diff options
Diffstat (limited to 'net/ieee80211/ieee80211_crypt_ccmp.c')
-rw-r--r-- | net/ieee80211/ieee80211_crypt_ccmp.c | 470 |
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 00000000000..f5f412ae7f2 --- /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); |