1 files changed, 103 insertions, 131 deletions

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 6cd5bb0ba380..896acad1f5f7 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -35,6 +35,7 @@
 /* selinuxfs pseudo filesystem for exporting the security policy API.
    Based on the proc code and the fs/nfsd/nfsctl.c code. */
 
+#include "initcalls.h"
 #include "flask.h"
 #include "avc.h"
 #include "avc_ss.h"
@@ -75,7 +76,6 @@ struct selinux_fs_info {
 	struct dentry *class_dir;
 	unsigned long last_class_ino;
 	bool policy_opened;
-	struct dentry *policycap_dir;
 	unsigned long last_ino;
 	struct super_block *sb;
 };
@@ -117,7 +117,6 @@ static void selinux_fs_info_free(struct super_block *sb)
 
 #define BOOL_DIR_NAME "booleans"
 #define CLASS_DIR_NAME "class"
-#define POLICYCAP_DIR_NAME "policy_capabilities"
 
 #define TMPBUFLEN	12
 static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
@@ -506,6 +505,7 @@ static int sel_make_policy_nodes(struct selinux_fs_info *fsi,
 {
 	int ret = 0;
 	struct dentry *tmp_parent, *tmp_bool_dir, *tmp_class_dir;
+	struct renamedata rd = {};
 	unsigned int bool_num = 0;
 	char **bool_names = NULL;
 	int *bool_values = NULL;
@@ -539,9 +539,14 @@ static int sel_make_policy_nodes(struct selinux_fs_info *fsi,
 	if (ret)
 		goto out;
 
-	lock_rename(tmp_parent, fsi->sb->s_root);
+	rd.old_parent = tmp_parent;
+	rd.new_parent = fsi->sb->s_root;
 
 	/* booleans */
+	ret = start_renaming_two_dentries(&rd, tmp_bool_dir, fsi->bool_dir);
+	if (ret)
+		goto out;
+
 	d_exchange(tmp_bool_dir, fsi->bool_dir);
 
 	swap(fsi->bool_num, bool_num);
@@ -549,12 +554,17 @@ static int sel_make_policy_nodes(struct selinux_fs_info *fsi,
 	swap(fsi->bool_pending_values, bool_values);
 
 	fsi->bool_dir = tmp_bool_dir;
+	end_renaming(&rd);
 
 	/* classes */
+	ret = start_renaming_two_dentries(&rd, tmp_class_dir, fsi->class_dir);
+	if (ret)
+		goto out;
+
 	d_exchange(tmp_class_dir, fsi->class_dir);
 	fsi->class_dir = tmp_class_dir;
 
-	unlock_rename(tmp_parent, fsi->sb->s_root);
+	end_renaming(&rd);
 
 out:
 	sel_remove_old_bool_data(bool_num, bool_names, bool_values);
@@ -1072,6 +1082,7 @@ static ssize_t sel_write_user(struct file *file, char *buf, size_t size)
 	pr_warn_ratelimited("SELinux: %s (%d) wrote to /sys/fs/selinux/user!"
 		" This will not be supported in the future; please update your"
 		" userspace.\n", current->comm, current->pid);
+	ssleep(5);
 
 	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 			      SECCLASS_SECURITY, SECURITY__COMPUTE_USER,
@@ -1198,11 +1209,31 @@ static struct inode *sel_make_inode(struct super_block *sb, umode_t mode)
 	return ret;
 }
 
