fscrypt.h (552c69b36ebd966186573b9c7a286b390935cce1) | fscrypt.h (643fa9612bf1a29153eee46fd398117632f93cbe) |
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1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * fscrypt.h: declarations for per-file encryption 4 * | 1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * fscrypt.h: declarations for per-file encryption 4 * |
5 * Filesystems that implement per-file encryption include this header 6 * file with the __FS_HAS_ENCRYPTION set according to whether that filesystem 7 * is being built with encryption support or not. | 5 * Filesystems that implement per-file encryption must include this header 6 * file. |
8 * 9 * Copyright (C) 2015, Google, Inc. 10 * 11 * Written by Michael Halcrow, 2015. 12 * Modified by Jaegeuk Kim, 2015. 13 */ 14#ifndef _LINUX_FSCRYPT_H 15#define _LINUX_FSCRYPT_H 16 17#include <linux/fs.h> | 7 * 8 * Copyright (C) 2015, Google, Inc. 9 * 10 * Written by Michael Halcrow, 2015. 11 * Modified by Jaegeuk Kim, 2015. 12 */ 13#ifndef _LINUX_FSCRYPT_H 14#define _LINUX_FSCRYPT_H 15 16#include <linux/fs.h> |
17#include <linux/mm.h> 18#include <linux/slab.h> |
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18 19#define FS_CRYPTO_BLOCK_SIZE 16 20 21struct fscrypt_ctx; 22struct fscrypt_info; 23 24struct fscrypt_str { 25 unsigned char *name; --- 11 unchanged lines hidden (view full) --- 37#define FSTR_INIT(n, l) { .name = n, .len = l } 38#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len) 39#define fname_name(p) ((p)->disk_name.name) 40#define fname_len(p) ((p)->disk_name.len) 41 42/* Maximum value for the third parameter of fscrypt_operations.set_context(). */ 43#define FSCRYPT_SET_CONTEXT_MAX_SIZE 28 44 | 19 20#define FS_CRYPTO_BLOCK_SIZE 16 21 22struct fscrypt_ctx; 23struct fscrypt_info; 24 25struct fscrypt_str { 26 unsigned char *name; --- 11 unchanged lines hidden (view full) --- 38#define FSTR_INIT(n, l) { .name = n, .len = l } 39#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len) 40#define fname_name(p) ((p)->disk_name.name) 41#define fname_len(p) ((p)->disk_name.len) 42 43/* Maximum value for the third parameter of fscrypt_operations.set_context(). */ 44#define FSCRYPT_SET_CONTEXT_MAX_SIZE 28 45 |
45#if __FS_HAS_ENCRYPTION 46#include <linux/fscrypt_supp.h> 47#else 48#include <linux/fscrypt_notsupp.h> 49#endif | 46#ifdef CONFIG_FS_ENCRYPTION 47/* 48 * fscrypt superblock flags 49 */ 50#define FS_CFLG_OWN_PAGES (1U << 1) |
50 | 51 |
52/* 53 * crypto operations for filesystems 54 */ 55struct fscrypt_operations { 56 unsigned int flags; 57 const char *key_prefix; 58 int (*get_context)(struct inode *, void *, size_t); 59 int (*set_context)(struct inode *, const void *, size_t, void *); 60 bool (*dummy_context)(struct inode *); 61 bool (*empty_dir)(struct inode *); 62 unsigned int max_namelen; 63}; 64 65struct fscrypt_ctx { 66 union { 67 struct { 68 struct page *bounce_page; /* Ciphertext page */ 69 struct page *control_page; /* Original page */ 70 } w; 71 struct { 72 struct bio *bio; 73 struct work_struct work; 74 } r; 75 struct list_head free_list; /* Free list */ 76 }; 77 u8 flags; /* Flags */ 78}; 79 80static inline bool fscrypt_has_encryption_key(const struct inode *inode) 81{ 82 return (inode->i_crypt_info != NULL); 83} 84 85static inline bool fscrypt_dummy_context_enabled(struct inode *inode) 86{ 87 return inode->i_sb->s_cop->dummy_context && 88 inode->i_sb->s_cop->dummy_context(inode); 89} 90 91/* crypto.c */ 92extern void fscrypt_enqueue_decrypt_work(struct work_struct *); 93extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t); 94extern void fscrypt_release_ctx(struct fscrypt_ctx *); 95extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *, 96 unsigned int, unsigned int, 97 u64, gfp_t); 98extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int, 99 unsigned int, u64); 100 101static inline struct page *fscrypt_control_page(struct page *page) 102{ 103 return ((struct fscrypt_ctx *)page_private(page))->w.control_page; 104} 105 106extern void fscrypt_restore_control_page(struct page *); 107 108/* policy.c */ 109extern int fscrypt_ioctl_set_policy(struct file *, const void __user *); 110extern int fscrypt_ioctl_get_policy(struct file *, void __user *); 111extern int fscrypt_has_permitted_context(struct inode *, struct inode *); 112extern int fscrypt_inherit_context(struct inode *, struct inode *, 113 void *, bool); 114/* keyinfo.c */ 115extern int fscrypt_get_encryption_info(struct inode *); 116extern void fscrypt_put_encryption_info(struct inode *); 117 118/* fname.c */ 119extern int fscrypt_setup_filename(struct inode *, const struct qstr *, 120 int lookup, struct fscrypt_name *); 121 122static inline void fscrypt_free_filename(struct fscrypt_name *fname) 123{ 124 kfree(fname->crypto_buf.name); 125} 126 127extern int fscrypt_fname_alloc_buffer(const struct inode *, u32, 128 struct fscrypt_str *); 129extern void fscrypt_fname_free_buffer(struct fscrypt_str *); 130extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32, 131 const struct fscrypt_str *, struct fscrypt_str *); 132 133#define FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE 32 134 135/* Extracts the second-to-last ciphertext block; see explanation below */ 136#define FSCRYPT_FNAME_DIGEST(name, len) \ 137 ((name) + round_down((len) - FS_CRYPTO_BLOCK_SIZE - 1, \ 138 FS_CRYPTO_BLOCK_SIZE)) 139 140#define FSCRYPT_FNAME_DIGEST_SIZE FS_CRYPTO_BLOCK_SIZE 141 |
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51/** | 142/** |
143 * fscrypt_digested_name - alternate identifier for an on-disk filename 144 * 145 * When userspace lists an encrypted directory without access to the key, 146 * filenames whose ciphertext is longer than FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE 147 * bytes are shown in this abbreviated form (base64-encoded) rather than as the 148 * full ciphertext (base64-encoded). This is necessary to allow supporting 149 * filenames up to NAME_MAX bytes, since base64 encoding expands the length. 150 * 151 * To make it possible for filesystems to still find the correct directory entry 152 * despite not knowing the full on-disk name, we encode any filesystem-specific 153 * 'hash' and/or 'minor_hash' which the filesystem may need for its lookups, 154 * followed by the second-to-last ciphertext block of the filename. Due to the 155 * use of the CBC-CTS encryption mode, the second-to-last ciphertext block 156 * depends on the full plaintext. (Note that ciphertext stealing causes the 157 * last two blocks to appear "flipped".) This makes accidental collisions very 158 * unlikely: just a 1 in 2^128 chance for two filenames to collide even if they 159 * share the same filesystem-specific hashes. 160 * 161 * However, this scheme isn't immune to intentional collisions, which can be 162 * created by anyone able to create arbitrary plaintext filenames and view them 163 * without the key. Making the "digest" be a real cryptographic hash like 164 * SHA-256 over the full ciphertext would prevent this, although it would be 165 * less efficient and harder to implement, especially since the filesystem would 166 * need to calculate it for each directory entry examined during a search. 167 */ 168struct fscrypt_digested_name { 169 u32 hash; 170 u32 minor_hash; 171 u8 digest[FSCRYPT_FNAME_DIGEST_SIZE]; 172}; 173 174/** 175 * fscrypt_match_name() - test whether the given name matches a directory entry 176 * @fname: the name being searched for 177 * @de_name: the name from the directory entry 178 * @de_name_len: the length of @de_name in bytes 179 * 180 * Normally @fname->disk_name will be set, and in that case we simply compare 181 * that to the name stored in the directory entry. The only exception is that 182 * if we don't have the key for an encrypted directory and a filename in it is 183 * very long, then we won't have the full disk_name and we'll instead need to 184 * match against the fscrypt_digested_name. 185 * 186 * Return: %true if the name matches, otherwise %false. 