symlink.c (20f8e032e6dc7053ab803f488e2a8839cd2f69a6) symlink.c (fceef393a538134f03b778c5d2519e670269342f)
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

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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
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

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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_follow_link(struct dentry *dentry, void **cookie)
26static const char *ext4_encrypted_get_link(struct dentry *dentry,
27 struct inode *inode,
28 struct delayed_call *done)
27{
28 struct page *cpage = NULL;
29 char *caddr, *paddr = NULL;
30 struct ext4_str cstr, pstr;
29{
30 struct page *cpage = NULL;
31 char *caddr, *paddr = NULL;
32 struct ext4_str cstr, pstr;
31 struct inode *inode = d_inode(dentry);
32 struct ext4_encrypted_symlink_data *sd;
33 loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
34 int res;
35 u32 plen, max_size = inode->i_sb->s_blocksize;
36
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
37 res = ext4_get_encryption_info(inode);
38 if (res)
39 return ERR_PTR(res);
40
41 if (ext4_inode_is_fast_symlink(inode)) {
42 caddr = (char *) EXT4_I(inode)->i_data;
43 max_size = sizeof(EXT4_I(inode)->i_data);
44 } else {
45 cpage = read_mapping_page(inode->i_mapping, 0, NULL);
46 if (IS_ERR(cpage))
47 return ERR_CAST(cpage);
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);
48 caddr = kmap(cpage);
52 caddr = page_address(cpage);
49 caddr[size] = 0;
50 }
51
52 /* Symlink is encrypted */
53 sd = (struct ext4_encrypted_symlink_data *)caddr;
54 cstr.name = sd->encrypted_path;
53 caddr[size] = 0;
54 }
55
56 /* Symlink is encrypted */
57 sd = (struct ext4_encrypted_symlink_data *)caddr;
58 cstr.name = sd->encrypted_path;
55 cstr.len = le16_to_cpu(sd->len);
59 cstr.len = le32_to_cpu(sd->len);
56 if ((cstr.len +
57 sizeof(struct ext4_encrypted_symlink_data) - 1) >
58 max_size) {
59 /* Symlink data on the disk is corrupted */
60 res = -EFSCORRUPTED;
61 goto errout;
62 }
63 plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?

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70 pstr.name = paddr;
71 pstr.len = plen;
72 res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
73 if (res < 0)
74 goto errout;
75 /* Null-terminate the name */
76 if (res <= plen)
77 paddr[res] = '\0';
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) ?

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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';
78 if (cpage) {
79 kunmap(cpage);
82 if (cpage)
80 page_cache_release(cpage);
83 page_cache_release(cpage);
81 }
82 return *cookie = paddr;
84 set_delayed_call(done, kfree_link, paddr);
85 return paddr;
83errout:
86errout:
84 if (cpage) {
85 kunmap(cpage);
87 if (cpage)
86 page_cache_release(cpage);
88 page_cache_release(cpage);
87 }
88 kfree(paddr);
89 return ERR_PTR(res);
90}
91
92const struct inode_operations ext4_encrypted_symlink_inode_operations = {
93 .readlink = generic_readlink,
89 kfree(paddr);
90 return ERR_PTR(res);
91}
92
93const struct inode_operations ext4_encrypted_symlink_inode_operations = {
94 .readlink = generic_readlink,
94 .follow_link = ext4_encrypted_follow_link,
95 .put_link = kfree_put_link,
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,
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 .follow_link = page_follow_link_light,
107 .put_link = page_put_link,
106 .get_link = page_get_link,
108 .setattr = ext4_setattr,
109 .setxattr = generic_setxattr,
110 .getxattr = generic_getxattr,
111 .listxattr = ext4_listxattr,
112 .removexattr = generic_removexattr,
113};
114
115const struct inode_operations ext4_fast_symlink_inode_operations = {
116 .readlink = generic_readlink,
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,
117 .follow_link = simple_follow_link,
116 .get_link = simple_get_link,
118 .setattr = ext4_setattr,
119 .setxattr = generic_setxattr,
120 .getxattr = generic_getxattr,
121 .listxattr = ext4_listxattr,
122 .removexattr = generic_removexattr,
123};
117 .setattr = ext4_setattr,
118 .setxattr = generic_setxattr,
119 .getxattr = generic_getxattr,
120 .listxattr = ext4_listxattr,
121 .removexattr = generic_removexattr,
122};