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 | |
26 | static 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(error: -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(ptr: bh)) |
44 | return ERR_CAST(ptr: bh); |
45 | if (!bh) { |
46 | EXT4_ERROR_INODE(inode, "bad symlink." ); |
47 | return ERR_PTR(error: -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 | |
58 | static 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 | |
68 | static void ext4_free_link(void *bh) |
69 | { |
70 | brelse(bh); |
71 | } |
72 | |
73 | static 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(error: -ECHILD); |
86 | |
87 | inline_link = ext4_read_inline_link(inode); |
88 | if (!IS_ERR(ptr: inline_link)) |
89 | set_delayed_call(call: callback, fn: kfree_link, arg: 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(ptr: bh)) |
96 | return ERR_CAST(ptr: bh); |
97 | if (!bh || !ext4_buffer_uptodate(bh)) |
98 | return ERR_PTR(error: -ECHILD); |
99 | } else { |
100 | bh = ext4_bread(NULL, inode, 0, 0); |
101 | if (IS_ERR(ptr: bh)) |
102 | return ERR_CAST(ptr: bh); |
103 | if (!bh) { |
104 | EXT4_ERROR_INODE(inode, "bad symlink." ); |
105 | return ERR_PTR(error: -EFSCORRUPTED); |
106 | } |
107 | } |
108 | |
109 | set_delayed_call(call: callback, fn: ext4_free_link, arg: bh); |
110 | nd_terminate_link(name: bh->b_data, len: inode->i_size, |
111 | maxlen: inode->i_sb->s_blocksize - 1); |
112 | return bh->b_data; |
113 | } |
114 | |
115 | const struct inode_operations ext4_encrypted_symlink_inode_operations = { |
116 | .get_link = ext4_encrypted_get_link, |
117 | .setattr = ext4_setattr, |
118 | .getattr = ext4_encrypted_symlink_getattr, |
119 | .listxattr = ext4_listxattr, |
120 | }; |
121 | |
122 | const struct inode_operations ext4_symlink_inode_operations = { |
123 | .get_link = ext4_get_link, |
124 | .setattr = ext4_setattr, |
125 | .getattr = ext4_getattr, |
126 | .listxattr = ext4_listxattr, |
127 | }; |
128 | |
129 | const struct inode_operations ext4_fast_symlink_inode_operations = { |
130 | .get_link = simple_get_link, |
131 | .setattr = ext4_setattr, |
132 | .getattr = ext4_getattr, |
133 | .listxattr = ext4_listxattr, |
134 | }; |
135 | |