Red Hat Bugzilla – Bug 714687
RFE: Clear screen including scroll-back buffer before log-in
Last modified: 2016-07-26 04:31:13 EDT
+++ This bug was initially created as a clone of Bug #691406 +++ There was a discussion (bug #681600) how to disable access to text printed by previous user on the console to prevent sensitive data leak. mingetty should instruct Linux virtual terminal to clear screen including scroll-back buffer. Once Linux will implement it (bug #684261), adapt mingetty to perform the safe clear. Because current behavior is not to clear the screen and there can be demand not to do it always (e.g. to debug broken login shell or to investigate init scripts output on /dev/console), new mingetty positional argument will be added to switch on/off the screen cleaning. --- Additional comment from ppisar@redhat.com on 2011-06-10 09:38:26 GMT --- F16 delivers kernel-3.0* that supports \E[3;J to clear screen including scroll-back buffer. F16 uses systemd as init that by default reallocate VT before spawning mingetty, thus the scroll-back buffer is always empty. To test this bug report, one can use following command: # openvt -f -c 10 -s -w -- /bin/bash \ -c 'dmesg; exec /sbin/mingetty --loginprog=/bin/false tty10' This allocates TTY10, switches console there, pollutes buffer with kernel log, and then executes mingetty. Now it's possible to press Shift-PgUp to verify the buffer has gone. I will add new positional argument to mingetty to enable safe console clearing. The clearing will be done by issuing the the new escape sequence followed by the older 2J variant to clean at least current visible area if mingetty run on system not supporting the new 3J sequence. --- Additional comment from ppisar@redhat.com on 2011-06-10 11:31:31 GMT --- Se there is already --noclear option defaulting to clear. So adding the new sequence seems to be enough. --- Additional comment from ppisar@redhat.com on 2011-06-10 12:26:42 GMT --- Created attachment 504091 [details] Implementation Tested with Linux 3.0-0.rc2.git0.1.fc16.x86_64 on VGA console. ----- Based on discussion with Steve Grubb, I propose this feature for RHEL-6.2 as an alternative to disabled scroll-back buffer.
This request was evaluated by Red Hat Product Management for inclusion in the current release of Red Hat Enterprise Linux. Because the affected component is not scheduled to be updated in the current release, Red Hat is unfortunately unable to address this request at this time. Red Hat invites you to ask your support representative to propose this request, if appropriate and relevant, in the next release of Red Hat Enterprise Linux. If you would like it considered as an exception in the current release, please ask your support representative.
This request was evaluated by Red Hat Product Management for inclusion in the current release of Red Hat Enterprise Linux. Because the affected component is not scheduled to be updated in the current release, Red Hat is unfortunately unable to address this request at this time. It has been proposed for the next release. If you would like it considered as an exception in the current release, please ask your support representative.
This request was evaluated by Red Hat Product Management for inclusion in the current release of Red Hat Enterprise Linux. Because the affected component is not scheduled to be updated in the current release, Red Hat is unable to address this request at this time. Red Hat invites you to ask your support representative to propose this request, if appropriate, in the next release of Red Hat Enterprise Linux.
Red Hat Enterprise Linux version 6 is entering the Production 2 phase of its lifetime and this bug doesn't meet the criteria for it, i.e. only high severity issues will be fixed. Please see https://access.redhat.com/support/policy/updates/errata/ for further information.