[NET] ieee80211 subsystem

Contributors:
Host AP contributors
James Ketrenos <jketreno@linux.intel.com>
Francois Romieu <romieu@fr.zoreil.com>
Adrian Bunk <bunk@stusta.de>
Matthew Galgoci <mgalgoci@parcelfarce.linux.th
eplanet.co.uk>

1 files changed, 470 insertions, 0 deletions

diff --git a/net/ieee80211/ieee80211_crypt_ccmp.c b/net/ieee80211/ieee80211_crypt_ccmp.c
new file mode 100644
index 0000000..f5f412a
--- /dev/null
+++ b/net/ieee80211/ieee80211_crypt_ccmp.c
@@ -0,0 +1,470 @@
+/*
+ * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
+ *
+ * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation. See README and COPYING for
+ * more details.
+ */
+
+#include <linux/config.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/if_ether.h>
+#include <linux/if_arp.h>
+#include <asm/string.h>
+#include <linux/wireless.h>
+
+#include <net/ieee80211.h>
+
+
+#include <linux/crypto.h>
+#include <asm/scatterlist.h>
+
+MODULE_AUTHOR("Jouni Malinen");
+MODULE_DESCRIPTION("Host AP crypt: CCMP");
+MODULE_LICENSE("GPL");
+
+#define AES_BLOCK_LEN 16
+#define CCMP_HDR_LEN 8
+#define CCMP_MIC_LEN 8
+#define CCMP_TK_LEN 16
+#define CCMP_PN_LEN 6
+
+struct ieee80211_ccmp_data {
+	u8 key[CCMP_TK_LEN];
+	int key_set;
+
+	u8 tx_pn[CCMP_PN_LEN];
+	u8 rx_pn[CCMP_PN_LEN];
+
+	u32 dot11RSNAStatsCCMPFormatErrors;
+	u32 dot11RSNAStatsCCMPReplays;
+	u32 dot11RSNAStatsCCMPDecryptErrors;
+
+	int key_idx;
+
+	struct crypto_tfm *tfm;
+
+	/* scratch buffers for virt_to_page() (crypto API) */
+	u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
+		tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
+	u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
+};
+
+void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
+			     const u8 pt[16], u8 ct[16])
+{
+	struct scatterlist src, dst;
+
+	src.page = virt_to_page(pt);
+	src.offset = offset_in_page(pt);
+	src.length = AES_BLOCK_LEN;
+
+	dst.page = virt_to_page(ct);
+	dst.offset = offset_in_page(ct);
+	dst.length = AES_BLOCK_LEN;
+
+	crypto_cipher_encrypt(tfm, &dst, &src, AES_BLOCK_LEN);
+}
+
+static void * ieee80211_ccmp_init(int key_idx)
+{
+	struct ieee80211_ccmp_data *priv;
+
+	priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
+	if (priv == NULL)
+		goto fail;
+	memset(priv, 0, sizeof(*priv));
+	priv->key_idx = key_idx;
+
+	priv->tfm = crypto_alloc_tfm("aes", 0);
+	if (priv->tfm == NULL) {
+		printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
+		       "crypto API aes\n");
+		goto fail;
+	}
+
+	return priv;
+
+fail:
+	if (priv) {
+		if (priv->tfm)
+			crypto_free_tfm(priv->tfm);
+		kfree(priv);
+	}
+
+	return NULL;
+}
+
+
+static void ieee80211_ccmp_deinit(void *priv)
+{
+	struct ieee80211_ccmp_data *_priv = priv;
+	if (_priv && _priv->tfm)
+		crypto_free_tfm(_priv->tfm);
+	kfree(priv);
+}
+
+
+static inline void xor_block(u8 *b, u8 *a, size_t len)
+{
+	int i;
+	for (i = 0; i < len; i++)
+		b[i] ^= a[i];
+}
+
+
+static void ccmp_init_blocks(struct crypto_tfm *tfm,
+			     struct ieee80211_hdr *hdr,
