From fa972e8681159a34ffc9c114e4fe3538a7f69046 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Mon, 19 Feb 2024 13:04:28 +0900
Subject: [PATCH] core/exec: do not crash with UtmpMode=user without User=
 setting

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=2264404.

Replaces #31356.

(cherry picked from commit d42b81f93f81e45f7a4053c6522ec3a2145ff136)
(cherry picked from commit cba1060f8854fd9a11dac8e2b02126d2f3bb14ba)
(cherry picked from commit 74ffb11efc851ecc291766abce8a1052746e715e)

Conflict:NA
Reference:https://github.com/systemd/systemd-stable/commit/fa972e8681159a34ffc9c114e4fe3538a7f69046

---
 src/core/execute.c     | 12 +++++++++++-
 src/shared/utmp-wtmp.c |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/core/execute.c b/src/core/execute.c
index 5b23be014c..dd524b734a 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -4652,6 +4652,16 @@ static int exec_child(
         }
 
         if (context->utmp_id) {
+                _cleanup_free_ char *username_alloc = NULL;
+
+                if (!username && context->utmp_mode == EXEC_UTMP_USER) {
+                        username_alloc = uid_to_name(uid_is_valid(uid) ? uid : saved_uid);
+                        if (!username_alloc) {
+                                *exit_status = EXIT_USER;
+                                return log_oom();
+                        }
+                }
+
                 const char *line = context->tty_path ?
                         (path_startswith(context->tty_path, "/dev/") ?: context->tty_path) :
                         NULL;
@@ -4660,7 +4670,7 @@ static int exec_child(
                                       context->utmp_mode == EXEC_UTMP_INIT  ? INIT_PROCESS :
                                       context->utmp_mode == EXEC_UTMP_LOGIN ? LOGIN_PROCESS :
                                       USER_PROCESS,
-                                      username);
+                                      username ?: username_alloc);
         }
 
         if (uid_is_valid(uid)) {
diff --git a/src/shared/utmp-wtmp.c b/src/shared/utmp-wtmp.c
index 2fa76cf47a..c93ae927ee 100644
--- a/src/shared/utmp-wtmp.c
+++ b/src/shared/utmp-wtmp.c
@@ -184,6 +184,7 @@ int utmp_put_init_process(const char *id, pid_t pid, pid_t sid, const char *line
         int r;
 
         assert(id);
+        assert(ut_type != USER_PROCESS || user);
 
         init_timestamp(&store, 0);
 
-- 
2.33.0

