X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=loginutils%2Flogin.c;h=3d8b8e540b0c7a39ac216b990964f3bee0c368d0;hb=24efe4f15fe45151681b41333f3713357ce8694b;hp=c0f4b72bbd1809dc859a7b1b1783331be727a883;hpb=2f50aa42c54fb92347058e83965ea7a668ab04af;p=oweals%2Fbusybox.git

diff --git a/loginutils/login.c b/loginutils/login.c
index c0f4b72bb..3d8b8e540 100644
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -3,37 +3,18 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <fcntl.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <syslog.h>
-#include <termios.h>
-#include <unistd.h>
+#include "busybox.h"
 #include <utmp.h>
 #include <sys/resource.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <ctype.h>
-#include <time.h>
+#include <syslog.h>
 
-#include "busybox.h"
-#ifdef CONFIG_SELINUX
+#if ENABLE_SELINUX
 #include <selinux/selinux.h>  /* for is_selinux_enabled()  */
 #include <selinux/get_context_list.h> /* for get_default_context() */
 #include <selinux/flask.h> /* for security class definitions  */
 #include <errno.h>
 #endif
 
-#ifdef CONFIG_FEATURE_UTMP
-// import from utmp.c
-static struct utmp utent;
-static void read_or_build_utent(int picky);
-static void write_utent(const char *username);
-#endif
-
 enum {
 	TIMEOUT = 60,
 	EMPTY_USERNAME_COUNT = 10,
@@ -41,22 +22,174 @@ enum {
 	TTYNAME_SIZE = 32,
 };
 
-static void die_if_nologin_and_non_root(int amroot);
+static char* short_tty;
+
+#if ENABLE_FEATURE_UTMP
+/* vv  Taken from tinylogin utmp.c  vv */
+/*
+ * read_or_build_utent - see if utmp file is correct for this process
+ *
+ *	System V is very picky about the contents of the utmp file
+ *	and requires that a slot for the current process exist.
+ *	The utmp file is scanned for an entry with the same process
+ *	ID.  If no entry exists the process exits with a message.
+ *
+ *	The "picky" flag is for network and other logins that may
+ *	use special flags.  It allows the pid checks to be overridden.
+ *	This means that getty should never invoke login with any
+ *	command line flags.
+ */
+
+static void read_or_build_utent(struct utmp *utptr, int picky)
+{
+	struct utmp *ut;
+	pid_t pid = getpid();
+
+	setutent();
+
+	/* First, try to find a valid utmp entry for this process.  */
+	while ((ut = getutent()))
+		if (ut->ut_pid == pid && ut->ut_line[0] && ut->ut_id[0] &&
+		(ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS))
+			break;
+
+	/* If there is one, just use it, otherwise create a new one.  */
+	if (ut) {
+		*utptr = *ut;
+	} else {
+		if (picky)
+			bb_error_msg_and_die("no utmp entry found");
+
+		memset(utptr, 0, sizeof(*utptr));
+		utptr->ut_type = LOGIN_PROCESS;
+		utptr->ut_pid = pid;
+		strncpy(utptr->ut_line, short_tty, sizeof(utptr->ut_line));
+		/* This one is only 4 chars wide. Try to fit something
+		 * remotely meaningful by skipping "tty"... */
+		strncpy(utptr->ut_id, short_tty + 3, sizeof(utptr->ut_id));
+		strncpy(utptr->ut_user, "LOGIN", sizeof(utptr->ut_user));
+		utptr->ut_time = time(NULL);
+	}
+	if (!picky)	/* root login */
+		memset(utptr->ut_host, 0, sizeof(utptr->ut_host));
+}
+
+/*
+ * write_utent - put a USER_PROCESS entry in the utmp file
+ *
+ *	write_utent changes the type of the current utmp entry to
+ *	USER_PROCESS.  the wtmp file will be updated as well.
+ */
+static void write_utent(struct utmp *utptr, const char *username)
+{
+	utptr->ut_type = USER_PROCESS;
+	strncpy(utptr->ut_user, username, sizeof(utptr->ut_user));
+	utptr->ut_time = time(NULL);
+	/* other fields already filled in by read_or_build_utent above */
+	setutent();
+	pututline(utptr);
+	endutent();
+#if ENABLE_FEATURE_WTMP
+	if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) {
+		close(creat(bb_path_wtmp_file, 0664));
+	}
+	updwtmp(bb_path_wtmp_file, utptr);
+#endif
+}
+#else /* !ENABLE_FEATURE_UTMP */
+#define read_or_build_utent(utptr, picky) ((void)0)
+#define write_utent(utptr, username) ((void)0)
+#endif /* !ENABLE_FEATURE_UTMP */
+
+static void die_if_nologin_and_non_root(int amroot)
+{
+	FILE *fp;
+	int c;
+
+	if (access(bb_path_nologin_file, F_OK))
+		return;
+
+	fp = fopen(bb_path_nologin_file, "r");
+	if (fp) {
+		while ((c = getc(fp)) != EOF)
+			putchar((c=='\n') ? '\r' : c);
+		fflush(stdout);
+		fclose(fp);
+	} else
+		puts("\r\nSystem closed for routine maintenance\r");
+	if (!amroot)
+		exit(1);
+	puts("\r\n[Disconnect bypassed -- root login allowed.]\r");
+}
 