+			     u8 *pn, size_t dlen, u8 *b0, u8 *auth,
+			     u8 *s0)
+{
+	u8 *pos, qc = 0;
+	size_t aad_len;
+	u16 fc;
+	int a4_included, qc_included;
+	u8 aad[2 * AES_BLOCK_LEN];
+
+	fc = le16_to_cpu(hdr->frame_ctl);
+	a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
+		       (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
+	qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
+		       (WLAN_FC_GET_STYPE(fc) & 0x08));
+	aad_len = 22;
+	if (a4_included)
+		aad_len += 6;
+	if (qc_included) {
+		pos = (u8 *) &hdr->addr4;
+		if (a4_included)
+			pos += 6;
+		qc = *pos & 0x0f;
+		aad_len += 2;
+	}
+
+	/* CCM Initial Block:
+	 * Flag (Include authentication header, M=3 (8-octet MIC),
+	 *       L=1 (2-octet Dlen))
+	 * Nonce: 0x00 | A2 | PN
+	 * Dlen */
+	b0[0] = 0x59;
+	b0[1] = qc;
+	memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
+	memcpy(b0 + 8, pn, CCMP_PN_LEN);
+	b0[14] = (dlen >> 8) & 0xff;
+	b0[15] = dlen & 0xff;
+
+	/* AAD:
+	 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
+	 * A1 | A2 | A3
+	 * SC with bits 4..15 (seq#) masked to zero
+	 * A4 (if present)
+	 * QC (if present)
+	 */
+	pos = (u8 *) hdr;
+	aad[0] = 0; /* aad_len >> 8 */
+	aad[1] = aad_len & 0xff;
+	aad[2] = pos[0] & 0x8f;
+	aad[3] = pos[1] & 0xc7;
+	memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
+	pos = (u8 *) &hdr->seq_ctl;
+	aad[22] = pos[0] & 0x0f;
+	aad[23] = 0; /* all bits masked */
+	memset(aad + 24, 0, 8);
+	if (a4_included)
+		memcpy(aad + 24, hdr->addr4, ETH_ALEN);
+	if (qc_included) {
+		aad[a4_included ? 30 : 24] = qc;
+		/* rest of QC masked */
+	}
+
+	/* Start with the first block and AAD */
+	ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
+	xor_block(auth, aad, AES_BLOCK_LEN);
+	ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
+	xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
+	ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
+	b0[0] &= 0x07;
+	b0[14] = b0[15] = 0;
+	ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
+}
+
+
+static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
+{
+	struct ieee80211_ccmp_data *key = priv;
+	int data_len, i, blocks, last, len;
+	u8 *pos, *mic;
+	struct ieee80211_hdr *hdr;
+	u8 *b0 = key->tx_b0;
+	u8 *b = key->tx_b;
+	u8 *e = key->tx_e;
+	u8 *s0 = key->tx_s0;
+
+	if (skb_headroom(skb) < CCMP_HDR_LEN ||
+	    skb_tailroom(skb) < CCMP_MIC_LEN ||
+	    skb->len < hdr_len)
+		return -1;
+
+	data_len = skb->len - hdr_len;
+	pos = skb_push(skb, CCMP_HDR_LEN);
+	memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
+	pos += hdr_len;
+	mic = skb_put(skb, CCMP_MIC_LEN);
+
+	i = CCMP_PN_LEN - 1;
+	while (i >= 0) {
+		key->tx_pn[i]++;
+		if (key->tx_pn[i] != 0)
+			break;
+		i--;
+	}
+
+	*pos++ = key->tx_pn[5];
+	*pos++ = key->tx_pn[4];
+	*pos++ = 0;
+	*pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
+	*pos++ = key->tx_pn[3];
+	*pos++ = key->tx_pn[2];
+	*pos++ = key->tx_pn[1];
+	*pos++ = key->tx_pn[0];
+
+	hdr = (struct ieee80211_hdr *) skb->data;