+static struct dentry *sel_attach(struct dentry *parent, const char *name,
+				 struct inode *inode)
+{
+	struct dentry *dentry = d_alloc_name(parent, name);
+	if (unlikely(!dentry)) {
+		iput(inode);
+		return ERR_PTR(-ENOMEM);
+	}
+	d_make_persistent(dentry, inode);
+	dput(dentry);
+	return dentry;
+}
+
+static int sel_attach_file(struct dentry *parent, const char *name,
+			   struct inode *inode)
+{
+	struct dentry *dentry = sel_attach(parent, name, inode);
+	return PTR_ERR_OR_ZERO(dentry);
+}
+
 static ssize_t sel_read_bool(struct file *filep, char __user *buf,
 			     size_t count, loff_t *ppos)
 {
 	struct selinux_fs_info *fsi = file_inode(filep)->i_sb->s_fs_info;
-	char *page = NULL;
+	char buffer[4];
 	ssize_t length;
 	ssize_t ret;
 	int cur_enforcing;
@@ -1216,27 +1247,19 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf,
 					     fsi->bool_pending_names[index]))
 		goto out_unlock;
 
-	ret = -ENOMEM;
-	page = (char *)get_zeroed_page(GFP_KERNEL);
-	if (!page)
-		goto out_unlock;
-
 	cur_enforcing = security_get_bool_value(index);
 	if (cur_enforcing < 0) {
 		ret = cur_enforcing;
 		goto out_unlock;
 	}
-	length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
-			  fsi->bool_pending_values[index]);
+	length = scnprintf(buffer, sizeof(buffer), "%d %d", !!cur_enforcing,
+			  !!fsi->bool_pending_values[index]);
 	mutex_unlock(&selinux_state.policy_mutex);
-	ret = simple_read_from_buffer(buf, count, ppos, page, length);
-out_free:
-	free_page((unsigned long)page);
-	return ret;
+	return simple_read_from_buffer(buf, count, ppos, buffer, length);
 
 out_unlock:
 	mutex_unlock(&selinux_state.policy_mutex);
-	goto out_free;
+	return ret;
 }
 
 static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
@@ -1365,8 +1388,7 @@ static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_
 	*bool_num = num;
 	*bool_pending_names = names;
 
-	for (i = 0; i < num; i++) {
-		struct dentry *dentry;
+	for (i = 0; !ret && i < num; i++) {
 		struct inode *inode;
 		struct inode_security_struct *isec;
 		ssize_t len;
@@ -1377,15 +1399,9 @@ static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_
 			ret = -ENAMETOOLONG;
 			break;
 		}
-		dentry = d_alloc_name(bool_dir, names[i]);
-		if (!dentry) {
-			ret = -ENOMEM;
-			break;
-		}
 
 		inode = sel_make_inode(bool_dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
 		if (!inode) {
-			dput(dentry);
 			ret = -ENOMEM;
 			break;
 		}
@@ -1403,7 +1419,8 @@ static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_
 		isec->initialized = LABEL_INITIALIZED;
 		inode->i_fop = &sel_bool_ops;
 		inode->i_ino = i|SEL_BOOL_INO_OFFSET;
-		d_add(dentry, inode);
+
+		ret = sel_attach_file(bool_dir, names[i], inode);
 	}
 out:
 	free_page((unsigned long)page);
@@ -1515,7 +1532,7 @@ static const struct file_operations sel_avc_hash_stats_ops = {
 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
 static struct avc_cache_stats *sel_avc_get_stat_idx(loff_t *idx)
 {
-	int cpu;
+	loff_t cpu;
 
 	for (cpu = *idx; cpu < nr_cpu_ids; ++cpu) {
 		if (!cpu_possible(cpu))
@@ -1588,6 +1605,7 @@ static int sel_make_avc_files(struct dentry *dir)
 	struct super_block *sb = dir->d_sb;
 	struct selinux_fs_info *fsi = sb->s_fs_info;
 	unsigned int i;
+	int err = 0;
 	static const struct tree_descr files[] = {
 		{ "cache_threshold",
 		  &sel_avc_cache_threshold_ops, S_IRUGO|S_IWUSR },
@@ -1597,26 +1615,20 @@ static int sel_make_avc_files(struct dentry *dir)
 #endif
 	};
 
