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TOMOYO Linux Cross Reference
Linux/crypto/skcipher.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  * Symmetric key cipher operations.
  4  *
  5  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
  6  * multiple page boundaries by using temporary blocks.  In user context,
  7  * the kernel is given a chance to schedule us once per page.
  8  *
  9  * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
 10  */
 11 
 12 #include <crypto/internal/aead.h>
 13 #include <crypto/internal/skcipher.h>
 14 #include <crypto/scatterwalk.h>
 15 #include <linux/bug.h>
 16 #include <linux/cryptouser.h>
 17 #include <linux/compiler.h>
 18 #include <linux/list.h>
 19 #include <linux/module.h>
 20 #include <linux/rtnetlink.h>
 21 #include <linux/seq_file.h>
 22 #include <net/netlink.h>
 23 
 24 #include "internal.h"
 25 
 26 enum {
 27         SKCIPHER_WALK_PHYS = 1 << 0,
 28         SKCIPHER_WALK_SLOW = 1 << 1,
 29         SKCIPHER_WALK_COPY = 1 << 2,
 30         SKCIPHER_WALK_DIFF = 1 << 3,
 31         SKCIPHER_WALK_SLEEP = 1 << 4,
 32 };
 33 
 34 struct skcipher_walk_buffer {
 35         struct list_head entry;
 36         struct scatter_walk dst;
 37         unsigned int len;
 38         u8 *data;
 39         u8 buffer[];
 40 };
 41 
 42 static int skcipher_walk_next(struct skcipher_walk *walk);
 43 
 44 static inline void skcipher_unmap(struct scatter_walk *walk, void *vaddr)
 45 {
 46         if (PageHighMem(scatterwalk_page(walk)))
 47                 kunmap_atomic(vaddr);
 48 }
 49 
 50 static inline void *skcipher_map(struct scatter_walk *walk)
 51 {
 52         struct page *page = scatterwalk_page(walk);
 53 
 54         return (PageHighMem(page) ? kmap_atomic(page) : page_address(page)) +
 55                offset_in_page(walk->offset);
 56 }
 57 
 58 static inline void skcipher_map_src(struct skcipher_walk *walk)
 59 {
 60         walk->src.virt.addr = skcipher_map(&walk->in);
 61 }
 62 
 63 static inline void skcipher_map_dst(struct skcipher_walk *walk)
 64 {
 65         walk->dst.virt.addr = skcipher_map(&walk->out);
 66 }
 67 
 68 static inline void skcipher_unmap_src(struct skcipher_walk *walk)
 69 {
 70         skcipher_unmap(&walk->in, walk->src.virt.addr);
 71 }
 72 
 73 static inline void skcipher_unmap_dst(struct skcipher_walk *walk)
 74 {
 75         skcipher_unmap(&walk->out, walk->dst.virt.addr);
 76 }
 77 
 78 static inline gfp_t skcipher_walk_gfp(struct skcipher_walk *walk)
 79 {
 80         return walk->flags & SKCIPHER_WALK_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
 81 }
 82 
 83 /* Get a spot of the specified length that does not straddle a page.
 84  * The caller needs to ensure that there is enough space for this operation.
 85  */
 86 static inline u8 *skcipher_get_spot(u8 *start, unsigned int len)
 87 {
 88         u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
 89 
 90         return max(start, end_page);
 91 }
 92 
 93 static int skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize)
 94 {
 95         u8 *addr;
 96 
 97         addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
 98         addr = skcipher_get_spot(addr, bsize);
 99         scatterwalk_copychunks(addr, &walk->out, bsize,
100                                (walk->flags & SKCIPHER_WALK_PHYS) ? 2 : 1);
101         return 0;
102 }
103 
104 int skcipher_walk_done(struct skcipher_walk *walk, int err)
105 {
106         unsigned int n = walk->nbytes;
107         unsigned int nbytes = 0;
108 
109         if (!n)
110                 goto finish;
111 
112         if (likely(err >= 0)) {
113                 n -= err;
114                 nbytes = walk->total - n;
115         }
116 
117         if (likely(!(walk->flags & (SKCIPHER_WALK_PHYS |
118                                     SKCIPHER_WALK_SLOW |
119                                     SKCIPHER_WALK_COPY |
120                                     SKCIPHER_WALK_DIFF)))) {
121 unmap_src:
122                 skcipher_unmap_src(walk);
123         } else if (walk->flags & SKCIPHER_WALK_DIFF) {
124                 skcipher_unmap_dst(walk);
125                 goto unmap_src;
126         } else if (walk->flags & SKCIPHER_WALK_COPY) {
127                 skcipher_map_dst(walk);
128                 memcpy(walk->dst.virt.addr, walk->page, n);
129                 skcipher_unmap_dst(walk);
130         } else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) {
131                 if (err > 0) {
132                         /*
133                          * Didn't process all bytes.  Either the algorithm is
134                          * broken, or this was the last step and it turned out
135                          * the message wasn't evenly divisible into blocks but
136                          * the algorithm requires it.
