d162a7b97

Denys Vlasenko

2022-01-12

SUCCESS Duration: 153s

Subject

sulogin: increase util-linux compatibility

No binary (build failed)

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

(log yok)

include/libbb.h+10 -8

@@ -1726,15 +1726,16 @@ extern void selinux_or_die(void) FAST_FUNC;


	/* setup_environment:
-	* if chdir pw->pw_dir: ok: else if to_tmp == 1: goto /tmp else: goto / or die
-	* if clear_env = 1: cd(pw->pw_dir), clear environment, then set
+	* if !SETUP_ENV_NO_CHDIR:
+	* if cd(pw->pw_dir): ok: else if SETUP_ENV_TO_TMP: cd(/tmp) else: cd(/) or die
+	* if SETUP_ENV_CLEARENV: cd(pw->pw_dir), clear environment, then set
	* TERM=(old value)
	* USER=pw->pw_name, LOGNAME=pw->pw_name
	* PATH=bb_default_[root_]path
	* HOME=pw->pw_dir
	* SHELL=shell
-	* else if change_env = 1:
-	* if not root (if pw->pw_uid != 0):
+	* else if SETUP_ENV_CHANGEENV:
+	* if not root (if pw->pw_uid != 0) or if SETUP_ENV_CHANGEENV_LOGNAME:
	* USER=pw->pw_name, LOGNAME=pw->pw_name
	* HOME=pw->pw_dir
	* SHELL=shell
@@ -1743,10 +1744,11 @@ extern void selinux_or_die(void) FAST_FUNC;
	* NB: CHANGEENV and CLEARENV use setenv() - this leaks memory!
	* If setup_environment() is used is vforked child, this leaks memory _in parent too_!
	*/
-	#define SETUP_ENV_CHANGEENV (1 << 0)
-	#define SETUP_ENV_CLEARENV (1 << 1)
-	#define SETUP_ENV_TO_TMP (1 << 2)
-	#define SETUP_ENV_NO_CHDIR (1 << 4)
+	#define SETUP_ENV_CHANGEENV (1 << 0)
+	#define SETUP_ENV_CHANGEENV_LOGNAME (1 << 1)
+	#define SETUP_ENV_CLEARENV (1 << 2)
+	#define SETUP_ENV_TO_TMP (1 << 3)
+	#define SETUP_ENV_NO_CHDIR (1 << 4)
	void setup_environment(const char shell, int flags, const struct passwd pw) FAST_FUNC;
	void nuke_str(char *str) FAST_FUNC;
	#if ENABLE_FEATURE_SECURETTY && !ENABLE_PAM

libbb/setup_environment.c+4 -4

@@ -54,15 +54,15 @@ void FAST_FUNC setup_environment(const char *shell, int flags, const struct pass
	xsetenv("TERM", term);
	xsetenv("PATH", (pw->pw_uid ? bb_default_path : bb_default_root_path));
	goto shortcut;
-	// No, gcc (4.2.1) is not clever enougn to do it itself.
+	// No, gcc (4.2.1) is not clever enough to do it itself.
	//xsetenv("USER", pw->pw_name);
	//xsetenv("LOGNAME", pw->pw_name);
	//xsetenv("HOME", pw->pw_dir);
	//xsetenv("SHELL", shell);
	} else if (flags & SETUP_ENV_CHANGEENV) {
-	/* Set HOME, SHELL, and if not becoming a super-user,
-	* USER and LOGNAME. */
-	if (pw->pw_uid) {
+	/* Set HOME, SHELL, and if not becoming a super-user
+	* or if SETUP_ENV_CHANGEENV_LOGNAME, USER and LOGNAME. */
+	if ((flags & SETUP_ENV_CHANGEENV_LOGNAME) \|\| pw->pw_uid != 0) {
	shortcut:
	xsetenv("USER", pw->pw_name);
	xsetenv("LOGNAME", pw->pw_name);

loginutils/sulogin.c+23 -0

@@ -28,6 +28,7 @@
	int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int sulogin_main(int argc UNUSED_PARAM, char **argv)
	{
+	int tsid;
	int timeout = 0;
	struct passwd *pwd;
	const char *shell;
@@ -88,6 +89,28 @@ int sulogin_main(int argc UNUSED_PARAM, char **argv)
	if (!shell)
	shell = pwd->pw_shell;

+	/* util-linux 2.36.1 compat: cd to root's HOME, set a few envvars */
+	setup_environment(shell, SETUP_ENV_CHANGEENV \| SETUP_ENV_CHANGEENV_LOGNAME, pwd);
+	// no SETUP_ENV_CLEARENV
+	// SETUP_ENV_CHANGEENV[+LOGNAME] - set HOME, SHELL, USER,and LOGNAME
+	// no SETUP_ENV_NO_CHDIR - IOW: cd to $HOME
+
+	/* util-linux 2.36.1 compat: steal ctty if we don't have it yet
+	* (yes, util-linux uses force=1) */
+	tsid = tcgetsid(STDIN_FILENO);
+	if (tsid < 0 \|\| getpid() != tsid) {
+	if (ioctl(STDIN_FILENO, TIOCSCTTY, /force:/ (long)1) != 0) {
+	// bb_perror_msg("TIOCSCTTY1 tsid:%d", tsid);
+	if (setsid() > 0) {
+	// bb_error_msg("done setsid()");
+	/* If it still does not work, ignore */
+	if (ioctl(STDIN_FILENO, TIOCSCTTY, /force:/ (long)1) != 0) {
+	// bb_perror_msg("TIOCSCTTY2 tsid:%d", tsid);
+	}
+	}
+	}
+	}
+
	/* Exec login shell with no additional parameters. Never returns. */
	exec_login_shell(shell);
	}