-	for (i = 0; i < ARRAY_SIZE(files); i++) {
+	for (i = 0; !err && i < ARRAY_SIZE(files); i++) {
 		struct inode *inode;
-		struct dentry *dentry;
-
-		dentry = d_alloc_name(dir, files[i].name);
-		if (!dentry)
-			return -ENOMEM;
 
 		inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
-		if (!inode) {
-			dput(dentry);
+		if (!inode)
 			return -ENOMEM;
-		}
 
 		inode->i_fop = files[i].ops;
 		inode->i_ino = ++fsi->last_ino;
-		d_add(dentry, inode);
+
+		err = sel_attach_file(dir, files[i].name, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static int sel_make_ss_files(struct dentry *dir)
@@ -1624,30 +1636,25 @@ static int sel_make_ss_files(struct dentry *dir)
 	struct super_block *sb = dir->d_sb;
 	struct selinux_fs_info *fsi = sb->s_fs_info;
 	unsigned int i;
+	int err = 0;
 	static const struct tree_descr files[] = {
 		{ "sidtab_hash_stats", &sel_sidtab_hash_stats_ops, S_IRUGO },
 	};
 
-	for (i = 0; i < ARRAY_SIZE(files); i++) {
+	for (i = 0; !err && i < ARRAY_SIZE(files); i++) {
 		struct inode *inode;
-		struct dentry *dentry;
-
-		dentry = d_alloc_name(dir, files[i].name);
-		if (!dentry)
-			return -ENOMEM;
 
 		inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
-		if (!inode) {
-			dput(dentry);
+		if (!inode)
 			return -ENOMEM;
-		}
 
 		inode->i_fop = files[i].ops;
 		inode->i_ino = ++fsi->last_ino;
-		d_add(dentry, inode);
+
+		err = sel_attach_file(dir, files[i].name, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static ssize_t sel_read_initcon(struct file *file, char __user *buf,
@@ -1675,30 +1682,25 @@ static const struct file_operations sel_initcon_ops = {
 static int sel_make_initcon_files(struct dentry *dir)
 {
 	unsigned int i;
+	int err = 0;
 
-	for (i = 1; i <= SECINITSID_NUM; i++) {
-		struct inode *inode;
-		struct dentry *dentry;
+	for (i = 1; !err && i <= SECINITSID_NUM; i++) {
 		const char *s = security_get_initial_sid_context(i);
+		struct inode *inode;
 
 		if (!s)
 			continue;
-		dentry = d_alloc_name(dir, s);
-		if (!dentry)
-			return -ENOMEM;
 
 		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
-		if (!inode) {
-			dput(dentry);
+		if (!inode)
 			return -ENOMEM;
-		}
 
 		inode->i_fop = &sel_initcon_ops;
 		inode->i_ino = i|SEL_INITCON_INO_OFFSET;
-		d_add(dentry, inode);
+		err = sel_attach_file(dir, s, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static inline unsigned long sel_class_to_ino(u16 class)
@@ -1780,29 +1782,21 @@ static int sel_make_perm_files(struct selinux_policy *newpolicy,
 	if (rc)
 		return rc;
 
-	for (i = 0; i < nperms; i++) {
+	for (i = 0; !rc && i < nperms; i++) {
 		struct inode *inode;
-		struct dentry *dentry;
-
-		rc = -ENOMEM;
-		dentry = d_alloc_name(dir, perms[i]);
-		if (!dentry)
-			goto out;
 
-		rc = -ENOMEM;
 		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
 		if (!inode) {
-			dput(dentry);
-			goto out;
+			rc = -ENOMEM;
+			break;
 		}
 
 		inode->i_fop = &sel_perm_ops;
 		/* i+1 since perm values are 1-indexed */
 		inode->i_ino = sel_perm_to_ino(classvalue, i + 1);
-		d_add(dentry, inode);
+
+		rc = sel_attach_file(dir, perms[i], inode);
 	}
-	rc = 0;
-out:
 	for (i = 0; i < nperms; i++)
 		kfree(perms[i]);
 	kfree(perms);
@@ -1817,20 +1811,18 @@ static int sel_make_class_dir_entries(struct selinux_policy *newpolicy,
 	struct selinux_fs_info *fsi = sb->s_fs_info;
 	struct dentry *dentry = NULL;
 	struct inode *inode = NULL;
-
-	dentry = d_alloc_name(dir, "index");
-	if (!dentry)
-		return -ENOMEM;
+	int err;
 