-#if defined CONFIG_FEATURE_SECURETTY
-static int check_securetty(void);
+#if ENABLE_FEATURE_SECURETTY
+static int check_securetty(void)
+{
+	FILE *fp;
+	int i;
+	char buf[BUFSIZ];
 
+	fp = fopen(bb_path_securetty_file, "r");
+	if (!fp) {
+		/* A missing securetty file is not an error. */
+		return 1;
+	}
+	while (fgets(buf, sizeof(buf)-1, fp)) {
+		for (i = strlen(buf)-1; i>=0; --i) {
+			if (!isspace(buf[i]))
+				break;
+		}
+		buf[++i] = '\0';
+		if ((buf[0]=='\0') || (buf[0]=='#'))
+			continue;
+		if (strcmp(buf, short_tty) == 0) {
+			fclose(fp);
+			return 1;
+		}
+	}
+	fclose(fp);
+	return 0;
+}
 #else
 static inline int check_securetty(void) { return 1; }
-
 #endif
 
-static void get_username_or_die(char *buf, int size_buf);
-static void motd(void);
+static void get_username_or_die(char *buf, int size_buf)
+{
+	int c, cntdown;
+	cntdown = EMPTY_USERNAME_COUNT;
+prompt:
+	/* skip whitespace */
+	print_login_prompt();
+	do {
+		c = getchar();
+		if (c == EOF) exit(1);
+		if (c == '\n') {
+			if (!--cntdown) exit(1);
+			goto prompt;
+		}
+	} while (isspace(c));
+
+	*buf++ = c;
+	if (!fgets(buf, size_buf-2, stdin))
+		exit(1);
+	if (!strchr(buf, '\n'))
+		exit(1);
+	while (isgraph(*buf)) buf++;
+	*buf = '\0';
+}
 
-static void nonblock(int fd)
+static void motd(void)
 {
-	fcntl(fd, F_SETFL, O_NONBLOCK | fcntl(fd, F_GETFL));
+	FILE *fp;
+	int c;
+
+	fp = fopen(bb_path_motd_file, "r");
+	if (fp) {
+		while ((c = getc(fp)) != EOF)
+			putchar(c);
+		fclose(fp);
+	}
 }
 
 static void alarm_handler(int sig ATTRIBUTE_UNUSED)
@@ -64,68 +197,46 @@ static void alarm_handler(int sig ATTRIBUTE_UNUSED)
 	/* This is the escape hatch!  Poor serial line users and the like
 	 * arrive here when their connection is broken.
 	 * We don't want to block here */
-	nonblock(1);
-	nonblock(2);
+	ndelay_on(1);
+	ndelay_on(2);
 	bb_info_msg("\r\nLogin timed out after %d seconds\r", TIMEOUT);
 	exit(EXIT_SUCCESS);
 }
 
-
-static char full_tty[TTYNAME_SIZE];
-static char* short_tty = full_tty;
-
-
+int login_main(int argc, char **argv);
 int login_main(int argc, char **argv)
 {
+	enum {
+		LOGIN_OPT_f = (1<<0),
+		LOGIN_OPT_h = (1<<1),
+		LOGIN_OPT_p = (1<<2),
+	};
 	char fromhost[512];
 	char username[USERNAME_SIZE];
 	const char *tmp;
 	int amroot;
-	int flag;
+	unsigned opt;
 	int count = 0;
 	struct passwd *pw;
-#ifdef CONFIG_WHEEL_GROUP
-	struct group *grp;
-#endif
-	int opt_preserve = 0;
-	int opt_fflag = 0;
-	char *opt_host = 0;
-#ifdef CONFIG_SELINUX
-	security_context_t user_sid = NULL;
-#endif
+	char *opt_host = NULL;
+	char *opt_user = NULL;
+	char full_tty[TTYNAME_SIZE];
+	USE_SELINUX(security_context_t user_sid = NULL;)
+	USE_FEATURE_UTMP(struct utmp utent;)
 
