linux/crypto/ablkcipher.c
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   1/*
   2 * Asynchronous block chaining cipher operations.
   3 *
   4 * This is the asynchronous version of blkcipher.c indicating completion
   5 * via a callback.
   6 *
   7 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   8 *
   9 * This program is free software; you can redistribute it and/or modify it
  10 * under the terms of the GNU General Public License as published by the Free
  11 * Software Foundation; either version 2 of the License, or (at your option)
  12 * any later version.
  13 *
  14 */
  15
  16#include <crypto/internal/skcipher.h>
  17#include <linux/err.h>
  18#include <linux/kernel.h>
  19#include <linux/slab.h>
  20#include <linux/seq_file.h>
  21#include <linux/cryptouser.h>
  22#include <net/netlink.h>
  23
  24#include <crypto/scatterwalk.h>
  25
  26#include "internal.h"
  27
  28struct ablkcipher_buffer {
  29        struct list_head        entry;
  30        struct scatter_walk     dst;
  31        unsigned int            len;
  32        void                    *data;
  33};
  34
  35enum {
  36        ABLKCIPHER_WALK_SLOW = 1 << 0,
  37};
  38
  39static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
  40{
  41        scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
  42}
  43
  44void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
  45{
  46        struct ablkcipher_buffer *p, *tmp;
  47
  48        list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
  49                ablkcipher_buffer_write(p);
  50                list_del(&p->entry);
  51                kfree(p);
  52        }
  53}
  54EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
  55
  56static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
  57                                          struct ablkcipher_buffer *p)
  58{
  59        p->dst = walk->out;
  60        list_add_tail(&p->entry, &walk->buffers);
  61}
  62
  63/* Get a spot of the specified length that does not straddle a page.
  64 * The caller needs to ensure that there is enough space for this operation.
  65 */
  66static inline u8 *ablkcipher_get_spot(u8 *start, unsigned int len)
  67{
  68        u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
  69
  70        return max(start, end_page);
  71}
  72
  73static inline unsigned int ablkcipher_done_slow(struct ablkcipher_walk *walk,
  74                                                unsigned int bsize)
  75{
  76        unsigned int n = bsize;
  77
  78        for (;;) {
  79                unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
  80
  81                if (len_this_page > n)
  82                        len_this_page = n;
  83                scatterwalk_advance(&walk->out, n);
  84                if (n == len_this_page)
  85                        break;
  86                n -= len_this_page;
  87                scatterwalk_start(&walk->out, sg_next(walk->out.sg));
  88        }
  89
  90        return bsize;
  91}
  92
  93static inline unsigned int ablkcipher_done_fast(struct ablkcipher_walk *walk,
  94                                                unsigned int n)
  95{
  96        scatterwalk_advance(&walk->in, n);
  97        scatterwalk_advance(&walk->out, n);
  98
  99        return n;
 100}
 101
 102static int ablkcipher_walk_next(struct ablkcipher_request *req,
 103                                struct ablkcipher_walk *walk);
 104
 105int ablkcipher_walk_done(struct ablkcipher_request *req,
 106                         struct ablkcipher_walk *walk, int err)
 107{
 108        struct crypto_tfm *tfm = req->base.tfm;
 109        unsigned int nbytes = 0;
 110
 111        if (likely(err >= 0)) {
 112                unsigned int n = walk->nbytes - err;
 113
 114                if (likely(!(walk->flags & ABLKCIPHER_WALK_SLOW)))
 115                        n = ablkcipher_done_fast(walk, n);
 116                else if (WARN_ON(err)) {
 117                        err = -EINVAL;
 118                        goto err;
 119                } else
 120                        n = ablkcipher_done_slow(walk, n);
 121
 122                nbytes = walk->total - n;
 123                err = 0;
 124        }
 125
 126        scatterwalk_done(&walk->in, 0, nbytes);
 127        scatterwalk_done(&walk->out, 1, nbytes);
 128
 129err:
 130        walk->total = nbytes;
 131        walk->nbytes = nbytes;
 132
 133        if (nbytes) {
 134                crypto_yield(req->base.flags);
 135                return ablkcipher_walk_next(req, walk);
 136        }
 137
 138        if (walk->iv != req->info)
 139                memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
 140        kfree(walk->iv_buffer);
 141
 142        return err;
 143}
 144EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
 145
 146static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
 147                                       struct ablkcipher_walk *walk,
 148                                       unsigned int bsize,
 149                                       unsigned int alignmask,
 150                                       void **src_p, void **dst_p)
 151{
 152        unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 153        struct ablkcipher_buffer *p;
 154        void *src, *dst, *base;
 155        unsigned int n;
 156
 157        n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
 158        n += (aligned_bsize * 3 - (alignmask + 1) +
 159              (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
 160
 161        p = kmalloc(n, GFP_ATOMIC);
 162        if (!p)
 163                return ablkcipher_walk_done(req, walk, -ENOMEM);
 164
 165        base = p + 1;
 166
 167        dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
 168        src = dst = ablkcipher_get_spot(dst, bsize);
 169
 170        p->len = bsize;
 171        p->data = dst;
 172
