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c1286ff4 JK |
1 | /* |
2 | * General per-file encryption definition | |
3 | * | |
4 | * Copyright (C) 2015, Google, Inc. | |
5 | * | |
6 | * Written by Michael Halcrow, 2015. | |
7 | * Modified by Jaegeuk Kim, 2015. | |
8 | */ | |
9 | ||
10 | #ifndef _LINUX_FSCRYPTO_H | |
11 | #define _LINUX_FSCRYPTO_H | |
12 | ||
13 | #include <linux/key.h> | |
14 | #include <linux/fs.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/bio.h> | |
17 | #include <linux/dcache.h> | |
18 | #include <crypto/skcipher.h> | |
19 | #include <uapi/linux/fs.h> | |
20 | ||
21 | #define FS_KEY_DERIVATION_NONCE_SIZE 16 | |
22 | #define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1 | |
23 | ||
24 | #define FS_POLICY_FLAGS_PAD_4 0x00 | |
25 | #define FS_POLICY_FLAGS_PAD_8 0x01 | |
26 | #define FS_POLICY_FLAGS_PAD_16 0x02 | |
27 | #define FS_POLICY_FLAGS_PAD_32 0x03 | |
28 | #define FS_POLICY_FLAGS_PAD_MASK 0x03 | |
29 | #define FS_POLICY_FLAGS_VALID 0x03 | |
30 | ||
31 | /* Encryption algorithms */ | |
32 | #define FS_ENCRYPTION_MODE_INVALID 0 | |
33 | #define FS_ENCRYPTION_MODE_AES_256_XTS 1 | |
34 | #define FS_ENCRYPTION_MODE_AES_256_GCM 2 | |
35 | #define FS_ENCRYPTION_MODE_AES_256_CBC 3 | |
36 | #define FS_ENCRYPTION_MODE_AES_256_CTS 4 | |
37 | ||
38 | /** | |
39 | * Encryption context for inode | |
40 | * | |
41 | * Protector format: | |
42 | * 1 byte: Protector format (1 = this version) | |
43 | * 1 byte: File contents encryption mode | |
44 | * 1 byte: File names encryption mode | |
45 | * 1 byte: Flags | |
46 | * 8 bytes: Master Key descriptor | |
47 | * 16 bytes: Encryption Key derivation nonce | |
48 | */ | |
49 | struct fscrypt_context { | |
50 | u8 format; | |
51 | u8 contents_encryption_mode; | |
52 | u8 filenames_encryption_mode; | |
53 | u8 flags; | |
54 | u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; | |
55 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; | |
56 | } __packed; | |
57 | ||
58 | /* Encryption parameters */ | |
59 | #define FS_XTS_TWEAK_SIZE 16 | |
60 | #define FS_AES_128_ECB_KEY_SIZE 16 | |
61 | #define FS_AES_256_GCM_KEY_SIZE 32 | |
62 | #define FS_AES_256_CBC_KEY_SIZE 32 | |
63 | #define FS_AES_256_CTS_KEY_SIZE 32 | |
64 | #define FS_AES_256_XTS_KEY_SIZE 64 | |
65 | #define FS_MAX_KEY_SIZE 64 | |
66 | ||
67 | #define FS_KEY_DESC_PREFIX "fscrypt:" | |
68 | #define FS_KEY_DESC_PREFIX_SIZE 8 | |
69 | ||
70 | /* This is passed in from userspace into the kernel keyring */ | |
71 | struct fscrypt_key { | |
72 | u32 mode; | |
73 | u8 raw[FS_MAX_KEY_SIZE]; | |
74 | u32 size; | |
75 | } __packed; | |
76 | ||
77 | struct fscrypt_info { | |
78 | u8 ci_data_mode; | |
79 | u8 ci_filename_mode; | |
80 | u8 ci_flags; | |
81 | struct crypto_skcipher *ci_ctfm; | |
82 | struct key *ci_keyring_key; | |
83 | u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE]; | |
84 | }; | |
85 | ||
86 | #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 | |
87 | #define FS_WRITE_PATH_FL 0x00000002 | |
88 | ||
89 | struct fscrypt_ctx { | |
90 | union { | |
91 | struct { | |
92 | struct page *bounce_page; /* Ciphertext page */ | |
93 | struct page *control_page; /* Original page */ | |
94 | } w; | |
95 | struct { | |
96 | struct bio *bio; | |
97 | struct work_struct work; | |
98 | } r; | |
99 | struct list_head free_list; /* Free list */ | |
100 | }; | |
101 | u8 flags; /* Flags */ | |
102 | u8 mode; /* Encryption mode for tfm */ | |
103 | }; | |
104 | ||
105 | struct fscrypt_completion_result { | |
106 | struct completion completion; | |
