projects/linux·blob master · refs

248 lines · 6.3 KiB

1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/quotaops.h>
4#include <linux/uuid.h>
5
6#include "ext4.h"
7#include "xattr.h"
8#include "ext4_jbd2.h"
9
10static void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
11 const struct fscrypt_name *src)
12{
13 memset(dst, 0, sizeof(*dst));
14
15 dst->usr_fname = src->usr_fname;
16 dst->disk_name = src->disk_name;
17 dst->hinfo.hash = src->hash;
18 dst->hinfo.minor_hash = src->minor_hash;
19 dst->crypto_buf = src->crypto_buf;
20}
21
22int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
23 int lookup, struct ext4_filename *fname)
24{
25 struct fscrypt_name name;
26 int err;
27
28 err = fscrypt_setup_filename(dir, iname, lookup, &name);
29 if (err)
30 return err;
31
32 ext4_fname_from_fscrypt_name(fname, &name);
33
34 err = ext4_fname_setup_ci_filename(dir, iname, fname);
35 if (err)
36 ext4_fname_free_filename(fname);
37
38 return err;
39}
40
41int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry,
42 struct ext4_filename *fname)
43{
44 struct fscrypt_name name;
45 int err;
46
47 err = fscrypt_prepare_lookup(dir, dentry, &name);
48 if (err)
49 return err;
50
51 ext4_fname_from_fscrypt_name(fname, &name);
52
53 err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
54 if (err)
55 ext4_fname_free_filename(fname);
56 return err;
57}
58
59void ext4_fname_free_filename(struct ext4_filename *fname)
60{
61 struct fscrypt_name name;
62
63 name.crypto_buf = fname->crypto_buf;
64 fscrypt_free_filename(&name);
65
66 fname->crypto_buf.name = NULL;
67 fname->usr_fname = NULL;
68 fname->disk_name.name = NULL;
69
70 ext4_fname_free_ci_filename(fname);
71}
72
73static bool uuid_is_zero(__u8 u[16])
74{
75 int i;
76
77 for (i = 0; i < 16; i++)
78 if (u[i])
79 return false;
80 return true;
81}
82
83int ext4_ioctl_get_encryption_pwsalt(struct file *filp, void __user *arg)
84{
85 struct super_block *sb = file_inode(filp)->i_sb;
86 struct ext4_sb_info *sbi = EXT4_SB(sb);
87 int err, err2;
88 handle_t *handle;
89
90 if (!ext4_has_feature_encrypt(sb))
91 return -EOPNOTSUPP;
92
93 if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
94 err = mnt_want_write_file(filp);
95 if (err)
96 return err;
97 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
98 if (IS_ERR(handle)) {
99 err = PTR_ERR(handle);
100 goto pwsalt_err_exit;
101 }
102 err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
103 EXT4_JTR_NONE);
104 if (err)
105 goto pwsalt_err_journal;
106 lock_buffer(sbi->s_sbh);
107 generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);
108 ext4_superblock_csum_set(sb);
109 unlock_buffer(sbi->s_sbh);
110 err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
111pwsalt_err_journal:
112 err2 = ext4_journal_stop(handle);
113 if (err2 && !err)
114 err = err2;
115pwsalt_err_exit:
116 mnt_drop_write_file(filp);
117 if (err)
118 return err;
119 }
120
121 if (copy_to_user(arg, sbi->s_es->s_encrypt_pw_salt, 16))
122 return -EFAULT;
123 return 0;
124}
125
126static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
127{
128 return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
129 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
130}
131
132static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
133 void *fs_data)
134{
135 handle_t *handle = fs_data;
136 int res, res2, credits, retries = 0;
137
138 /*
139 * Encrypting the root directory is not allowed because e2fsck expects
140 * lost+found to exist and be unencrypted, and encrypting the root
141 * directory would imply encrypting the lost+found directory as well as
142 * the filename "lost+found" itself.
143 */
144 if (inode->i_ino == EXT4_ROOT_INO)
145 return -EPERM;
146
147 /*
148 * For new encrypted inodes, S_DAX is never set in the first place.
149 *
150 * For existing inodes, this is called only on empty directories. ext4
151 * never sets S_DAX on directories.
152 */
153 if (WARN_ON_ONCE(IS_DAX(inode)))
154 return -EINVAL;
155
156 if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
157 return -EOPNOTSUPP;
158
159 res = ext4_convert_inline_data(inode);
160 if (res)
161 return res;
162
163 /*
164 * If a journal handle was specified, then the encryption context is
165 * being set on a new inode via inheritance and is part of a larger
166 * transaction to create the inode. Otherwise the encryption context is
167 * being set on an existing inode in its own transaction. Only in the
168 * latter case should the "retry on ENOSPC" logic be used.
169 */
170
171 if (handle) {
172 /*
173 * __ext4_new_inode() should have already set the encrypt flag
174 * on the inode and avoided enabling inline data.
175 */
176 if (WARN_ON_ONCE(!IS_ENCRYPTED(inode)))
177 return -EINVAL;
178 if (WARN_ON_ONCE(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)))
179 return -EINVAL;
180 /*
181 * Since the inode is new it is ok to pass the
182 * XATTR_CREATE flag. This is necessary to match the
183 * remaining journal credits check in the set_handle
184 * function with the credits allocated for the new
185 * inode.
186 */
187 return ext4_xattr_set_handle(handle, inode,
188 EXT4_XATTR_INDEX_ENCRYPTION,
189 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
190 ctx, len, XATTR_CREATE);
191 }
192
193 res = dquot_initialize(inode);
194 if (res)
195 return res;
196retry:
197 res = ext4_xattr_set_credits(inode, len, false /* is_create */,
198 &credits);
199 if (res)
200 return res;
201
202 handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
203 if (IS_ERR(handle))
204 return PTR_ERR(handle);
205
206 res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION,
207 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
208 ctx, len, 0);
209 if (!res) {
210 ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
211 /* Update inode->i_flags to set S_ENCRYPTED. */
212 ext4_set_inode_flags(inode, false);
213 res = ext4_mark_inode_dirty(handle, inode);
214 if (res)
215 EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
216 }
217 res2 = ext4_journal_stop(handle);
218
219 if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
220 goto retry;
221 if (!res)
222 res = res2;
223 return res;
224}
225
226static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb)
227{
228 return EXT4_SB(sb)->s_dummy_enc_policy.policy;
229}
230
231static bool ext4_has_stable_inodes(struct super_block *sb)
232{
233 return ext4_has_feature_stable_inodes(sb);
234}
235
236const struct fscrypt_operations ext4_cryptops = {
237 .inode_info_offs = (int)offsetof(struct ext4_inode_info, i_crypt_info) -
238 (int)offsetof(struct ext4_inode_info, vfs_inode),
239 .is_block_based = 1,
240 .has_32bit_inodes = 1,
241 .supports_subblock_data_units = 1,
242 .legacy_key_prefix = "ext4:",
243 .get_context = ext4_get_context,
244 .set_context = ext4_set_context,
245 .get_dummy_policy = ext4_get_dummy_policy,
246 .empty_dir = ext4_empty_dir,
247 .has_stable_inodes = ext4_has_stable_inodes,
248};