 173        scatterwalk_copychunks(src, &walk->in, bsize, 0);
 174
 175        ablkcipher_queue_write(walk, p);
 176
 177        walk->nbytes = bsize;
 178        walk->flags |= ABLKCIPHER_WALK_SLOW;
 179
 180        *src_p = src;
 181        *dst_p = dst;
 182
 183        return 0;
 184}
 185
 186static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
 187                                     struct crypto_tfm *tfm,
 188                                     unsigned int alignmask)
 189{
 190        unsigned bs = walk->blocksize;
 191        unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
 192        unsigned aligned_bs = ALIGN(bs, alignmask + 1);
 193        unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
 194                            (alignmask + 1);
 195        u8 *iv;
 196
 197        size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 198        walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
 199        if (!walk->iv_buffer)
 200                return -ENOMEM;
 201
 202        iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
 203        iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 204        iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 205        iv = ablkcipher_get_spot(iv, ivsize);
 206
 207        walk->iv = memcpy(iv, walk->iv, ivsize);
 208        return 0;
 209}
 210
 211static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
 212                                       struct ablkcipher_walk *walk)
 213{
 214        walk->src.page = scatterwalk_page(&walk->in);
 215        walk->src.offset = offset_in_page(walk->in.offset);
 216        walk->dst.page = scatterwalk_page(&walk->out);
 217        walk->dst.offset = offset_in_page(walk->out.offset);
 218
 219        return 0;
 220}
 221
 222static int ablkcipher_walk_next(struct ablkcipher_request *req,
 223                                struct ablkcipher_walk *walk)
 224{
 225        struct crypto_tfm *tfm = req->base.tfm;
 226        unsigned int alignmask, bsize, n;
 227        void *src, *dst;
 228        int err;
 229
 230        alignmask = crypto_tfm_alg_alignmask(tfm);
 231        n = walk->total;
 232        if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
 233                req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 234                return ablkcipher_walk_done(req, walk, -EINVAL);
 235        }
 236
 237        walk->flags &= ~ABLKCIPHER_WALK_SLOW;
 238        src = dst = NULL;
 239
 240        bsize = min(walk->blocksize, n);
 241        n = scatterwalk_clamp(&walk->in, n);
 242        n = scatterwalk_clamp(&walk->out, n);
 243
 244        if (n < bsize ||
 245            !scatterwalk_aligned(&walk->in, alignmask) ||
 246            !scatterwalk_aligned(&walk->out, alignmask)) {
 247                err = ablkcipher_next_slow(req, walk, bsize, alignmask,
 248                                           &src, &dst);
 249                goto set_phys_lowmem;
 250        }
 251
 252        walk->nbytes = n;
 253
 254        return ablkcipher_next_fast(req, walk);
 255
 256set_phys_lowmem:
 257        if (err >= 0) {
 258                walk->src.page = virt_to_page(src);
 259                walk->dst.page = virt_to_page(dst);
 260                walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
 261                walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
 262        }
 263
 264        return err;
 265}
 266
 267static int ablkcipher_walk_first(struct ablkcipher_request *req,
 268                                 struct ablkcipher_walk *walk)
 269{
 270        struct crypto_tfm *tfm = req->base.tfm;
 271        unsigned int alignmask;
 272
 273        alignmask = crypto_tfm_alg_alignmask(tfm);
 274        if (WARN_ON_ONCE(in_irq()))
 275                return -EDEADLK;
 276
 277        walk->iv = req->info;
 278        walk->nbytes = walk->total;
 279        if (unlikely(!walk->total))
 280                return 0;
 281
 282        walk->iv_buffer = NULL;
 283        if (unlikely(((unsigned long)walk->iv & alignmask))) {
 284                int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 285
 286                if (err)
 287                        return err;
 288        }
 289
 290        scatterwalk_start(&walk->in, walk->in.sg);
 291        scatterwalk_start(&walk->out, walk->out.sg);
 292
 293        return ablkcipher_walk_next(req, walk);
 294}
 295
 296int ablkcipher_walk_phys(struct ablkcipher_request *req,
 297                         struct ablkcipher_walk *walk)
 298{
 299        walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
 300        return ablkcipher_walk_first(req, walk);
 301}
 302EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
 303
 304static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 305                            unsigned int keylen)
 306{
 307        struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 308        unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 309        int ret;
 310        u8 *buffer, *alignbuffer;
 311        unsigned long absize;
 312
 313        absize = keylen + alignmask;
 314        buffer = kmalloc(absize, GFP_ATOMIC);
 315        if (!buffer)
 316                return -ENOMEM;
 317
 318        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 319        memcpy(alignbuffer, key, keylen);
 320        ret = cipher->setkey(tfm, alignbuffer, keylen);
 321        memset(alignbuffer, 0, keylen);
 322        kfree(buffer);
 323        return ret;
 324}
 325
 326static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 327                  unsigned int keylen)
 328{
 329        struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 330        unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 331
 332        if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 333                crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 334                return -EINVAL;
 335        }