 	inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
-	if (!inode) {
-		dput(dentry);
+	if (!inode)
 		return -ENOMEM;
-	}
 
 	inode->i_fop = &sel_class_ops;
 	inode->i_ino = sel_class_to_ino(index);
-	d_add(dentry, inode);
+
+	err = sel_attach_file(dir, "index", inode);
+	if (err)
+		return err;
 
 	dentry = sel_make_dir(dir, "perms", &fsi->last_class_ino);
 	if (IS_ERR(dentry))
@@ -1878,61 +1870,51 @@ out:
 	return rc;
 }
 
-static int sel_make_policycap(struct selinux_fs_info *fsi)
+static int sel_make_policycap(struct dentry *dir)
 {
+	struct super_block *sb = dir->d_sb;
 	unsigned int iter;
-	struct dentry *dentry = NULL;
 	struct inode *inode = NULL;
+	int err = 0;
+
+	for (iter = 0; !err && iter <= POLICYDB_CAP_MAX; iter++) {
+		const char *name;
 
-	for (iter = 0; iter <= POLICYDB_CAP_MAX; iter++) {
 		if (iter < ARRAY_SIZE(selinux_policycap_names))
-			dentry = d_alloc_name(fsi->policycap_dir,
-					      selinux_policycap_names[iter]);
+			name = selinux_policycap_names[iter];
 		else
-			dentry = d_alloc_name(fsi->policycap_dir, "unknown");
+			name = "unknown";
 
-		if (dentry == NULL)
+		inode = sel_make_inode(sb, S_IFREG | 0444);
+		if (!inode)
 			return -ENOMEM;
 
-		inode = sel_make_inode(fsi->sb, S_IFREG | 0444);
-		if (inode == NULL) {
-			dput(dentry);
-			return -ENOMEM;
-		}
-
 		inode->i_fop = &sel_policycap_ops;
 		inode->i_ino = iter | SEL_POLICYCAP_INO_OFFSET;
-		d_add(dentry, inode);
+		err = sel_attach_file(dir, name, inode);
 	}
 
-	return 0;
+	return err;
 }
 
 static struct dentry *sel_make_dir(struct dentry *dir, const char *name,
 			unsigned long *ino)
 {
-	struct dentry *dentry = d_alloc_name(dir, name);
 	struct inode *inode;
 
-	if (!dentry)
-		return ERR_PTR(-ENOMEM);
-
 	inode = sel_make_inode(dir->d_sb, S_IFDIR | S_IRUGO | S_IXUGO);
-	if (!inode) {
-		dput(dentry);
+	if (!inode)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	inode->i_op = &simple_dir_inode_operations;
 	inode->i_fop = &simple_dir_operations;
 	inode->i_ino = ++(*ino);
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
-	d_add(dentry, inode);
 	/* bump link count on parent directory, too */
 	inc_nlink(d_inode(dir));
 
-	return dentry;
+	return sel_attach(dir, name, inode);
 }
 
 static int reject_all(struct mnt_idmap *idmap, struct inode *inode, int mask)
@@ -1965,10 +1947,11 @@ static struct dentry *sel_make_swapover_dir(struct super_block *sb,
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
 	inode_lock(sb->s_root->d_inode);
-	d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
 	inc_nlink(sb->s_root->d_inode);
 	inode_unlock(sb->s_root->d_inode);
-	return dentry;
+	dput(dentry);
+	return dentry;	// borrowed
 }
 
