'Review Request 126203: Disable ptrace for kcheckpass and the greeter'

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List:       kde-panel-devel
Subject:    Review Request 126203: Disable ptrace for kcheckpass and the greeter
From:       Martin_Gräßlin <mgraesslin () kde ! org>
Date:       2015-11-30 8:01:19
Message-ID: 20151130080119.29696.4589 () mimi ! kde ! org
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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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Review request for Plasma and Tobias Berner.

Repository: kscreenlocker

Description
-------

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
-----

  greeter/main.cpp e4e679e7ef40b319665428281fdba5f4e0b4eb25 
  kcheckpass/kcheckpass.c fd2d2215bf2199f159a121bb0ce08e7b2b254aaa 

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

Testing
-------

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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      This is an automatically generated e-mail. To reply, visit:
      <a href="https://git.reviewboard.kde.org/r/126203/">https://git.reviewboard.kde.org/r/126203/</a>
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<div>Review request for Plasma and Tobias Berner.</div>
<div>By Martin Gräßlin.</div>

<div style="margin-top: 1.5em;">
 <b style="color: #575012; font-size: 10pt;">Repository: </b>
kscreenlocker
</div>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
 <table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" \
style="border: 1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">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:</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">ptrace: Operation not permitted.</p> <p \
style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: \
inherit;">For kscreenlocker_greet ptrace is permitted in testing mode.</p> <p \
style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: \
inherit;">As root it's still possible to attach to the process.</p> <hr \
style="text-rendering: inherit;margin: 0;padding: 0;white-space: normal;border: 1px \
solid #ddd;line-height: inherit;" /> <p style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: inherit;">@Tobias: I assume this \
is a strong linux-ism. Is there a FreeBSD compareable functionality?</p> <p \
style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: \
inherit;">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.</p></pre>  </td>
 </tr>
</table>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: \
1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">Tried to gdb into the processes: failed Tried to gdb \
into kscreenlocker_greet --testing: succeeded Tried to gdb into kscreenlocker_greet \
as root: succeeded</p></pre>  </td>
 </tr>
</table>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
<ul style="margin-left: 3em; padding-left: 0;">

 <li>greeter/main.cpp <span style="color: \
grey">(e4e679e7ef40b319665428281fdba5f4e0b4eb25)</span></li>

 <li>kcheckpass/kcheckpass.c <span style="color: \
grey">(fd2d2215bf2199f159a121bb0ce08e7b2b254aaa)</span></li>

</ul>

<p><a href="https://git.reviewboard.kde.org/r/126203/diff/" style="margin-left: \
3em;">View Diff</a></p>

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