107 | int res; | |
108 | }; | |
109 | ||
110 | #define DECLARE_FS_COMPLETION_RESULT(ecr) \ | |
111 | struct fscrypt_completion_result ecr = { \ | |
112 | COMPLETION_INITIALIZER((ecr).completion), 0 } | |
113 | ||
c1286ff4 JK |
114 | #define FS_FNAME_NUM_SCATTER_ENTRIES 4 |
115 | #define FS_CRYPTO_BLOCK_SIZE 16 | |
116 | #define FS_FNAME_CRYPTO_DIGEST_SIZE 32 | |
117 | ||
118 | /** | |
119 | * For encrypted symlinks, the ciphertext length is stored at the beginning | |
120 | * of the string in little-endian format. | |
121 | */ | |
122 | struct fscrypt_symlink_data { | |
123 | __le16 len; | |
124 | char encrypted_path[1]; | |
125 | } __packed; | |
126 | ||
127 | /** | |
128 | * This function is used to calculate the disk space required to | |
129 | * store a filename of length l in encrypted symlink format. | |
130 | */ | |
131 | static inline u32 fscrypt_symlink_data_len(u32 l) | |
132 | { | |
133 | if (l < FS_CRYPTO_BLOCK_SIZE) | |
134 | l = FS_CRYPTO_BLOCK_SIZE; | |
135 | return (l + sizeof(struct fscrypt_symlink_data) - 1); | |
136 | } | |
137 | ||
138 | struct fscrypt_str { | |
139 | unsigned char *name; | |
140 | u32 len; | |
141 | }; | |
142 | ||
143 | struct fscrypt_name { | |
144 | const struct qstr *usr_fname; | |
145 | struct fscrypt_str disk_name; | |
146 | u32 hash; | |
147 | u32 minor_hash; | |
148 | struct fscrypt_str crypto_buf; | |
149 | }; | |
150 | ||
151 | #define FSTR_INIT(n, l) { .name = n, .len = l } | |
152 | #define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len) | |
153 | #define fname_name(p) ((p)->disk_name.name) | |
154 | #define fname_len(p) ((p)->disk_name.len) | |
155 | ||
156 | /* | |
157 | * crypto opertions for filesystems | |
158 | */ | |
159 | struct fscrypt_operations { | |
160 | int (*get_context)(struct inode *, void *, size_t); | |
161 | int (*key_prefix)(struct inode *, u8 **); | |
162 | int (*prepare_context)(struct inode *); | |
163 | int (*set_context)(struct inode *, const void *, size_t, void *); | |
164 | int (*dummy_context)(struct inode *); | |
165 | bool (*is_encrypted)(struct inode *); | |
166 | bool (*empty_dir)(struct inode *); | |
167 | unsigned (*max_namelen)(struct inode *); | |
168 | }; | |
169 | ||
170 | static inline bool fscrypt_dummy_context_enabled(struct inode *inode) | |
171 | { | |
172 | if (inode->i_sb->s_cop->dummy_context && | |
173 | inode->i_sb->s_cop->dummy_context(inode)) | |
174 | return true; | |
175 | return false; | |
176 | } | |
177 | ||
178 | static inline bool fscrypt_valid_contents_enc_mode(u32 mode) | |
179 | { | |
180 | return (mode == FS_ENCRYPTION_MODE_AES_256_XTS); | |
181 | } | |
182 | ||
183 | static inline bool fscrypt_valid_filenames_enc_mode(u32 mode) | |
184 | { | |
185 | return (mode == FS_ENCRYPTION_MODE_AES_256_CTS); | |
186 | } | |
187 | ||
c1286ff4 JK |
188 | static inline bool fscrypt_is_dot_dotdot(const struct qstr *str) |
189 | { | |
190 | if (str->len == 1 && str->name[0] == '.') | |
191 | return true; | |
192 | ||
193 | if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.') | |
194 | return true; | |
195 | ||
196 | return false; | |
197 | } | |
198 | ||
199 | static inline struct page *fscrypt_control_page(struct page *page) | |
200 | { | |
201 | #if IS_ENABLED(CONFIG_FS_ENCRYPTION) | |
202 | return ((struct fscrypt_ctx *)page_private(page))->w.control_page; | |
203 | #else | |
204 | WARN_ON_ONCE(1); | |
205 | return ERR_PTR(-EINVAL); | |
206 | #endif | |
207 | } | |
208 | ||
209 | static inline int fscrypt_has_encryption_key(struct inode *inode) | |
