diff --git a/src/core/execute.c b/src/core/execute.c index a08e3105bf..87add14a73 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -2835,10 +2835,22 @@ static int exec_child( } } + /* We are about to invoke NSS and PAM modules. Let's tell them what we are doing here, maybe they care. This is + * used by nss-resolve to disable itself when we are about to start systemd-resolved, to avoid deadlocks. Note + * that these env vars do not survive the execve(), which means they really only apply to the PAM and NSS + * invocations themselves. Also note that while we'll only invoke NSS modules involved in user management they + * might internally call into other NSS modules that are involved in hostname resolution, we never know. */ + if (setenv("SYSTEMD_ACTIVATION_UNIT", unit->id, true) != 0 || + setenv("SYSTEMD_ACTIVATION_SCOPE", MANAGER_IS_SYSTEM(unit->manager) ? "system" : "user", true) != 0) { + *exit_status = EXIT_MEMORY; + return log_unit_error_errno(unit, errno, "Failed to update environment: %m"); + } + if (context->dynamic_user && dcreds) { _cleanup_strv_free_ char **suggested_paths = NULL; - /* Make sure we bypass our own NSS module for any NSS checks */ + /* On top of that, make sure we bypass our own NSS module nss-systemd comprehensively for any NSS + * checks, if DynamicUser=1 is used, as we shouldn't create a feedback loop with ourselves here.*/ if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, errno, "Failed to update environment: %m");