<html>
<body>
<div style="font-family: Verdana, Arial, Helvetica, Sans-Serif;">
<table bgcolor="#f9f3c9" width="100%" cellpadding="12" style="border: 1px #c9c399 solid; border-radius: 6px; -moz-border-radius: 6px; -webkit-border-radius: 6px;">
<tr>
<td>
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>
</td>
</tr>
</table>
<br />
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<p style="margin-top: 0;">On November 30th, 2015, 10:34 a.m. EET, <b>Tobias Berner</b> wrote:</p>
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<pre style="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;">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".</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">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.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">I will have to ask someone more familiar with that.</p></pre>
</blockquote>
<p>On November 30th, 2015, 10:43 a.m. EET, <b>Martin Gräßlin</b> wrote:</p>
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><blockquote style="text-rendering: inherit;padding: 0 0 0 1em;border-left: 1px solid #bbb;white-space: normal;margin: 0 0 0 0.5em;line-height: inherit;">
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">how do I get kwin to output the debug output for the framebuffer backend, with qcdebug lines,</p>
</blockquote>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">Given the notes on it, that seems fine. It's not my intention to protect against kernel or root.</p></pre>
</blockquote>
<p>On November 30th, 2015, 12:22 p.m. EET, <b>Raphael Kubo da Costa</b> wrote:</p>
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<pre style="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;">From a non-Linux perspective, it would be good if there was a CMake check for <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">prctl()</code> and <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">PR_SET_DUMPABLE/PROC_TRACE_CTL</code> with a big warning in case none was found. The oldest supported FreeBSD release (9.x) will be supported until the end of 2016 and it does not have this functionality, and neither do {Net,DragonFly,Open}BSD, so adding the calls without additional checks will just create additional problems for those packaging kscreenlocker for those platforms, and I doubt they will be able to add a replacement for this without help from their kernel (and existing releases would still be broken).</p></pre>
</blockquote>
<p>On November 30th, 2015, 5:41 p.m. EET, <b>Martin Gräßlin</b> wrote:</p>
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<pre style="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;">The CMake check seems like a good idea to me - this also allows to make a nice HAVE_PRCTL_DUMPABABLE flag which I would prefer over QOSLINUX or something like that. Anybody know how to write such a check? I assume trying to compile and check whether it compiles?</p></pre>
</blockquote>
</blockquote>
<pre style="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;">I think so. Something like this (untested):</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;"><div class="codehilite" style="background: #f8f8f8"><pre style="line-height: 125%">include(CheckIncludeFile)
include(CheckSymbolExists)
check_include_file("sys/prctl.h" HAVE_SYS_PRCTL_H)
check_symbol_exists(PR_SET_DUMPABLE "sys/prctl.h" HAVE_PR_SET_DUMPABLE)
check_include_file("sys/procctl.h" HAVE_SYS_PROCCTL_H)
check_symbol_exists(PROC_TRACE_CTL "sys/procctl.h" HAVE_PROC_TRACE_CTL)
if (NOT HAVE_PR_SET_DUMPABLE OR NOT HAVE_PROC_TRACE_CTL)
message(WARNING "Support for disabling ptrace(2) and core dumps via prctl/procctl is not available. <scary message here>.")
endif ()
configure_file(...)
</pre></div>
</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">It's unfortunate that the naming could not be standardized, as now one needs to check for those macros and call different functions with different arguments depending on their values.</p></pre>
<br />
<p>- Raphael</p>
<br />
<p>On November 30th, 2015, 10:01 a.m. EET, Martin Gräßlin wrote:</p>
<table bgcolor="#fefadf" width="100%" cellspacing="0" cellpadding="12" style="border: 1px #888a85 solid; border-radius: 6px; -moz-border-radius: 6px; -webkit-border-radius: 6px;">
<tr>
<td>
<div>Review request for Plasma and Tobias Berner.</div>
<div>By Martin Gräßlin.</div>
<p style="color: grey;"><i>Updated Nov. 30, 2015, 10:01 a.m.</i></p>
<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>
</td>
</tr>
</table>
</div>
</body>
</html>