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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 Google LLC
4 */
5
6/*
7 * Refer to Documentation/block/inline-encryption.rst for detailed explanation.
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/slab.h>
17
18#include "blk-crypto-internal.h"
19
20const struct blk_crypto_mode blk_crypto_modes[] = {
21 [BLK_ENCRYPTION_MODE_AES_256_XTS] = {
22 .name = "AES-256-XTS",
23 .cipher_str = "xts(aes)",
24 .keysize = 64,
25 .ivsize = 16,
26 },
27 [BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV] = {
28 .name = "AES-128-CBC-ESSIV",
29 .cipher_str = "essiv(cbc(aes),sha256)",
30 .keysize = 16,
31 .ivsize = 16,
32 },
33 [BLK_ENCRYPTION_MODE_ADIANTUM] = {
34 .name = "Adiantum",
35 .cipher_str = "adiantum(xchacha12,aes)",
36 .keysize = 32,
37 .ivsize = 32,
38 },
39 [BLK_ENCRYPTION_MODE_SM4_XTS] = {
40 .name = "SM4-XTS",
41 .cipher_str = "xts(sm4)",
42 .keysize = 32,
43 .ivsize = 16,
44 },
45};
46
47/*
48 * This number needs to be at least (the number of threads doing IO
49 * concurrently) * (maximum recursive depth of a bio), so that we don't
50 * deadlock on crypt_ctx allocations. The default is chosen to be the same
51 * as the default number of post read contexts in both EXT4 and F2FS.
52 */
53static int num_prealloc_crypt_ctxs = 128;
54
55module_param(num_prealloc_crypt_ctxs, int, 0444);
56MODULE_PARM_DESC(num_prealloc_crypt_ctxs,
57 "Number of bio crypto contexts to preallocate");
58
59static struct kmem_cache *bio_crypt_ctx_cache;
60static mempool_t *bio_crypt_ctx_pool;
61
62static int __init bio_crypt_ctx_init(void)
63{
64 size_t i;
65
66 bio_crypt_ctx_cache = KMEM_CACHE(bio_crypt_ctx, 0);
67 if (!bio_crypt_ctx_cache)
68 goto out_no_mem;
69
70 bio_crypt_ctx_pool = mempool_create_slab_pool(num_prealloc_crypt_ctxs,
71 bio_crypt_ctx_cache);
72 if (!bio_crypt_ctx_pool)
73 goto out_no_mem;
74
75 /* This is assumed in various places. */
76 BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0);
77
78 /* Sanity check that no algorithm exceeds the defined limits. */
79 for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) {
80 BUG_ON(blk_crypto_modes[i].keysize > BLK_CRYPTO_MAX_KEY_SIZE);
81 BUG_ON(blk_crypto_modes[i].ivsize > BLK_CRYPTO_MAX_IV_SIZE);
82 }
83
84 return 0;
85out_no_mem:
86 panic("Failed to allocate mem for bio crypt ctxs\n");
87}
88subsys_initcall(bio_crypt_ctx_init);
89
90void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
91 const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE], gfp_t gfp_mask)
92{
93 struct bio_crypt_ctx *bc;
94
95 /*
96 * The caller must use a gfp_mask that contains __GFP_DIRECT_RECLAIM so
97 * that the mempool_alloc() can't fail.
98 */
99 WARN_ON_ONCE(!(gfp_mask & __GFP_DIRECT_RECLAIM));
100
101 bc = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
102
103 bc->bc_key = key;
104 memcpy(bc->bc_dun, dun, sizeof(bc->bc_dun));
105
106 bio->bi_crypt_context = bc;
107}
108
109void __bio_crypt_free_ctx(struct bio *bio)
110{
111 mempool_free(bio->bi_crypt_context, bio_crypt_ctx_pool);
112 bio->bi_crypt_context = NULL;
113}
114
115int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
116{
117 dst->bi_crypt_context = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
118 if (!dst->bi_crypt_context)
119 return -ENOMEM;
120 *dst->bi_crypt_context = *src->bi_crypt_context;
121 return 0;
122}
123
124/* Increments @dun by @inc, treating @dun as a multi-limb integer. */
125void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
126 unsigned int inc)
127{
128 int i;
129
130 for (i = 0; inc && i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
131 dun[i] += inc;
132 /*
133 * If the addition in this limb overflowed, then we need to
134 * carry 1 into the next limb. Else the carry is 0.
