This is intentional change in behavior to improve security which I believe was introduced in 19.10. To restore the older behavior, create `/etc/sysctl.d/protect-links.conf` with the contents:
fs.protected_fifos = 0 Then restart procps: sudo systemctl restart procps.service To verify run: $ sudo sysctl fs.protected_fifos fs.protected_fifos = 0 References: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=30aba6656f61ed44cba445a3c0d38b296fa9e8f5 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=915797 ** Bug watch added: Debian Bug tracker #915797 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=915797 ** Changed in: linux (Ubuntu) Status: Confirmed => Invalid -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1875225 Title: /tmp sticky bit do not permit writing fifo file inside Status in linux package in Ubuntu: Invalid Bug description: Trying to write into a fifo pipe inside /tmp (echo "hello" > /tmp/fifo) whit normal permissions (drwxrwxrwt, sticky bit) and the fifo with prw-rw-rw- permissions and with "other" user than user and group owner ends in this error: bash: /tmp/fifo: Permission denied. It occurs since upgrading to Ubuntu 20.04, in 19.04 it worked as expected. When I remove the sticky bit (drwxrwxrwx) from tmp it works normally. I think it is a misbehaviour, with sticky bit you cannot rename or remove files inside that folder, but could be able to write into them. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1875225/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