137                          */
138                         err = -EINVAL;
139                         nbytes = 0;
140                 } else
141                         n = skcipher_done_slow(walk, n);
142         }
143 
144         if (err > 0)
145                 err = 0;
146 
147         walk->total = nbytes;
148         walk->nbytes = 0;
149 
150         scatterwalk_advance(&walk->in, n);
151         scatterwalk_advance(&walk->out, n);
152         scatterwalk_done(&walk->in, 0, nbytes);
153         scatterwalk_done(&walk->out, 1, nbytes);
154 
155         if (nbytes) {
156                 crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ?
157                              CRYPTO_TFM_REQ_MAY_SLEEP : 0);
158                 return skcipher_walk_next(walk);
159         }
160 
161 finish:
162         /* Short-circuit for the common/fast path. */
163         if (!((unsigned long)walk->buffer | (unsigned long)walk->page))
164                 goto out;
165 
166         if (walk->flags & SKCIPHER_WALK_PHYS)
167                 goto out;
168 
169         if (walk->iv != walk->oiv)
170                 memcpy(walk->oiv, walk->iv, walk->ivsize);
171         if (walk->buffer != walk->page)
172                 kfree(walk->buffer);
173         if (walk->page)
174                 free_page((unsigned long)walk->page);
175 
176 out:
177         return err;
178 }
179 EXPORT_SYMBOL_GPL(skcipher_walk_done);
180 
181 void skcipher_walk_complete(struct skcipher_walk *walk, int err)
182 {
183         struct skcipher_walk_buffer *p, *tmp;
184 
185         list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
186                 u8 *data;
187 
188                 if (err)
189                         goto done;
190 
191                 data = p->data;
192                 if (!data) {
193                         data = PTR_ALIGN(&p->buffer[0], walk->alignmask + 1);
194                         data = skcipher_get_spot(data, walk->stride);
195                 }
196 
197                 scatterwalk_copychunks(data, &p->dst, p->len, 1);
198 
199                 if (offset_in_page(p->data) + p->len + walk->stride >
200                     PAGE_SIZE)
201                         free_page((unsigned long)p->data);
202 
203 done:
204                 list_del(&p->entry);
205                 kfree(p);
206         }
207 
208         if (!err && walk->iv != walk->oiv)
209                 memcpy(walk->oiv, walk->iv, walk->ivsize);
210         if (walk->buffer != walk->page)
211                 kfree(walk->buffer);
212         if (walk->page)
213                 free_page((unsigned long)walk->page);
214 }
215 EXPORT_SYMBOL_GPL(skcipher_walk_complete);
216 
217 static void skcipher_queue_write(struct skcipher_walk *walk,
218                                  struct skcipher_walk_buffer *p)
219 {
220         p->dst = walk->out;
221         list_add_tail(&p->entry, &walk->buffers);
222 }
223 
224 static int skcipher_next_slow(struct skcipher_walk *walk, unsigned int bsize)
225 {
226         bool phys = walk->flags & SKCIPHER_WALK_PHYS;
227         unsigned alignmask = walk->alignmask;
228         struct skcipher_walk_buffer *p;
229         unsigned a;
230         unsigned n;
231         u8 *buffer;
232         void *v;
233 
234         if (!phys) {
235                 if (!walk->buffer)
236                         walk->buffer = walk->page;
237                 buffer = walk->buffer;
238                 if (buffer)
239                         goto ok;
240         }
241 
242         /* Start with the minimum alignment of kmalloc. */
243         a = crypto_tfm_ctx_alignment() - 1;
244         n = bsize;
245 
246         if (phys) {
247                 /* Calculate the minimum alignment of p->buffer. */
248                 a &= (sizeof(*p) ^ (sizeof(*p) - 1)) >> 1;
249                 n += sizeof(*p);
250         }
251 
252         /* Minimum size to align p->buffer by alignmask. */
253         n += alignmask & ~a;
254 
255         /* Minimum size to ensure p->buffer does not straddle a page. */
256         n += (bsize - 1) & ~(alignmask | a);
257 
258         v = kzalloc(n, skcipher_walk_gfp(walk));
259         if (!v)
260                 return skcipher_walk_done(walk, -ENOMEM);
261 
262         if (phys) {
263                 p = v;
264                 p->len = bsize;
265                 skcipher_queue_write(walk, p);
266                 buffer = p->buffer;
267         } else {
268                 walk->buffer = v;
