Root/crypto/blkcipher.c

1/*
2 * Block chaining cipher operations.
3 *
4 * Generic encrypt/decrypt wrapper for ciphers, handles operations across
5 * multiple page boundaries by using temporary blocks. In user context,
6 * the kernel is given a chance to schedule us once per page.
7 *
8 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 *
15 */
16
17#include <crypto/internal/skcipher.h>
18#include <crypto/scatterwalk.h>
19#include <linux/errno.h>
20#include <linux/hardirq.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/scatterlist.h>
24#include <linux/seq_file.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27#include <linux/cryptouser.h>
28#include <net/netlink.h>
29
30#include "internal.h"
31
32enum {
33    BLKCIPHER_WALK_PHYS = 1 << 0,
34    BLKCIPHER_WALK_SLOW = 1 << 1,
35    BLKCIPHER_WALK_COPY = 1 << 2,
36    BLKCIPHER_WALK_DIFF = 1 << 3,
37};
38
39static int blkcipher_walk_next(struct blkcipher_desc *desc,
40                   struct blkcipher_walk *walk);
41static int blkcipher_walk_first(struct blkcipher_desc *desc,
42                struct blkcipher_walk *walk);
43
44static inline void blkcipher_map_src(struct blkcipher_walk *walk)
45{
46    walk->src.virt.addr = scatterwalk_map(&walk->in);
47}
48
49static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
50{
51    walk->dst.virt.addr = scatterwalk_map(&walk->out);
52}
53
54static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
55{
56    scatterwalk_unmap(walk->src.virt.addr);
57}
58
59static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
60{
61    scatterwalk_unmap(walk->dst.virt.addr);
62}
63
64/* Get a spot of the specified length that does not straddle a page.
65 * The caller needs to ensure that there is enough space for this operation.
66 */
67static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
68{
69    u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
70    return max(start, end_page);
71}
72
73static inline unsigned int blkcipher_done_slow(struct blkcipher_walk *walk,
74                           unsigned int bsize)
75{
76    u8 *addr;
77
78    addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
79    addr = blkcipher_get_spot(addr, bsize);
80    scatterwalk_copychunks(addr, &walk->out, bsize, 1);
81    return bsize;
82}
83
84static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
85                           unsigned int n)
86{
87    if (walk->flags & BLKCIPHER_WALK_COPY) {
88        blkcipher_map_dst(walk);
89        memcpy(walk->dst.virt.addr, walk->page, n);
90        blkcipher_unmap_dst(walk);
91    } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
92        if (walk->flags & BLKCIPHER_WALK_DIFF)
93            blkcipher_unmap_dst(walk);
94        blkcipher_unmap_src(walk);
95    }
96
97    scatterwalk_advance(&walk->in, n);
98    scatterwalk_advance(&walk->out, n);
99
100    return n;
101}
102
103int blkcipher_walk_done(struct blkcipher_desc *desc,
104            struct blkcipher_walk *walk, int err)
105{
106    unsigned int nbytes = 0;
107
108    if (likely(err >= 0)) {
109        unsigned int n = walk->nbytes - err;
110
111        if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
112            n = blkcipher_done_fast(walk, n);
113        else if (WARN_ON(err)) {
114            err = -EINVAL;
115            goto err;
116        } else
117            n = blkcipher_done_slow(walk, n);
118
119        nbytes = walk->total - n;
120        err = 0;
121    }
122
123    scatterwalk_done(&walk->in, 0, nbytes);
124    scatterwalk_done(&walk->out, 1, nbytes);
125
126err:
127    walk->total = nbytes;
128    walk->nbytes = nbytes;
129
130    if (nbytes) {
131        crypto_yield(desc->flags);
132        return blkcipher_walk_next(desc, walk);
133    }
134
135    if (walk->iv != desc->info)
136        memcpy(desc->info, walk->iv, walk->ivsize);
137    if (walk->buffer != walk->page)
138        kfree(walk->buffer);
139    if (walk->page)
140        free_page((unsigned long)walk->page);
141
142    return err;
143}
144EXPORT_SYMBOL_GPL(blkcipher_walk_done);
145
146static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
147                      struct blkcipher_walk *walk,
148                      unsigned int bsize,
