[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / symlink.c

/*
 *  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"

#ifdef CONFIG_EXT4_FS_ENCRYPTION
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 ext4_str cstr, pstr;
	struct ext4_encrypted_symlink_data *sd;
	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
	int res;
	u32 plen, max_size = inode->i_sb->s_blocksize;

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

	res = ext4_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);
		caddr[size] = 0;
	}

	/* Symlink is encrypted */
	sd = (struct ext4_encrypted_symlink_data *)caddr;
	cstr.name = sd->encrypted_path;
	cstr.len  = le16_to_cpu(sd->len);
	if ((cstr.len +
	     sizeof(struct ext4_encrypted_symlink_data) - 1) >
	    max_size) {
		/* Symlink data on the disk is corrupted */
		res = -EFSCORRUPTED;
		goto errout;
	}
	plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
		EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
	paddr = kmalloc(plen + 1, GFP_NOFS);
	if (!paddr) {
		res = -ENOMEM;
		goto errout;
	}
	pstr.name = paddr;
	pstr.len = plen;
	res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
	if (res < 0)
		goto errout;
	/* Null-terminate the name */
	if (res <= plen)
		paddr[res] = '\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 = {
	.readlink	= generic_readlink,
	.get_link	= ext4_encrypted_get_link,
	.setattr	= ext4_setattr,
	.setxattr	= generic_setxattr,
	.getxattr	= generic_getxattr,
	.listxattr	= ext4_listxattr,
	.removexattr	= generic_removexattr,
};
#endif

const struct inode_operations ext4_symlink_inode_operations = {
	.readlink	= generic_readlink,
	.get_link	= page_get_link,
	.setattr	= ext4_setattr,
	.setxattr	= generic_setxattr,
	.getxattr	= generic_getxattr,
	.listxattr	= ext4_listxattr,
	.removexattr	= generic_removexattr,
};

const struct inode_operations ext4_fast_symlink_inode_operations = {
	.readlink	= generic_readlink,
	.get_link	= simple_get_link,
	.setattr	= ext4_setattr,
	.setxattr	= generic_setxattr,
	.getxattr	= generic_getxattr,
	.listxattr	= ext4_listxattr,
	.removexattr	= generic_removexattr,
};
Commit	Line	Data
ac27a0ec	1	/*
617ba13b	2	* linux/fs/ext4/symlink.c
ac27a0ec DK	3	*
	4	* Only fast symlinks left here - the rest is done by generic code. AV, 1999
	5	*
	6	* Copyright (C) 1992, 1993, 1994, 1995
	7	* Remy Card (card@masi.ibp.fr)
	8	* Laboratoire MASI - Institut Blaise Pascal
	9	* Universite Pierre et Marie Curie (Paris VI)
	10	*
	11	* from
	12	*
	13	* linux/fs/minix/symlink.c
	14	*
	15	* Copyright (C) 1991, 1992 Linus Torvalds
	16	*
617ba13b	17	* ext4 symlink handling code
ac27a0ec DK	18	*/
	19
	20	#include <linux/fs.h>
ac27a0ec	21	#include <linux/namei.h>
3dcf5451	22	#include "ext4.h"
ac27a0ec DK	23	#include "xattr.h"
ac27a0ec DK	24
f348c252	25	#ifdef CONFIG_EXT4_FS_ENCRYPTION
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;
	32	struct ext4_str cstr, pstr;
f348c252 TT	33	struct ext4_encrypted_symlink_data *sd;
	34	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
	35	int res;
	36	u32 plen, max_size = inode->i_sb->s_blocksize;
	37
6b255391 AV	38	if (!dentry)
	39	return ERR_PTR(-ECHILD);
	40
c936e1ec	41	res = ext4_get_encryption_info(inode);
b7236e21 TT	42	if (res)
b7236e21 TT	43	return ERR_PTR(res);
f348c252 TT	44
f348c252 TT	45	if (ext4_inode_is_fast_symlink(inode)) {
9ec3a646 LT	46	caddr = (char *) EXT4_I(inode)->i_data;
9ec3a646 LT	47	max_size = sizeof(EXT4_I(inode)->i_data);
f348c252 TT	48	} else {
f348c252 TT	49	cpage = read_mapping_page(inode->i_mapping, 0, NULL);
b7236e21	50	if (IS_ERR(cpage))
680baacb	51	return ERR_CAST(cpage);
21fc61c7	52	caddr = page_address(cpage);
f348c252 TT	53	caddr[size] = 0;
	54	}
	55
	56	/* Symlink is encrypted */
	57	sd = (struct ext4_encrypted_symlink_data *)caddr;
	58	cstr.name = sd->encrypted_path;
5a1c7f47	59	cstr.len = le16_to_cpu(sd->len);
f348c252 TT	60	if ((cstr.len +
	61	sizeof(struct ext4_encrypted_symlink_data) - 1) >
	62	max_size) {
	63	/* Symlink data on the disk is corrupted */
6a797d27	64	res = -EFSCORRUPTED;
f348c252 TT	65	goto errout;
	66	}
	67	plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
	68	EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
	69	paddr = kmalloc(plen + 1, GFP_NOFS);
	70	if (!paddr) {
	71	res = -ENOMEM;
	72	goto errout;
	73	}
	74	pstr.name = paddr;
d2299590	75	pstr.len = plen;
b7236e21	76	res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
f348c252 TT	77	if (res < 0)
	78	goto errout;
	79	/* Null-terminate the name */
	80	if (res <= plen)
	81	paddr[res] = '\0';
21fc61c7	82	if (cpage)
09cbfeaf	83	put_page(cpage);
fceef393 AV	84	set_delayed_call(done, kfree_link, paddr);
fceef393 AV	85	return paddr;
f348c252	86	errout:
21fc61c7	87	if (cpage)
09cbfeaf	88	put_page(cpage);
f348c252 TT	89	kfree(paddr);
	90	return ERR_PTR(res);
	91	}
	92
a7a67e8a AV	93	const struct inode_operations ext4_encrypted_symlink_inode_operations = {
a7a67e8a AV	94	.readlink = generic_readlink,
6b255391	95	.get_link = ext4_encrypted_get_link,
a7a67e8a AV	96	.setattr = ext4_setattr,
	97	.setxattr = generic_setxattr,
	98	.getxattr = generic_getxattr,
	99	.listxattr = ext4_listxattr,
	100	.removexattr = generic_removexattr,
	101	};
f348c252 TT	102	#endif
f348c252 TT	103
754661f1	104	const struct inode_operations ext4_symlink_inode_operations = {
ac27a0ec	105	.readlink = generic_readlink,
6b255391	106	.get_link = page_get_link,
256a4535	107	.setattr = ext4_setattr,
ac27a0ec DK	108	.setxattr = generic_setxattr,
ac27a0ec DK	109	.getxattr = generic_getxattr,
617ba13b	110	.listxattr = ext4_listxattr,
ac27a0ec	111	.removexattr = generic_removexattr,
ac27a0ec DK	112	};
ac27a0ec DK	113
754661f1	114	const struct inode_operations ext4_fast_symlink_inode_operations = {
ac27a0ec	115	.readlink = generic_readlink,
6b255391	116	.get_link = simple_get_link,
256a4535	117	.setattr = ext4_setattr,
ac27a0ec DK	118	.setxattr = generic_setxattr,
ac27a0ec DK	119	.getxattr = generic_getxattr,
617ba13b	120	.listxattr = ext4_listxattr,
ac27a0ec	121	.removexattr = generic_removexattr,
ac27a0ec	122	};