269                 buffer = v;
270         }
271 
272 ok:
273         walk->dst.virt.addr = PTR_ALIGN(buffer, alignmask + 1);
274         walk->dst.virt.addr = skcipher_get_spot(walk->dst.virt.addr, bsize);
275         walk->src.virt.addr = walk->dst.virt.addr;
276 
277         scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
278 
279         walk->nbytes = bsize;
280         walk->flags |= SKCIPHER_WALK_SLOW;
281 
282         return 0;
283 }
284 
285 static int skcipher_next_copy(struct skcipher_walk *walk)
286 {
287         struct skcipher_walk_buffer *p;
288         u8 *tmp = walk->page;
289 
290         skcipher_map_src(walk);
291         memcpy(tmp, walk->src.virt.addr, walk->nbytes);
292         skcipher_unmap_src(walk);
293 
294         walk->src.virt.addr = tmp;
295         walk->dst.virt.addr = tmp;
296 
297         if (!(walk->flags & SKCIPHER_WALK_PHYS))
298                 return 0;
299 
300         p = kmalloc(sizeof(*p), skcipher_walk_gfp(walk));
301         if (!p)
302                 return -ENOMEM;
303 
304         p->data = walk->page;
305         p->len = walk->nbytes;
306         skcipher_queue_write(walk, p);
307 
308         if (offset_in_page(walk->page) + walk->nbytes + walk->stride >
309             PAGE_SIZE)
310                 walk->page = NULL;
311         else
312                 walk->page += walk->nbytes;
313 
314         return 0;
315 }
316 
317 static int skcipher_next_fast(struct skcipher_walk *walk)
318 {
319         unsigned long diff;
320 
321         walk->src.phys.page = scatterwalk_page(&walk->in);
322         walk->src.phys.offset = offset_in_page(walk->in.offset);
323         walk->dst.phys.page = scatterwalk_page(&walk->out);
324         walk->dst.phys.offset = offset_in_page(walk->out.offset);
325 
326         if (walk->flags & SKCIPHER_WALK_PHYS)
327                 return 0;
328 
329         diff = walk->src.phys.offset - walk->dst.phys.offset;
330         diff |= walk->src.virt.page - walk->dst.virt.page;
331 
332         skcipher_map_src(walk);
333         walk->dst.virt.addr = walk->src.virt.addr;
334 
335         if (diff) {
336                 walk->flags |= SKCIPHER_WALK_DIFF;
337                 skcipher_map_dst(walk);
338         }
339 
340         return 0;
341 }
342 
343 static int skcipher_walk_next(struct skcipher_walk *walk)
344 {
345         unsigned int bsize;
346         unsigned int n;
347         int err;
348 
349         walk->flags &= ~(SKCIPHER_WALK_SLOW | SKCIPHER_WALK_COPY |
350                          SKCIPHER_WALK_DIFF);
351 
352         n = walk->total;
353         bsize = min(walk->stride, max(n, walk->blocksize));
354         n = scatterwalk_clamp(&walk->in, n);
355         n = scatterwalk_clamp(&walk->out, n);
356 
357         if (unlikely(n < bsize)) {
358                 if (unlikely(walk->total < walk->blocksize))
359                         return skcipher_walk_done(walk, -EINVAL);
360 
361 slow_path:
362                 err = skcipher_next_slow(walk, bsize);
363                 goto set_phys_lowmem;
364         }
365 
366         if (unlikely((walk->in.offset | walk->out.offset) & walk->alignmask)) {
367                 if (!walk->page) {
368                         gfp_t gfp = skcipher_walk_gfp(walk);
369 
370                         walk->page = (void *)__get_free_page(gfp);
371                         if (!walk->page)
372                                 goto slow_path;
373                 }
374 
375                 walk->nbytes = min_t(unsigned, n,
376                                      PAGE_SIZE - offset_in_page(walk->page));
377                 walk->flags |= SKCIPHER_WALK_COPY;
378                 err = skcipher_next_copy(walk);
379                 goto set_phys_lowmem;
380         }
381 
382         walk->nbytes = n;
383 
384         return skcipher_next_fast(walk);
385 
386 set_phys_lowmem:
387         if (!err && (walk->flags & SKCIPHER_WALK_PHYS)) {
388                 walk->src.phys.page = virt_to_page(walk->src.virt.addr);
389                 walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
390                 walk->src.phys.offset &= PAGE_SIZE - 1;
391                 walk->dst.phys.offset &= PAGE_SIZE - 1;
392         }
393         return err;
394 }
395 
396 static int skcipher_copy_iv(struct skcipher_walk *walk)
397 {
398         unsigned a = crypto_tfm_ctx_alignment() - 1;
399         unsigned alignmask = walk->alignmask;
400         unsigned ivsize = walk->ivsize;
401         unsigned bs = walk->stride;