+	short_tty = full_tty;
 	username[0] = '\0';
 	amroot = (getuid() == 0);
 	signal(SIGALRM, alarm_handler);
 	alarm(TIMEOUT);
 
-	while ((flag = getopt(argc, argv, "f:h:p")) != EOF) {
-		switch (flag) {
-		case 'p':
-			opt_preserve = 1;
-			break;
-		case 'f':
-			/*
-			 * username must be a separate token
-			 * (-f root, *NOT* -froot). --marekm
-			 */
-			if (optarg != argv[optind-1])
-				bb_show_usage();
-
-			if (!amroot)	/* Auth bypass only if real UID is zero */
-				bb_error_msg_and_die("-f is for root only");
-
-			safe_strncpy(username, optarg, sizeof(username));
-			opt_fflag = 1;
-			break;
-		case 'h':
-			opt_host = optarg;
-			break;
-		default:
-			bb_show_usage();
-		}
+	opt = getopt32(argc, argv, "f:h:p", &opt_user, &opt_host);
+	if (opt & LOGIN_OPT_f) {
+		if (!amroot)
+			bb_error_msg_and_die("-f is for root only");
+		safe_strncpy(username, opt_user, sizeof(username));
 	}
-	if (optind < argc)             /* user from command line (getty) */
+	if (optind < argc) /* user from command line (getty) */
 		safe_strncpy(username, argv[optind], sizeof(username));
 
 	/* Let's find out and memorize our tty */
@@ -139,24 +250,20 @@ int login_main(int argc, char **argv)
 			short_tty = full_tty + 5;
 	}
 
-	if (ENABLE_FEATURE_UTMP) {
-		read_or_build_utent(!amroot);
-		if (amroot)
-			memset(utent.ut_host, 0, sizeof(utent.ut_host));
-	}
+	read_or_build_utent(&utent, !amroot);
 
 	if (opt_host) {
-		if (ENABLE_FEATURE_UTMP)
+		USE_FEATURE_UTMP(
 			safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
-		snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s' from "
-					"`%.200s'", short_tty, opt_host);
-	}
-	else
-		snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s'", short_tty);
+		)
+		snprintf(fromhost, sizeof(fromhost)-1, " on '%.100s' from "
+					"'%.200s'", short_tty, opt_host);
+	} else
+		snprintf(fromhost, sizeof(fromhost)-1, " on '%.100s'", short_tty);
 
 	bb_setpgrp;
 
-	openlog(bb_applet_name, LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
+	openlog(applet_name, LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
 
 	while (1) {
 		if (!username[0])
@@ -171,7 +278,7 @@ int login_main(int argc, char **argv)
 		if (pw->pw_passwd[0] == '!' || pw->pw_passwd[0] == '*')
 			goto auth_failed;
 
-		if (opt_fflag)
+		if (opt & LOGIN_OPT_f)
 			break; /* -f USER: success without asking passwd */
 
 		if (pw->pw_uid == 0 && !check_securetty())
@@ -179,18 +286,18 @@ int login_main(int argc, char **argv)
 
 		/* Don't check the password if password entry is empty (!) */
 		if (!pw->pw_passwd[0])
-			break; 
+			break;
 
 		/* authorization takes place here */
 		if (correct_password(pw))
-			break; 
+			break;
 
 auth_failed:
-		opt_fflag = 0;
+		opt &= ~LOGIN_OPT_f;
 		bb_do_delay(FAIL_DELAY);
 		puts("Login incorrect");
 		if (++count == 3) {
-			syslog(LOG_WARNING, "invalid password for `%s'%s",
+			syslog(LOG_WARNING, "invalid password for '%s'%s",
 						username, fromhost);
 			return EXIT_FAILURE;
 		}
@@ -200,28 +307,27 @@ auth_failed:
 	alarm(0);
 	die_if_nologin_and_non_root(pw->pw_uid == 0);
 
-	if (ENABLE_FEATURE_UTMP)
-		write_utent(username);
+	write_utent(&utent, username);
 
