linux/crypto/ahash.c
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   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
  27static int hash_walk_next(struct crypto_hash_walk *walk)
  28{
  29        unsigned int alignmask = walk->alignmask;
  30        unsigned int offset = walk->offset;
  31        unsigned int nbytes = min(walk->entrylen,
  32                                  ((unsigned int)(PAGE_SIZE)) - offset);
  33
  34        walk->data = crypto_kmap(walk->pg, 0);
  35        walk->data += offset;
  36
  37        if (offset & alignmask)
  38                nbytes = alignmask + 1 - (offset & alignmask);
  39
  40        walk->entrylen -= nbytes;
  41        return nbytes;
  42}
  43
  44static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  45{
  46        struct scatterlist *sg;
  47
  48        sg = walk->sg;
  49        walk->pg = sg_page(sg);
  50        walk->offset = sg->offset;
  51        walk->entrylen = sg->length;
  52
  53        if (walk->entrylen > walk->total)
  54                walk->entrylen = walk->total;
  55        walk->total -= walk->entrylen;
  56
  57        return hash_walk_next(walk);
  58}
  59
  60int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  61{
  62        unsigned int alignmask = walk->alignmask;
  63        unsigned int nbytes = walk->entrylen;
  64
  65        walk->data -= walk->offset;
  66
  67        if (nbytes && walk->offset & alignmask && !err) {
  68                walk->offset += alignmask - 1;
  69                walk->offset = ALIGN(walk->offset, alignmask + 1);
  70                walk->data += walk->offset;
  71
  72                nbytes = min(nbytes,
  73                             ((unsigned int)(PAGE_SIZE)) - walk->offset);
  74                walk->entrylen -= nbytes;
  75
  76                return nbytes;
  77        }
  78
  79        crypto_kunmap(walk->data, 0);
  80        crypto_yield(walk->flags);
  81
  82        if (err)
  83                return err;
  84
  85        if (nbytes) {
  86                walk->offset = 0;
  87                walk->pg++;
  88                return hash_walk_next(walk);
  89        }
  90
  91        if (!walk->total)
  92                return 0;
  93
  94        walk->sg = scatterwalk_sg_next(walk->sg);
  95
  96        return hash_walk_new_entry(walk);
  97}
  98EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
  99
 100int crypto_hash_walk_first(struct ahash_request *req,
 101                           struct crypto_hash_walk *walk)
 102{
 103        walk->total = req->nbytes;
 104
 105        if (!walk->total)
 106                return 0;
 107
 108        walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 109        walk->sg = req->src;
 110        walk->flags = req->base.flags;
 111
 112        return hash_walk_new_entry(walk);
 113}
 114EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 115
 116int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 117                                  struct crypto_hash_walk *walk,
 118                                  struct scatterlist *sg, unsigned int len)
 119{
 120        walk->total = len;
 121
 122        if (!walk->total)
 123                return 0;
 124
 125        walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 126        walk->sg = sg;
 127        walk->flags = hdesc->flags;
 128
 129        return hash_walk_new_entry(walk);
 130}
 131
 132static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 133                                unsigned int keylen)
 134{
 135        struct ahash_alg *ahash = crypto_ahash_alg(tfm);
 136        unsigned long alignmask = crypto_ahash_alignmask(tfm);
 137        int ret;
 138        u8 *buffer, *alignbuffer;
 139        unsigned long absize;
 140
 141        absize = keylen + alignmask;
 142        buffer = kmalloc(absize, GFP_ATOMIC);
 143        if (!buffer)
 144                return -ENOMEM;
 145
 146        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 147        memcpy(alignbuffer, key, keylen);
 148        ret = ahash->setkey(tfm, alignbuffer, keylen);
 149        memset(alignbuffer, 0, keylen);
 150        kfree(buffer);
 151        return ret;
 152}
 153
 154static int ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 155                        unsigned int keylen)
 156{
 157        struct ahash_alg *ahash = crypto_ahash_alg(tfm);
 158        unsigned long alignmask = crypto_ahash_alignmask(tfm);
 159
 160        if ((unsigned long)key & alignmask)
 161                return ahash_setkey_unaligned(tfm, key, keylen);
 162
 163        return ahash->setkey(tfm, key, keylen);
 164}
 165
 166static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 167                          unsigned int keylen)
 168{
 169        return -ENOSYS;
 170}
 171
 172int crypto_ahash_import(struct ahash_request *req, const u8 *in)
 173{
 174        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 175        struct ahash_alg *alg = crypto_ahash_alg(tfm);
 176
 177        memcpy(ahash_request_ctx(req), in, crypto_ahash_reqsize(tfm));
 178
 179        if (alg->reinit)
 180                alg->reinit(req);
 181
 182        return 0;
 183}
 184EXPORT_SYMBOL_GPL(crypto_ahash_import);
 185
 186static unsigned int crypto_ahash_ctxsize(struct crypto_alg *alg, u32 type,
 187                                        u32 mask)
 188{
 189        return alg->cra_ctxsize;
 190}
 191
 192static int crypto_init_ahash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 193{
 194        struct ahash_alg *alg = &tfm->__crt_alg->cra_ahash;
 195        struct ahash_tfm *crt   = &tfm->crt_ahash;
 196
 197        if (alg->digestsize > PAGE_SIZE / 8)
 198                return -EINVAL;
 199
 200        crt->init = alg->init;
 201        crt->update = alg->update;
 202        crt->final  = alg->final;
 203        crt->digest = alg->digest;
 204        crt->setkey = alg->setkey ? ahash_setkey : ahash_nosetkey;
 205        crt->digestsize = alg->digestsize;
 206
 207        return 0;
 208}
 209
 210static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 211        __attribute__ ((unused));
 212static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 213{
 214        seq_printf(m, "type         : ahash\n");
 215        seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 216                                             "yes" : "no");
 217        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 218        seq_printf(m, "digestsize   : %u\n", alg->cra_ahash.digestsize);
 219}
 220
 221const struct crypto_type crypto_ahash_type = {
 222        .ctxsize = crypto_ahash_ctxsize,
 223        .init = crypto_init_ahash_ops,
 224#ifdef CONFIG_PROC_FS
 225        .show = crypto_ahash_show,
 226#endif
 227};
 228EXPORT_SYMBOL_GPL(crypto_ahash_type);
 229
 230MODULE_LICENSE("GPL");
 231MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
 232