149                      unsigned int alignmask)
150{
151    unsigned int n;
152    unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
153
154    if (walk->buffer)
155        goto ok;
156
157    walk->buffer = walk->page;
158    if (walk->buffer)
159        goto ok;
160
161    n = aligned_bsize * 3 - (alignmask + 1) +
162        (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
163    walk->buffer = kmalloc(n, GFP_ATOMIC);
164    if (!walk->buffer)
165        return blkcipher_walk_done(desc, walk, -ENOMEM);
166
167ok:
168    walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
169                      alignmask + 1);
170    walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
171    walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
172                         aligned_bsize, bsize);
173
174    scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
175
176    walk->nbytes = bsize;
177    walk->flags |= BLKCIPHER_WALK_SLOW;
178
179    return 0;
180}
181
182static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
183{
184    u8 *tmp = walk->page;
185
186    blkcipher_map_src(walk);
187    memcpy(tmp, walk->src.virt.addr, walk->nbytes);
188    blkcipher_unmap_src(walk);
189
190    walk->src.virt.addr = tmp;
191    walk->dst.virt.addr = tmp;
192
193    return 0;
194}
195
196static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
197                      struct blkcipher_walk *walk)
198{
199    unsigned long diff;
200
201    walk->src.phys.page = scatterwalk_page(&walk->in);
202    walk->src.phys.offset = offset_in_page(walk->in.offset);
203    walk->dst.phys.page = scatterwalk_page(&walk->out);
204    walk->dst.phys.offset = offset_in_page(walk->out.offset);
205
206    if (walk->flags & BLKCIPHER_WALK_PHYS)
207        return 0;
208
209    diff = walk->src.phys.offset - walk->dst.phys.offset;
210    diff |= walk->src.virt.page - walk->dst.virt.page;
211
212    blkcipher_map_src(walk);
213    walk->dst.virt.addr = walk->src.virt.addr;
214
215    if (diff) {
216        walk->flags |= BLKCIPHER_WALK_DIFF;
217        blkcipher_map_dst(walk);
218    }
219
220    return 0;
221}
222
223static int blkcipher_walk_next(struct blkcipher_desc *desc,
224                   struct blkcipher_walk *walk)
225{
226    unsigned int bsize;
227    unsigned int n;
228    int err;
229
230    n = walk->total;
231    if (unlikely(n < walk->cipher_blocksize)) {
232        desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
233        return blkcipher_walk_done(desc, walk, -EINVAL);
234    }
235
236    walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
237             BLKCIPHER_WALK_DIFF);
238    if (!scatterwalk_aligned(&walk->in, walk->alignmask) ||
239        !scatterwalk_aligned(&walk->out, walk->alignmask)) {
240        walk->flags |= BLKCIPHER_WALK_COPY;
241        if (!walk->page) {
242            walk->page = (void *)__get_free_page(GFP_ATOMIC);
243            if (!walk->page)
244                n = 0;
245        }
246    }
247
248    bsize = min(walk->walk_blocksize, n);
249    n = scatterwalk_clamp(&walk->in, n);
250    n = scatterwalk_clamp(&walk->out, n);
251
252    if (unlikely(n < bsize)) {
253        err = blkcipher_next_slow(desc, walk, bsize, walk->alignmask);
254        goto set_phys_lowmem;
255    }
256
257    walk->nbytes = n;
258    if (walk->flags & BLKCIPHER_WALK_COPY) {
259        err = blkcipher_next_copy(walk);
260        goto set_phys_lowmem;
261    }
262
263    return blkcipher_next_fast(desc, walk);
264
265set_phys_lowmem:
266    if (walk->flags & BLKCIPHER_WALK_PHYS) {
267        walk->src.phys.page = virt_to_page(walk->src.virt.addr);
268        walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
269        walk->src.phys.offset &= PAGE_SIZE - 1;
270        walk->dst.phys.offset &= PAGE_SIZE - 1;
271    }
272    return err;
273}
274
275static inline int blkcipher_copy_iv(struct blkcipher_walk *walk)
276{
277    unsigned bs = walk->walk_blocksize;
278    unsigned aligned_bs = ALIGN(bs, walk->alignmask + 1);
279    unsigned int size = aligned_bs * 2 +
280                walk->ivsize + max(aligned_bs, walk->ivsize) -
281                (walk->alignmask + 1);
282    u8 *iv;
283
284    size += walk->alignmask & ~(crypto_tfm_ctx_alignment() - 1);
