[linux-2.6-block.git] / fs / ext4 / symlink.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ext4/symlink.c
 *
 * Only fast symlinks left here - the rest is done by generic code. AV, 1999
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/symlink.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  ext4 symlink handling code
 */

#include <linux/fs.h>
#include <linux/namei.h>
#include "ext4.h"
#include "xattr.h"

static const char *ext4_encrypted_get_link(struct dentry *dentry,
					   struct inode *inode,
					   struct delayed_call *done)
{
	struct page *cpage = NULL;
	char *caddr, *paddr = NULL;
	struct fscrypt_str cstr, pstr;
	struct fscrypt_symlink_data *sd;
	int res;
	u32 max_size = inode->i_sb->s_blocksize;

	if (!dentry)
		return ERR_PTR(-ECHILD);

	res = fscrypt_get_encryption_info(inode);
	if (res)
		return ERR_PTR(res);

	if (ext4_inode_is_fast_symlink(inode)) {
		caddr = (char *) EXT4_I(inode)->i_data;
		max_size = sizeof(EXT4_I(inode)->i_data);
	} else {
		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
		if (IS_ERR(cpage))
			return ERR_CAST(cpage);
		caddr = page_address(cpage);
	}

	/* Symlink is encrypted */
	sd = (struct fscrypt_symlink_data *)caddr;
	cstr.name = sd->encrypted_path;
	cstr.len  = le16_to_cpu(sd->len);
	if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > max_size) {
		/* Symlink data on the disk is corrupted */
		res = -EFSCORRUPTED;
		goto errout;
	}

	res = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr);
	if (res)
		goto errout;
	paddr = pstr.name;

	res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
	if (res)
		goto errout;

	/* Null-terminate the name */
	paddr[pstr.len] = '\0';
	if (cpage)
		put_page(cpage);
	set_delayed_call(done, kfree_link, paddr);
	return paddr;
errout:
	if (cpage)
		put_page(cpage);
	kfree(paddr);
	return ERR_PTR(res);
}

const struct inode_operations ext4_encrypted_symlink_inode_operations = {
	.get_link	= ext4_encrypted_get_link,
	.setattr	= ext4_setattr,
	.getattr	= ext4_getattr,
	.listxattr	= ext4_listxattr,
};

const struct inode_operations ext4_symlink_inode_operations = {
	.get_link	= page_get_link,
	.setattr	= ext4_setattr,
	.getattr	= ext4_getattr,
	.listxattr	= ext4_listxattr,
};

const struct inode_operations ext4_fast_symlink_inode_operations = {
	.get_link	= simple_get_link,
	.setattr	= ext4_setattr,
	.getattr	= ext4_getattr,
	.listxattr	= ext4_listxattr,
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
ac27a0ec	2	/*
617ba13b	3	* linux/fs/ext4/symlink.c
ac27a0ec DK	4	*
	5	* Only fast symlinks left here - the rest is done by generic code. AV, 1999
	6	*
	7	* Copyright (C) 1992, 1993, 1994, 1995
	8	* Remy Card (card@masi.ibp.fr)
	9	* Laboratoire MASI - Institut Blaise Pascal
	10	* Universite Pierre et Marie Curie (Paris VI)
	11	*
	12	* from
	13	*
	14	* linux/fs/minix/symlink.c
	15	*
	16	* Copyright (C) 1991, 1992 Linus Torvalds
	17	*
617ba13b	18	* ext4 symlink handling code
ac27a0ec DK	19	*/
	20
	21	#include <linux/fs.h>
ac27a0ec	22	#include <linux/namei.h>
3dcf5451	23	#include "ext4.h"
ac27a0ec DK	24	#include "xattr.h"
ac27a0ec DK	25
6b255391	26	static const char ext4_encrypted_get_link(struct dentry dentry,
fceef393 AV	27	struct inode *inode,
fceef393 AV	28	struct delayed_call *done)
f348c252 TT	29	{
	30	struct page *cpage = NULL;
	31	char caddr, paddr = NULL;
a7550b30 JK	32	struct fscrypt_str cstr, pstr;
a7550b30 JK	33	struct fscrypt_symlink_data *sd;
f348c252	34	int res;
a7550b30	35	u32 max_size = inode->i_sb->s_blocksize;
f348c252	36
6b255391 AV	37	if (!dentry)
	38	return ERR_PTR(-ECHILD);
	39
a7550b30	40	res = fscrypt_get_encryption_info(inode);
b7236e21 TT	41	if (res)
b7236e21 TT	42	return ERR_PTR(res);
f348c252 TT	43
f348c252 TT	44	if (ext4_inode_is_fast_symlink(inode)) {
9ec3a646 LT	45	caddr = (char *) EXT4_I(inode)->i_data;
9ec3a646 LT	46	max_size = sizeof(EXT4_I(inode)->i_data);
f348c252 TT	47	} else {
f348c252 TT	48	cpage = read_mapping_page(inode->i_mapping, 0, NULL);
b7236e21	49	if (IS_ERR(cpage))
680baacb	50	return ERR_CAST(cpage);
21fc61c7	51	caddr = page_address(cpage);
f348c252 TT	52	}
	53
	54	/* Symlink is encrypted */
a7550b30	55	sd = (struct fscrypt_symlink_data *)caddr;
f348c252	56	cstr.name = sd->encrypted_path;
5a1c7f47	57	cstr.len = le16_to_cpu(sd->len);
a7550b30	58	if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > max_size) {
f348c252	59	/* Symlink data on the disk is corrupted */
6a797d27	60	res = -EFSCORRUPTED;
f348c252 TT	61	goto errout;
f348c252 TT	62	}
a7550b30 JK	63
	64	res = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr);
	65	if (res)
f348c252	66	goto errout;
dcce7a46	67	paddr = pstr.name;
a7550b30 JK	68
a7550b30 JK	69	res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
ef1eb3aa	70	if (res)
f348c252	71	goto errout;
a7550b30	72
f348c252	73	/* Null-terminate the name */
ef1eb3aa	74	paddr[pstr.len] = '\0';
21fc61c7	75	if (cpage)
09cbfeaf	76	put_page(cpage);
fceef393 AV	77	set_delayed_call(done, kfree_link, paddr);
fceef393 AV	78	return paddr;
f348c252	79	errout:
21fc61c7	80	if (cpage)
09cbfeaf	81	put_page(cpage);
f348c252 TT	82	kfree(paddr);
	83	return ERR_PTR(res);
	84	}
	85
a7a67e8a	86	const struct inode_operations ext4_encrypted_symlink_inode_operations = {
6b255391	87	.get_link = ext4_encrypted_get_link,
a7a67e8a	88	.setattr = ext4_setattr,
99652ea5	89	.getattr = ext4_getattr,
a7a67e8a	90	.listxattr = ext4_listxattr,
a7a67e8a	91	};
f348c252	92
754661f1	93	const struct inode_operations ext4_symlink_inode_operations = {
6b255391	94	.get_link = page_get_link,
256a4535	95	.setattr = ext4_setattr,
99652ea5	96	.getattr = ext4_getattr,
617ba13b	97	.listxattr = ext4_listxattr,
ac27a0ec DK	98	};
ac27a0ec DK	99
754661f1	100	const struct inode_operations ext4_fast_symlink_inode_operations = {
6b255391	101	.get_link = simple_get_link,
256a4535	102	.setattr = ext4_setattr,
99652ea5	103	.getattr = ext4_getattr,
617ba13b	104	.listxattr = ext4_listxattr,
ac27a0ec	105	};