diff --git a/src/systemctl.c b/src/systemctl.c index 8cdc01a..c09b31d 100644 --- a/src/systemctl.c +++ b/src/systemctl.c @@ -141,6 +141,9 @@ static void spawn_ask_password_agent(void) { if (!arg_ask_password) return; + if (arg_user) + return; + parent = getpid(); /* Spawns a temporary TTY agent, making sure it goes away when @@ -151,13 +154,15 @@ static void spawn_ask_password_agent(void) { if (child == 0) { /* In the child */ - const char * const args[] = { SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, "--watch", NULL }; + int fd; + + /* Make sure the agent goes away when the parent dies */ if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) _exit(EXIT_FAILURE); @@ -166,6 +171,31 @@ static void spawn_ask_password_agent(void) { if (getppid() != parent) _exit(EXIT_SUCCESS); + /* Don't leak fds to the agent */ + close_all_fds(NULL, 0); + + /* Detach from stdin/stdout/stderr. and reopen + * /dev/tty for them. This is important to ensure that + * when systemctl is started via popen() or a similar + * call that expects to read EOF we actually do + * generate EOF and not delay this indefinitely by + * because we keep an unused copy of stdin around. */ + if ((fd = open("/dev/tty", O_RDWR)) < 0) { + log_error("Failed to open /dev/tty: %m"); + _exit(EXIT_FAILURE); + } + + close(STDIN_FILENO); + close(STDOUT_FILENO); + close(STDERR_FILENO); + + dup2(fd, STDIN_FILENO); + dup2(fd, STDOUT_FILENO); + dup2(fd, STDERR_FILENO); + + if (fd > 2) + close(fd); + execv(args[0], (char **) args); _exit(EXIT_FAILURE); }