285    walk->buffer = kmalloc(size, GFP_ATOMIC);
286    if (!walk->buffer)
287        return -ENOMEM;
288
289    iv = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
290    iv = blkcipher_get_spot(iv, bs) + aligned_bs;
291    iv = blkcipher_get_spot(iv, bs) + aligned_bs;
292    iv = blkcipher_get_spot(iv, walk->ivsize);
293
294    walk->iv = memcpy(iv, walk->iv, walk->ivsize);
295    return 0;
296}
297
298int blkcipher_walk_virt(struct blkcipher_desc *desc,
299            struct blkcipher_walk *walk)
300{
301    walk->flags &= ~BLKCIPHER_WALK_PHYS;
302    walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
303    walk->cipher_blocksize = walk->walk_blocksize;
304    walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
305    walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
306    return blkcipher_walk_first(desc, walk);
307}
308EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
309
310int blkcipher_walk_phys(struct blkcipher_desc *desc,
311            struct blkcipher_walk *walk)
312{
313    walk->flags |= BLKCIPHER_WALK_PHYS;
314    walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
315    walk->cipher_blocksize = walk->walk_blocksize;
316    walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
317    walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
318    return blkcipher_walk_first(desc, walk);
319}
320EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
321
322static int blkcipher_walk_first(struct blkcipher_desc *desc,
323                struct blkcipher_walk *walk)
324{
325    if (WARN_ON_ONCE(in_irq()))
326        return -EDEADLK;
327
328    walk->nbytes = walk->total;
329    if (unlikely(!walk->total))
330        return 0;
331
332    walk->buffer = NULL;
333    walk->iv = desc->info;
334    if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
335        int err = blkcipher_copy_iv(walk);
336        if (err)
337            return err;
338    }
339
340    scatterwalk_start(&walk->in, walk->in.sg);
341    scatterwalk_start(&walk->out, walk->out.sg);
342    walk->page = NULL;
343
344    return blkcipher_walk_next(desc, walk);
345}
346
347int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
348                  struct blkcipher_walk *walk,
349                  unsigned int blocksize)
350{
351    walk->flags &= ~BLKCIPHER_WALK_PHYS;
352    walk->walk_blocksize = blocksize;
353    walk->cipher_blocksize = crypto_blkcipher_blocksize(desc->tfm);
354    walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
355    walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
356    return blkcipher_walk_first(desc, walk);
357}
358EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
359
360int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
361                   struct blkcipher_walk *walk,
362                   struct crypto_aead *tfm,
363                   unsigned int blocksize)
364{
365    walk->flags &= ~BLKCIPHER_WALK_PHYS;
366    walk->walk_blocksize = blocksize;
367    walk->cipher_blocksize = crypto_aead_blocksize(tfm);
368    walk->ivsize = crypto_aead_ivsize(tfm);
369    walk->alignmask = crypto_aead_alignmask(tfm);
370    return blkcipher_walk_first(desc, walk);
371}
372EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
373
374static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
375                unsigned int keylen)
376{
377    struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
378    unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
379    int ret;
380    u8 *buffer, *alignbuffer;
381    unsigned long absize;
382
383    absize = keylen + alignmask;
384    buffer = kmalloc(absize, GFP_ATOMIC);
385    if (!buffer)
386        return -ENOMEM;
387
388    alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
389    memcpy(alignbuffer, key, keylen);
390    ret = cipher->setkey(tfm, alignbuffer, keylen);
391    memset(alignbuffer, 0, keylen);
392    kfree(buffer);
393    return ret;
394}
395
396static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
397{
398    struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
399    unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
400
401    if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