187 */ 188static inline bool fscrypt_match_name(const struct fscrypt_name *fname, 189 const u8 *de_name, u32 de_name_len) 190{ 191 if (unlikely(!fname->disk_name.name)) { 192 const struct fscrypt_digested_name *n = 193 (const void *)fname->crypto_buf.name; 194 if (WARN_ON_ONCE(fname->usr_fname->name[0] != '_')) 195 return false; 196 if (de_name_len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) 197 return false; 198 return !memcmp(FSCRYPT_FNAME_DIGEST(de_name, de_name_len), 199 n->digest, FSCRYPT_FNAME_DIGEST_SIZE); 200 } 201 202 if (de_name_len != fname->disk_name.len) 203 return false; 204 return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len); 205} 206 207/* bio.c */ 208extern void fscrypt_decrypt_bio(struct bio *); 209extern void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, 210 struct bio *bio); 211extern void fscrypt_pullback_bio_page(struct page **, bool); 212extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t, 213 unsigned int); 214 215/* hooks.c */ 216extern int fscrypt_file_open(struct inode *inode, struct file *filp); 217extern int __fscrypt_prepare_link(struct inode *inode, struct inode *dir); 218extern int __fscrypt_prepare_rename(struct inode *old_dir, 219 struct dentry *old_dentry, 220 struct inode *new_dir, 221 struct dentry *new_dentry, 222 unsigned int flags); 223extern int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry); 224extern int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len, 225 unsigned int max_len, 226 struct fscrypt_str *disk_link); 227extern int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, 228 unsigned int len, 229 struct fscrypt_str *disk_link); 230extern const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, 231 unsigned int max_size, 232 struct delayed_call *done); 233#else /* !CONFIG_FS_ENCRYPTION */ 234 235static inline bool fscrypt_has_encryption_key(const struct inode *inode) 236{ 237 return false; 238} 239 240static inline bool fscrypt_dummy_context_enabled(struct inode *inode) 241{ 242 return false; 243} 244 245/* crypto.c */ 246static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) 247{ 248} 249 250static inline struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode, 251 gfp_t gfp_flags) 252{ 253 return ERR_PTR(-EOPNOTSUPP); 254} 255 256static inline void fscrypt_release_ctx(struct fscrypt_ctx *ctx) 257{ 258 return; 259} 260 261static inline struct page *fscrypt_encrypt_page(const struct inode *inode, 262 struct page *page, 263 unsigned int len, 264 unsigned int offs, 265 u64 lblk_num, gfp_t gfp_flags) 266{ 267 return ERR_PTR(-EOPNOTSUPP); 268} 269 270static inline int fscrypt_decrypt_page(const struct inode *inode, 271 struct page *page, 272 unsigned int len, unsigned int offs, 273 u64 lblk_num) 274{ 275 return -EOPNOTSUPP; 276} 277 278static inline struct page *fscrypt_control_page(struct page *page) 279{ 280 WARN_ON_ONCE(1); 281 return ERR_PTR(-EINVAL); 282} 283 284static inline void fscrypt_restore_control_page(struct page *page) 285{ 286 return; 287} 288 289/* policy.c */ 290static inline int fscrypt_ioctl_set_policy(struct file *filp, 291 const void __user *arg) 292{ 293 return -EOPNOTSUPP; 294} 295 296static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg) 297{ 298 return -EOPNOTSUPP; 299} 300 301static inline int fscrypt_has_permitted_context(struct inode *parent, 302 struct inode *child) 303{ 304 return 0; 305} 306 307static inline int fscrypt_inherit_context(struct inode *parent, 308 struct inode *child, 309 void *fs_data, bool preload) 310{ 311 return -EOPNOTSUPP; 312} 313 314/* keyinfo.c */ 315static inline int fscrypt_get_encryption_info(struct inode *inode) 316{ 317 return -EOPNOTSUPP; 318} 319 320static inline void fscrypt_put_encryption_info(struct inode *inode) 321{ 322 return; 323} 324 