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 }
85