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 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
  44 static 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
  60 int 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         walk->offset = 0;
  86
  87         if (nbytes)
  88                 return hash_walk_next(walk);
  89
  90         if (!walk->total)
  91                 return 0;
  92
  93         walk->sg = scatterwalk_sg_next(walk->sg);
  94
  95         return hash_walk_new_entry(walk);
  96 }
  97 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
  98
  99 int crypto_hash_walk_first(struct ahash_request *req,
 100                            struct crypto_hash_walk *walk)
 101 {
 102         walk->total = req->nbytes;
 103
 104         if (!walk->total)
 105                 return 0;
 106
 107         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 108         walk->sg = req->src;
 109         walk->flags = req->base.flags;
 110
 111         return hash_walk_new_entry(walk);
 112 }
 113 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 114
 115 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 116                                 unsigned int keylen)
 117 {
 118         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
 119         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 120         int ret;
 121         u8 *buffer, *alignbuffer;
 122         unsigned long absize;
 123
 124         absize = keylen + alignmask;
 125         buffer = kmalloc(absize, GFP_ATOMIC);
 126         if (!buffer)
 127                 return -ENOMEM;
 128
 129         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 130         memcpy(alignbuffer, key, keylen);
 131         ret = ahash->setkey(tfm, alignbuffer, keylen);
 132         memset(alignbuffer, 0, keylen);
 133         kfree(buffer);
 134         return ret;
 135 }
 136
 137 static int ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 138                         unsigned int keylen)
 139 {
 140         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
 141         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 142
 143         if ((unsigned long)key & alignmask)
 144                 return ahash_setkey_unaligned(tfm, key, keylen);
 145
 146         return ahash->setkey(tfm, key, keylen);
 147 }
 148
 149 static unsigned int crypto_ahash_ctxsize(struct crypto_alg *alg, u32 type,
 150                                         u32 mask)
 151 {
 152         return alg->cra_ctxsize;
 153 }
 154
 155 static int crypto_init_ahash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 156 {
 157         struct ahash_alg *alg = &tfm->__crt_alg->cra_ahash;
 158         struct ahash_tfm *crt   = &tfm->crt_ahash;
 159
 160         if (alg->digestsize > PAGE_SIZE / 8)
 161                 return -EINVAL;
 162
 163         crt->init = alg->init;
 164         crt->update = alg->update;
 165         crt->final  = alg->final;
 166         crt->digest = alg->digest;
 167         crt->setkey = ahash_setkey;
 168         crt->digestsize = alg->digestsize;
 169
 170         return 0;
 171 }
 172
 173 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 174         __attribute__ ((unused));
 175 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 176 {
 177         seq_printf(m, "type         : ahash\n");
 178         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 179                                              "yes" : "no");
 180         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 181         seq_printf(m, "digestsize   : %u\n", alg->cra_hash.digestsize);
 182 }
 183
 184 const struct crypto_type crypto_ahash_type = {
 185         .ctxsize = crypto_ahash_ctxsize,
 186         .init = crypto_init_ahash_ops,
 187 #ifdef CONFIG_PROC_FS
 188         .show = crypto_ahash_show,
 189 #endif
 190 };
 191 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 192
 193 MODULE_LICENSE("GPL");
 194 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");