Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

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:
 /bin/su should print a warning if stack size is a low number

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


[+] How reproducible:
Always

[+] Steps to Reproduce:
1. $ ulimit -s 275
2. $ su
3.

[+] Actual results:
$ /bin/su
Segmentation fault

[+] Expected results:
$ /bin/su
Warning - stack size is $(ulimit -s)
This may cause unwanted results
Segmentation fault

[+] Additional info:
As of util-linux 2.23.2-26.el7, the tested minimal required stack size is 276.  Anything lower will cause /bin/su to segfault.  The /bin/su application should have an if, then (example) rule that if it matches 300 (example number) or lower, it prints a warning.

Since su is written in C, example:

if ( $(ulimit -s) < 300 )
    printf( "Warning - stack size is less than 300" );

Or, a more long-term solution would be to implement a separate function that allows itself to calculate it's own stack requirement and then match that against what is available and cleanly exit if the requirement is less than available.

By "cleanly exit if the requirement is less than available" I meant "cleanly exit if the requirement is greater than available".

This bug was accidentally moved from POST to MODIFIED via an error in automation, please see mmccune with any questions

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://rhn.redhat.com/errata/RHSA-2016-2605.html