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,
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_shash("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_shash(priv->tx_tfm_mic);
44 	if (priv->rx_tfm_mic)
45 		crypto_free_shash(priv->rx_tfm_mic);
46 }
47 
48 int orinoco_mic(struct crypto_shash *tfm_michael, u8 *key,
49 		u8 *da, u8 *sa, u8 priority,
50 		u8 *data, size_t data_len, u8 *mic)
51 {
52 	SHASH_DESC_ON_STACK(desc, tfm_michael);
53 	u8 hdr[ETH_HLEN + 2]; /* size of header + padding */
54 	int err;
55 
56 	if (tfm_michael == NULL) {
57 		printk(KERN_WARNING "orinoco_mic: tfm_michael == NULL\n");
58 		return -1;
59 	}
60 
61 	/* Copy header into buffer. We need the padding on the end zeroed */
62 	memcpy(&hdr[0], da, ETH_ALEN);
63 	memcpy(&hdr[ETH_ALEN], sa, ETH_ALEN);
64 	hdr[ETH_ALEN * 2] = priority;
65 	hdr[ETH_ALEN * 2 + 1] = 0;
66 	hdr[ETH_ALEN * 2 + 2] = 0;
67 	hdr[ETH_ALEN * 2 + 3] = 0;
68 
69 	desc->tfm = tfm_michael;
70 	desc->flags = 0;
71 
72 	err = crypto_shash_setkey(tfm_michael, key, MIC_KEYLEN);
73 	if (err)
74 		return err;
75 
76 	err = crypto_shash_init(desc);
77 	if (err)
78 		return err;
79 
80 	err = crypto_shash_update(desc, hdr, sizeof(hdr));
81 	if (err)
82 		return err;
83 
84 	err = crypto_shash_update(desc, data, data_len);
85 	if (err)
86 		return err;
87 
88 	err = crypto_shash_final(desc, mic);
89 	shash_desc_zero(desc);
90 
91 	return err;
92 }
93