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1/*
2 * linux/fs/ext4/symlink.c
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 *
17 * ext4 symlink handling code
18 */
19
20#include <linux/fs.h>
21#include <linux/namei.h>
22#include "ext4.h"
23#include "xattr.h"
24
25#ifdef CONFIG_EXT4_FS_ENCRYPTION
26static const char *ext4_encrypted_get_link(struct dentry *dentry,
27 struct inode *inode,
28 struct delayed_call *done)
29{
30 struct page *cpage = NULL;
31 char *caddr, *paddr = NULL;
32 struct ext4_str cstr, pstr;
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
38 if (!dentry)
39 return ERR_PTR(-ECHILD);
40
41 res = ext4_get_encryption_info(inode);
42 if (res)
43 return ERR_PTR(res);
44
45 if (ext4_inode_is_fast_symlink(inode)) {
46 caddr = (char *) EXT4_I(inode)->i_data;
47 max_size = sizeof(EXT4_I(inode)->i_data);
48 } else {
49 cpage = read_mapping_page(inode->i_mapping, 0, NULL);
50 if (IS_ERR(cpage))
51 return ERR_CAST(cpage);
52 caddr = page_address(cpage);
53 caddr[size] = 0;
54 }
55
56 /* Symlink is encrypted */
57 sd = (struct ext4_encrypted_symlink_data *)caddr;
58 cstr.name = sd->encrypted_path;
59 cstr.len = le16_to_cpu(sd->len);
60 if ((cstr.len +
61 sizeof(struct ext4_encrypted_symlink_data) - 1) >
62 max_size) {
63 /* Symlink data on the disk is corrupted */
64 res = -EFSCORRUPTED;
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;
75 pstr.len = plen;
76 res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
77 if (res < 0)
78 goto errout;
79 /* Null-terminate the name */
80 if (res <= plen)
81 paddr[res] = '\0';
82 if (cpage)
83 put_page(cpage);
84 set_delayed_call(done, kfree_link, paddr);
85 return paddr;
86errout:
87 if (cpage)
88 put_page(cpage);
89 kfree(paddr);
90 return ERR_PTR(res);
91}
92
93const struct inode_operations ext4_encrypted_symlink_inode_operations = {
94 .readlink = generic_readlink,
95 .get_link = ext4_encrypted_get_link,
96 .setattr = ext4_setattr,
97 .setxattr = generic_setxattr,
98 .getxattr = generic_getxattr,
99 .listxattr = ext4_listxattr,
100 .removexattr = generic_removexattr,
101};
102#endif
103
104const struct inode_operations ext4_symlink_inode_operations = {
105 .readlink = generic_readlink,
106 .get_link = page_get_link,
107 .setattr = ext4_setattr,
108 .setxattr = generic_setxattr,
109 .getxattr = generic_getxattr,
110 .listxattr = ext4_listxattr,
111 .removexattr = generic_removexattr,
112};
113
114const struct inode_operations ext4_fast_symlink_inode_operations = {
115 .readlink = generic_readlink,
116 .get_link = simple_get_link,
117 .setattr = ext4_setattr,
118 .setxattr = generic_setxattr,
119 .getxattr = generic_getxattr,
120 .listxattr = ext4_listxattr,
121 .removexattr = generic_removexattr,
122};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/symlink.c
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 *
18 * ext4 symlink handling code
19 */
20
21#include <linux/fs.h>
22#include <linux/namei.h>
23#include "ext4.h"
24#include "xattr.h"
25
26static const char *ext4_encrypted_get_link(struct dentry *dentry,
27 struct inode *inode,
28 struct delayed_call *done)
29{
30 struct buffer_head *bh = NULL;
31 const void *caddr;
32 unsigned int max_size;
33 const char *paddr;
34
35 if (!dentry)
36 return ERR_PTR(-ECHILD);
37
38 if (ext4_inode_is_fast_symlink(inode)) {
39 caddr = EXT4_I(inode)->i_data;
40 max_size = sizeof(EXT4_I(inode)->i_data);
41 } else {
42 bh = ext4_bread(NULL, inode, 0, 0);
43 if (IS_ERR(bh))
44 return ERR_CAST(bh);
45 if (!bh) {
46 EXT4_ERROR_INODE(inode, "bad symlink.");
47 return ERR_PTR(-EFSCORRUPTED);
48 }
49 caddr = bh->b_data;
50 max_size = inode->i_sb->s_blocksize;
51 }
52
53 paddr = fscrypt_get_symlink(inode, caddr, max_size, done);
54 brelse(bh);
55 return paddr;
56}
57
58static int ext4_encrypted_symlink_getattr(struct mnt_idmap *idmap,
59 const struct path *path,
60 struct kstat *stat, u32 request_mask,
61 unsigned int query_flags)
62{
63 ext4_getattr(idmap, path, stat, request_mask, query_flags);
64
65 return fscrypt_symlink_getattr(path, stat);
66}
67
68static void ext4_free_link(void *bh)
69{
70 brelse(bh);
71}
72
73static const char *ext4_get_link(struct dentry *dentry, struct inode *inode,
74 struct delayed_call *callback)
75{
76 struct buffer_head *bh;
77 char *inline_link;
78
79 /*
80 * Create a new inlined symlink is not supported, just provide a
81 * method to read the leftovers.
82 */
83 if (ext4_has_inline_data(inode)) {
84 if (!dentry)
85 return ERR_PTR(-ECHILD);
86
87 inline_link = ext4_read_inline_link(inode);
88 if (!IS_ERR(inline_link))
89 set_delayed_call(callback, kfree_link, inline_link);
90 return inline_link;
91 }
92
93 if (!dentry) {
94 bh = ext4_getblk(NULL, inode, 0, EXT4_GET_BLOCKS_CACHED_NOWAIT);
95 if (IS_ERR(bh) || !bh)
96 return ERR_PTR(-ECHILD);
97 if (!ext4_buffer_uptodate(bh)) {
98 brelse(bh);
99 return ERR_PTR(-ECHILD);
100 }
101 } else {
102 bh = ext4_bread(NULL, inode, 0, 0);
103 if (IS_ERR(bh))
104 return ERR_CAST(bh);
105 if (!bh) {
106 EXT4_ERROR_INODE(inode, "bad symlink.");
107 return ERR_PTR(-EFSCORRUPTED);
108 }
109 }
110
111 set_delayed_call(callback, ext4_free_link, bh);
112 nd_terminate_link(bh->b_data, inode->i_size,
113 inode->i_sb->s_blocksize - 1);
114 return bh->b_data;
115}
116
117const struct inode_operations ext4_encrypted_symlink_inode_operations = {
118 .get_link = ext4_encrypted_get_link,
119 .setattr = ext4_setattr,
120 .getattr = ext4_encrypted_symlink_getattr,
121 .listxattr = ext4_listxattr,
122};
123
124const struct inode_operations ext4_symlink_inode_operations = {
125 .get_link = ext4_get_link,
126 .setattr = ext4_setattr,
127 .getattr = ext4_getattr,
128 .listxattr = ext4_listxattr,
129};
130
131const struct inode_operations ext4_fast_symlink_inode_operations = {
132 .get_link = simple_get_link,
133 .setattr = ext4_setattr,
134 .getattr = ext4_getattr,
135 .listxattr = ext4_listxattr,
136};