135 */
136 if (dun[i] < inc)
137 inc = 1;
138 else
139 inc = 0;
140 }
141}
142
143void __bio_crypt_advance(struct bio *bio, unsigned int bytes)
144{
145 struct bio_crypt_ctx *bc = bio->bi_crypt_context;
146
147 bio_crypt_dun_increment(bc->bc_dun,
148 bytes >> bc->bc_key->data_unit_size_bits);
149}
150
151/*
152 * Returns true if @bc->bc_dun plus @bytes converted to data units is equal to
153 * @next_dun, treating the DUNs as multi-limb integers.
154 */
155bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
156 unsigned int bytes,
157 const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
158{
159 int i;
160 unsigned int carry = bytes >> bc->bc_key->data_unit_size_bits;
161
162 for (i = 0; i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
163 if (bc->bc_dun[i] + carry != next_dun[i])
164 return false;
165 /*
166 * If the addition in this limb overflowed, then we need to
167 * carry 1 into the next limb. Else the carry is 0.
168 */
169 if ((bc->bc_dun[i] + carry) < carry)
170 carry = 1;
171 else
172 carry = 0;
173 }
174
175 /* If the DUN wrapped through 0, don't treat it as contiguous. */
176 return carry == 0;
177}
178
179/*
180 * Checks that two bio crypt contexts are compatible - i.e. that
181 * they are mergeable except for data_unit_num continuity.
182 */
183static bool bio_crypt_ctx_compatible(struct bio_crypt_ctx *bc1,
184 struct bio_crypt_ctx *bc2)
185{
186 if (!bc1)
187 return !bc2;
188
189 return bc2 && bc1->bc_key == bc2->bc_key;
190}
191
192bool bio_crypt_rq_ctx_compatible(struct request *rq, struct bio *bio)
193{
194 return bio_crypt_ctx_compatible(rq->crypt_ctx, bio->bi_crypt_context);
195}
196
197/*
198 * Checks that two bio crypt contexts are compatible, and also
199 * that their data_unit_nums are continuous (and can hence be merged)
200 * in the order @bc1 followed by @bc2.
201 */
202bool bio_crypt_ctx_mergeable(struct bio_crypt_ctx *bc1, unsigned int bc1_bytes,
203 struct bio_crypt_ctx *bc2)
204{
205 if (!bio_crypt_ctx_compatible(bc1, bc2))
206 return false;
207
208 return !bc1 || bio_crypt_dun_is_contiguous(bc1, bc1_bytes, bc2->bc_dun);
209}
210
211/* Check that all I/O segments are data unit aligned. */
212static bool bio_crypt_check_alignment(struct bio *bio)
213{
214 const unsigned int data_unit_size =
215 bio->bi_crypt_context->bc_key->crypto_cfg.data_unit_size;
216 struct bvec_iter iter;
217 struct bio_vec bv;
218
219 bio_for_each_segment(bv, bio, iter) {
220 if (!IS_ALIGNED(bv.bv_len | bv.bv_offset, data_unit_size))
221 return false;
222 }
223
224 return true;
225}
226
227blk_status_t __blk_crypto_init_request(struct request *rq)
228{
229 return blk_crypto_get_keyslot(rq->q->crypto_profile,
230 rq->crypt_ctx->bc_key,
231 &rq->crypt_keyslot);
232}
233
234/**
235 * __blk_crypto_free_request - Uninitialize the crypto fields of a request.
236 *
237 * @rq: The request whose crypto fields to uninitialize.
238 *
239 * Completely uninitializes the crypto fields of a request. If a keyslot has
240 * been programmed into some inline encryption hardware, that keyslot is
241 * released. The rq->crypt_ctx is also freed.
242 */
243void __blk_crypto_free_request(struct request *rq)
244{
245 blk_crypto_put_keyslot(rq->crypt_keyslot);
246 mempool_free(rq->crypt_ctx, bio_crypt_ctx_pool);
247 blk_crypto_rq_set_defaults(rq);
248}
249
250/**
251 * __blk_crypto_bio_prep - Prepare bio for inline encryption
252 *
253 * @bio_ptr: pointer to original bio pointer
254 *
255 * If the bio crypt context provided for the bio is supported by the underlying
256 * device's inline encryption hardware, do nothing.
