ubifs: Add support for encrypted symlinks

Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 54 insertions, 1 deletions

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 4c50f8feb0d5..aa0625f4f642 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1657,6 +1657,59 @@ static int ubifs_file_open(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static const char *ubifs_get_link(struct dentry *dentry,
+					    struct inode *inode,
+					    struct delayed_call *done)
+{
+	int err;
+	struct fscrypt_symlink_data *sd;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	struct fscrypt_str cstr;
+	struct fscrypt_str pstr;
+
+	if (!ubifs_crypt_is_encrypted(inode))
+		return ui->data;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	err = fscrypt_get_encryption_info(inode);
+	if (err)
+		return ERR_PTR(err);
+
+	sd = (struct fscrypt_symlink_data *)ui->data;
+	cstr.name = sd->encrypted_path;
+	cstr.len = le16_to_cpu(sd->len);
+
+	if (cstr.len == 0)
+		return ERR_PTR(-ENOENT);
+
+	if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > ui->data_len)
+		return ERR_PTR(-EIO);
+
+	err = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr);
+	if (err)
+		return ERR_PTR(err);
+
+	err = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
+	if (err) {
+		fscrypt_fname_free_buffer(&pstr);
+		return ERR_PTR(err);
+	}
+
+	pstr.name[pstr.len] = '\0';
+
+	// XXX this probably won't happen anymore...
+	if (pstr.name[0] == '\0') {
+		fscrypt_fname_free_buffer(&pstr);
+		return ERR_PTR(-ENOENT);
+	}
+
+	set_delayed_call(done, kfree_link, pstr.name);
+	return pstr.name;
+}
+
+
 const struct address_space_operations ubifs_file_address_operations = {
 	.readpage       = ubifs_readpage,
 	.writepage      = ubifs_writepage,
@@ -1681,7 +1734,7 @@ const struct inode_operations ubifs_file_inode_operations = {
 
 const struct inode_operations ubifs_symlink_inode_operations = {
 	.readlink    = generic_readlink,
-	.get_link    = simple_get_link,
+	.get_link    = ubifs_get_link,
 	.setattr     = ubifs_setattr,
 	.getattr     = ubifs_getattr,
 	.listxattr   = ubifs_listxattr,