402         unsigned aligned_bs;
403         unsigned size;
404         u8 *iv;
405 
406         aligned_bs = ALIGN(bs, alignmask + 1);
407 
408         /* Minimum size to align buffer by alignmask. */
409         size = alignmask & ~a;
410 
411         if (walk->flags & SKCIPHER_WALK_PHYS)
412                 size += ivsize;
413         else {
414                 size += aligned_bs + ivsize;
415 
416                 /* Minimum size to ensure buffer does not straddle a page. */
417                 size += (bs - 1) & ~(alignmask | a);
418         }
419 
420         walk->buffer = kmalloc(size, skcipher_walk_gfp(walk));
421         if (!walk->buffer)
422                 return -ENOMEM;
423 
424         iv = PTR_ALIGN(walk->buffer, alignmask + 1);
425         iv = skcipher_get_spot(iv, bs) + aligned_bs;
426 
427         walk->iv = memcpy(iv, walk->iv, walk->ivsize);
428         return 0;
429 }
430 
431 static int skcipher_walk_first(struct skcipher_walk *walk)
432 {
433         if (WARN_ON_ONCE(in_irq()))
434                 return -EDEADLK;
435 
436         walk->buffer = NULL;
437         if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
438                 int err = skcipher_copy_iv(walk);
439                 if (err)
440                         return err;
441         }
442 
443         walk->page = NULL;
444 
445         return skcipher_walk_next(walk);
446 }
447 
448 static int skcipher_walk_skcipher(struct skcipher_walk *walk,
449                                   struct skcipher_request *req)
450 {
451         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
452 
453         walk->total = req->cryptlen;
454         walk->nbytes = 0;
455         walk->iv = req->iv;
456         walk->oiv = req->iv;
457 
458         if (unlikely(!walk->total))
459                 return 0;
460 
461         scatterwalk_start(&walk->in, req->src);
462         scatterwalk_start(&walk->out, req->dst);
463 
464         walk->flags &= ~SKCIPHER_WALK_SLEEP;
465         walk->flags |= req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
466                        SKCIPHER_WALK_SLEEP : 0;
467 
468         walk->blocksize = crypto_skcipher_blocksize(tfm);
469         walk->stride = crypto_skcipher_walksize(tfm);
470         walk->ivsize = crypto_skcipher_ivsize(tfm);
471         walk->alignmask = crypto_skcipher_alignmask(tfm);
472 
473         return skcipher_walk_first(walk);
474 }
475 
476 int skcipher_walk_virt(struct skcipher_walk *walk,
477                        struct skcipher_request *req, bool atomic)
478 {
479         int err;
480 
481         might_sleep_if(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
482 
483         walk->flags &= ~SKCIPHER_WALK_PHYS;
484 
485         err = skcipher_walk_skcipher(walk, req);
486 
487         walk->flags &= atomic ? ~SKCIPHER_WALK_SLEEP : ~0;
488 
489         return err;
490 }
491 EXPORT_SYMBOL_GPL(skcipher_walk_virt);
492 
493 void skcipher_walk_atomise(struct skcipher_walk *walk)
494 {
495         walk->flags &= ~SKCIPHER_WALK_SLEEP;
496 }
497 EXPORT_SYMBOL_GPL(skcipher_walk_atomise);
498 
499 int skcipher_walk_async(struct skcipher_walk *walk,
500                         struct skcipher_request *req)
501 {
502         walk->flags |= SKCIPHER_WALK_PHYS;
503 
504         INIT_LIST_HEAD(&walk->buffers);
505 
506         return skcipher_walk_skcipher(walk, req);
507 }
508 EXPORT_SYMBOL_GPL(skcipher_walk_async);
509 
510 static int skcipher_walk_aead_common(struct skcipher_walk *walk,
511                                      struct aead_request *req, bool atomic)
512 {
513         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
514         int err;
515 
516         walk->nbytes = 0;
517         walk->iv = req->iv;
518         walk->oiv = req->iv;
519 
520         if (unlikely(!walk->total))
521                 return 0;
522 
523         walk->flags &= ~SKCIPHER_WALK_PHYS;
524 
525         scatterwalk_start(&walk->in, req->src);
526         scatterwalk_start(&walk->out, req->dst);
527 
528         scatterwalk_copychunks(NULL, &walk->in, req->assoclen, 2);
529         scatterwalk_copychunks(NULL, &walk->out, req->assoclen, 2);
530 
531         scatterwalk_done(&walk->in, 0, walk->total);
532         scatterwalk_done(&walk->out, 0, walk->total);
533 
534         if (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP)
535                 walk->flags |= SKCIPHER_WALK_SLEEP;
536         else
537                 walk->flags &= ~SKCIPHER_WALK_SLEEP;