257 *
258 * Otherwise, try to perform en/decryption for this bio by falling back to the
259 * kernel crypto API. When the crypto API fallback is used for encryption,
260 * blk-crypto may choose to split the bio into 2 - the first one that will
261 * continue to be processed and the second one that will be resubmitted via
262 * submit_bio_noacct. A bounce bio will be allocated to encrypt the contents
263 * of the aforementioned "first one", and *bio_ptr will be updated to this
264 * bounce bio.
265 *
266 * Caller must ensure bio has bio_crypt_ctx.
267 *
268 * Return: true on success; false on error (and bio->bi_status will be set
269 * appropriately, and bio_endio() will have been called so bio
270 * submission should abort).
271 */
272bool __blk_crypto_bio_prep(struct bio **bio_ptr)
273{
274 struct bio *bio = *bio_ptr;
275 const struct blk_crypto_key *bc_key = bio->bi_crypt_context->bc_key;
276
277 /* Error if bio has no data. */
278 if (WARN_ON_ONCE(!bio_has_data(bio))) {
279 bio->bi_status = BLK_STS_IOERR;
280 goto fail;
281 }
282
283 if (!bio_crypt_check_alignment(bio)) {
284 bio->bi_status = BLK_STS_IOERR;
285 goto fail;
286 }
287
288 /*
289 * Success if device supports the encryption context, or if we succeeded
290 * in falling back to the crypto API.
291 */
292 if (blk_crypto_config_supported_natively(bio->bi_bdev,
293 &bc_key->crypto_cfg))
294 return true;
295 if (blk_crypto_fallback_bio_prep(bio_ptr))
296 return true;
297fail:
298 bio_endio(*bio_ptr);
299 return false;
300}
301
302int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
303 gfp_t gfp_mask)
304{
305 if (!rq->crypt_ctx) {
306 rq->crypt_ctx = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
307 if (!rq->crypt_ctx)
308 return -ENOMEM;
309 }
310 *rq->crypt_ctx = *bio->bi_crypt_context;
311 return 0;
312}
313
314/**
315 * blk_crypto_init_key() - Prepare a key for use with blk-crypto
316 * @blk_key: Pointer to the blk_crypto_key to initialize.
317 * @raw_key: Pointer to the raw key. Must be the correct length for the chosen
318 * @crypto_mode; see blk_crypto_modes[].
319 * @crypto_mode: identifier for the encryption algorithm to use
320 * @dun_bytes: number of bytes that will be used to specify the DUN when this
321 * key is used
322 * @data_unit_size: the data unit size to use for en/decryption
323 *
324 * Return: 0 on success, -errno on failure. The caller is responsible for
325 * zeroizing both blk_key and raw_key when done with them.
326 */
327int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key,
328 enum blk_crypto_mode_num crypto_mode,
329 unsigned int dun_bytes,
330 unsigned int data_unit_size)
331{
332 const struct blk_crypto_mode *mode;
333
334 memset(blk_key, 0, sizeof(*blk_key));
335
336 if (crypto_mode >= ARRAY_SIZE(blk_crypto_modes))
337 return -EINVAL;
338
339 mode = &blk_crypto_modes[crypto_mode];
340 if (mode->keysize == 0)
341 return -EINVAL;
342
343 if (dun_bytes == 0 || dun_bytes > mode->ivsize)
344 return -EINVAL;
345
346 if (!is_power_of_2(data_unit_size))
347 return -EINVAL;
348
349 blk_key->crypto_cfg.crypto_mode = crypto_mode;
350 blk_key->crypto_cfg.dun_bytes = dun_bytes;
351 blk_key->crypto_cfg.data_unit_size = data_unit_size;
352 blk_key->data_unit_size_bits = ilog2(data_unit_size);
353 blk_key->size = mode->keysize;
354 memcpy(blk_key->raw, raw_key, mode->keysize);
355
356 return 0;
357}
358
359bool blk_crypto_config_supported_natively(struct block_device *bdev,
360 const struct blk_crypto_config *cfg)
361{
362 return __blk_crypto_cfg_supported(bdev_get_queue(bdev)->crypto_profile,
363 cfg);
364}
365
366/*
367 * Check if bios with @cfg can be en/decrypted by blk-crypto (i.e. either the
368 * block_device it's submitted to supports inline crypto, or the
369 * blk-crypto-fallback is enabled and supports the cfg).