402        tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
403        return -EINVAL;
404    }
405
406    if ((unsigned long)key & alignmask)
407        return setkey_unaligned(tfm, key, keylen);
408
409    return cipher->setkey(tfm, key, keylen);
410}
411
412static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
413            unsigned int keylen)
414{
415    return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
416}
417
418static int async_encrypt(struct ablkcipher_request *req)
419{
420    struct crypto_tfm *tfm = req->base.tfm;
421    struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
422    struct blkcipher_desc desc = {
423        .tfm = __crypto_blkcipher_cast(tfm),
424        .info = req->info,
425        .flags = req->base.flags,
426    };
427
428
429    return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
430}
431
432static int async_decrypt(struct ablkcipher_request *req)
433{
434    struct crypto_tfm *tfm = req->base.tfm;
435    struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
436    struct blkcipher_desc desc = {
437        .tfm = __crypto_blkcipher_cast(tfm),
438        .info = req->info,
439        .flags = req->base.flags,
440    };
441
442    return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
443}
444
445static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
446                         u32 mask)
447{
448    struct blkcipher_alg *cipher = &alg->cra_blkcipher;
449    unsigned int len = alg->cra_ctxsize;
450
451    if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK &&
452        cipher->ivsize) {
453        len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
454        len += cipher->ivsize;
455    }
456
457    return len;
458}
459
460static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
461{
462    struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
463    struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
464
465    crt->setkey = async_setkey;
466    crt->encrypt = async_encrypt;
467    crt->decrypt = async_decrypt;
468    if (!alg->ivsize) {
469        crt->givencrypt = skcipher_null_givencrypt;
470        crt->givdecrypt = skcipher_null_givdecrypt;
471    }
472    crt->base = __crypto_ablkcipher_cast(tfm);
473    crt->ivsize = alg->ivsize;
474
475    return 0;
476}
477
478static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
479{
480    struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
481    struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
482    unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
483    unsigned long addr;
484
485    crt->setkey = setkey;
486    crt->encrypt = alg->encrypt;
487    crt->decrypt = alg->decrypt;
488
489    addr = (unsigned long)crypto_tfm_ctx(tfm);
490    addr = ALIGN(addr, align);
491    addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
492    crt->iv = (void *)addr;
493
494    return 0;
495}
496
497static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
498{
499    struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
500
501    if (alg->ivsize > PAGE_SIZE / 8)
502        return -EINVAL;
503
504    if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK)
505        return crypto_init_blkcipher_ops_sync(tfm);
506    else
507        return crypto_init_blkcipher_ops_async(tfm);
508}
509
510#ifdef CONFIG_NET
511static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
512{
513    struct crypto_report_blkcipher rblkcipher;
514
515    strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));
516    strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>",
517        sizeof(rblkcipher.geniv));
518
519    rblkcipher.blocksize = alg->cra_blocksize;
520    rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
521    rblkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
522    rblkcipher.ivsize = alg->cra_blkcipher.ivsize;
523
524    if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
525            sizeof(struct crypto_report_blkcipher), &rblkcipher))
526        goto nla_put_failure;
527    return 0;
528
529nla_put_failure:
530    return -EMSGSIZE;
531}
532#else
533static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
534{
535    return -ENOSYS;
536}
537#endif
538
