0de3c55b4

Denis Vlasenko

2007-04-12

FAILED Duration: 11s

Subject

login: remove setpgrp call (makes it work from shell prompt again). login: sanitize stdio descriptors (we are suid, need to be careful!) shrink login and set_environment by ~100 bytes.

Binary

No binary (build failed)

Architecture & Compiler Flags

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

—

Build Log

(log yok)

Commit Diff GitHub →

include/platform.h +3 -3 libbb/info_msg.c +0 -4 libbb/setup_environment.c +4 -11 loginutils/login.c +25 -20

include/platform.h+3 -3

@@ -259,8 +259,8 @@ static ATTRIBUTE_ALWAYS_INLINE char* strchrnul(const char *s, char c) {
	#define HAVE_INTTYPES_H
	#define PRIu32 "u"

-	/* use legacy setpgrp(pidt_,pid_t) for now. move to platform.c */
-	#define bb_setpgrp do { pid_t __me = getpid(); setpgrp(__me,__me); } while (0)
+	/* use legacy setpgrp(pid_t,pid_t) for now. move to platform.c */
+	#define bb_setpgrp() do { pid_t __me = getpid(); setpgrp(__me,__me); } while (0)

	#if !defined ADJ_OFFSET_SINGLESHOT && defined MOD_CLKA && defined MOD_OFFSET
	#define ADJ_OFFSET_SINGLESHOT (MOD_CLKA \| MOD_OFFSET)
@@ -276,7 +276,7 @@ static ATTRIBUTE_ALWAYS_INLINE char* strchrnul(const char *s, char c) {
	#endif

	#else
-	#define bb_setpgrp setpgrp()
+	#define bb_setpgrp() setpgrp()
	#endif

	#if defined(__linux__)

libbb/info_msg.c+0 -4

@@ -7,10 +7,6 @@
	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
	*/

-	#include <stdio.h>
-	#include <errno.h>
-	#include <string.h>
-	#include <stdlib.h>
	#include "libbb.h"

	void bb_info_msg(const char *s, ...)

libbb/setup_environment.c+4 -11

@@ -28,19 +28,12 @@
	* SUCH DAMAGE.
	*/

-	#include <stdio.h>
-	#include <errno.h>
-	#include <unistd.h>
-	#include <string.h>
-	#include <stdlib.h>
-	#include <syslog.h>
-	#include <ctype.h>
	#include "libbb.h"

-
-
-	#define DEFAULT_LOGIN_PATH "/bin:/usr/bin"
-	#define DEFAULT_ROOT_LOGIN_PATH "/usr/sbin:/bin:/usr/bin:/sbin"
+	/* util-linux manpage says /sbin:/bin:/usr/sbin:/usr/bin,
+	* but I want to save a few bytes here */
+	static const char DEFAULT_ROOT_LOGIN_PATH[] = "/sbin:/usr/sbin:/bin:/usr/bin";
+	#define DEFAULT_LOGIN_PATH (DEFAULT_ROOT_LOGIN_PATH + sizeof("/sbin:/usr/sbin"))

	void setup_environment(const char shell, int loginshell, int changeenv, const struct passwd pw)
	{

loginutils/login.c+25 -20

@@ -181,14 +181,13 @@ prompt:

	static void motd(void)
	{
-	FILE *fp;
-	int c;
+	int fd;

-	fp = fopen(bb_path_motd_file, "r");
-	if (fp) {
-	while ((c = getc(fp)) != EOF)
-	putchar(c);
-	fclose(fp);
+	fd = open(bb_path_motd_file, O_RDONLY);
+	if (fd) {
+	fflush(stdout);
+	bb_copyfd_eof(fd, STDOUT_FILENO);
+	close(fd);
	}
	}

@@ -199,7 +198,7 @@ static void alarm_handler(int sig ATTRIBUTE_UNUSED)
	* We don't want to block here */
	ndelay_on(1);
	ndelay_on(2);
-	bb_info_msg("\r\nLogin timed out after %d seconds\r", TIMEOUT);
+	printf("\r\nLogin timed out after %d seconds\r\n", TIMEOUT);
	exit(EXIT_SUCCESS);
	}

@@ -230,6 +229,12 @@ int login_main(int argc, char **argv)
	signal(SIGALRM, alarm_handler);
	alarm(TIMEOUT);

+	/* Mandatory paranoia for suid applet:
+	* ensure that fd# 0,1,2 are opened (at least to /dev/null)
+	* and any extra open fd's are closed.
+	* (The name of the function is misleading. Not daemonizing here.) */
+	bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE \| DAEMON_CLOSE_EXTRA_FDS, NULL);
+
	opt = getopt32(argc, argv, "f:h:p", &opt_user, &opt_host);
	if (opt & LOGIN_OPT_f) {
	if (!amroot)
@@ -261,7 +266,8 @@ int login_main(int argc, char **argv)
	} else
	snprintf(fromhost, sizeof(fromhost)-1, " on '%.100s'", short_tty);

-	bb_setpgrp;
+	// Was breaking "login <username>" from shell command line:
+	// bb_setpgrp();

	openlog(applet_name, LOG_PID \| LOG_CONS \| LOG_NOWAIT, LOG_AUTH);

@@ -292,7 +298,7 @@ int login_main(int argc, char **argv)
	if (correct_password(pw))
	break;

-	auth_failed:
+	auth_failed:
	opt &= ~LOGIN_OPT_f;
	bb_do_delay(FAIL_DELAY);
	puts("Login incorrect");
@@ -343,17 +349,13 @@ auth_failed:
	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);
+	xsetenv("LOGIN_TTY", full_tty);
+	xsetenv("LOGIN_USER", pw->pw_name);
+	xsetenv("LOGIN_UID", utoa(pw->pw_uid));
+	xsetenv("LOGIN_GID", utoa(pw->pw_gid));
+	xsetenv("LOGIN_SHELL", pw->pw_shell);
	xspawn(argv); /* NOMMU-friendly */
-	unsetenv("LOGIN_TTY");
-	unsetenv("LOGIN_USER");
-	unsetenv("LOGIN_UID");
-	unsetenv("LOGIN_GID");
-	unsetenv("LOGIN_SHELL");
+	/* All variables are unset by setup_environment */
	wait(NULL);
	}
	}
@@ -379,6 +381,9 @@ auth_failed:
	// setsid();
	// /* TIOCSCTTY: steal tty from other process group */
	// if (ioctl(0, TIOCSCTTY, 1)) error_msg...
+	// BBox login used to do this (see above):
+	// bb_setpgrp();
+	// If this stuff is really needed, add it and explain why!

	/* set signals to defaults */
	signal(SIGALRM, SIG_DFL);