+	ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
+
+	blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
+	last = data_len % AES_BLOCK_LEN;
+
+	for (i = 1; i <= blocks; i++) {
+		len = (i == blocks && last) ? last : AES_BLOCK_LEN;
+		/* Authentication */
+		xor_block(b, pos, len);
+		ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
+		/* Encryption, with counter */
+		b0[14] = (i >> 8) & 0xff;
+		b0[15] = i & 0xff;
+		ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
+		xor_block(pos, e, len);
+		pos += len;
+	}
+
+	for (i = 0; i < CCMP_MIC_LEN; i++)
+		mic[i] = b[i] ^ s0[i];
+
+	return 0;
+}
+
+
+static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
+{
+	struct ieee80211_ccmp_data *key = priv;
+	u8 keyidx, *pos;
+	struct ieee80211_hdr *hdr;
+	u8 *b0 = key->rx_b0;
+	u8 *b = key->rx_b;
+	u8 *a = key->rx_a;
+	u8 pn[6];
+	int i, blocks, last, len;
+	size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
+	u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
+
+	if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
+		key->dot11RSNAStatsCCMPFormatErrors++;
+		return -1;
+	}
+
+	hdr = (struct ieee80211_hdr *) skb->data;
+	pos = skb->data + hdr_len;
+	keyidx = pos[3];
+	if (!(keyidx & (1 << 5))) {
+		if (net_ratelimit()) {
+			printk(KERN_DEBUG "CCMP: received packet without ExtIV"
+			       " flag from " MAC_FMT "\n", MAC_ARG(hdr->addr2));
+		}
+		key->dot11RSNAStatsCCMPFormatErrors++;
+		return -2;
+	}
+	keyidx >>= 6;
+	if (key->key_idx != keyidx) {
+		printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
+		       "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
+		return -6;
+	}
+	if (!key->key_set) {
+		if (net_ratelimit()) {
+			printk(KERN_DEBUG "CCMP: received packet from " MAC_FMT
+			       " with keyid=%d that does not have a configured"
+			       " key\n", MAC_ARG(hdr->addr2), keyidx);
+		}
+		return -3;
+	}
+
+	pn[0] = pos[7];
+	pn[1] = pos[6];
+	pn[2] = pos[5];
+	pn[3] = pos[4];
+	pn[4] = pos[1];
+	pn[5] = pos[0];
+	pos += 8;
+
+	if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
+		if (net_ratelimit()) {
+			printk(KERN_DEBUG "CCMP: replay detected: STA=" MAC_FMT
+			       " previous PN %02x%02x%02x%02x%02x%02x "
+			       "received PN %02x%02x%02x%02x%02x%02x\n",
+			       MAC_ARG(hdr->addr2), MAC_ARG(key->rx_pn),
+			       MAC_ARG(pn));
+		}
+		key->dot11RSNAStatsCCMPReplays++;
+		return -4;
+	}
+
+	ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
+	xor_block(mic, b, CCMP_MIC_LEN);
+
+	blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
+	last = data_len % AES_BLOCK_LEN;
+
+	for (i = 1; i <= blocks; i++) {
+		len = (i == blocks && last) ? last : AES_BLOCK_LEN;
+		/* Decrypt, with counter */
+		b0[14] = (i >> 8) & 0xff;
+		b0[15] = i & 0xff;
+		ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
+		xor_block(pos, b, len);
+		/* Authentication */
+		xor_block(a, pos, len);
+		ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
+		pos += len;
+	}
+
