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Commit cbaf042a authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs crypto: add symlink encryption 



This patch implements encryption support for symlink.

Signed-off-by: default avatarUday Savagaonkar <savagaon@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent e7d55452

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -1920,6 +1920,7 @@ extern const struct address_space_operations f2fs_node_aops; 
extern const struct address_space_operations f2fs_meta_aops;

extern const struct inode_operations f2fs_dir_inode_operations;

extern const struct inode_operations f2fs_symlink_inode_operations;

extern const struct inode_operations f2fs_encrypted_symlink_inode_operations;

extern const struct inode_operations f2fs_special_inode_operations;

extern struct kmem_cache *inode_entry_slab;

fs/f2fs/inode.c

+4 −1
Original line number Diff line number Diff line
@@ -198,6 +198,9 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) 
		inode->i_mapping->a_ops = &f2fs_dblock_aops;

		mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_HIGH_ZERO);

	} else if (S_ISLNK(inode->i_mode)) {

		if (f2fs_encrypted_inode(inode))

			inode->i_op = &f2fs_encrypted_symlink_inode_operations;

		else

			inode->i_op = &f2fs_symlink_inode_operations;

		inode->i_mapping->a_ops = &f2fs_dblock_aops;

	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||

fs/f2fs/namei.c

+137 −5
Original line number Diff line number Diff line
@@ -338,15 +338,25 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, 
{

	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);

	struct inode *inode;

	size_t symlen = strlen(symname) + 1;

	size_t len = strlen(symname);

	size_t p_len;

	char *p_str;

	struct f2fs_str disk_link = FSTR_INIT(NULL, 0);

	struct f2fs_encrypted_symlink_data *sd = NULL;

	int err;



	if (len > dir->i_sb->s_blocksize)

		return -ENAMETOOLONG;



	f2fs_balance_fs(sbi);



	inode = f2fs_new_inode(dir, S_IFLNK | S_IRWXUGO);

	if (IS_ERR(inode))

		return PTR_ERR(inode);



	if (f2fs_encrypted_inode(inode))

		inode->i_op = &f2fs_encrypted_symlink_inode_operations;

	else

		inode->i_op = &f2fs_symlink_inode_operations;

	inode->i_mapping->a_ops = &f2fs_dblock_aops;
@@ -355,10 +365,50 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, 
	if (err)

		goto out;

	f2fs_unlock_op(sbi);



	err = page_symlink(inode, symname, symlen);

	alloc_nid_done(sbi, inode->i_ino);



	if (f2fs_encrypted_inode(dir)) {

		struct qstr istr = QSTR_INIT(symname, len);



		err = f2fs_inherit_context(dir, inode, NULL);

		if (err)

			goto err_out;



		err = f2fs_setup_fname_crypto(inode);

		if (err)

			goto err_out;



		err = f2fs_fname_crypto_alloc_buffer(inode, len, &disk_link);

		if (err)

			goto err_out;



		err = f2fs_fname_usr_to_disk(inode, &istr, &disk_link);

		if (err < 0)

			goto err_out;



		p_len = encrypted_symlink_data_len(disk_link.len) + 1;



		if (p_len > dir->i_sb->s_blocksize) {

			err = -ENAMETOOLONG;

			goto err_out;

		}



		sd = kzalloc(p_len, GFP_NOFS);

		if (!sd) {

			err = -ENOMEM;

			goto err_out;

		}

		memcpy(sd->encrypted_path, disk_link.name, disk_link.len);

		sd->len = cpu_to_le16(disk_link.len);

		p_str = (char *)sd;

	} else {

		p_len = len + 1;

		p_str = (char *)symname;

	}



	err = page_symlink(inode, p_str, p_len);



err_out:

	d_instantiate(dentry, inode);

	unlock_new_inode(inode);
@@ -371,10 +421,14 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, 
	 * If the symlink path is stored into inline_data, there is no

	 * performance regression.

	 */

	filemap_write_and_wait_range(inode->i_mapping, 0, symlen - 1);

	if (!err)

		filemap_write_and_wait_range(inode->i_mapping, 0, p_len - 1);



	if (IS_DIRSYNC(dir))

		f2fs_sync_fs(sbi->sb, 1);



	kfree(sd);

	f2fs_fname_crypto_free_buffer(&disk_link);

	return err;

out:

	handle_failed_inode(inode);
@@ -818,6 +872,84 @@ static int f2fs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) 
	return err;

}



#ifdef CONFIG_F2FS_FS_ENCRYPTION

static void *f2fs_encrypted_follow_link(struct dentry *dentry,

						struct nameidata *nd)

{

	struct page *cpage = NULL;

	char *caddr, *paddr = NULL;

	struct f2fs_str cstr;

	struct f2fs_str pstr = FSTR_INIT(NULL, 0);

	struct inode *inode = d_inode(dentry);

	struct f2fs_encrypted_symlink_data *sd;

	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);

	u32 max_size = inode->i_sb->s_blocksize;

	int res;



	res = f2fs_setup_fname_crypto(inode);

	if (res)

		return ERR_PTR(res);



	cpage = read_mapping_page(inode->i_mapping, 0, NULL);

	if (IS_ERR(cpage))

		return cpage;

	caddr = kmap(cpage);

	caddr[size] = 0;



	/* Symlink is encrypted */

	sd = (struct f2fs_encrypted_symlink_data *)caddr;

	cstr.name = sd->encrypted_path;

	cstr.len = le16_to_cpu(sd->len);



	/* this is broken symlink case */

	if (cstr.name[0] == 0 && cstr.len == 0) {

		res = -ENOENT;

		goto errout;

	}



	if ((cstr.len + sizeof(struct f2fs_encrypted_symlink_data) - 1) >

								max_size) {

		/* Symlink data on the disk is corrupted */

		res = -EIO;

		goto errout;

	}

	res = f2fs_fname_crypto_alloc_buffer(inode, cstr.len, &pstr);

	if (res)

		goto errout;



	res = f2fs_fname_disk_to_usr(inode, NULL, &cstr, &pstr);

	if (res < 0)

		goto errout;



	paddr = pstr.name;



	/* Null-terminate the name */

	paddr[res] = '\0';

	nd_set_link(nd, paddr);



	kunmap(cpage);

	page_cache_release(cpage);

	return NULL;

errout:

	f2fs_fname_crypto_free_buffer(&pstr);

	kunmap(cpage);

	page_cache_release(cpage);

	return ERR_PTR(res);

}



const struct inode_operations f2fs_encrypted_symlink_inode_operations = {

	.readlink       = generic_readlink,

	.follow_link    = f2fs_encrypted_follow_link,

	.put_link       = kfree_put_link,

	.getattr	= f2fs_getattr,

	.setattr	= f2fs_setattr,

	.setxattr	= generic_setxattr,

	.getxattr	= generic_getxattr,

	.listxattr	= f2fs_listxattr,

	.removexattr	= generic_removexattr,

};

#endif



const struct inode_operations f2fs_dir_inode_operations = {

	.create		= f2fs_create,

	.lookup		= f2fs_lookup,