[1/1] Add security.selinux XATTR support for the UBIFS. Also fix couple of bugs in UBIFS extended attribute storage.

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 6834920..ef98495 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -253,6 +253,52 @@  out:
 	return ERR_PTR(err);
 }
 
+static void ubifs_init_security(struct dentry *dentry, struct inode *inode,
+		struct inode *dir)
+{
+	int err;
+	char *name;
+	void *value = NULL;
+	size_t len = 0;
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	const struct qstr *qname = &dentry->d_name;
+
+	mutex_lock(&dir_ui->ui_mutex);
+	mutex_lock(&dentry->d_inode->i_mutex);
+	err = security_inode_init_security(inode, dir, qname, &name, &value,
+		&len);
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			return;
+		ubifs_err("unable to retrieve security context, error %d", err);
+		mutex_unlock(&dentry->d_inode->i_mutex);
+		mutex_unlock(&dir_ui->ui_mutex);
+		return;
+	}
+
+	if (strncmp(name, "selinux", strlen("selinux")) == 0) {
+		kfree(name);
+		name = kstrdup("security.selinux", GFP_NOFS);
+		if (!name) {
+			ubifs_err("unable to set security context %.*s error",
+				dentry->d_name.len, dentry->d_name.name);
+			kfree(value);
+			mutex_unlock(&dentry->d_inode->i_mutex);
+			mutex_unlock(&dir_ui->ui_mutex);
+			return;
+		}
+	}
+
+	err = ubifs_setxattr(dentry, name, value, len, 0);
+	if (err)
+		ubifs_err("unable to set security context name %.*s error %d",
+			dentry->d_name.len, dentry->d_name.name, err);
+	kfree(name);
+	kfree(value);
+	mutex_unlock(&dentry->d_inode->i_mutex);
+	mutex_unlock(&dir_ui->ui_mutex);
+}
+
 static int ubifs_create(struct inode *dir, struct dentry *dentry, int mode,
 			struct nameidata *nd)
 {
@@ -293,6 +339,7 @@  static int ubifs_create(struct inode *dir, struct dentry *dentry, int mode,
 	ubifs_release_budget(c, &req);
 	insert_inode_hash(inode);
 	d_instantiate(dentry, inode);
+	ubifs_init_security(dentry, inode, dir);
 	return 0;
 
 out_cancel:
@@ -754,6 +801,7 @@  static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
 	ubifs_release_budget(c, &req);
 	d_instantiate(dentry, inode);
+	ubifs_init_security(dentry, inode, dir);
 	return 0;
 
 out_cancel:
@@ -831,6 +879,7 @@  static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
 	ubifs_release_budget(c, &req);
 	insert_inode_hash(inode);
 	d_instantiate(dentry, inode);
+	ubifs_init_security(dentry, inode, dir);
 	return 0;
 
 out_cancel:
@@ -907,6 +956,7 @@  static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 	ubifs_release_budget(c, &req);
 	insert_inode_hash(inode);
 	d_instantiate(dentry, inode);
+	ubifs_init_security(dentry, inode, dir);
 	return 0;
 
 out_cancel:
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index f9c234b..ba33491 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1575,6 +1575,12 @@  const struct inode_operations ubifs_symlink_inode_operations = {
 	.follow_link = ubifs_follow_link,
 	.setattr     = ubifs_setattr,
 	.getattr     = ubifs_getattr,
+#ifdef CONFIG_UBIFS_FS_XATTR
+	.setxattr    = ubifs_symlink_setxattr,
+	.getxattr    = ubifs_symlink_getxattr,
+	.listxattr   = ubifs_listxattr,
+	.removexattr = ubifs_removexattr,
+#endif
 };
 
 const struct file_operations ubifs_file_operations = {
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index cef0460..5e1ebdb 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -553,7 +553,8 @@  int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
 
 	dbg_jnl("ino %lu, dent '%.*s', data len %d in dir ino %lu",
 		inode->i_ino, nm->len, nm->name, ui->data_len, dir->i_ino);
-	ubifs_assert(dir_ui->data_len == 0);
+	if (!xent)
+		ubifs_assert(dir_ui->data_len == 0);
 	ubifs_assert(mutex_is_locked(&dir_ui->ui_mutex));
 
 	dlen = UBIFS_DENT_NODE_SZ + nm->len + 1;
@@ -572,7 +573,11 @@  int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
 
 	aligned_dlen = ALIGN(dlen, 8);
 	aligned_ilen = ALIGN(ilen, 8);
-	len = aligned_dlen + aligned_ilen + UBIFS_INO_NODE_SZ;
+	/* Make sure to account for dir_ui+data_len in length calculation
+	 * in case there is extended attribute.
+	*/
+	len = aligned_dlen + aligned_ilen + UBIFS_INO_NODE_SZ
+		+ dir_ui->data_len;
 	dent = kmalloc(len, GFP_NOFS);
 	if (!dent)
 		return -ENOMEM;
@@ -643,7 +648,7 @@  int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
 	 */
 	ino_key_init(c, &ino_key, inode->i_ino);
 	ino_offs = dent_offs + aligned_dlen;
-	err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen);
+	err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen+dir_ui->data_len);
 	if (err)
 		goto out_ro;
 
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index b281212..025e5d0 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2062,6 +2062,7 @@  static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 	if (c->max_inode_sz > MAX_LFS_FILESIZE)
 		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
 	sb->s_op = &ubifs_super_operations;
+	sb->s_xattr = ubifs_xattr_handlers;
 
 	mutex_lock(&c->umount_mutex);
 	err = mount_ubifs(c);
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 27f2255..1e00ec5 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -36,6 +36,7 @@ 
 #include <linux/mtd/ubi.h>
 #include <linux/pagemap.h>
 #include <linux/backing-dev.h>
+#include <linux/security.h>
 #include "ubifs-media.h"
 