538 
539         walk->blocksize = crypto_aead_blocksize(tfm);
540         walk->stride = crypto_aead_chunksize(tfm);
541         walk->ivsize = crypto_aead_ivsize(tfm);
542         walk->alignmask = crypto_aead_alignmask(tfm);
543 
544         err = skcipher_walk_first(walk);
545 
546         if (atomic)
547                 walk->flags &= ~SKCIPHER_WALK_SLEEP;
548 
549         return err;
550 }
551 
552 int skcipher_walk_aead_encrypt(struct skcipher_walk *walk,
553                                struct aead_request *req, bool atomic)
554 {
555         walk->total = req->cryptlen;
556 
557         return skcipher_walk_aead_common(walk, req, atomic);
558 }
559 EXPORT_SYMBOL_GPL(skcipher_walk_aead_encrypt);
560 
561 int skcipher_walk_aead_decrypt(struct skcipher_walk *walk,
562                                struct aead_request *req, bool atomic)
563 {
564         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
565 
566         walk->total = req->cryptlen - crypto_aead_authsize(tfm);
567 
568         return skcipher_walk_aead_common(walk, req, atomic);
569 }
570 EXPORT_SYMBOL_GPL(skcipher_walk_aead_decrypt);
571 
572 static void skcipher_set_needkey(struct crypto_skcipher *tfm)
573 {
574         if (crypto_skcipher_max_keysize(tfm) != 0)
575                 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
576 }
577 
578 static int skcipher_setkey_unaligned(struct crypto_skcipher *tfm,
579                                      const u8 *key, unsigned int keylen)
580 {
581         unsigned long alignmask = crypto_skcipher_alignmask(tfm);
582         struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
583         u8 *buffer, *alignbuffer;
584         unsigned long absize;
585         int ret;
586 
587         absize = keylen + alignmask;
588         buffer = kmalloc(absize, GFP_ATOMIC);
589         if (!buffer)
590                 return -ENOMEM;
591 
592         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
593         memcpy(alignbuffer, key, keylen);
594         ret = cipher->setkey(tfm, alignbuffer, keylen);
595         kzfree(buffer);
596         return ret;
597 }
598 
599 int crypto_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
600                            unsigned int keylen)
601 {
602         struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
603         unsigned long alignmask = crypto_skcipher_alignmask(tfm);
604         int err;
605 
606         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize)
607                 return -EINVAL;
608 
609         if ((unsigned long)key & alignmask)
610                 err = skcipher_setkey_unaligned(tfm, key, keylen);
611         else
612                 err = cipher->setkey(tfm, key, keylen);
613 
614         if (unlikely(err)) {
615                 skcipher_set_needkey(tfm);
616                 return err;
617         }
618 
619         crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
620         return 0;
621 }
622 EXPORT_SYMBOL_GPL(crypto_skcipher_setkey);
623 
624 int crypto_skcipher_encrypt(struct skcipher_request *req)
625 {
626         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
627         struct crypto_alg *alg = tfm->base.__crt_alg;
628         unsigned int cryptlen = req->cryptlen;
629         int ret;
630 
631         crypto_stats_get(alg);
632         if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
633                 ret = -ENOKEY;
634         else
635                 ret = crypto_skcipher_alg(tfm)->encrypt(req);
636         crypto_stats_skcipher_encrypt(cryptlen, ret, alg);
637         return ret;
638 }
639 EXPORT_SYMBOL_GPL(crypto_skcipher_encrypt);
640 
641 int crypto_skcipher_decrypt(struct skcipher_request *req)
642 {
643         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
644         struct crypto_alg *alg = tfm->base.__crt_alg;
645         unsigned int cryptlen = req->cryptlen;
646         int ret;
647 
648         crypto_stats_get(alg);
649         if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
650                 ret = -ENOKEY;
651         else
652                 ret = crypto_skcipher_alg(tfm)->decrypt(req);
653         crypto_stats_skcipher_decrypt(cryptlen, ret, alg);
654         return ret;
655 }
656 EXPORT_SYMBOL_GPL(crypto_skcipher_decrypt);
657 
658 static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
659 {
660         struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
661         struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