 #ifdef CONFIG_SELINUX
 	if (is_selinux_enabled()) {
 		security_context_t old_tty_sid, new_tty_sid;
 
 		if (get_default_context(username, NULL, &user_sid)) {
-			bb_error_msg_and_die("unable to get SID for %s",
+			bb_error_msg_and_die("cannot get SID for %s",
 					username);
 		}
 		if (getfilecon(full_tty, &old_tty_sid) < 0) {
-			bb_perror_msg_and_die("getfilecon(%.100s) failed",
+			bb_perror_msg_and_die("getfilecon(%s) failed",
 					full_tty);
 		}
 		if (security_compute_relabel(user_sid, old_tty_sid,
 					SECCLASS_CHR_FILE, &new_tty_sid) != 0) {
-			bb_perror_msg_and_die("security_change_sid(%.100s) failed",
+			bb_perror_msg_and_die("security_change_sid(%s) failed",
 					full_tty);
 		}
 		if (setfilecon(full_tty, new_tty_sid) != 0) {
-			bb_perror_msg_and_die("chsid(%.100s, %s) failed",
+			bb_perror_msg_and_die("chsid(%s, %s) failed",
 					full_tty, new_tty_sid);
 		}
 	}
@@ -232,23 +338,23 @@ auth_failed:
 	fchmod(0, 0600);
 
 	if (ENABLE_LOGIN_SCRIPTS) {
-		char *script = getenv("LOGIN_PRE_SUID_SCRIPT");
-		if (script) {
-			char *t_argv[2] = { script, NULL };
-			switch (fork()) {
-			case -1: break;
-			case 0: /* child */
-				xchdir("/");
-				setenv("LOGIN_TTY", full_tty, 1);
-				setenv("LOGIN_USER", pw->pw_name, 1);
-				setenv("LOGIN_UID", utoa(pw->pw_uid), 1);
-				setenv("LOGIN_GID", utoa(pw->pw_gid), 1);
-				setenv("LOGIN_SHELL", pw->pw_shell, 1);
-				execvp(script, t_argv);
-				exit(1);
-			default: /* parent */
-				wait(NULL);
-			}
+		char *t_argv[2];
+
+		t_argv[0] = getenv("LOGIN_PRE_SUID_SCRIPT");
+		if (t_argv[0]) {
+			t_argv[1] = NULL;
+			setenv("LOGIN_TTY", full_tty, 1);
+			setenv("LOGIN_USER", pw->pw_name, 1);
+			setenv("LOGIN_UID", utoa(pw->pw_uid), 1);
+			setenv("LOGIN_GID", utoa(pw->pw_gid), 1);
+			setenv("LOGIN_SHELL", pw->pw_shell, 1);
+			xspawn(argv); /* NOMMU-friendly */
+			unsetenv("LOGIN_TTY");
+			unsetenv("LOGIN_USER");
+			unsetenv("LOGIN_UID");
+			unsetenv("LOGIN_GID");
+			unsetenv("LOGIN_SHELL");
+			wait(NULL);
 		}
 	}
 
@@ -256,10 +362,9 @@ auth_failed:
 	tmp = pw->pw_shell;
 	if (!tmp || !*tmp)
 		tmp = DEFAULT_SHELL;
-	setup_environment(tmp, 1, !opt_preserve, pw);
+	setup_environment(tmp, 1, !(opt & LOGIN_OPT_p), pw);
 
