many KDE processes have rwx memory mappings

[Laurent Bonnaud]

SUMMARY

As a defense against machine code injection against buffer overflow bugs, most Linux distributions have worked over the years to remove as many rwx memory mappings as possible in processes.

I checked this on several of my systems and unfortunately I found that many KDE processes do have rwx memory mappings.

I chose to report this bug against the kded package because it is one of the most fundamental affected KDE process I found. However, the problem seems to be more general in KDE. I apologize in advance for not finding a better software package to report this problem.

STEPS TO REPRODUCE
1. Log in Plasma
2. Run the following command:

$ grep rwx /proc/$(pidof kded5)/maps

OBSERVED RESULT

$ grep rwx /proc/$(pidof kded5)/maps
7f68d7c2a000-7f68d7c3a000 rwxp 00000000 00:00 0

EXPECTED RESULT

No output

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: kded5 5.56.0-0ubuntu1
Uname: Linux 5.1.1-050101-generic x86_64
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
CurrentDesktop: KDE
Date: Tue May 14 08:41:00 2019
SourcePackage: kded
UpgradeStatus: No upgrade log present (probably fresh install)

[Laurent Bonnaud (laurent-bonnaud)]

This problem is also present in KDE Neon:

  https://bugs.kde.org/show_bug.cgi?id=407496

Unfortunately, this distribution is not listed in launchpad.

[L.Bonnaud (l.bonnaud-redhat-bugs)]

Description of problem:

As a defense against machine code injection made possible by buffer overflow bugs, most Linux distributions have worked over the years to remove as many rwx memory mappings as possible in processes.

I checked this on several of my systems and unfortunately I found that many KDE processes do have rwx memory mappings.

I chose to report this bug against the kded package because it is one of the most fundamental affected KDE process I found. However, the problem seems to be more general in KDE. I apologize in advance for not finding a better software package to report this problem.

Version-Release number of selected component (if applicable):

Fedora 30 packages updated today.

How reproducible:

always

Steps to Reproduce:
1. Log in Plasma
2. Run the following command:

$ grep rwx /proc/$(pidof kded5)/maps

Actual results:

$ grep rwx /proc/$(pidof kded5)/maps
7f68d7c2a000-7f68d7c3a000 rwxp 00000000 00:00 0

Expected results:

No output

Additional info:

According to comments in this bug report:
  https://bugs.kde.org/show_bug.cgi?id=407496
other Linux distributions do not have the same problem.

[Laurent Bonnaud (laurent-bonnaud)]

Hi,

according to upstream KDE developers who tested on other distribution, this bug is Debian/Ubuntu specific.

And it still exists in lunar:

# grep rwx /proc/$(pidof kded5)/maps
7f28a406e000-7f28a407e000 rwxp 00000000 00:00 0
7f28a89ea000-7f28a89eb000 rwxp 00000000 00:00 0