662 
663         alg->exit(skcipher);
664 }
665 
666 static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
667 {
668         struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
669         struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
670 
671         skcipher_set_needkey(skcipher);
672 
673         if (alg->exit)
674                 skcipher->base.exit = crypto_skcipher_exit_tfm;
675 
676         if (alg->init)
677                 return alg->init(skcipher);
678 
679         return 0;
680 }
681 
682 static void crypto_skcipher_free_instance(struct crypto_instance *inst)
683 {
684         struct skcipher_instance *skcipher =
685                 container_of(inst, struct skcipher_instance, s.base);
686 
687         skcipher->free(skcipher);
688 }
689 
690 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
691         __maybe_unused;
692 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
693 {
694         struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
695                                                      base);
696 
697         seq_printf(m, "type         : skcipher\n");
698         seq_printf(m, "async        : %s\n",
699                    alg->cra_flags & CRYPTO_ALG_ASYNC ?  "yes" : "no");
700         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
701         seq_printf(m, "min keysize  : %u\n", skcipher->min_keysize);
702         seq_printf(m, "max keysize  : %u\n", skcipher->max_keysize);
703         seq_printf(m, "ivsize       : %u\n", skcipher->ivsize);
704         seq_printf(m, "chunksize    : %u\n", skcipher->chunksize);
705         seq_printf(m, "walksize     : %u\n", skcipher->walksize);
706 }
707 
708 #ifdef CONFIG_NET
709 static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
710 {
711         struct crypto_report_blkcipher rblkcipher;
712         struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
713                                                      base);
714 
715         memset(&rblkcipher, 0, sizeof(rblkcipher));
716 
717         strscpy(rblkcipher.type, "skcipher", sizeof(rblkcipher.type));
718         strscpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));
719 
720         rblkcipher.blocksize = alg->cra_blocksize;
721         rblkcipher.min_keysize = skcipher->min_keysize;
722         rblkcipher.max_keysize = skcipher->max_keysize;
723         rblkcipher.ivsize = skcipher->ivsize;
724 
725         return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
726                        sizeof(rblkcipher), &rblkcipher);
727 }
728 #else
729 static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
730 {
731         return -ENOSYS;
732 }
733 #endif
734 
735 static const struct crypto_type crypto_skcipher_type = {
736         .extsize = crypto_alg_extsize,
737         .init_tfm = crypto_skcipher_init_tfm,
738         .free = crypto_skcipher_free_instance,
739 #ifdef CONFIG_PROC_FS
740         .show = crypto_skcipher_show,
741 #endif
742         .report = crypto_skcipher_report,
743         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
744         .maskset = CRYPTO_ALG_TYPE_MASK,
745         .type = CRYPTO_ALG_TYPE_SKCIPHER,
746         .tfmsize = offsetof(struct crypto_skcipher, base),
747 };
748 
749 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn,
750                          struct crypto_instance *inst,
751                          const char *name, u32 type, u32 mask)
752 {
753         spawn->base.frontend = &crypto_skcipher_type;
754         return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
755 }
756 EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
757 
758 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
759                                               u32 type, u32 mask)
760 {
761         return crypto_alloc_tfm(alg_name, &crypto_skcipher_type, type, mask);
762 }
763 EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);
764 
765 struct crypto_sync_skcipher *crypto_alloc_sync_skcipher(
766                                 const char *alg_name, u32 type, u32 mask)
767 {
768         struct crypto_skcipher *tfm;
769 
770         /* Only sync algorithms allowed. */
771         mask |= CRYPTO_ALG_ASYNC;
772 
773         tfm = crypto_alloc_tfm(alg_name, &crypto_skcipher_type, type, mask);
774 
775         /*
776          * Make sure we do not allocate something that might get used with
777          * an on-stack request: check the request size.
