> 
> For kscreenlocker_greet ptrace is permitted in testing mode.
> 
> As root it's still possible to attach to the process.
> 
> ---
> 
> @Tobias: I assume this is a strong linux-ism. Is there a FreeBSD compareable functionality?
> 
> I'm considering to push this explicitly without an ifdef. It's a new security feature and I want to make non-Linux systems aware of the fact that it adds a new feature and that a replacement should be added.
> 
> 
> Diffs
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> 
>   greeter/main.cpp e4e679e7ef40b319665428281fdba5f4e0b4eb25 
>   kcheckpass/kcheckpass.c fd2d2215bf2199f159a121bb0ce08e7b2b254aaa 
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> Diff: https://git.reviewboard.kde.org/r/126203/diff/
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> 
> Testing
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> 
> Tried to gdb into the processes: failed
> Tried to gdb into kscreenlocker_greet --testing: succeeded
> Tried to gdb into kscreenlocker_greet as root: succeeded
> 
> 
> Thanks,
> 
> Martin Gräßlin
> 
>

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