drivers/net/wireless/intersil/orinoco/mic.c

   1 /* Orinoco MIC helpers
   2  *
   3  * See copyright notice in main.c
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/string.h>
   7 #include <linux/if_ether.h>
   8 #include <linux/scatterlist.h>
   9 #include <crypto/hash.h>
  10
  11 #include "orinoco.h"
  12 #include "mic.h"
  13
  14 /********************************************************************/
  15 /* Michael MIC crypto setup                                         */
  16 /********************************************************************/
  17 int orinoco_mic_init(struct orinoco_private *priv)
  18 {
  19         priv->tx_tfm_mic = crypto_alloc_ahash("michael_mic", 0,
  20                                               CRYPTO_ALG_ASYNC);
  21         if (IS_ERR(priv->tx_tfm_mic)) {
  22                 printk(KERN_DEBUG "orinoco_mic_init: could not allocate "
  23                        "crypto API michael_mic\n");
  24                 priv->tx_tfm_mic = NULL;
  25                 return -ENOMEM;
  26         }
  27
  28         priv->rx_tfm_mic = crypto_alloc_ahash("michael_mic", 0,
  29                                               CRYPTO_ALG_ASYNC);
  30         if (IS_ERR(priv->rx_tfm_mic)) {
  31                 printk(KERN_DEBUG "orinoco_mic_init: could not allocate "
  32                        "crypto API michael_mic\n");
  33                 priv->rx_tfm_mic = NULL;
  34                 return -ENOMEM;
  35         }
  36
  37         return 0;
  38 }
  39
  40 void orinoco_mic_free(struct orinoco_private *priv)
  41 {
  42         if (priv->tx_tfm_mic)
  43                 crypto_free_ahash(priv->tx_tfm_mic);
  44         if (priv->rx_tfm_mic)
  45                 crypto_free_ahash(priv->rx_tfm_mic);
  46 }
  47
  48 int orinoco_mic(struct crypto_ahash *tfm_michael, u8 *key,
  49                 u8 *da, u8 *sa, u8 priority,
  50                 u8 *data, size_t data_len, u8 *mic)
  51 {
  52         AHASH_REQUEST_ON_STACK(req, tfm_michael);
  53         struct scatterlist sg[2];
  54         u8 hdr[ETH_HLEN + 2]; /* size of header + padding */
  55         int err;
  56
  57         if (tfm_michael == NULL) {
  58                 printk(KERN_WARNING "orinoco_mic: tfm_michael == NULL\n");
  59                 return -1;
  60         }
  61
  62         /* Copy header into buffer. We need the padding on the end zeroed */
  63         memcpy(&hdr[0], da, ETH_ALEN);
  64         memcpy(&hdr[ETH_ALEN], sa, ETH_ALEN);
  65         hdr[ETH_ALEN * 2] = priority;
  66         hdr[ETH_ALEN * 2 + 1] = 0;
  67         hdr[ETH_ALEN * 2 + 2] = 0;
  68         hdr[ETH_ALEN * 2 + 3] = 0;
  69
  70         /* Use scatter gather to MIC header and data in one go */
  71         sg_init_table(sg, 2);
  72         sg_set_buf(&sg[0], hdr, sizeof(hdr));
  73         sg_set_buf(&sg[1], data, data_len);
  74
  75         if (crypto_ahash_setkey(tfm_michael, key, MIC_KEYLEN))
  76                 return -1;
  77
  78         ahash_request_set_tfm(req, tfm_michael);
  79         ahash_request_set_callback(req, 0, NULL, NULL);
  80         ahash_request_set_crypt(req, sg, mic, data_len + sizeof(hdr));
  81         err = crypto_ahash_digest(req);
  82         ahash_request_zero(req);
  83         return err;
  84 }