linux/crypto/blkcipher.c
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   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