 336
 337        if ((unsigned long)key & alignmask)
 338                return setkey_unaligned(tfm, key, keylen);
 339
 340        return cipher->setkey(tfm, key, keylen);
 341}
 342
 343static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 344                                              u32 mask)
 345{
 346        return alg->cra_ctxsize;
 347}
 348
 349static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
 350                                      u32 mask)
 351{
 352        struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 353        struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 354
 355        if (alg->ivsize > PAGE_SIZE / 8)
 356                return -EINVAL;
 357
 358        crt->setkey = setkey;
 359        crt->encrypt = alg->encrypt;
 360        crt->decrypt = alg->decrypt;
 361        crt->base = __crypto_ablkcipher_cast(tfm);
 362        crt->ivsize = alg->ivsize;
 363
 364        return 0;
 365}
 366
 367#ifdef CONFIG_NET
 368static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 369{
 370        struct crypto_report_blkcipher rblkcipher;
 371
 372        strncpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
 373        strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",
 374                sizeof(rblkcipher.geniv));
 375
 376        rblkcipher.blocksize = alg->cra_blocksize;
 377        rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 378        rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 379        rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 380
 381        if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 382                    sizeof(struct crypto_report_blkcipher), &rblkcipher))
 383                goto nla_put_failure;
 384        return 0;
 385
 386nla_put_failure:
 387        return -EMSGSIZE;
 388}
 389#else
 390static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 391{
 392        return -ENOSYS;
 393}
 394#endif
 395
 396static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 397        __attribute__ ((unused));
 398static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 399{
 400        struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 401
 402        seq_printf(m, "type         : ablkcipher\n");
 403        seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 404                                             "yes" : "no");
 405        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 406        seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 407        seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 408        seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 409        seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<default>");
 410}
 411
 412const struct crypto_type crypto_ablkcipher_type = {
 413        .ctxsize = crypto_ablkcipher_ctxsize,
 414        .init = crypto_init_ablkcipher_ops,
 415#ifdef CONFIG_PROC_FS
 416        .show = crypto_ablkcipher_show,
 417#endif
 418        .report = crypto_ablkcipher_report,
 419};
 420EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
 421
 422static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
 423                                      u32 mask)
 424{
 425        struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 426        struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 427
 428        if (alg->ivsize > PAGE_SIZE / 8)
 429                return -EINVAL;
 430
 431        crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
 432                      alg->setkey : setkey;
 433        crt->encrypt = alg->encrypt;
 434        crt->decrypt = alg->decrypt;
 435        crt->base = __crypto_ablkcipher_cast(tfm);
 436        crt->ivsize = alg->ivsize;
 437
 438        return 0;
 439}
 440
 441#ifdef CONFIG_NET
 442static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 443{
 444        struct crypto_report_blkcipher rblkcipher;
 445
 446        strncpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type));
 447        strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<built-in>",
 448                sizeof(rblkcipher.geniv));
 449
 450        rblkcipher.blocksize = alg->cra_blocksize;
 451        rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 452        rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 453        rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 454
 455        if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 456                    sizeof(struct crypto_report_blkcipher), &rblkcipher))
 457                goto nla_put_failure;
 458        return 0;
 459
 460nla_put_failure:
 461        return -EMSGSIZE;
 462}
 463#else
 464static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 465{
 466        return -ENOSYS;
 467}
 468#endif
 469
 470static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 471        __attribute__ ((unused));
 472static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 473{
 474        struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 475
 476        seq_printf(m, "type         : givcipher\n");
 477        seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 478                                             "yes" : "no");
 479        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 480        seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 481        seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 482        seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 483        seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<built-in>");
 484}
 485
 486const struct crypto_type crypto_givcipher_type = {
 487        .ctxsize = crypto_ablkcipher_ctxsize,
 488        .init = crypto_init_givcipher_ops,
 489#ifdef CONFIG_PROC_FS
 490        .show = crypto_givcipher_show,
 491#endif
 492        .report = crypto_givcipher_report,
 493};
 494EXPORT_SYMBOL_GPL(crypto_givcipher_type);
 495