mount: recognize "dirsync" (closes bug 835)

mount: sanitize environ if called by non-root
*: adjust for slightly different sanitize routine

include/libbb.h

@@ -684,8 +684,8 @@ enum {
 #endif
 void bb_daemonize_or_rexec(int flags, char **argv);
 void bb_sanitize_stdio(void);
-/* Clear dangerous stuff, set PATH */
+/* Clear dangerous stuff, set PATH. Return 1 if was run by different user. */
-void sanitize_env_for_suid(void);
+int sanitize_env_if_suid(void);
 
 
 extern const char *opt_complementary;

libbb/login.c

@@ -116,12 +116,19 @@ static const char forbid[] ALIGN1 =
 	"LD_NOWARN" "\0"
 	"LD_KEEPDIR" "\0";
 
-void sanitize_env_for_suid(void)
+int sanitize_env_if_suid(void)
 {
-	const char *p = forbid;
+	const char *p;
+
+	if (getuid() == geteuid())
+		return 0;
+
+	p = forbid;
 	do {
 		unsetenv(p);
 		p += strlen(p) + 1;
 	} while (*p);
 	putenv((char*)bb_PATH_root_path);
+
+	return 1; /* we indeed were run by different user! */
 }

loginutils/login.c

@@ -254,20 +254,17 @@ int login_main(int argc, char **argv)
 
 	short_tty = full_tty;
 	username[0] = '\0';
-	amroot = (getuid() == 0);
 	signal(SIGALRM, alarm_handler);
 	alarm(TIMEOUT);
 
+	/* More of suid paranoia if called by non-root */
+	amroot = !sanitize_env_if_suid(); /* Clear dangerous stuff, set PATH */
+
 	/* 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);
-	/* More of suid paranoia if called by non-root */
-	if (!amroot) {
-	        /* Clear dangerous stuff, set PATH */
-		sanitize_env_for_suid();
-	}
 
 	opt = getopt32(argv, "f:h:p", &opt_user, &opt_host);
 	if (opt & LOGIN_OPT_f) {

loginutils/sulogin.c

@@ -49,7 +49,7 @@ int sulogin_main(int argc, char **argv)
 	}
 
 	/* Clear dangerous stuff, set PATH */
-	sanitize_env_for_suid();
+	sanitize_env_if_suid();
 
 // bb_askpass() already handles this
 //	signal(SIGALRM, catchalarm);

miscutils/crontab.c

@@ -97,7 +97,6 @@ int crontab_main(int argc, char **argv)
 	char *user_name;  /* -u USER */
 	int fd;
 	int opt_ler;
-	uid_t my_uid;
 
 	/* file [opts]     Replace crontab from file
 	 * - [opts]        Replace crontab from stdin
@@ -118,25 +117,22 @@ int crontab_main(int argc, char **argv)
 		OPT_ler = OPT_l + OPT_e + OPT_r,
 	};
 
-	my_uid = getuid();
-
 	opt_complementary = "?1:dr"; /* max one argument; -d implies -r */
 	opt_ler = getopt32(argv, "u:c:lerd", &user_name, &crontab_dir);
 	argv += optind;
 
-	if (my_uid != geteuid()) { /* run by non-root? */
+	if (sanitize_env_if_suid()) { /* Clears dangerous stuff, sets PATH */
+		/* run by non-root? */
 		if (opt_ler & (OPT_u|OPT_c))
 			bb_error_msg_and_die("only root can use -c or -u");
-		/* Clear dangerous stuff, set PATH */
-		sanitize_env_for_suid();
 	}
 
 	if (opt_ler & OPT_u) {
 		pas = getpwnam(user_name);
 		if (!pas)
 			bb_error_msg_and_die("user %s is not known", user_name);
-		my_uid = pas->pw_uid;
 	} else {
+		uid_t my_uid = getuid();
 		pas = getpwuid(my_uid);
 		if (!pas)
 			bb_perror_msg_and_die("no user record for UID %u",
@@ -144,7 +140,6 @@ int crontab_main(int argc, char **argv)
 	}
 
 #define user_name DONT_USE_ME_BEYOND_THIS_POINT
-#define my_uid    DONT_USE_ME_BEYOND_THIS_POINT
 
 	/* From now on, keep only -l, -e, -r bits */
 	opt_ler &= OPT_ler;

networking/nc.c

@@ -44,13 +44,16 @@ int nc_main(int argc, char **argv)
 		while ((opt = getopt(argc, argv,
 		        "" USE_NC_SERVER("lp:") USE_NC_EXTRA("w:i:f:e:") )) > 0
 		) {
-			if (ENABLE_NC_SERVER && opt=='l')      USE_NC_SERVER(do_listen++);
+			if (ENABLE_NC_SERVER && opt=='l')
-			else if (ENABLE_NC_SERVER && opt=='p') {
+				USE_NC_SERVER(do_listen++);
+			else if (ENABLE_NC_SERVER && opt=='p')
 				USE_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
-			}
+			else if (ENABLE_NC_EXTRA && opt=='w')
-			else if (ENABLE_NC_EXTRA && opt=='w') USE_NC_EXTRA( wsecs = xatou(optarg));
+				USE_NC_EXTRA( wsecs = xatou(optarg));
-			else if (ENABLE_NC_EXTRA && opt=='i') USE_NC_EXTRA( delay = xatou(optarg));
+			else if (ENABLE_NC_EXTRA && opt=='i')
-			else if (ENABLE_NC_EXTRA && opt=='f') USE_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
+				USE_NC_EXTRA( delay = xatou(optarg));
+			else if (ENABLE_NC_EXTRA && opt=='f')
+				USE_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
 			else if (ENABLE_NC_EXTRA && opt=='e' && optind <= argc) {
 				/* We cannot just 'break'. We should let getopt finish.
 				** Or else we won't be able to find where

util-linux/mount.c

@@ -33,6 +33,11 @@
 #ifndef MS_SILENT
 #define MS_SILENT	(1 << 15)
 #endif
+/* Grab more as needed from util-linux's mount/mount_constants.h */
+#ifndef MS_DIRSYNC
+#define MS_DIRSYNC      128     /* Directory modifications are synchronous */
+#endif
+
 
 #if defined(__dietlibc__)
 /* 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
@@ -122,6 +127,7 @@ static const int32_t mount_options[] = {
 		/* "exec"        */ ~MS_NOEXEC,
 		/* "noexec"      */ MS_NOEXEC,
 		/* "sync"        */ MS_SYNCHRONOUS,
+		/* "dirsync"     */ MS_DIRSYNC,
 		/* "async"       */ ~MS_SYNCHRONOUS,
 		/* "atime"       */ ~MS_NOATIME,
 		/* "noatime"     */ MS_NOATIME,
@@ -171,6 +177,7 @@ static const char mount_option_str[] =
 		"exec" "\0"
 		"noexec" "\0"
 		"sync" "\0"
+		"dirsync" "\0"
 		"async" "\0"
 		"atime" "\0"
 		"noatime" "\0"
@@ -1665,6 +1672,8 @@ int mount_main(int argc, char **argv)
 	SKIP_DESKTOP(const int nonroot = 0;)
 	USE_DESKTOP( int nonroot = (getuid() != 0);)
 
+	sanitize_env_if_suid();
+
 	/* parse long options, like --bind and --move.  Note that -o option
 	 * and --option are synonymous.  Yes, this means --remount,rw works. */