systemd/SOURCES/1127-user-sessions-do-not-remove-etc-nologin.patch

83 lines
3.7 KiB
Diff

From 01e0a19a9c38f1b935d627c9b02b2950e835b8c5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Sat, 25 Mar 2023 11:34:47 +0100
Subject: [PATCH] user-sessions: do not remove /etc/nologin
pam_nologin looks for /etc/nologin and /run/nologin.
user-sessions creates (and removes) /run/nologin, but also removes
/etc/nologin. (This behaviour is unchanged since the introduction
of the binary in e92787416c691c3f34f47349e5eae3fa68eae856.)
By not removing pam_nologin we fully drop compatibility with PAM < 1.1.
This has the advantage that now /etc/nologin can be used by administrator to
disable user logins, e.g. for extended maintanance. We already specified
PAM >= 1.1.2 as dependency, so this was already covered.
The makes the code match the man page.
Fixes #26965.
(cherry picked from commit a78413baae0e999384b535d327203ebf417b1e24)
Resolves: RHEL-85467
---
src/shared/fileio-label.c | 12 +++++++++---
src/user-sessions/user-sessions.c | 13 +++++--------
2 files changed, 14 insertions(+), 11 deletions(-)
diff --git a/src/shared/fileio-label.c b/src/shared/fileio-label.c
index d03b0548ec..572b8f62ad 100644
--- a/src/shared/fileio-label.c
+++ b/src/shared/fileio-label.c
@@ -23,9 +23,15 @@ int write_string_file_atomic_label_ts(const char *fn, const char *line, struct t
int create_shutdown_run_nologin_or_warn(void) {
int r;
- /* This is used twice: once in systemd-user-sessions.service, in order to block logins when we actually go
- * down, and once in systemd-logind.service when shutdowns are scheduled, and logins are to be turned off a bit
- * in advance. We use the same wording of the message in both cases. */
+ /* This is used twice: once in systemd-user-sessions.service, in order to block logins when we
+ * actually go down, and once in systemd-logind.service when shutdowns are scheduled, and logins are
+ * to be turned off a bit in advance. We use the same wording of the message in both cases.
+ *
+ * Traditionally, there was only /etc/nologin, and we managed that. Then, in PAM 1.1
+ * support for /run/nologin was added as alternative
+ * (https://github.com/linux-pam/linux-pam/commit/e9e593f6ddeaf975b7fe8446d184e6bc387d450b).
+ * 13 years later we stopped managing /etc/nologin, leaving it for the administrator to manage.
+ */
r = write_string_file_atomic_label("/run/nologin",
"System is going down. Unprivileged users are not permitted to log in anymore. "
diff --git a/src/user-sessions/user-sessions.c b/src/user-sessions/user-sessions.c
index 6b7493fd88..37867ee3ed 100644
--- a/src/user-sessions/user-sessions.c
+++ b/src/user-sessions/user-sessions.c
@@ -15,7 +15,7 @@
#include "string-util.h"
static int run(int argc, char *argv[]) {
- int r, k;
+ int r;
if (argc != 2)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
@@ -29,14 +29,11 @@ static int run(int argc, char *argv[]) {
if (r < 0)
return r;
- if (streq(argv[1], "start")) {
- r = unlink_or_warn("/run/nologin");
- k = unlink_or_warn("/etc/nologin");
- if (r < 0)
- return r;
- return k;
+ /* We only touch /run/nologin. See create_shutdown_run_nologin_or_warn() for details. */
- } else if (streq(argv[1], "stop"))
+ if (streq(argv[1], "start"))
+ return unlink_or_warn("/run/nologin");
+ if (streq(argv[1], "stop"))
return create_shutdown_run_nologin_or_warn();
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Unknown verb '%s'.", argv[1]);