539static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
540    __attribute__ ((unused));
541static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
542{
543    seq_printf(m, "type : blkcipher\n");
544    seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
545    seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize);
546    seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize);
547    seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize);
548    seq_printf(m, "geniv : %s\n", alg->cra_blkcipher.geniv ?:
549                         "<default>");
550}
551
552const struct crypto_type crypto_blkcipher_type = {
553    .ctxsize = crypto_blkcipher_ctxsize,
554    .init = crypto_init_blkcipher_ops,
555#ifdef CONFIG_PROC_FS
556    .show = crypto_blkcipher_show,
557#endif
558    .report = crypto_blkcipher_report,
559};
560EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
561
562static int crypto_grab_nivcipher(struct crypto_skcipher_spawn *spawn,
563                const char *name, u32 type, u32 mask)
564{
565    struct crypto_alg *alg;
566    int err;
567
568    type = crypto_skcipher_type(type);
569    mask = crypto_skcipher_mask(mask)| CRYPTO_ALG_GENIV;
570
571    alg = crypto_alg_mod_lookup(name, type, mask);
572    if (IS_ERR(alg))
573        return PTR_ERR(alg);
574
575    err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
576    crypto_mod_put(alg);
577    return err;
578}
579
580struct crypto_instance *skcipher_geniv_alloc(struct crypto_template *tmpl,
581                         struct rtattr **tb, u32 type,
582                         u32 mask)
583{
584    struct {
585        int (*setkey)(struct crypto_ablkcipher *tfm, const u8 *key,
586                  unsigned int keylen);
587        int (*encrypt)(struct ablkcipher_request *req);
588        int (*decrypt)(struct ablkcipher_request *req);
589
590        unsigned int min_keysize;
591        unsigned int max_keysize;
592        unsigned int ivsize;
593
594        const char *geniv;
595    } balg;
596    const char *name;
597    struct crypto_skcipher_spawn *spawn;
598    struct crypto_attr_type *algt;
599    struct crypto_instance *inst;
600    struct crypto_alg *alg;
601    int err;
602
603    algt = crypto_get_attr_type(tb);
604    if (IS_ERR(algt))
605        return ERR_CAST(algt);
606
607    if ((algt->type ^ (CRYPTO_ALG_TYPE_GIVCIPHER | CRYPTO_ALG_GENIV)) &
608        algt->mask)
609        return ERR_PTR(-EINVAL);
610
611    name = crypto_attr_alg_name(tb[1]);
612    if (IS_ERR(name))
613        return ERR_CAST(name);
614
615    inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
616    if (!inst)
617        return ERR_PTR(-ENOMEM);
618
619    spawn = crypto_instance_ctx(inst);
620
621    /* Ignore async algorithms if necessary. */
622    mask |= crypto_requires_sync(algt->type, algt->mask);
623
624    crypto_set_skcipher_spawn(spawn, inst);
625    err = crypto_grab_nivcipher(spawn, name, type, mask);
626    if (err)
627        goto err_free_inst;
628
629    alg = crypto_skcipher_spawn_alg(spawn);
630
631    if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
632        CRYPTO_ALG_TYPE_BLKCIPHER) {
633        balg.ivsize = alg->cra_blkcipher.ivsize;
634        balg.min_keysize = alg->cra_blkcipher.min_keysize;
635        balg.max_keysize = alg->cra_blkcipher.max_keysize;
636
637        balg.setkey = async_setkey;
638        balg.encrypt = async_encrypt;
639        balg.decrypt = async_decrypt;
640
641        balg.geniv = alg->cra_blkcipher.geniv;
642    } else {
643        balg.ivsize = alg->cra_ablkcipher.ivsize;
644        balg.min_keysize = alg->cra_ablkcipher.min_keysize;
645        balg.max_keysize = alg->cra_ablkcipher.max_keysize;
646
647        balg.setkey = alg->cra_ablkcipher.setkey;
648        balg.encrypt = alg->cra_ablkcipher.encrypt;
649        balg.decrypt = alg->cra_ablkcipher.decrypt;
650
651        balg.geniv = alg->cra_ablkcipher.geniv;
652    }
653
654    err = -EINVAL;
655    if (!balg.ivsize)
656        goto err_drop_alg;
657
658    /*
659     * This is only true if we're constructing an algorithm with its
660     * default IV generator. For the default generator we elide the
661     * template name and double-check the IV generator.
