On Mon, Nov 20, 2023 at 08:50:05PM -0000, Andrew J. Caines wrote: > You are of course quite right that the risk associated with a file > created with a "random" six character case-insensitive alphanumeric > suffix and run a moment later is far smaller than more obviously risky > misuses of /tmp.
No. The use of a random filename is not a security feature; it is a mechanism to avoid filename *collisions* (either accidental or as part of a denial of service). > or if the code checks for the presence of the file before trying to create > it (which I trust it does) That is not how you securely handle temp files. I'm sorry, but you have a very incomplete understanding of how secure temp file handling works. You have /tmp mounted noexec on your system. This is fine, and supported. It is not a protection against vulnerable system code. It is a mechanism to protect against attackers from writing payload code to /tmp and then executing it. System software must handle temp files under /tmp securely *independently of whether the files it's writing are intended to be executed*. You have something on your system trying to write a file to /tmp and then execute it. That should be fixed. But it's not a bug in perl, and it's not a bug in apt-utils, and it's entirely unclear what code is doing this since this in not part of the standard debconf code path. If you can identify where this is coming from in Ubuntu, we can reassign the bug report and get it fixed. The rest is off-topic for an Ubuntu bug report. -- Steve Langasek Give me a lever long enough and a Free OS Debian Developer to set it on, and I can move the world. Ubuntu Developer https://www.debian.org/ slanga...@ubuntu.com vor...@debian.org -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to perl in Ubuntu. https://bugs.launchpad.net/bugs/2043711 Title: Open3.pm tries to run code in /tmp when updating ubuntu-drivers-common Status in perl package in Ubuntu: Invalid Bug description: During update of ubuntu-drivers-common: Can't exec "/tmp/ubuntu-drivers-common.config.55GJ8b": Permission denied at /usr/lib/x86_64-linux-gnu/perl-base/IPC/Open3.pm line 178, <GEN0> line 1. open2: exec of /tmp/ubuntu-drivers-common.config.55GJ8b configure 1:0.9.6.2~0.22.04.4 failed: Permission denied at /usr/share/perl5/Debconf/ConfModule.pm line 59. Preconfiguring packages ... Can't exec "/tmp/ubuntu-drivers-common.config.uSPrCH": Permission denied at /usr/lib/x86_64-linux-gnu/perl-base/IPC/Open3.pm line 178, <GEN0> line 1. open2: exec of /tmp/ubuntu-drivers-common.config.uSPrCH configure 1:0.9.6.2~0.22.04.4 failed: Permission denied at /usr/share/perl5/Debconf/ConfModule.pm line 59. /tmp is mounted with noexec because running code from /tmp has been a vulnerability vector for several decades, hence reporting this as a vulnerability in perl-base. This error did not appear to prevent the update of ubuntu-drivers- common and "dpkg --verify ubuntu-drivers-common" returns 0. ___________________________________________________________________________________________________________ Attempting to use the package search on this form by clicking the 🔍 created a modal in which there is an error Sorry, something went wrong with your search. We've recorded what happened, and we'll fix it as soon as possible. (Error ID: OOPS-c80f71590b02908a1187b9f743c53eac) which is repeated with any attempt to search for a package. ___________________________________________________________________________________________________________ Submitting this form gives an error "perl-base" does not exist in Ubuntu. Please choose a different package. If you're unsure, please select "I don't know" $ dpkg -S /usr/lib/x86_64-linux-gnu/perl-base/IPC/Open3.pm perl-base: /usr/lib/x86_64-linux-gnu/perl-base/IPC/Open3.pm $ dpkg -l perl-base Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Architecture Description +++-==============-=================-============-=============================> ii perl-base 5.34.0-3ubuntu1.2 amd64 minimal Perl system Looks like a package to me. Nevertheless, using "Did you mean..." offers "perl". ProblemType: Bug DistroRelease: Ubuntu 22.04 Package: perl-base 5.34.0-3ubuntu1.2 ProcVersionSignature: Ubuntu 6.5.0-1007.7-oem 6.5.3 Uname: Linux 6.5.0-1007-oem x86_64 ApportVersion: 2.20.11-0ubuntu82.5 Architecture: amd64 CasperMD5CheckResult: unknown CurrentDesktop: ubuntu:GNOME Date: Thu Nov 16 10:08:48 2023 InstallationDate: Installed on 2016-04-23 (2763 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) ProcEnviron: TERM=rxvt PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: perl UpgradeStatus: Upgraded to jammy on 2022-08-19 (453 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/perl/+bug/2043711/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