778          */
779         if (!IS_ERR(tfm) && WARN_ON(crypto_skcipher_reqsize(tfm) >
780                                     MAX_SYNC_SKCIPHER_REQSIZE)) {
781                 crypto_free_skcipher(tfm);
782                 return ERR_PTR(-EINVAL);
783         }
784 
785         return (struct crypto_sync_skcipher *)tfm;
786 }
787 EXPORT_SYMBOL_GPL(crypto_alloc_sync_skcipher);
788 
789 int crypto_has_skcipher(const char *alg_name, u32 type, u32 mask)
790 {
791         return crypto_type_has_alg(alg_name, &crypto_skcipher_type, type, mask);
792 }
793 EXPORT_SYMBOL_GPL(crypto_has_skcipher);
794 
795 static int skcipher_prepare_alg(struct skcipher_alg *alg)
796 {
797         struct crypto_alg *base = &alg->base;
798 
799         if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8 ||
800             alg->walksize > PAGE_SIZE / 8)
801                 return -EINVAL;
802 
803         if (!alg->chunksize)
804                 alg->chunksize = base->cra_blocksize;
805         if (!alg->walksize)
806                 alg->walksize = alg->chunksize;
807 
808         base->cra_type = &crypto_skcipher_type;
809         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
810         base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;
811 
812         return 0;
813 }
814 
815 int crypto_register_skcipher(struct skcipher_alg *alg)
816 {
817         struct crypto_alg *base = &alg->base;
818         int err;
819 
820         err = skcipher_prepare_alg(alg);
821         if (err)
822                 return err;
823 
824         return crypto_register_alg(base);
825 }
826 EXPORT_SYMBOL_GPL(crypto_register_skcipher);
827 
828 void crypto_unregister_skcipher(struct skcipher_alg *alg)
829 {
830         crypto_unregister_alg(&alg->base);
831 }
832 EXPORT_SYMBOL_GPL(crypto_unregister_skcipher);
833 
834 int crypto_register_skciphers(struct skcipher_alg *algs, int count)
835 {
836         int i, ret;
837 
838         for (i = 0; i < count; i++) {
839                 ret = crypto_register_skcipher(&algs[i]);
840                 if (ret)
841                         goto err;
842         }
843 
844         return 0;
845 
846 err:
847         for (--i; i >= 0; --i)
848                 crypto_unregister_skcipher(&algs[i]);
849 
850         return ret;
851 }
852 EXPORT_SYMBOL_GPL(crypto_register_skciphers);
853 
854 void crypto_unregister_skciphers(struct skcipher_alg *algs, int count)
855 {
856         int i;
857 
858         for (i = count - 1; i >= 0; --i)
859                 crypto_unregister_skcipher(&algs[i]);
860 }
861 EXPORT_SYMBOL_GPL(crypto_unregister_skciphers);
862 
863 int skcipher_register_instance(struct crypto_template *tmpl,
864                            struct skcipher_instance *inst)
865 {
866         int err;
867 
868         if (WARN_ON(!inst->free))
869                 return -EINVAL;
870 
871         err = skcipher_prepare_alg(&inst->alg);
872         if (err)
873                 return err;
874 
875         return crypto_register_instance(tmpl, skcipher_crypto_instance(inst));
876 }
877 EXPORT_SYMBOL_GPL(skcipher_register_instance);
878 
879 static int skcipher_setkey_simple(struct crypto_skcipher *tfm, const u8 *key,
880                                   unsigned int keylen)
881 {
882         struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
883 
884         crypto_cipher_clear_flags(cipher, CRYPTO_TFM_REQ_MASK);
885         crypto_cipher_set_flags(cipher, crypto_skcipher_get_flags(tfm) &
886                                 CRYPTO_TFM_REQ_MASK);
887         return crypto_cipher_setkey(cipher, key, keylen);
888 }
889 
890 static int skcipher_init_tfm_simple(struct crypto_skcipher *tfm)
891 {
892         struct skcipher_instance *inst = skcipher_alg_instance(tfm);
893         struct crypto_cipher_spawn *spawn = skcipher_instance_ctx(inst);
894         struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm);
895         struct crypto_cipher *cipher;
896 
897         cipher = crypto_spawn_cipher(spawn);