662     */
663    if (algt->mask & CRYPTO_ALG_GENIV) {
664        if (!balg.geniv)
665            balg.geniv = crypto_default_geniv(alg);
666        err = -EAGAIN;
667        if (strcmp(tmpl->name, balg.geniv))
668            goto err_drop_alg;
669
670        memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
671        memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
672               CRYPTO_MAX_ALG_NAME);
673    } else {
674        err = -ENAMETOOLONG;
675        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
676                 "%s(%s)", tmpl->name, alg->cra_name) >=
677            CRYPTO_MAX_ALG_NAME)
678            goto err_drop_alg;
679        if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
680                 "%s(%s)", tmpl->name, alg->cra_driver_name) >=
681            CRYPTO_MAX_ALG_NAME)
682            goto err_drop_alg;
683    }
684
685    inst->alg.cra_flags = CRYPTO_ALG_TYPE_GIVCIPHER | CRYPTO_ALG_GENIV;
686    inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
687    inst->alg.cra_priority = alg->cra_priority;
688    inst->alg.cra_blocksize = alg->cra_blocksize;
689    inst->alg.cra_alignmask = alg->cra_alignmask;
690    inst->alg.cra_type = &crypto_givcipher_type;
691
692    inst->alg.cra_ablkcipher.ivsize = balg.ivsize;
693    inst->alg.cra_ablkcipher.min_keysize = balg.min_keysize;
694    inst->alg.cra_ablkcipher.max_keysize = balg.max_keysize;
695    inst->alg.cra_ablkcipher.geniv = balg.geniv;
696
697    inst->alg.cra_ablkcipher.setkey = balg.setkey;
698    inst->alg.cra_ablkcipher.encrypt = balg.encrypt;
699    inst->alg.cra_ablkcipher.decrypt = balg.decrypt;
700
701out:
702    return inst;
703
704err_drop_alg:
705    crypto_drop_skcipher(spawn);
706err_free_inst:
707    kfree(inst);
708    inst = ERR_PTR(err);
709    goto out;
710}
711EXPORT_SYMBOL_GPL(skcipher_geniv_alloc);
712
713void skcipher_geniv_free(struct crypto_instance *inst)
714{
715    crypto_drop_skcipher(crypto_instance_ctx(inst));
716    kfree(inst);
717}
718EXPORT_SYMBOL_GPL(skcipher_geniv_free);
719
720int skcipher_geniv_init(struct crypto_tfm *tfm)
721{
722    struct crypto_instance *inst = (void *)tfm->__crt_alg;
723    struct crypto_ablkcipher *cipher;
724
725    cipher = crypto_spawn_skcipher(crypto_instance_ctx(inst));
726    if (IS_ERR(cipher))
727        return PTR_ERR(cipher);
728
729    tfm->crt_ablkcipher.base = cipher;
730    tfm->crt_ablkcipher.reqsize += crypto_ablkcipher_reqsize(cipher);
731
732    return 0;
733}
734EXPORT_SYMBOL_GPL(skcipher_geniv_init);
735
736void skcipher_geniv_exit(struct crypto_tfm *tfm)
737{
738    crypto_free_ablkcipher(tfm->crt_ablkcipher.base);
739}
740EXPORT_SYMBOL_GPL(skcipher_geniv_exit);
741
742MODULE_LICENSE("GPL");
743MODULE_DESCRIPTION("Generic block chaining cipher type");
744

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