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_shash("michael_mic", 0, 0);
20 	if (IS_ERR(priv->tx_tfm_mic)) {
21 		printk(KERN_DEBUG "%s: could not allocate "
22 		       "crypto API michael_mic\n", __func__);
23 		priv->tx_tfm_mic = NULL;
24 		return -ENOMEM;
25 	}
26 
27 	priv->rx_tfm_mic = crypto_alloc_shash("michael_mic", 0, 0);
28 	if (IS_ERR(priv->rx_tfm_mic)) {
29 		printk(KERN_DEBUG "%s: could not allocate "
30 		       "crypto API michael_mic\n", __func__);
31 		priv->rx_tfm_mic = NULL;
32 		return -ENOMEM;
33 	}
34 
35 	return 0;
36 }
37 
38 void orinoco_mic_free(struct orinoco_private *priv)
39 {
40 	if (priv->tx_tfm_mic)
41 		crypto_free_shash(priv->tx_tfm_mic);
42 	if (priv->rx_tfm_mic)
43 		crypto_free_shash(priv->rx_tfm_mic);
44 }
45 
46 int orinoco_mic(struct crypto_shash *tfm_michael, u8 *key,
47 		u8 *da, u8 *sa, u8 priority,
48 		u8 *data, size_t data_len, u8 *mic)
49 {
50 	SHASH_DESC_ON_STACK(desc, tfm_michael);
51 	u8 hdr[ETH_HLEN + 2]; /* size of header + padding */
52 	int err;
53 
54 	if (tfm_michael == NULL) {
55 		printk(KERN_WARNING "%s: tfm_michael == NULL\n", __func__);
56 		return -1;
57 	}
58 
59 	/* Copy header into buffer. We need the padding on the end zeroed */
60 	memcpy(&hdr[0], da, ETH_ALEN);
61 	memcpy(&hdr[ETH_ALEN], sa, ETH_ALEN);
62 	hdr[ETH_ALEN * 2] = priority;
63 	hdr[ETH_ALEN * 2 + 1] = 0;
64 	hdr[ETH_ALEN * 2 + 2] = 0;
65 	hdr[ETH_ALEN * 2 + 3] = 0;
66 
67 	desc->tfm = tfm_michael;
68 
69 	err = crypto_shash_setkey(tfm_michael, key, MIC_KEYLEN);
70 	if (err)
71 		return err;
72 
73 	err = crypto_shash_init(desc);
74 	if (err)
75 		return err;
76 
77 	err = crypto_shash_update(desc, hdr, sizeof(hdr));
78 	if (err)
79 		return err;
80 
81 	err = crypto_shash_update(desc, data, data_len);
82 	if (err)
83 		return err;
84 
85 	err = crypto_shash_final(desc, mic);
86 	shash_desc_zero(desc);
87 
88 	return err;
89 }
90