RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Description of problem:
When the remote system doesn't have the space to increase the size of authorized_keys or authorized_keys2, the ssh-copy-id command hangs indefinitely

Version-Release number of selected component (if applicable):
openssh-7.8p1-4.el8.x86_64

How reproducible:
always

Steps to Reproduce:
1. on remote system: ln -s /dev/full /home/$USER_NAME/.ssh/authorized_keys
2. on remote system: ln -s /dev/full /home/$USER_NAME/.ssh/authorized_keys2
3. locally: ssh-copy-id remote_user@remote_system

Actual results:
command hangs

Expected results:
cat: write error: No space left on device
ssh-copy-id return code of 1

Additional info:
This is regression from RHEL-7.

This is an issue with the check making sure there is a newline added to the authorized_keys file if it is missing initially (new in OpenSSH 7.5 or so).

The command that hangs is the following, which does not work with your reproducer (/dev/full returns unlimited stream of zeroes):

  tail -1c .ssh/authorized_keys

Even though I believe if the above would pass, the following does not have a check and would lead to fail without error message, because it is missing a guard " || exit 1" as the other write:

  echo >> .ssh/authorized_keys

At this moment, I see a simple solution for a real-world use cases (adding the check above), but I do not see a simple way how to make also your test happy.

I do not consider this as a blocker for 8.0 release so I postponed this bug to 8.1.

Looks like patches are ready, updating status accordingly.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2019:3702