370 */
371bool blk_crypto_config_supported(struct block_device *bdev,
372 const struct blk_crypto_config *cfg)
373{
374 return IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) ||
375 blk_crypto_config_supported_natively(bdev, cfg);
376}
377
378/**
379 * blk_crypto_start_using_key() - Start using a blk_crypto_key on a device
380 * @bdev: block device to operate on
381 * @key: A key to use on the device
382 *
383 * Upper layers must call this function to ensure that either the hardware
384 * supports the key's crypto settings, or the crypto API fallback has transforms
385 * for the needed mode allocated and ready to go. This function may allocate
386 * an skcipher, and *should not* be called from the data path, since that might
387 * cause a deadlock
388 *
389 * Return: 0 on success; -ENOPKG if the hardware doesn't support the key and
390 * blk-crypto-fallback is either disabled or the needed algorithm
391 * is disabled in the crypto API; or another -errno code.
392 */
393int blk_crypto_start_using_key(struct block_device *bdev,
394 const struct blk_crypto_key *key)
395{
396 if (blk_crypto_config_supported_natively(bdev, &key->crypto_cfg))
397 return 0;
398 return blk_crypto_fallback_start_using_mode(key->crypto_cfg.crypto_mode);
399}
400
401/**
402 * blk_crypto_evict_key() - Evict a key from any inline encryption hardware
403 * it may have been programmed into
404 * @bdev: The block_device who's associated inline encryption hardware this key
405 * might have been programmed into
406 * @key: The key to evict
407 *
408 * Upper layers (filesystems) must call this function to ensure that a key is
409 * evicted from any hardware that it might have been programmed into. The key
410 * must not be in use by any in-flight IO when this function is called.
411 *
412 * Return: 0 on success or if the key wasn't in any keyslot; -errno on error.
413 */
414int blk_crypto_evict_key(struct block_device *bdev,
415 const struct blk_crypto_key *key)
416{
417 struct request_queue *q = bdev_get_queue(bdev);
418
419 if (blk_crypto_config_supported_natively(bdev, &key->crypto_cfg))
420 return __blk_crypto_evict_key(q->crypto_profile, key);
421
422 /*
423 * If the block_device didn't support the key, then blk-crypto-fallback
424 * may have been used, so try to evict the key from blk-crypto-fallback.
425 */
426 return blk_crypto_fallback_evict_key(key);
427}
428EXPORT_SYMBOL_GPL(blk_crypto_evict_key);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 Google LLC
4 */
5
6/*
7 * Refer to Documentation/block/inline-encryption.rst for detailed explanation.
8 */
9
10#define pr_fmt(fmt) "blk-crypto: " fmt
11
12#include <linux/bio.h>
13#include <linux/blkdev.h>
14#include <linux/keyslot-manager.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17
18#include "blk-crypto-internal.h"
19
20const struct blk_crypto_mode blk_crypto_modes[] = {
21 [BLK_ENCRYPTION_MODE_AES_256_XTS] = {
22 .cipher_str = "xts(aes)",
23 .keysize = 64,
24 .ivsize = 16,
25 },
26 [BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV] = {
27 .cipher_str = "essiv(cbc(aes),sha256)",
28 .keysize = 16,
29 .ivsize = 16,
30 },
31 [BLK_ENCRYPTION_MODE_ADIANTUM] = {
32 .cipher_str = "adiantum(xchacha12,aes)",
33 .keysize = 32,
34 .ivsize = 32,
35 },
36};
37
38/*
39 * This number needs to be at least (the number of threads doing IO
40 * concurrently) * (maximum recursive depth of a bio), so that we don't
41 * deadlock on crypt_ctx allocations. The default is chosen to be the same
42 * as the default number of post read contexts in both EXT4 and F2FS.
