X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev%2Fudev-node.c;h=71488c93ad00f4ffd7303f583f804c153e568600;hp=8339eb732f0bd8b42e9a57be8aed5d5a823c9a26;hb=b3e44c5291f60c0d70af941514ab58c8d31f14a7;hpb=761dfddcc027d0a4be881d779cc2f62edafbb2eb

diff --git a/udev/udev-node.c b/udev/udev-node.c
index 8339eb732..71488c93a 100644
--- a/udev/udev-node.c
+++ b/udev/udev-node.c
@@ -52,14 +52,23 @@ int udev_node_mknod(struct udev_device *dev, const char *file, mode_t mode, uid_
 	if (lstat(file, &stats) == 0) {
 		if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devnum)) {
 			info(udev, "preserve file '%s', because it has correct dev_t\n", file);
-			if (stats.st_mode != mode || stats.st_uid != uid || stats.st_gid != gid) {
+			if ((stats.st_mode & 0777) != (mode & 0777) || stats.st_uid != uid || stats.st_gid != gid) {
+				/* preserve 'sticky' bit, if already set */
+				mode |= stats.st_mode & 01000;
 				info(udev, "set permissions %s, %#o, uid=%u, gid=%u\n", file, mode, uid, gid);
 				chmod(file, mode);
 				chown(file, uid, gid);
-				udev_selinux_lsetfilecon(udev, file, mode);
 			} else {
 				info(udev, "preserve permissions %s, %#o, uid=%u, gid=%u\n", file, mode, uid, gid);
 			}
+			/*
+			 * Set initial selinux file context only on add events.
+			 * We set the proper context on bootup (triger) or for newly
+			 * added devices, but we don't change it later, in case
+			 * something else has set a custom context in the meantime.
+			 */
+			if (strcmp(udev_device_get_action(dev), "add") == 0)
+				udev_selinux_lsetfilecon(udev, file, mode);
 			/* always update timestamp when we re-use the node, like on media change events */
 			utimensat(AT_FDCWD, file, NULL, 0);
 		} else {
@@ -89,7 +98,7 @@ int udev_node_mknod(struct udev_device *dev, const char *file, mode_t mode, uid_
 	} else {
 		info(udev, "mknod '%s' %u:%u %#o\n", file, major(devnum), minor(devnum), mode);
 		do {
-			err = util_create_path(udev, file);
+			err = util_create_path_selinux(udev, file);
 			if (err != 0 && err != -ENOENT)
 				break;
 			udev_selinux_setfscreatecon(udev, file, mode);
@@ -177,7 +186,7 @@ static int node_symlink(struct udev *udev, const char *node, const char *slink)
 	} else {
 		info(udev, "creating symlink '%s' to '%s'\n", slink, target);
 		do {
-			err = util_create_path(udev, slink);
+			err = util_create_path_selinux(udev, slink);
 			if (err != 0 && err != -ENOENT)
 				break;
 			udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
@@ -194,7 +203,7 @@ static int node_symlink(struct udev *udev, const char *node, const char *slink)
 	util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
 	unlink(slink_tmp);
 	do {
-		err = util_create_path(udev, slink_tmp);
+		err = util_create_path_selinux(udev, slink_tmp);
 		if (err != 0 && err != -ENOENT)
 			break;
 		udev_selinux_setfscreatecon(udev, slink_tmp, S_IFLNK);
@@ -236,26 +245,20 @@ static const char *link_find_prioritized(struct udev_device *dev, bool add, cons
 	for (;;) {
 		struct udev_device *dev_db;
 		struct dirent *dent;
-		int maj, min;
-		char type, type2;
-		dev_t devnum;
 
 		dent = readdir(dir);
 		if (dent == NULL || dent->d_name[0] == '\0')
 			break;
 		if (dent->d_name[0] == '.')
 			continue;
-		if (sscanf(dent->d_name, "%c%i:%i", &type, &maj, &min) != 3)
-			continue;
-		info(udev, "found '%c%i:%i' claiming '%s'\n", type, maj, min, stackdir);
-		devnum = makedev(maj, min);
+
+		info(udev, "found '%s' claiming '%s'\n", dent->d_name, stackdir);
 
