1 // SPDX-License-Identifier: GPL-2.0 1
2 /*
3 * Copyright 2019 Google LLC
4 */
5
6 /*
7 * Refer to Documentation/block/inline-encrypt
8 */
9
10 #define pr_fmt(fmt) "blk-crypto: " fmt
11
12 #include <linux/bio.h>
13 #include <linux/blkdev.h>
14 #include <linux/blk-crypto-profile.h>
15 #include <linux/module.h>
16 #include <linux/ratelimit.h>
17 #include <linux/slab.h>
18
19 #include "blk-crypto-internal.h"
20
21 const struct blk_crypto_mode blk_crypto_modes[
22 [BLK_ENCRYPTION_MODE_AES_256_XTS] = {
23 .name = "AES-256-XTS",
24 .cipher_str = "xts(aes)",
25 .keysize = 64,
26 .ivsize = 16,
27 },
28 [BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV
29 .name = "AES-128-CBC-ESSIV",
30 .cipher_str = "essiv(cbc(aes),
31 .keysize = 16,
32 .ivsize = 16,
33 },
34 [BLK_ENCRYPTION_MODE_ADIANTUM] = {
35 .name = "Adiantum",
36 .cipher_str = "adiantum(xchach
37 .keysize = 32,
38 .ivsize = 32,
39 },
40 [BLK_ENCRYPTION_MODE_SM4_XTS] = {
41 .name = "SM4-XTS",
42 .cipher_str = "xts(sm4)",
43 .keysize = 32,
44 .ivsize = 16,
45 },
46 };
47
48 /*
49 * This number needs to be at least (the numbe
50 * concurrently) * (maximum recursive depth of
51 * deadlock on crypt_ctx allocations. The defa
52 * as the default number of post read contexts
53 */
54 static int num_prealloc_crypt_ctxs = 128;
55
56 module_param(num_prealloc_crypt_ctxs, int, 044
57 MODULE_PARM_DESC(num_prealloc_crypt_ctxs,
58 "Number of bio crypto contexts
59
60 static struct kmem_cache *bio_crypt_ctx_cache;
61 static mempool_t *bio_crypt_ctx_pool;
62
63 static int __init bio_crypt_ctx_init(void)
64 {
65 size_t i;
66
67 bio_crypt_ctx_cache = KMEM_CACHE(bio_c
68 if (!bio_crypt_ctx_cache)
69 goto out_no_mem;
70
71 bio_crypt_ctx_pool = mempool_create_sl
72
73 if (!bio_crypt_ctx_pool)
74 goto out_no_mem;
75
76 /* This is assumed in various places.
77 BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVAL
78
79 /* Sanity check that no algorithm exce
80 for (i = 0; i < BLK_ENCRYPTION_MODE_MA
81 BUG_ON(blk_crypto_modes[i].key
82 BUG_ON(blk_crypto_modes[i].ivs
83 }
84
85 return 0;
86 out_no_mem:
87 panic("Failed to allocate mem for bio
88 }
89 subsys_initcall(bio_crypt_ctx_init);
90
91 void bio_crypt_set_ctx(struct bio *bio, const
92 const u64 dun[BLK_CRYPT
93 {
94 struct bio_crypt_ctx *bc;
95
96 /*
97 * The caller must use a gfp_mask that
98 * that the mempool_alloc() can't fail
99 */
100 WARN_ON_ONCE(!(gfp_mask & __GFP_DIRECT
101
102 bc = mempool_alloc(bio_crypt_ctx_pool,
103
104 bc->bc_key = key;
105 memcpy(bc->bc_dun, dun, sizeof(bc->bc_
106
107 bio->bi_crypt_context = bc;
108 }
109
110 void __bio_crypt_free_ctx(struct bio *bio)
111 {
112 mempool_free(bio->bi_crypt_context, bi
113 bio->bi_crypt_context = NULL;
114 }
115
116 int __bio_crypt_clone(struct bio *dst, struct
117 {
118 dst->bi_crypt_context = mempool_alloc(
119 if (!dst->bi_crypt_context)
120 return -ENOMEM;
121 *dst->bi_crypt_context = *src->bi_cryp
122 return 0;
123 }
124
125 /* Increments @dun by @inc, treating @dun as a
126 void bio_crypt_dun_increment(u64 dun[BLK_CRYPT
127 unsigned int inc)
128 {
129 int i;
130
131 for (i = 0; inc && i < BLK_CRYPTO_DUN_
132 dun[i] += inc;
133 /*
134 * If the addition in this lim
135 * carry 1 into the next limb.