 	motd();
-	signal(SIGALRM, SIG_DFL);	/* default alarm signal */
 
 	if (pw->pw_uid == 0)
 		syslog(LOG_INFO, "root login%s", fromhost);
@@ -268,175 +373,24 @@ auth_failed:
 	 * but let's play the game for now */
 	set_current_security_context(user_sid);
 #endif
-	run_shell(tmp, 1, 0, 0);	/* exec the shell finally. */
-
-	return EXIT_FAILURE;
-}
-
-
-static void get_username_or_die(char *buf, int size_buf)
-{
-	int c, cntdown;
-	cntdown = EMPTY_USERNAME_COUNT;
-prompt:
-	/* skip whitespace */
-	print_login_prompt();
-	do {
-		c = getchar();
-		if (c == EOF) exit(1);
-		if (c == '\n') {
-			if (!--cntdown) exit(1);
-			goto prompt;
-		}
-	} while (isspace(c));
-
-	*buf++ = c;
-	if (!fgets(buf, size_buf-2, stdin))
-		exit(1);
-	if (!strchr(buf, '\n'))
-		exit(1);
-	while (isgraph(*buf)) buf++;
-	*buf = '\0';
-}
-
-
-static void die_if_nologin_and_non_root(int amroot)
-{
-	FILE *fp;
-	int c;
-
-	if (access(bb_path_nologin_file, F_OK))
-		return;
-
-	fp = fopen(bb_path_nologin_file, "r");
-	if (fp) {
-		while ((c = getc(fp)) != EOF)
-			putchar((c=='\n') ? '\r' : c);
-		fflush(stdout);
-		fclose(fp);
-	} else
-		puts("\r\nSystem closed for routine maintenance\r");
-	if (!amroot)
-		exit(1);
-	puts("\r\n[Disconnect bypassed -- root login allowed.]\r");
-}
-
-#ifdef CONFIG_FEATURE_SECURETTY
-
-static int check_securetty(void)
-{
-	FILE *fp;
-	int i;
-	char buf[BUFSIZ];
-
-	fp = fopen(bb_path_securetty_file, "r");
-	if (!fp) {
-		/* A missing securetty file is not an error. */
-		return 1;
-	}
-	while (fgets(buf, sizeof(buf)-1, fp)) {
-		for(i = strlen(buf)-1; i>=0; --i) {
-			if (!isspace(buf[i]))
-				break;
-		}
-		buf[++i] = '\0';
-		if ((buf[0]=='\0') || (buf[0]=='#'))
-			continue;
-		if (strcmp(buf, short_tty) == 0) {
-			fclose(fp);
-			return 1;
-		}
-	}
-	fclose(fp);
-	return 0;
-}
-
-#endif
-
-static void motd(void)
-{
-	FILE *fp;
-	int c;
-
-	fp = fopen(bb_path_motd_file, "r");
-	if (fp) {
-		while ((c = getc(fp)) != EOF)
-			putchar(c);
-		fclose(fp);
-	}
-}
-
-
-#ifdef CONFIG_FEATURE_UTMP
-/* vv  Taken from tinylogin utmp.c  vv */
-
-/*
- * read_or_build_utent - see if utmp file is correct for this process
- *
- *	System V is very picky about the contents of the utmp file
- *	and requires that a slot for the current process exist.
- *	The utmp file is scanned for an entry with the same process
- *	ID.  If no entry exists the process exits with a message.
- *
- *	The "picky" flag is for network and other logins that may
- *	use special flags.  It allows the pid checks to be overridden.
- *	This means that getty should never invoke login with any
- *	command line flags.
- */
-
-static void read_or_build_utent(int picky)
-{
-	struct utmp *ut;
-	pid_t pid = getpid();
-
-	setutent();
 
-	/* First, try to find a valid utmp entry for this process.  */
-	while ((ut = getutent()))
-		if (ut->ut_pid == pid && ut->ut_line[0] && ut->ut_id[0] &&
-		(ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS))
-			break;
-
-	/* If there is one, just use it, otherwise create a new one.  */
-	if (ut) {
-		utent = *ut;
-	} else {
-		if (picky)
-			bb_error_msg_and_die("no utmp entry found");
+	// util-linux login also does:
+	// /* start new session */
+	// setsid();
+	// /* TIOCSCTTY: steal tty from other process group */
+	// if (ioctl(0, TIOCSCTTY, 1)) error_msg...
 
-		memset(&utent, 0, sizeof(utent));
-		utent.ut_type = LOGIN_PROCESS;
-		utent.ut_pid = pid;
-		strncpy(utent.ut_line, short_tty, sizeof(utent.ut_line));
-		/* This one is only 4 chars wide. Try to fit something
-		 * remotely meaningful by skipping "tty"... */
-		strncpy(utent.ut_id, short_tty + 3, sizeof(utent.ut_id));
-		strncpy(utent.ut_user, "LOGIN", sizeof(utent.ut_user));
-		utent.ut_time = time(NULL);
-	}
-}
+	/* set signals to defaults */
+	signal(SIGALRM, SIG_DFL);
+	/* Is this correct? This way user can ctrl-c out of /etc/profile,
+	 * potentially creating security breach (tested with bash 3.0).
+	 * But without this, bash 3.0 will not enable ctrl-c either.
+	 * Maybe bash is buggy?
+	 * Need to find out what standards say about /bin/login -
+	 * should it leave SIGINT etc enabled or disabled? */
+	signal(SIGINT, SIG_DFL);
 
-/*
- * write_utent - put a USER_PROCESS entry in the utmp file
- *
- *	write_utent changes the type of the current utmp entry to
- *	USER_PROCESS.  the wtmp file will be updated as well.
- */
+	run_shell(tmp, 1, 0, 0);	/* exec the shell finally */
 
-static void write_utent(const char *username)
-{
-	utent.ut_type = USER_PROCESS;
-	strncpy(utent.ut_user, username, sizeof(utent.ut_user));
-	utent.ut_time = time(NULL);
-	/* other fields already filled in by read_or_build_utent above */
-	setutent();
-	pututline(&utent);
-	endutent();
-#ifdef CONFIG_FEATURE_WTMP
-	if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) {
-		close(creat(bb_path_wtmp_file, 0664));
-	}
-	updwtmp(bb_path_wtmp_file, &utent);
-#endif
+	return EXIT_FAILURE;
 }
-#endif /* CONFIG_FEATURE_UTMP */