 		/* did we find ourself? */
-		type2 = strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c';
-		if (udev_device_get_devnum(dev) == devnum && type == type2)
+		if (strcmp(dent->d_name, udev_device_get_id_filename(dev)) == 0)
 			continue;
 
-		dev_db = udev_device_new_from_devnum(udev, type, devnum);
+		dev_db = udev_device_new_from_id_filename(udev, dent->d_name);
 		if (dev_db != NULL) {
 			const char *devnode;
 
@@ -291,22 +294,20 @@ static void link_update(struct udev_device *dev, const char *slink, bool add)
 	dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
 
 	util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
-	snprintf(dirname, sizeof(dirname), "%s/.udev/links/%s", udev_get_dev_path(udev), name_enc);
-	snprintf(filename, sizeof(filename), "%s/%c%u:%u", dirname,
-		 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c',
-		 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
+	util_strscpyl(dirname, sizeof(dirname), udev_get_run_path(udev), "/links/", name_enc, NULL);
+	util_strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL);
 
 	if (!add) {
 		dbg(udev, "removing index: '%s'\n", filename);
-		unlink(filename);
-		util_delete_path(udev, filename);
+		if (unlink(filename) == 0)
+			rmdir(dirname);
 	}
 
 	target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
 	if (target == NULL) {
 		info(udev, "no reference left, remove '%s'\n", slink);
-		unlink(slink);
-		util_delete_path(udev, slink);
+		if (unlink(slink) == 0)
+			util_delete_path(udev, slink);
 	} else {
 		info(udev, "creating link '%s' to '%s'\n", slink, target);
 		node_symlink(udev, target, slink);
@@ -322,7 +323,7 @@ static void link_update(struct udev_device *dev, const char *slink, bool add)
 			err = util_create_path(udev, filename);
 			if (err != 0 && err != -ENOENT)
 				break;
-			fd = open(filename, O_WRONLY|O_CREAT|O_NOFOLLOW, 0444);
+			fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
 			if (fd >= 0)
 				close(fd);
 			else
@@ -364,6 +365,7 @@ void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev
 int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
 {
 	struct udev *udev = udev_device_get_udev(dev);
+	char filename[UTIL_PATH_SIZE];
 	struct udev_list_entry *list_entry;
 	int err = 0;
 
@@ -377,9 +379,16 @@ int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
 		goto exit;
 	}
 
+	/* always add /dev/{block,char}/$major:$minor */
+	snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
+		 udev_get_dev_path(udev),
+		 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
+		 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
+	node_symlink(udev, udev_device_get_devnode(dev), filename);
+
 	/* create/update symlinks, add symlinks to name index */
 	udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
-		if (udev_list_entry_get_flags(list_entry))
+		if (udev_list_entry_get_num(list_entry))
 			/* simple unmanaged link name */
 			node_symlink(udev, udev_device_get_devnode(dev), udev_list_entry_get_name(list_entry));
 		else
@@ -396,6 +405,7 @@ int udev_node_remove(struct udev_device *dev)
 	const char *devnode;
 	struct stat stats;
 	struct udev_device *dev_check;
+	char filename[UTIL_PATH_SIZE];
 	int err = 0;
 
 	/* remove/update symlinks, remove symlinks from name index */
@@ -417,6 +427,11 @@ int udev_node_remove(struct udev_device *dev)
 		goto out;
 	}
 
+	if (stats.st_mode & 01000) {
+		info(udev, "device node '%s' has sticky bit set, skip removal\n", devnode);
+		goto out;
+	}
+
 	dev_check = udev_device_new_from_syspath(udev, udev_device_get_syspath(dev));
 	if (dev_check != NULL) {
 		/* do not remove device node if the same sys-device is re-created in the meantime */
@@ -427,7 +442,15 @@ int udev_node_remove(struct udev_device *dev)
 
 	info(udev, "removing device node '%s'\n", devnode);
 	err = util_unlink_secure(udev, devnode);
-	util_delete_path(udev, devnode);
+	if (err == 0)
+		util_delete_path(udev, devnode);
+
+	/* remove /dev/{block,char}/$major:$minor */
+	snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
+		 udev_get_dev_path(udev),
+		 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
+		 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
+	unlink(filename);
 out:
 	return err;
 }