43 */
44static int num_prealloc_crypt_ctxs = 128;
45
46module_param(num_prealloc_crypt_ctxs, int, 0444);
47MODULE_PARM_DESC(num_prealloc_crypt_ctxs,
48 "Number of bio crypto contexts to preallocate");
49
50static struct kmem_cache *bio_crypt_ctx_cache;
51static mempool_t *bio_crypt_ctx_pool;
52
53static int __init bio_crypt_ctx_init(void)
54{
55 size_t i;
56
57 bio_crypt_ctx_cache = KMEM_CACHE(bio_crypt_ctx, 0);
58 if (!bio_crypt_ctx_cache)
59 goto out_no_mem;
60
61 bio_crypt_ctx_pool = mempool_create_slab_pool(num_prealloc_crypt_ctxs,
62 bio_crypt_ctx_cache);
63 if (!bio_crypt_ctx_pool)
64 goto out_no_mem;
65
66 /* This is assumed in various places. */
67 BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0);
68
69 /* Sanity check that no algorithm exceeds the defined limits. */
70 for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) {
71 BUG_ON(blk_crypto_modes[i].keysize > BLK_CRYPTO_MAX_KEY_SIZE);
72 BUG_ON(blk_crypto_modes[i].ivsize > BLK_CRYPTO_MAX_IV_SIZE);
73 }
74
75 return 0;
76out_no_mem:
77 panic("Failed to allocate mem for bio crypt ctxs\n");
78}
79subsys_initcall(bio_crypt_ctx_init);
80
81void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
82 const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE], gfp_t gfp_mask)
83{
84 struct bio_crypt_ctx *bc = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
85
86 bc->bc_key = key;
87 memcpy(bc->bc_dun, dun, sizeof(bc->bc_dun));
88
89 bio->bi_crypt_context = bc;
90}
91
92void __bio_crypt_free_ctx(struct bio *bio)
93{
94 mempool_free(bio->bi_crypt_context, bio_crypt_ctx_pool);
95 bio->bi_crypt_context = NULL;
96}
97
98void __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
99{
100 dst->bi_crypt_context = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
101 *dst->bi_crypt_context = *src->bi_crypt_context;
102}
103EXPORT_SYMBOL_GPL(__bio_crypt_clone);
104
105/* Increments @dun by @inc, treating @dun as a multi-limb integer. */
106void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
107 unsigned int inc)
108{
109 int i;
110
111 for (i = 0; inc && i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
112 dun[i] += inc;
113 /*
114 * If the addition in this limb overflowed, then we need to
115 * carry 1 into the next limb. Else the carry is 0.
116 */
117 if (dun[i] < inc)
118 inc = 1;
119 else
120 inc = 0;
121 }
122}
123
124void __bio_crypt_advance(struct bio *bio, unsigned int bytes)
125{
126 struct bio_crypt_ctx *bc = bio->bi_crypt_context;
127
128 bio_crypt_dun_increment(bc->bc_dun,
129 bytes >> bc->bc_key->data_unit_size_bits);
130}
131
132/*
133 * Returns true if @bc->bc_dun plus @bytes converted to data units is equal to
134 * @next_dun, treating the DUNs as multi-limb integers.
135 */
136bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
137 unsigned int bytes,
138 const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
139{
140 int i;
141 unsigned int carry = bytes >> bc->bc_key->data_unit_size_bits;
142
143 for (i = 0; i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
144 if (bc->bc_dun[i] + carry != next_dun[i])
145 return false;
146 /*
147 * If the addition in this limb overflowed, then we need to
148 * carry 1 into the next limb. Else the carry is 0.
149 */
150 if ((bc->bc_dun[i] + carry) < carry)
151 carry = 1;
152 else
153 carry = 0;
154 }
155
156 /* If the DUN wrapped through 0, don't treat it as contiguous. */
157 return carry == 0;
158}
159
160/*
161 * Checks that two bio crypt contexts are compatible - i.e. that
162 * they are mergeable except for data_unit_num continuity.
163 */
164static bool bio_crypt_ctx_compatible(struct bio_crypt_ctx *bc1,
165 struct bio_crypt_ctx *bc2)
166{
167 if (!bc1)
168 return !bc2;
169
170 return bc2 && bc1->bc_key == bc2->bc_key;
171}
172
173bool bio_crypt_rq_ctx_compatible(struct request *rq, struct bio *bio)
174{
175 return bio_crypt_ctx_compatible(rq->crypt_ctx, bio->bi_crypt_context);
176}
177
178/*
179 * Checks that two bio crypt contexts are compatible, and also
180 * that their data_unit_nums are continuous (and can hence be merged)
181 * in the order @bc1 followed by @bc2.