136 */
137 if (dun[i] < inc)
138 inc = 1;
139 else
140 inc = 0;
141 }
142 }
143
144 void __bio_crypt_advance(struct bio *bio, unsi
145 {
146 struct bio_crypt_ctx *bc = bio->bi_cry
147
148 bio_crypt_dun_increment(bc->bc_dun,
149 bytes >> bc->b
150 }
151
152 /*
153 * Returns true if @bc->bc_dun plus @bytes con
154 * @next_dun, treating the DUNs as multi-limb
155 */
156 bool bio_crypt_dun_is_contiguous(const struct
157 unsigned int
158 const u64 nex
159 {
160 int i;
161 unsigned int carry = bytes >> bc->bc_k
162
163 for (i = 0; i < BLK_CRYPTO_DUN_ARRAY_S
164 if (bc->bc_dun[i] + carry != n
165 return false;
166 /*
167 * If the addition in this lim
168 * carry 1 into the next limb.
169 */
170 if ((bc->bc_dun[i] + carry) <
171 carry = 1;
172 else
173 carry = 0;
174 }
175
176 /* If the DUN wrapped through 0, don't
177 return carry == 0;
178 }
179
180 /*
181 * Checks that two bio crypt contexts are comp
182 * they are mergeable except for data_unit_num
183 */
184 static bool bio_crypt_ctx_compatible(struct bi
185 struct bi
186 {
187 if (!bc1)
188 return !bc2;
189
190 return bc2 && bc1->bc_key == bc2->bc_k
191 }
192
193 bool bio_crypt_rq_ctx_compatible(struct reques
194 {
195 return bio_crypt_ctx_compatible(rq->cr
196 }
197
198 /*
199 * Checks that two bio crypt contexts are comp
200 * that their data_unit_nums are continuous (a
201 * in the order @bc1 followed by @bc2.
202 */
203 bool bio_crypt_ctx_mergeable(struct bio_crypt_
204 struct bio_crypt_
205 {
206 if (!bio_crypt_ctx_compatible(bc1, bc2
207 return false;
208
209 return !bc1 || bio_crypt_dun_is_contig
210 }
211
212 /* Check that all I/O segments are data unit a
213 static bool bio_crypt_check_alignment(struct b
214 {
215 const unsigned int data_unit_size =
216 bio->bi_crypt_context->bc_key-
217 struct bvec_iter iter;
218 struct bio_vec bv;
219
220 bio_for_each_segment(bv, bio, iter) {
221 if (!IS_ALIGNED(bv.bv_len | bv
222 return false;
223 }
224
225 return true;
226 }
227
228 blk_status_t __blk_crypto_rq_get_keyslot(struc
229 {
230 return blk_crypto_get_keyslot(rq->q->c
231 rq->cryp
232 &rq->cry
233 }
234
235 void __blk_crypto_rq_put_keyslot(struct reques
236 {
237 blk_crypto_put_keyslot(rq->crypt_keysl
238 rq->crypt_keyslot = NULL;
239 }
240
241 void __blk_crypto_free_request(struct request
242 {
243 /* The keyslot, if one was needed, sho
244 if (WARN_ON_ONCE(rq->crypt_keyslot))
245 __blk_crypto_rq_put_keyslot(rq
246
247 mempool_free(rq->crypt_ctx, bio_crypt_
248 rq->crypt_ctx = NULL;
249 }
250
251 /**
252 * __blk_crypto_bio_prep - Prepare bio for inl
253 *
254 * @bio_ptr: pointer to original bio pointer
255 *
256 * If the bio crypt context provided for the b
257 * device's inline encryption hardware, do not
258 *
259 * Otherwise, try to perform en/decryption for
260 * kernel crypto API. When the crypto API fall
261 * blk-crypto may choose to split the bio into
262 * continue to be processed and the second one
263 * submit_bio_noacct. A bounce bio will be all
264 * of the aforementioned "first one", and *bio
265 * bounce bio.
266 *
267 * Caller must ensure bio has bio_crypt_ctx.
268 *
269 * Return: true on success; false on error (an
270 * appropriately, and bio_endio() will
271 * submission should abort).
272 */
273 bool __blk_crypto_bio_prep(struct bio **bio_pt
274 {
275 struct bio *bio = *bio_ptr;
276 const struct blk_crypto_key *bc_key =
277
278 /* Error if bio has no data. */
279 if (WARN_ON_ONCE(!bio_has_data(bio)))
280 bio->bi_status = BLK_STS_IOERR
281 goto fail;
282 }
283
284 if (!bio_crypt_check_alignment(bio)) {
285 bio->bi_status = BLK_STS_IOERR
286 goto fail;
287 }
288
289 /*
290 * Success if device supports the encr
291 * in falling back to the crypto API.