+	if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
+		if (net_ratelimit()) {
+			printk(KERN_DEBUG "CCMP: decrypt failed: STA="
+			       MAC_FMT "\n", MAC_ARG(hdr->addr2));
+		}
+		key->dot11RSNAStatsCCMPDecryptErrors++;
+		return -5;
+	}
+
+	memcpy(key->rx_pn, pn, CCMP_PN_LEN);
+
+	/* Remove hdr and MIC */
+	memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
+	skb_pull(skb, CCMP_HDR_LEN);
+	skb_trim(skb, skb->len - CCMP_MIC_LEN);
+
+	return keyidx;
+}
+
+
+static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
+{
+	struct ieee80211_ccmp_data *data = priv;
+	int keyidx;
+	struct crypto_tfm *tfm = data->tfm;
+
+	keyidx = data->key_idx;
+	memset(data, 0, sizeof(*data));
+	data->key_idx = keyidx;
+	data->tfm = tfm;
+	if (len == CCMP_TK_LEN) {
+		memcpy(data->key, key, CCMP_TK_LEN);
+		data->key_set = 1;
+		if (seq) {
+			data->rx_pn[0] = seq[5];
+			data->rx_pn[1] = seq[4];
+			data->rx_pn[2] = seq[3];
+			data->rx_pn[3] = seq[2];
+			data->rx_pn[4] = seq[1];
+			data->rx_pn[5] = seq[0];
+		}
+		crypto_cipher_setkey(data->tfm, data->key, CCMP_TK_LEN);
+	} else if (len == 0)
+		data->key_set = 0;
+	else
+		return -1;
+
+	return 0;
+}
+
+
+static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
+{
+	struct ieee80211_ccmp_data *data = priv;
+
+	if (len < CCMP_TK_LEN)
+		return -1;
+
+	if (!data->key_set)
+		return 0;
+	memcpy(key, data->key, CCMP_TK_LEN);
+
+	if (seq) {
+		seq[0] = data->tx_pn[5];
+		seq[1] = data->tx_pn[4];
+		seq[2] = data->tx_pn[3];
+		seq[3] = data->tx_pn[2];
+		seq[4] = data->tx_pn[1];
+		seq[5] = data->tx_pn[0];
+	}
+
+	return CCMP_TK_LEN;
+}
+
+
+static char * ieee80211_ccmp_print_stats(char *p, void *priv)
+{
+	struct ieee80211_ccmp_data *ccmp = priv;
+	p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
+		     "tx_pn=%02x%02x%02x%02x%02x%02x "
+		     "rx_pn=%02x%02x%02x%02x%02x%02x "
+		     "format_errors=%d replays=%d decrypt_errors=%d\n",
+		     ccmp->key_idx, ccmp->key_set,
+		     MAC_ARG(ccmp->tx_pn), MAC_ARG(ccmp->rx_pn),
+		     ccmp->dot11RSNAStatsCCMPFormatErrors,
+		     ccmp->dot11RSNAStatsCCMPReplays,
+		     ccmp->dot11RSNAStatsCCMPDecryptErrors);
+
+	return p;
+}
+
+
+static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
+	.name			= "CCMP",
+	.init			= ieee80211_ccmp_init,
+	.deinit			= ieee80211_ccmp_deinit,
+	.encrypt_mpdu		= ieee80211_ccmp_encrypt,
+	.decrypt_mpdu		= ieee80211_ccmp_decrypt,
+	.encrypt_msdu		= NULL,
+	.decrypt_msdu		= NULL,
+	.set_key		= ieee80211_ccmp_set_key,
+	.get_key		= ieee80211_ccmp_get_key,
+	.print_stats		= ieee80211_ccmp_print_stats,
+	.extra_prefix_len	= CCMP_HDR_LEN,
+	.extra_postfix_len	= CCMP_MIC_LEN,
+	.owner			= THIS_MODULE,
+};
+
+
+static int __init ieee80211_crypto_ccmp_init(void)
+{
+	return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
+}
+
+
+static void __exit ieee80211_crypto_ccmp_exit(void)
+{
+	ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
+}
+
+
+module_init(ieee80211_crypto_ccmp_init);
+module_exit(ieee80211_crypto_ccmp_exit);