182 */
183bool bio_crypt_ctx_mergeable(struct bio_crypt_ctx *bc1, unsigned int bc1_bytes,
184 struct bio_crypt_ctx *bc2)
185{
186 if (!bio_crypt_ctx_compatible(bc1, bc2))
187 return false;
188
189 return !bc1 || bio_crypt_dun_is_contiguous(bc1, bc1_bytes, bc2->bc_dun);
190}
191
192/* Check that all I/O segments are data unit aligned. */
193static bool bio_crypt_check_alignment(struct bio *bio)
194{
195 const unsigned int data_unit_size =
196 bio->bi_crypt_context->bc_key->crypto_cfg.data_unit_size;
197 struct bvec_iter iter;
198 struct bio_vec bv;
199
200 bio_for_each_segment(bv, bio, iter) {
201 if (!IS_ALIGNED(bv.bv_len | bv.bv_offset, data_unit_size))
202 return false;
203 }
204
205 return true;
206}
207
208blk_status_t __blk_crypto_init_request(struct request *rq)
209{
210 return blk_ksm_get_slot_for_key(rq->q->ksm, rq->crypt_ctx->bc_key,
211 &rq->crypt_keyslot);
212}
213
214/**
215 * __blk_crypto_free_request - Uninitialize the crypto fields of a request.
216 *
217 * @rq: The request whose crypto fields to uninitialize.
218 *
219 * Completely uninitializes the crypto fields of a request. If a keyslot has
220 * been programmed into some inline encryption hardware, that keyslot is
221 * released. The rq->crypt_ctx is also freed.
222 */
223void __blk_crypto_free_request(struct request *rq)
224{
225 blk_ksm_put_slot(rq->crypt_keyslot);
226 mempool_free(rq->crypt_ctx, bio_crypt_ctx_pool);
227 blk_crypto_rq_set_defaults(rq);
228}
229
230/**
231 * __blk_crypto_bio_prep - Prepare bio for inline encryption
232 *
233 * @bio_ptr: pointer to original bio pointer
234 *
235 * If the bio crypt context provided for the bio is supported by the underlying
236 * device's inline encryption hardware, do nothing.
237 *
238 * Otherwise, try to perform en/decryption for this bio by falling back to the
239 * kernel crypto API. When the crypto API fallback is used for encryption,
240 * blk-crypto may choose to split the bio into 2 - the first one that will
241 * continue to be processed and the second one that will be resubmitted via
242 * submit_bio_noacct. A bounce bio will be allocated to encrypt the contents
243 * of the aforementioned "first one", and *bio_ptr will be updated to this
244 * bounce bio.
245 *
246 * Caller must ensure bio has bio_crypt_ctx.
247 *
248 * Return: true on success; false on error (and bio->bi_status will be set
249 * appropriately, and bio_endio() will have been called so bio
250 * submission should abort).
251 */
252bool __blk_crypto_bio_prep(struct bio **bio_ptr)
253{
254 struct bio *bio = *bio_ptr;
255 const struct blk_crypto_key *bc_key = bio->bi_crypt_context->bc_key;
256
257 /* Error if bio has no data. */
258 if (WARN_ON_ONCE(!bio_has_data(bio))) {
259 bio->bi_status = BLK_STS_IOERR;
260 goto fail;
261 }
262
263 if (!bio_crypt_check_alignment(bio)) {
264 bio->bi_status = BLK_STS_IOERR;
265 goto fail;
266 }
267
268 /*
269 * Success if device supports the encryption context, or if we succeeded
270 * in falling back to the crypto API.
271 */
272 if (blk_ksm_crypto_cfg_supported(bio->bi_disk->queue->ksm,
273 &bc_key->crypto_cfg))
274 return true;
275
276 if (blk_crypto_fallback_bio_prep(bio_ptr))
277 return true;
278fail:
279 bio_endio(*bio_ptr);
280 return false;
281}
282
283/**
284 * __blk_crypto_rq_bio_prep - Prepare a request's crypt_ctx when its first bio
285 * is inserted
286 *
287 * @rq: The request to prepare
288 * @bio: The first bio being inserted into the request
289 * @gfp_mask: gfp mask
290 */
291void __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
292 gfp_t gfp_mask)
293{
294 if (!rq->crypt_ctx)
295 rq->crypt_ctx = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
296 *rq->crypt_ctx = *bio->bi_crypt_context;
297}
298
299/**
300 * blk_crypto_init_key() - Prepare a key for use with blk-crypto
301 * @blk_key: Pointer to the blk_crypto_key to initialize.
