crypto/ahash.c

   1 /*
   2  * Asynchronous Cryptographic Hash operations.
   3  *
   4  * This is the asynchronous version of hash.c with notification of
   5  * completion via a callback.
   6  *
   7  * Copyright (c) 2008 Loc Ho <lho@amcc.com>
   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/hash.h>
  17 #include <crypto/scatterwalk.h>
  18 #include <linux/err.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <linux/seq_file.h>
  24
  25 #include "internal.h"
  26
  27 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  28 {
  29         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  30                             halg);
  31 }
  32
  33 static int hash_walk_next(struct crypto_hash_walk *walk)
  34 {
  35         unsigned int alignmask = walk->alignmask;
  36         unsigned int offset = walk->offset;
  37         unsigned int nbytes = min(walk->entrylen,
  38                                   ((unsigned int)(PAGE_SIZE)) - offset);
  39
  40         walk->data = crypto_kmap(walk->pg, 0);
  41         walk->data += offset;
  42
  43         if (offset & alignmask)
  44                 nbytes = alignmask + 1 - (offset & alignmask);
  45
  46         walk->entrylen -= nbytes;
  47         return nbytes;
  48 }
  49
  50 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  51 {
  52         struct scatterlist *sg;
  53
  54         sg = walk->sg;
  55         walk->pg = sg_page(sg);
  56         walk->offset = sg->offset;
  57         walk->entrylen = sg->length;
  58
  59         if (walk->entrylen > walk->total)
  60                 walk->entrylen = walk->total;
  61         walk->total -= walk->entrylen;
  62
  63         return hash_walk_next(walk);
  64 }
  65
  66 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  67 {
  68         unsigned int alignmask = walk->alignmask;
  69         unsigned int nbytes = walk->entrylen;
  70
  71         walk->data -= walk->offset;
  72
  73         if (nbytes && walk->offset & alignmask && !err) {
  74                 walk->offset += alignmask - 1;
  75                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  76                 walk->data += walk->offset;
  77
  78                 nbytes = min(nbytes,
  79                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  80                 walk->entrylen -= nbytes;
  81
  82                 return nbytes;
  83         }
  84
  85         crypto_kunmap(walk->data, 0);
  86         crypto_yield(walk->flags);
  87
  88         if (err)
  89                 return err;
  90
  91         if (nbytes) {
  92                 walk->offset = 0;
  93                 walk->pg++;
  94                 return hash_walk_next(walk);
  95         }
  96
  97         if (!walk->total)
  98                 return 0;
  99
 100         walk->sg = scatterwalk_sg_next(walk->sg);
 101
 102         return hash_walk_new_entry(walk);
 103 }
 104 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 105
 106 int crypto_hash_walk_first(struct ahash_request *req,
 107                            struct crypto_hash_walk *walk)
 108 {
 109         walk->total = req->nbytes;
 110
 111         if (!walk->total)
 112                 return 0;
 113
 114         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 115         walk->sg = req->src;
 116         walk->flags = req->base.flags;
 117
 118         return hash_walk_new_entry(walk);
 119 }
 120 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 121
 122 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 123                                   struct crypto_hash_walk *walk,
 124                                   struct scatterlist *sg, unsigned int len)
 125 {
 126         walk->total = len;
 127
 128         if (!walk->total)
 129                 return 0;
 130
 131         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 132         walk->sg = sg;
 133         walk->flags = hdesc->flags;
 134
 135         return hash_walk_new_entry(walk);
 136 }
 137
 138 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 139                                 unsigned int keylen)
 140 {
 141         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
 142         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 143         int ret;
 144         u8 *buffer, *alignbuffer;
 145         unsigned long absize;
 146
 147         absize = keylen + alignmask;
 148         buffer = kmalloc(absize, GFP_ATOMIC);
 149         if (!buffer)
 150                 return -ENOMEM;
 151
 152         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 153         memcpy(alignbuffer, key, keylen);
 154         ret = ahash->setkey(tfm, alignbuffer, keylen);
 155         memset(alignbuffer, 0, keylen);
 156         kfree(buffer);
 157         return ret;
 158 }
 159
 160 static int ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 161                         unsigned int keylen)
 162 {
 163         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