898         if (IS_ERR(cipher))
899                 return PTR_ERR(cipher);
900 
901         ctx->cipher = cipher;
902         return 0;
903 }
904 
905 static void skcipher_exit_tfm_simple(struct crypto_skcipher *tfm)
906 {
907         struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm);
908 
909         crypto_free_cipher(ctx->cipher);
910 }
911 
912 static void skcipher_free_instance_simple(struct skcipher_instance *inst)
913 {
914         crypto_drop_cipher(skcipher_instance_ctx(inst));
915         kfree(inst);
916 }
917 
918 /**
919  * skcipher_alloc_instance_simple - allocate instance of simple block cipher mode
920  *
921  * Allocate an skcipher_instance for a simple block cipher mode of operation,
922  * e.g. cbc or ecb.  The instance context will have just a single crypto_spawn,
923  * that for the underlying cipher.  The {min,max}_keysize, ivsize, blocksize,
924  * alignmask, and priority are set from the underlying cipher but can be
925  * overridden if needed.  The tfm context defaults to skcipher_ctx_simple, and
926  * default ->setkey(), ->init(), and ->exit() methods are installed.
927  *
928  * @tmpl: the template being instantiated
929  * @tb: the template parameters
930  *
931  * Return: a pointer to the new instance, or an ERR_PTR().  The caller still
932  *         needs to register the instance.
933  */
934 struct skcipher_instance *skcipher_alloc_instance_simple(
935         struct crypto_template *tmpl, struct rtattr **tb)
936 {
937         struct crypto_attr_type *algt;
938         u32 mask;
939         struct skcipher_instance *inst;
940         struct crypto_cipher_spawn *spawn;
941         struct crypto_alg *cipher_alg;
942         int err;
943 
944         algt = crypto_get_attr_type(tb);
945         if (IS_ERR(algt))
946                 return ERR_CAST(algt);
947 
948         if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
949                 return ERR_PTR(-EINVAL);
950 
951         mask = crypto_requires_off(algt->type, algt->mask,
952                                    CRYPTO_ALG_NEED_FALLBACK);
953 
954         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
955         if (!inst)
956                 return ERR_PTR(-ENOMEM);
957         spawn = skcipher_instance_ctx(inst);
958 
959         err = crypto_grab_cipher(spawn, skcipher_crypto_instance(inst),
960                                  crypto_attr_alg_name(tb[1]), 0, mask);
961         if (err)
962                 goto err_free_inst;
963         cipher_alg = crypto_spawn_cipher_alg(spawn);
964 
965         err = crypto_inst_setname(skcipher_crypto_instance(inst), tmpl->name,
966                                   cipher_alg);
967         if (err)
968                 goto err_free_inst;
969 
970         inst->free = skcipher_free_instance_simple;
971 
972         /* Default algorithm properties, can be overridden */
973         inst->alg.base.cra_blocksize = cipher_alg->cra_blocksize;
974         inst->alg.base.cra_alignmask = cipher_alg->cra_alignmask;
975         inst->alg.base.cra_priority = cipher_alg->cra_priority;
976         inst->alg.min_keysize = cipher_alg->cra_cipher.cia_min_keysize;
977         inst->alg.max_keysize = cipher_alg->cra_cipher.cia_max_keysize;
978         inst->alg.ivsize = cipher_alg->cra_blocksize;
979 
980         /* Use skcipher_ctx_simple by default, can be overridden */
981         inst->alg.base.cra_ctxsize = sizeof(struct skcipher_ctx_simple);
982         inst->alg.setkey = skcipher_setkey_simple;
983         inst->alg.init = skcipher_init_tfm_simple;
984         inst->alg.exit = skcipher_exit_tfm_simple;
985 
986         return inst;
987 
988 err_free_inst:
989         skcipher_free_instance_simple(inst);
990         return ERR_PTR(err);
991 }
992 EXPORT_SYMBOL_GPL(skcipher_alloc_instance_simple);
993 
994 MODULE_LICENSE("GPL");
995 MODULE_DESCRIPTION("Symmetric key cipher type");
996 

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