210 | { | |
211 | #if IS_ENABLED(CONFIG_FS_ENCRYPTION) | |
212 | return (inode->i_crypt_info != NULL); | |
213 | #else | |
214 | return 0; | |
215 | #endif | |
216 | } | |
217 | ||
218 | static inline void fscrypt_set_encrypted_dentry(struct dentry *dentry) | |
219 | { | |
220 | #if IS_ENABLED(CONFIG_FS_ENCRYPTION) | |
221 | spin_lock(&dentry->d_lock); | |
222 | dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY; | |
223 | spin_unlock(&dentry->d_lock); | |
224 | #endif | |
225 | } | |
226 | ||
227 | #if IS_ENABLED(CONFIG_FS_ENCRYPTION) | |
228 | extern const struct dentry_operations fscrypt_d_ops; | |
229 | #endif | |
230 | ||
231 | static inline void fscrypt_set_d_op(struct dentry *dentry) | |
232 | { | |
233 | #if IS_ENABLED(CONFIG_FS_ENCRYPTION) | |
234 | d_set_d_op(dentry, &fscrypt_d_ops); | |
235 | #endif | |
236 | } | |
237 | ||
238 | #if IS_ENABLED(CONFIG_FS_ENCRYPTION) | |
239 | /* crypto.c */ | |
240 | extern struct kmem_cache *fscrypt_info_cachep; | |
241 | int fscrypt_initialize(void); | |
242 | ||
243 | extern struct fscrypt_ctx *fscrypt_get_ctx(struct inode *, gfp_t); | |
244 | extern void fscrypt_release_ctx(struct fscrypt_ctx *); | |
245 | extern struct page *fscrypt_encrypt_page(struct inode *, struct page *, gfp_t); | |
246 | extern int fscrypt_decrypt_page(struct page *); | |
247 | extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *); | |
248 | extern void fscrypt_pullback_bio_page(struct page **, bool); | |
249 | extern void fscrypt_restore_control_page(struct page *); | |
250 | extern int fscrypt_zeroout_range(struct inode *, pgoff_t, sector_t, | |
251 | unsigned int); | |
252 | /* policy.c */ | |
13f00235 JK |
253 | extern int fscrypt_ioctl_set_policy(struct file *, const void __user *); |
254 | extern int fscrypt_ioctl_get_policy(struct file *, void __user *); | |
c1286ff4 JK |
255 | extern int fscrypt_has_permitted_context(struct inode *, struct inode *); |
256 | extern int fscrypt_inherit_context(struct inode *, struct inode *, | |
257 | void *, bool); | |
258 | /* keyinfo.c */ | |
259 | extern int get_crypt_info(struct inode *); | |
260 | extern int fscrypt_get_encryption_info(struct inode *); | |
261 | extern void fscrypt_put_encryption_info(struct inode *, struct fscrypt_info *); | |
262 | ||
263 | /* fname.c */ | |
264 | extern int fscrypt_setup_filename(struct inode *, const struct qstr *, | |
265 | int lookup, struct fscrypt_name *); | |
266 | extern void fscrypt_free_filename(struct fscrypt_name *); | |
267 | extern u32 fscrypt_fname_encrypted_size(struct inode *, u32); | |
268 | extern int fscrypt_fname_alloc_buffer(struct inode *, u32, | |
269 | struct fscrypt_str *); | |
270 | extern void fscrypt_fname_free_buffer(struct fscrypt_str *); | |
271 | extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32, | |
272 | const struct fscrypt_str *, struct fscrypt_str *); | |
273 | extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *, | |
274 | struct fscrypt_str *); | |
275 | #endif | |
276 | ||
277 | /* crypto.c */ | |
278 | static inline struct fscrypt_ctx *fscrypt_notsupp_get_ctx(struct inode *i, | |
279 | gfp_t f) | |
280 | { | |
281 | return ERR_PTR(-EOPNOTSUPP); | |
282 | } | |
283 | ||
284 | static inline void fscrypt_notsupp_release_ctx(struct fscrypt_ctx *c) | |
285 | { | |
286 | return; | |
287 | } | |
288 | ||
289 | static inline struct page *fscrypt_notsupp_encrypt_page(struct inode *i, | |
290 | struct page *p, gfp_t f) | |
291 | { | |
292 | return ERR_PTR(-EOPNOTSUPP); | |
293 | } | |
294 | ||