302 * @raw_key: Pointer to the raw key. Must be the correct length for the chosen
303 * @crypto_mode; see blk_crypto_modes[].
304 * @crypto_mode: identifier for the encryption algorithm to use
305 * @dun_bytes: number of bytes that will be used to specify the DUN when this
306 * key is used
307 * @data_unit_size: the data unit size to use for en/decryption
308 *
309 * Return: 0 on success, -errno on failure. The caller is responsible for
310 * zeroizing both blk_key and raw_key when done with them.
311 */
312int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key,
313 enum blk_crypto_mode_num crypto_mode,
314 unsigned int dun_bytes,
315 unsigned int data_unit_size)
316{
317 const struct blk_crypto_mode *mode;
318
319 memset(blk_key, 0, sizeof(*blk_key));
320
321 if (crypto_mode >= ARRAY_SIZE(blk_crypto_modes))
322 return -EINVAL;
323
324 mode = &blk_crypto_modes[crypto_mode];
325 if (mode->keysize == 0)
326 return -EINVAL;
327
328 if (dun_bytes == 0 || dun_bytes > BLK_CRYPTO_MAX_IV_SIZE)
329 return -EINVAL;
330
331 if (!is_power_of_2(data_unit_size))
332 return -EINVAL;
333
334 blk_key->crypto_cfg.crypto_mode = crypto_mode;
335 blk_key->crypto_cfg.dun_bytes = dun_bytes;
336 blk_key->crypto_cfg.data_unit_size = data_unit_size;
337 blk_key->data_unit_size_bits = ilog2(data_unit_size);
338 blk_key->size = mode->keysize;
339 memcpy(blk_key->raw, raw_key, mode->keysize);
340
341 return 0;
342}
343
344/*
345 * Check if bios with @cfg can be en/decrypted by blk-crypto (i.e. either the
346 * request queue it's submitted to supports inline crypto, or the
347 * blk-crypto-fallback is enabled and supports the cfg).
348 */
349bool blk_crypto_config_supported(struct request_queue *q,
350 const struct blk_crypto_config *cfg)
351{
352 return IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) ||
353 blk_ksm_crypto_cfg_supported(q->ksm, cfg);
354}
355
356/**
357 * blk_crypto_start_using_key() - Start using a blk_crypto_key on a device
358 * @key: A key to use on the device
359 * @q: the request queue for the device
360 *
361 * Upper layers must call this function to ensure that either the hardware
362 * supports the key's crypto settings, or the crypto API fallback has transforms
363 * for the needed mode allocated and ready to go. This function may allocate
364 * an skcipher, and *should not* be called from the data path, since that might
365 * cause a deadlock
366 *
367 * Return: 0 on success; -ENOPKG if the hardware doesn't support the key and
368 * blk-crypto-fallback is either disabled or the needed algorithm
369 * is disabled in the crypto API; or another -errno code.
370 */
371int blk_crypto_start_using_key(const struct blk_crypto_key *key,
372 struct request_queue *q)
373{
374 if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
375 return 0;
376 return blk_crypto_fallback_start_using_mode(key->crypto_cfg.crypto_mode);
377}
378
379/**
380 * blk_crypto_evict_key() - Evict a key from any inline encryption hardware
381 * it may have been programmed into
382 * @q: The request queue who's associated inline encryption hardware this key
383 * might have been programmed into
384 * @key: The key to evict
385 *
386 * Upper layers (filesystems) must call this function to ensure that a key is
387 * evicted from any hardware that it might have been programmed into. The key
388 * must not be in use by any in-flight IO when this function is called.
389 *
390 * Return: 0 on success or if key is not present in the q's ksm, -err on error.
391 */
392int blk_crypto_evict_key(struct request_queue *q,
393 const struct blk_crypto_key *key)
394{
395 if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
396 return blk_ksm_evict_key(q->ksm, key);
397
398 /*
399 * If the request queue's associated inline encryption hardware didn't
400 * have support for the key, then the key might have been programmed
401 * into the fallback keyslot manager, so try to evict from there.
402 */
403 return blk_crypto_fallback_evict_key(key);
404}