325 /* fname.c */ 326static inline int fscrypt_setup_filename(struct inode *dir, 327 const struct qstr *iname, 328 int lookup, struct fscrypt_name *fname) 329{ 330 if (IS_ENCRYPTED(dir)) 331 return -EOPNOTSUPP; 332 333 memset(fname, 0, sizeof(struct fscrypt_name)); 334 fname->usr_fname = iname; 335 fname->disk_name.name = (unsigned char *)iname->name; 336 fname->disk_name.len = iname->len; 337 return 0; 338} 339 340static inline void fscrypt_free_filename(struct fscrypt_name *fname) 341{ 342 return; 343} 344 345static inline int fscrypt_fname_alloc_buffer(const struct inode *inode, 346 u32 max_encrypted_len, 347 struct fscrypt_str *crypto_str) 348{ 349 return -EOPNOTSUPP; 350} 351 352static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str) 353{ 354 return; 355} 356 357static inline int fscrypt_fname_disk_to_usr(struct inode *inode, 358 u32 hash, u32 minor_hash, 359 const struct fscrypt_str *iname, 360 struct fscrypt_str *oname) 361{ 362 return -EOPNOTSUPP; 363} 364 365static inline bool fscrypt_match_name(const struct fscrypt_name *fname, 366 const u8 *de_name, u32 de_name_len) 367{ 368 /* Encryption support disabled; use standard comparison */ 369 if (de_name_len != fname->disk_name.len) 370 return false; 371 return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len); 372} 373 374/* bio.c */ 375static inline void fscrypt_decrypt_bio(struct bio *bio) 376{ 377} 378 379static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, 380 struct bio *bio) 381{ 382} 383 384static inline void fscrypt_pullback_bio_page(struct page **page, bool restore) 385{ 386 return; 387} 388 389static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, 390 sector_t pblk, unsigned int len) 391{ 392 return -EOPNOTSUPP; 393} 394 395/* hooks.c */ 396 397static inline int fscrypt_file_open(struct inode *inode, struct file *filp) 398{ 399 if (IS_ENCRYPTED(inode)) 400 return -EOPNOTSUPP; 401 return 0; 402} 403 404static inline int __fscrypt_prepare_link(struct inode *inode, 405 struct inode *dir) 406{ 407 return -EOPNOTSUPP; 408} 409 410static inline int __fscrypt_prepare_rename(struct inode *old_dir, 411 struct dentry *old_dentry, 412 struct inode *new_dir, 413 struct dentry *new_dentry, 414 unsigned int flags) 415{ 416 return -EOPNOTSUPP; 417} 418 419static inline int __fscrypt_prepare_lookup(struct inode *dir, 420 struct dentry *dentry) 421{ 422 return -EOPNOTSUPP; 423} 424 425static inline int __fscrypt_prepare_symlink(struct inode *dir, 426 unsigned int len, 427 unsigned int max_len, 428 struct fscrypt_str *disk_link) 429{ 430 return -EOPNOTSUPP; 431} 432 433 434static inline int __fscrypt_encrypt_symlink(struct inode *inode, 435 const char *target, 436 unsigned int len, 437 struct fscrypt_str *disk_link) 438{ 439 return -EOPNOTSUPP; 440} 441 442static inline const char *fscrypt_get_symlink(struct inode *inode, 443 const void *caddr, 444 unsigned int max_size, 445 struct delayed_call *done) 446{ 447 return ERR_PTR(-EOPNOTSUPP); 448} 449#endif /* !CONFIG_FS_ENCRYPTION */ 450 451/** |
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52 * fscrypt_require_key - require an inode's encryption key 53 * @inode: the inode we need the key for 54 * 55 * If the inode is encrypted, set up its encryption key if not already done. 56 * Then require that the key be present and return -ENOKEY otherwise. 57 * 58 * No locks are needed, and the key will live as long as the struct inode --- so 59 * it won't go away from under you. --- 195 unchanged lines hidden --- | 452 * fscrypt_require_key - require an inode's encryption key 453 * @inode: the inode we need the key for 454 * 455 * If the inode is encrypted, set up its encryption key if not already done. 456 * Then require that the key be present and return -ENOKEY otherwise. 457 * 458 * No locks are needed, and the key will live as long as the struct inode --- so 459 * it won't go away from under you. --- 195 unchanged lines hidden --- |