 /* Version of this UBIFS implementation */
@@ -1457,6 +1458,7 @@  extern spinlock_t ubifs_infos_lock;
 extern atomic_long_t ubifs_clean_zn_cnt;
 extern struct kmem_cache *ubifs_inode_slab;
 extern const struct super_operations ubifs_super_operations;
+extern const struct xattr_handler *ubifs_xattr_handlers[];
 extern const struct address_space_operations ubifs_file_address_operations;
 extern const struct file_operations ubifs_file_operations;
 extern const struct inode_operations ubifs_file_inode_operations;
@@ -1741,8 +1743,12 @@  int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 /* xattr.c */
 int ubifs_setxattr(struct dentry *dentry, const char *name,
 		   const void *value, size_t size, int flags);
+int ubifs_symlink_setxattr(struct dentry *dentry, const char *name,
+		   const void *value, size_t size, int flags);
 ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
 		       size_t size);
+ssize_t ubifs_symlink_getxattr(struct dentry *dentry, const char *name,
+		       void *buf, size_t size);
 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 int ubifs_removexattr(struct dentry *dentry, const char *name);
 
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index 16f19f5..cfacab9 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -211,11 +211,11 @@  static int change_xattr(struct ubifs_info *c, struct inode *host,
 	}
 	memcpy(ui->data, value, size);
 	inode->i_size = ui->ui_size = size;
-	ui->data_len = size;
 
 	mutex_lock(&host_ui->ui_mutex);
 	host->i_ctime = ubifs_current_time(host);
 	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
+	ui->data_len = size;
 	host_ui->xattr_size += CALC_XATTR_BYTES(size);
 
 	/*
@@ -295,18 +295,16 @@  static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
 	return ERR_PTR(-EINVAL);
 }
 
-int ubifs_setxattr(struct dentry *dentry, const char *name,
+static int __ubifs_setxattr(struct inode *host, const char *name,
 		   const void *value, size_t size, int flags)
 {
-	struct inode *inode, *host = dentry->d_inode;
+	struct inode *inode;
 	struct ubifs_info *c = host->i_sb->s_fs_info;
 	struct qstr nm = { .name = name, .len = strlen(name) };
 	struct ubifs_dent_node *xent;
 	union ubifs_key key;
 	int err, type;
 
-	dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
-		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
 	ubifs_assert(mutex_is_locked(&host->i_mutex));
 
 	if (size > UBIFS_MAX_INO_DATA)
@@ -358,10 +356,29 @@  out_free:
 	return err;
 }
 
-ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
+int ubifs_symlink_setxattr(struct dentry *dentry, const char *name,
+		   const void *value, size_t size, int flags)
+{
+	struct inode *host = dentry->d_inode;
+	dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
+		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+	return __ubifs_setxattr(host, name, value, size, flags);
+}
+
+int ubifs_setxattr(struct dentry *dentry, const char *name,
+		   const void *value, size_t size, int flags)
+{
+	struct inode *host = dentry->d_inode;
+	dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
+		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+	return __ubifs_setxattr(host, name, value, size, flags);
+}
+
+static
+ssize_t __ubifs_getxattr(struct inode *host, const char *name, void *buf,
 		       size_t size)
 {
-	struct inode *inode, *host = dentry->d_inode;
+	struct inode *inode;
 	struct ubifs_info *c = host->i_sb->s_fs_info;
 	struct qstr nm = { .name = name, .len = strlen(name) };
 	struct ubifs_inode *ui;
@@ -369,9 +386,6 @@  ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
 	union ubifs_key key;
 	int err;
 
-	dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
-		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
-
 	err = check_namespace(&nm);
 	if (err < 0)
 		return err;
@@ -418,6 +432,25 @@  out_unlock:
 	return err;
 }
 
+ssize_t ubifs_symlink_getxattr(struct dentry *dentry, const char *name,
+		void *buf, size_t size)
+{
+	struct inode *host = dentry->d_inode;
+	dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
+		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+	return __ubifs_getxattr(host, name, buf, size);
+}
+
+ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
+		       size_t size)
+{
+	struct inode *host = dentry->d_inode;
+	dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
+		host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+	return __ubifs_getxattr(host, name, buf, size);
+}
+
+
 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 {
 	union ubifs_key key;
@@ -570,3 +603,47 @@  out_free:
 	kfree(xent);
 	return err;
 }
+
+size_t
+ubifs_security_listxattr(struct dentry *d, char *list, size_t list_size,
+		const char *name, size_t name_len, int flags)
+{
+	const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
+	const size_t total_len = prefix_len + name_len + 1;
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+
+int ubifs_security_getxattr(struct dentry *d, const char *name,
+		void *buffer, size_t size, int flags)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return __ubifs_getxattr(d->d_inode, XATTR_NAME_SELINUX, buffer, size);
+}
+
+int ubifs_security_setxattr(struct dentry *d, const char *name,
+	const void *value, size_t size, int flags, int handler_flags)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return __ubifs_setxattr(d->d_inode, XATTR_NAME_SELINUX, value,
+			size, flags);
+}
+
+struct xattr_handler ubifs_xattr_security_handler = {
+	.prefix = XATTR_SECURITY_PREFIX,
+	.list   = ubifs_security_listxattr,
+	.get    = ubifs_security_getxattr,
+	.set    = ubifs_security_setxattr,
+};
+
+const struct xattr_handler *ubifs_xattr_handlers[] = {
+	&ubifs_xattr_security_handler,
+	NULL
+};