Review Request 126203: Disable ptrace for kcheckpass and the greeter

[Martin Gräßlin]

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https://git.reviewboard.kde.org/r/126203/
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(Updated Dec. 2, 2015, 8:11 a.m.)


Status
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This change has been marked as submitted.


Review request for Plasma and Tobias Berner.


Changes
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Submitted with commit 88a497e4c6b7599cf859703e25d65ba8bb2873ce by Martin Gräßlin to branch master.


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.

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@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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  CMakeLists.txt f48bd53cafc188f79e041518dae0769d57597c69 
  config-kscreenlocker.h.cmake 2a034dee8ec21e426bc1db1d56b0ed152d3de2ca 
  greeter/main.cpp e4e679e7ef40b319665428281fdba5f4e0b4eb25 
  kcheckpass/kcheckpass.c fd2d2215bf2199f159a121bb0ce08e7b2b254aaa 

Diff: https://git.reviewboard.kde.org/r/126203/diff/


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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