295 | static inline int fscrypt_notsupp_decrypt_page(struct page *p) | |
296 | { | |
297 | return -EOPNOTSUPP; | |
298 | } | |
299 | ||
300 | static inline void fscrypt_notsupp_decrypt_bio_pages(struct fscrypt_ctx *c, | |
301 | struct bio *b) | |
302 | { | |
303 | return; | |
304 | } | |
305 | ||
306 | static inline void fscrypt_notsupp_pullback_bio_page(struct page **p, bool b) | |
307 | { | |
308 | return; | |
309 | } | |
310 | ||
311 | static inline void fscrypt_notsupp_restore_control_page(struct page *p) | |
312 | { | |
313 | return; | |
314 | } | |
315 | ||
316 | static inline int fscrypt_notsupp_zeroout_range(struct inode *i, pgoff_t p, | |
317 | sector_t s, unsigned int f) | |
318 | { | |
319 | return -EOPNOTSUPP; | |
320 | } | |
321 | ||
322 | /* policy.c */ | |
13f00235 JK |
323 | static inline int fscrypt_notsupp_ioctl_set_policy(struct file *f, |
324 | const void __user *arg) | |
c1286ff4 JK |
325 | { |
326 | return -EOPNOTSUPP; | |
327 | } | |
328 | ||
13f00235 JK |
329 | static inline int fscrypt_notsupp_ioctl_get_policy(struct file *f, |
330 | void __user *arg) | |
c1286ff4 JK |
331 | { |
332 | return -EOPNOTSUPP; | |
333 | } | |
334 | ||
335 | static inline int fscrypt_notsupp_has_permitted_context(struct inode *p, | |
336 | struct inode *i) | |
337 | { | |
338 | return 0; | |
339 | } | |
340 | ||
341 | static inline int fscrypt_notsupp_inherit_context(struct inode *p, | |
342 | struct inode *i, void *v, bool b) | |
343 | { | |
344 | return -EOPNOTSUPP; | |
345 | } | |
346 | ||
347 | /* keyinfo.c */ | |
348 | static inline int fscrypt_notsupp_get_encryption_info(struct inode *i) | |
349 | { | |
350 | return -EOPNOTSUPP; | |
351 | } | |
352 | ||
353 | static inline void fscrypt_notsupp_put_encryption_info(struct inode *i, | |
354 | struct fscrypt_info *f) | |
355 | { | |
356 | return; | |
357 | } | |
358 | ||
359 | /* fname.c */ | |
360 | static inline int fscrypt_notsupp_setup_filename(struct inode *dir, | |
361 | const struct qstr *iname, | |
362 | int lookup, struct fscrypt_name *fname) | |
363 | { | |
364 | if (dir->i_sb->s_cop->is_encrypted(dir)) | |
365 | return -EOPNOTSUPP; | |
366 | ||
367 | memset(fname, 0, sizeof(struct fscrypt_name)); | |
368 | fname->usr_fname = iname; | |
369 | fname->disk_name.name = (unsigned char *)iname->name; | |
370 | fname->disk_name.len = iname->len; | |
371 | return 0; | |
372 | } | |
373 | ||
374 | static inline void fscrypt_notsupp_free_filename(struct fscrypt_name *fname) | |
375 | { | |
376 | return; | |
377 | } | |
378 | ||
379 | static inline u32 fscrypt_notsupp_fname_encrypted_size(struct inode *i, u32 s) | |
380 | { | |
381 | /* never happens */ | |
382 | WARN_ON(1); | |
383 | return 0; | |
384 | } | |
385 | ||
386 | static inline int fscrypt_notsupp_fname_alloc_buffer(struct inode *inode, | |
387 | u32 ilen, struct fscrypt_str *crypto_str) | |
388 | { | |
389 | return -EOPNOTSUPP; | |
390 | } | |
391 | ||
392 | static inline void fscrypt_notsupp_fname_free_buffer(struct fscrypt_str *c) | |
393 | { | |
394 | return; | |
395 | } | |
396 | ||
397 | static inline int fscrypt_notsupp_fname_disk_to_usr(struct inode *inode, | |
398 | u32 hash, u32 minor_hash, | |
399 | const struct fscrypt_str *iname, | |
400 | struct fscrypt_str *oname) | |
401 | { | |
402 | return -EOPNOTSUPP; | |
403 | } | |
404 | ||
405 | static inline int fscrypt_notsupp_fname_usr_to_disk(struct inode *inode, | |
406 | const struct qstr *iname, | |
407 | struct fscrypt_str *oname) | |
408 | { | |
409 | return -EOPNOTSUPP; | |
410 | } | |
411 | #endif /* _LINUX_FSCRYPTO_H */ |