[Impact]
Removal of the /etc/securetty file from the system results in useless log messages whenever pam_unix is invoked, which for some systems is quite a lot of logging. /etc/securetty is not coming back, and this is not an error.
[Test Plan]
1. Run 'sudo -s'. Confirm that 'journalctl | grep sudo.*securetty' returns a line 'sudo[...]: pam_unix(sudo:auth): Couldn't open /etc/securetty: No such file or directory'.
2. Install libpam-modules update from -proposed.
3. Confirm that 'grep nullok_secure' /etc/pam.d/common-auth returns no lines.
4. Run 'sudo -k'.
5. Run 'sudo -s' again.
6. Confirm that sudo succeeds and gives you a root shell.
7. Confirm that 'journalctl | grep sudo.*securetty' does not show any new lines.
[Where problems could occur]
PAM is a sensitive package because it's used in all authentication operations on the system. A bug here could render a user unable to log in to their system.
Risks are mitigated by:
- including a patch that treats the obsolete 'nullok_secure' as an alias for 'nullok' to ensure any user-edited configurations continue to work rather than throwing errors about unknown options
- editing the system-managed /etc/pam.d/common-auth config to use 'nullok' instead of 'nullok_secure' for future compatibility.
Because we are editing the system config, this could also cause issues on future upgrades with undesirable prompts to the user. However, the maintainer scripts are not meant to prompt on changes to the pam-config, and this code has been in Debian for a while with no reports of problems.
[Original description]
Hello, after upgrading to focal I found the following in my journalctl output:
Jan 24 23:07:00 millbarge sudo[32120]: pam_unix(sudo:auth): Couldn't open /etc/securetty: No such file or directory
Jan 24 23:07:01 millbarge sudo[32120]: pam_unix(sudo:auth): Couldn't open /etc/securetty: No such file or directory
The login package stopped packaging this file:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=731656
and now forcibly removes the file:
https://paste.ubuntu.com/p/myh9cGWrHD/
However, the pam package's pam_unix.so module has not yet been adapted to ignore this file:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=674857#25
Thanks
ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: libpam-modules 1.3.1-5ubuntu4
ProcVersionSignature: Ubuntu 5.4.0-9.12-generic 5.4.3
Uname: Linux 5.4.0-9-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu15
Architecture: amd64
Date: Fri Jan 24 23:35:33 2020
ProcEnviron:
TERM=rxvt-unicode-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: pam
UpgradeStatus: Upgraded to focal on 2020-01-24 (0 days ago)
Looks like Balint has been looking at that problem from the Debian side, assigning to him
@Balint, feel free to unassign if I got that wrong :)