 #define NULL_FILE_NAME "null"
@@ -2001,7 +1984,7 @@ static int sel_fill_super(struct super_block *sb, struct fs_context *fc)
 		[SEL_POLICY] = {"policy", &sel_policy_ops, S_IRUGO},
 		[SEL_VALIDATE_TRANS] = {"validatetrans", &sel_transition_ops,
 					S_IWUGO},
-		/* last one */ {""}
+		/* last one */ {"", NULL, 0}
 	};
 
 	ret = selinux_fs_info_create(sb);
@@ -2021,16 +2004,9 @@ static int sel_fill_super(struct super_block *sb, struct fs_context *fc)
 	}
 
 	ret = -ENOMEM;
-	dentry = d_alloc_name(sb->s_root, NULL_FILE_NAME);
-	if (!dentry)
-		goto err;
-
-	ret = -ENOMEM;
 	inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
-	if (!inode) {
-		dput(dentry);
+	if (!inode)
 		goto err;
-	}
 
 	inode->i_ino = ++fsi->last_ino;
 	isec = selinux_inode(inode);
@@ -2039,7 +2015,9 @@ static int sel_fill_super(struct super_block *sb, struct fs_context *fc)
 	isec->initialized = LABEL_INITIALIZED;
 
 	init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
-	d_add(dentry, inode);
+	ret = sel_attach_file(sb->s_root, NULL_FILE_NAME, inode);
+	if (ret)
+		goto err;
 
 	dentry = sel_make_dir(sb->s_root, "avc", &fsi->last_ino);
 	if (IS_ERR(dentry)) {
@@ -2078,15 +2056,13 @@ static int sel_fill_super(struct super_block *sb, struct fs_context *fc)
 		goto err;
 	}
 
-	fsi->policycap_dir = sel_make_dir(sb->s_root, POLICYCAP_DIR_NAME,
-					  &fsi->last_ino);
-	if (IS_ERR(fsi->policycap_dir)) {
-		ret = PTR_ERR(fsi->policycap_dir);
-		fsi->policycap_dir = NULL;
+	dentry = sel_make_dir(sb->s_root, "policy_capabilities", &fsi->last_ino);
+	if (IS_ERR(dentry)) {
+		ret = PTR_ERR(dentry);
 		goto err;
 	}
 
-	ret = sel_make_policycap(fsi);
+	ret = sel_make_policycap(dentry);
 	if (ret) {
 		pr_err("SELinux: failed to load policy capabilities\n");
 		goto err;
@@ -2097,8 +2073,6 @@ err:
 	pr_err("SELinux: %s:  failed while creating inodes\n",
 		__func__);
 
-	selinux_fs_info_free(sb);
-
 	return ret;
 }
 
@@ -2120,7 +2094,7 @@ static int sel_init_fs_context(struct fs_context *fc)
 static void sel_kill_sb(struct super_block *sb)
 {
 	selinux_fs_info_free(sb);
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 }
 
 static struct file_system_type sel_fs_type = {
@@ -2131,7 +2105,7 @@ static struct file_system_type sel_fs_type = {
 
 struct path selinux_null __ro_after_init;
 
-static int __init init_sel_fs(void)
+int __init init_sel_fs(void)
 {
 	struct qstr null_name = QSTR_INIT(NULL_FILE_NAME,
 					  sizeof(NULL_FILE_NAME)-1);
@@ -2158,8 +2132,8 @@ static int __init init_sel_fs(void)
 		return err;
 	}
 
-	selinux_null.dentry = d_hash_and_lookup(selinux_null.mnt->mnt_root,
-						&null_name);
+	selinux_null.dentry = try_lookup_noperm(&null_name,
+						  selinux_null.mnt->mnt_root);
 	if (IS_ERR(selinux_null.dentry)) {
 		pr_err("selinuxfs:  could not lookup null!\n");
 		err = PTR_ERR(selinux_null.dentry);
@@ -2175,5 +2149,3 @@ static int __init init_sel_fs(void)
 
 	return err;
 }
-
-__initcall(init_sel_fs);