292 */
293 if (blk_crypto_config_supported_native
294
295 return true;
296 if (blk_crypto_fallback_bio_prep(bio_p
297 return true;
298 fail:
299 bio_endio(*bio_ptr);
300 return false;
301 }
302
303 int __blk_crypto_rq_bio_prep(struct request *r
304 gfp_t gfp_mask)
305 {
306 if (!rq->crypt_ctx) {
307 rq->crypt_ctx = mempool_alloc(
308 if (!rq->crypt_ctx)
309 return -ENOMEM;
310 }
311 *rq->crypt_ctx = *bio->bi_crypt_contex
312 return 0;
313 }
314
315 /**
316 * blk_crypto_init_key() - Prepare a key for u
317 * @blk_key: Pointer to the blk_crypto_key to
318 * @raw_key: Pointer to the raw key. Must be t
319 * @crypto_mode; see blk_crypto_mode
320 * @crypto_mode: identifier for the encryption
321 * @dun_bytes: number of bytes that will be us
322 * key is used
323 * @data_unit_size: the data unit size to use
324 *
325 * Return: 0 on success, -errno on failure. T
326 * zeroizing both blk_key and raw_key
327 */
328 int blk_crypto_init_key(struct blk_crypto_key
329 enum blk_crypto_mode_n
330 unsigned int dun_bytes
331 unsigned int data_unit
332 {
333 const struct blk_crypto_mode *mode;
334
335 memset(blk_key, 0, sizeof(*blk_key));
336
337 if (crypto_mode >= ARRAY_SIZE(blk_cryp
338 return -EINVAL;
339
340 mode = &blk_crypto_modes[crypto_mode];
341 if (mode->keysize == 0)
342 return -EINVAL;
343
344 if (dun_bytes == 0 || dun_bytes > mode
345 return -EINVAL;
346
347 if (!is_power_of_2(data_unit_size))
348 return -EINVAL;
349
350 blk_key->crypto_cfg.crypto_mode = cryp
351 blk_key->crypto_cfg.dun_bytes = dun_by
352 blk_key->crypto_cfg.data_unit_size = d
353 blk_key->data_unit_size_bits = ilog2(d
354 blk_key->size = mode->keysize;
355 memcpy(blk_key->raw, raw_key, mode->ke
356
357 return 0;
358 }
359
360 bool blk_crypto_config_supported_natively(stru
361 cons
362 {
363 return __blk_crypto_cfg_supported(bdev
364 cfg)
365 }
366
367 /*
368 * Check if bios with @cfg can be en/decrypted
369 * block_device it's submitted to supports inl
370 * blk-crypto-fallback is enabled and supports
371 */
372 bool blk_crypto_config_supported(struct block_
373 const struct
374 {
375 return IS_ENABLED(CONFIG_BLK_INLINE_EN
376 blk_crypto_config_supported_nat
377 }
378
379 /**
380 * blk_crypto_start_using_key() - Start using
381 * @bdev: block device to operate on
382 * @key: A key to use on the device
383 *
384 * Upper layers must call this function to ens
385 * supports the key's crypto settings, or the
386 * for the needed mode allocated and ready to
387 * an skcipher, and *should not* be called fro
388 * cause a deadlock
389 *
390 * Return: 0 on success; -ENOPKG if the hardwa
391 * blk-crypto-fallback is either disab
392 * is disabled in the crypto API; or a
393 */
394 int blk_crypto_start_using_key(struct block_de
395 const struct bl
396 {
397 if (blk_crypto_config_supported_native
398 return 0;
399 return blk_crypto_fallback_start_using
400 }
401
402 /**
403 * blk_crypto_evict_key() - Evict a blk_crypto
404 * @bdev: a block_device on which I/O using th
405 * @key: the key to evict
406 *
407 * For a given block_device, this function rem
408 * the keyslot management structures and evict
409 * keyslot(s) or blk-crypto-fallback keyslot i
410 *
411 * Upper layers must call this before freeing
412 * called for every block_device the key may h
413 * longer be in use by any I/O when this funct
414 *
415 * Context: May sleep.
416 */
417 void blk_crypto_evict_key(struct block_device
418 const struct blk_cry
419 {
420 struct request_queue *q = bdev_get_que
421 int err;
422
423 if (blk_crypto_config_supported_native
424 err = __blk_crypto_evict_key(q
425 else
426 err = blk_crypto_fallback_evic
427 /*
428 * An error can only occur here if the
429 * keyslot (due to a hardware or drive
430 * use by I/O (due to a kernel bug).
431 * still unlinked from the keyslot man
432 * is allowed and expected to free it
433 * callers can do to handle errors, so
434 */
435 if (err)
436 pr_warn_ratelimited("%pg: erro
437 }
438 EXPORT_SYMBOL_GPL(blk_crypto_evict_key);
439
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