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Commit | Line | Data |
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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" |
24 | ||
f348c252 | 25 | #ifdef CONFIG_EXT4_FS_ENCRYPTION |
af5bc92d | 26 | static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd) |
f348c252 TT |
27 | { |
28 | struct page *cpage = NULL; | |
29 | char *caddr, *paddr = NULL; | |
30 | struct ext4_str cstr, pstr; | |
9ec3a646 | 31 | struct inode *inode = d_inode(dentry); |
f348c252 TT |
32 | struct ext4_fname_crypto_ctx *ctx = NULL; |
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 (!ext4_encrypted_inode(inode)) | |
39 | return page_follow_link_light(dentry, nd); | |
40 | ||
41 | ctx = ext4_get_fname_crypto_ctx(inode, inode->i_sb->s_blocksize); | |
42 | if (IS_ERR(ctx)) | |
43 | return ctx; | |
44 | ||
45 | if (ext4_inode_is_fast_symlink(inode)) { | |
9ec3a646 LT |
46 | caddr = (char *) EXT4_I(inode)->i_data; |
47 | max_size = sizeof(EXT4_I(inode)->i_data); | |
f348c252 TT |
48 | } else { |
49 | cpage = read_mapping_page(inode->i_mapping, 0, NULL); | |
50 | if (IS_ERR(cpage)) { | |
51 | ext4_put_fname_crypto_ctx(&ctx); | |
52 | return cpage; | |
53 | } | |
54 | caddr = kmap(cpage); | |
55 | caddr[size] = 0; | |
56 | } | |
57 | ||
58 | /* Symlink is encrypted */ | |
59 | sd = (struct ext4_encrypted_symlink_data *)caddr; | |
60 | cstr.name = sd->encrypted_path; | |
61 | cstr.len = le32_to_cpu(sd->len); | |
62 | if ((cstr.len + | |
63 | sizeof(struct ext4_encrypted_symlink_data) - 1) > | |
64 | max_size) { | |
65 | /* Symlink data on the disk is corrupted */ | |
66 | res = -EIO; | |
67 | goto errout; | |
68 | } | |
69 | plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ? | |
70 | EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len; | |
71 | paddr = kmalloc(plen + 1, GFP_NOFS); | |
72 | if (!paddr) { | |
73 | res = -ENOMEM; | |
74 | goto errout; | |
75 | } | |
76 | pstr.name = paddr; | |
5de0b4d0 | 77 | res = _ext4_fname_disk_to_usr(ctx, NULL, &cstr, &pstr); |
f348c252 TT |
78 | if (res < 0) |
79 | goto errout; | |
80 | /* Null-terminate the name */ | |
81 | if (res <= plen) | |
82 | paddr[res] = '\0'; | |
83 | nd_set_link(nd, paddr); | |
84 | ext4_put_fname_crypto_ctx(&ctx); | |
85 | if (cpage) { | |
86 | kunmap(cpage); | |
87 | page_cache_release(cpage); | |
88 | } | |
89 | return NULL; | |
90 | errout: | |
91 | ext4_put_fname_crypto_ctx(&ctx); | |
92 | if (cpage) { | |
93 | kunmap(cpage); | |
94 | page_cache_release(cpage); | |
95 | } | |
96 | kfree(paddr); | |
97 | return ERR_PTR(res); | |
98 | } | |
99 | ||
100 | static void ext4_put_link(struct dentry *dentry, struct nameidata *nd, | |
101 | void *cookie) | |
102 | { | |
103 | struct page *page = cookie; | |
104 | ||
105 | if (!page) { | |
106 | kfree(nd_get_link(nd)); | |
107 | } else { | |
108 | kunmap(page); | |
109 | page_cache_release(page); | |
110 | } | |
111 | } | |
112 | #endif | |
113 | ||
114 | static void *ext4_follow_fast_link(struct dentry *dentry, struct nameidata *nd) | |
ac27a0ec | 115 | { |
2b0143b5 | 116 | struct ext4_inode_info *ei = EXT4_I(d_inode(dentry)); |
af5bc92d | 117 | nd_set_link(nd, (char *) ei->i_data); |
ac27a0ec DK |
118 | return NULL; |
119 | } | |
120 | ||
754661f1 | 121 | const struct inode_operations ext4_symlink_inode_operations = { |
ac27a0ec | 122 | .readlink = generic_readlink, |
f348c252 TT |
123 | #ifdef CONFIG_EXT4_FS_ENCRYPTION |
124 | .follow_link = ext4_follow_link, | |
125 | .put_link = ext4_put_link, | |
126 | #else | |
ac27a0ec DK |
127 | .follow_link = page_follow_link_light, |
128 | .put_link = page_put_link, | |
f348c252 | 129 | #endif |
256a4535 | 130 | .setattr = ext4_setattr, |
ac27a0ec DK |
131 | .setxattr = generic_setxattr, |
132 | .getxattr = generic_getxattr, | |
617ba13b | 133 | .listxattr = ext4_listxattr, |
ac27a0ec | 134 | .removexattr = generic_removexattr, |
ac27a0ec DK |
135 | }; |
136 | ||
754661f1 | 137 | const struct inode_operations ext4_fast_symlink_inode_operations = { |
ac27a0ec | 138 | .readlink = generic_readlink, |
f348c252 | 139 | .follow_link = ext4_follow_fast_link, |
256a4535 | 140 | .setattr = ext4_setattr, |
ac27a0ec DK |
141 | .setxattr = generic_setxattr, |
142 | .getxattr = generic_getxattr, | |
617ba13b | 143 | .listxattr = ext4_listxattr, |
ac27a0ec | 144 | .removexattr = generic_removexattr, |
ac27a0ec | 145 | }; |