 164         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 165
 166         if ((unsigned long)key & alignmask)
 167                 return ahash_setkey_unaligned(tfm, key, keylen);
 168
 169         return ahash->setkey(tfm, key, keylen);
 170 }
 171
 172 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 173                           unsigned int keylen)
 174 {
 175         return -ENOSYS;
 176 }
 177
 178 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 179 {
 180         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 181         struct ahash_alg *alg = crypto_ahash_alg(hash);
 182
 183         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 184                 return crypto_init_shash_ops_async(tfm);
 185
 186         hash->init = alg->init;
 187         hash->update = alg->update;
 188         hash->final  = alg->final;
 189         hash->digest = alg->digest;
 190         hash->setkey = alg->setkey ? ahash_setkey : ahash_nosetkey;
 191
 192         return 0;
 193 }
 194
 195 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 196 {
 197         if (alg->cra_type == &crypto_ahash_type)
 198                 return alg->cra_ctxsize;
 199
 200         return sizeof(struct crypto_shash *);
 201 }
 202
 203 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 204         __attribute__ ((unused));
 205 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 206 {
 207         seq_printf(m, "type         : ahash\n");
 208         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 209                                              "yes" : "no");
 210         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 211         seq_printf(m, "digestsize   : %u\n",
 212                    __crypto_hash_alg_common(alg)->digestsize);
 213 }
 214
 215 const struct crypto_type crypto_ahash_type = {
 216         .extsize = crypto_ahash_extsize,
 217         .init_tfm = crypto_ahash_init_tfm,
 218 #ifdef CONFIG_PROC_FS
 219         .show = crypto_ahash_show,
 220 #endif
 221         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 222         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 223         .type = CRYPTO_ALG_TYPE_AHASH,
 224         .tfmsize = offsetof(struct crypto_ahash, base),
 225 };
 226 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 227
 228 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 229                                         u32 mask)
 230 {
 231         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 232 }
 233 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 234
 235 static int ahash_prepare_alg(struct ahash_alg *alg)
 236 {
 237         struct crypto_alg *base = &alg->halg.base;
 238
 239         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 240             alg->halg.statesize > PAGE_SIZE / 8)
 241                 return -EINVAL;
 242
 243         base->cra_type = &crypto_ahash_type;
 244         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 245         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 246
 247         return 0;
 248 }
 249
 250 int crypto_register_ahash(struct ahash_alg *alg)
 251 {
 252         struct crypto_alg *base = &alg->halg.base;
 253         int err;
 254
 255         err = ahash_prepare_alg(alg);
 256         if (err)
 257                 return err;
 258
 259         return crypto_register_alg(base);
 260 }
 261 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 262
 263 int crypto_unregister_ahash(struct ahash_alg *alg)
 264 {
 265         return crypto_unregister_alg(&alg->halg.base);
 266 }
 267 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 268
 269 int ahash_register_instance(struct crypto_template *tmpl,
 270                             struct ahash_instance *inst)
 271 {
 272         int err;
 273
 274         err = ahash_prepare_alg(&inst->alg);
 275         if (err)
 276                 return err;
 277
 278         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 279 }
 280 EXPORT_SYMBOL_GPL(ahash_register_instance);
 281
 282 void ahash_free_instance(struct crypto_instance *inst)
 283 {
 284         crypto_drop_spawn(crypto_instance_ctx(inst));
 285         kfree(ahash_instance(inst));
 286 }
 287 EXPORT_SYMBOL_GPL(ahash_free_instance);
 288
 289 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 290                             struct hash_alg_common *alg,
 291                             struct crypto_instance *inst)
 292 {
 293         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 294                                   &crypto_ahash_type);
 295 }
 296 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 297
 298 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 299 {
 300         struct crypto_alg *alg;
 301
 302         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 303         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 304 }
 305 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 306
 307 MODULE_LICENSE("GPL");
 308 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");