lib80211: absorb crypto bits from net/ieee80211

These bits are shared already between ipw2x00 and hostap, and could
probably be shared both more cleanly and with other drivers.  This
commit simply relocates the code to lib80211 and adjusts the drivers
appropriately.

Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 492 insertions, 0 deletions

diff --git a/net/wireless/lib80211_crypt_ccmp.c b/net/wireless/lib80211_crypt_ccmp.c
new file mode 100644
index 000000000000..db428194c16a
--- /dev/null
+++ b/net/wireless/lib80211_crypt_ccmp.c
@@ -0,0 +1,492 @@
+/*
+ * lib80211 crypt: host-based CCMP encryption implementation for lib80211
+ *
+ * Copyright (c) 2003-2004, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2008, John W. Linville <linville@tuxdriver.com>
+ *
+ * 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/kernel.h>
+#include <linux/err.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 <linux/ieee80211.h>
+
+#include <linux/crypto.h>
+
+#include <net/lib80211.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 lib80211_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_cipher *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];
+};
+
+static inline void lib80211_ccmp_aes_encrypt(struct crypto_cipher *tfm,
+                                              const u8 pt[16], u8 ct[16])
+{
+        crypto_cipher_encrypt_one(tfm, ct, pt);
+}
+
+static void *lib80211_ccmp_init(int key_idx)
+{
+        struct lib80211_ccmp_data *priv;
+
+        priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
+        if (priv == NULL)
+                goto fail;
+        priv->key_idx = key_idx;
+
+        priv->tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
+        if (IS_ERR(priv->tfm)) {
+                printk(KERN_DEBUG "lib80211_crypt_ccmp: could not allocate "
+                       "crypto API aes\n");
+                priv->tfm = NULL;
+                goto fail;
+        }
+
+        return priv;
+
+      fail:
+        if (priv) {
+                if (priv->tfm)
+                        crypto_free_cipher(priv->tfm);
+                kfree(priv);
+        }
+
+        return NULL;
+}
+
+static void lib80211_ccmp_deinit(void *priv)
+{
+        struct lib80211_ccmp_data *_priv = priv;
+        if (_priv && _priv->tfm)
+                crypto_free_cipher(_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_cipher *tfm,
+                             struct ieee80211_hdr *hdr,
+                             u8 * pn, size_t dlen, u8 * b0, u8 * auth, u8 * s0)
+{
+        u8 *pos, qc = 0;
+        size_t aad_len;
+        int a4_included, qc_included;
+        u8 aad[2 * AES_BLOCK_LEN];
+
+        a4_included = ieee80211_has_a4(hdr->frame_control);
+        qc_included = ieee80211_is_data_qos(hdr->frame_control);
+
+        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_ctrl;
+        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 */
+        lib80211_ccmp_aes_encrypt(tfm, b0, auth);
+        xor_block(auth, aad, AES_BLOCK_LEN);
+        lib80211_ccmp_aes_encrypt(tfm, auth, auth);
+        xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
+        lib80211_ccmp_aes_encrypt(tfm, auth, auth);
+        b0[0] &= 0x07;
+        b0[14] = b0[15] = 0;
+        lib80211_ccmp_aes_encrypt(tfm, b0, s0);
+}
+
+static int lib80211_ccmp_hdr(struct sk_buff *skb, int hdr_len,
+                              u8 *aeskey, int keylen, void *priv)
+{
+        struct lib80211_ccmp_data *key = priv;
+        int i;
+        u8 *pos;
+
+        if (skb_headroom(skb) < CCMP_HDR_LEN || skb->len < hdr_len)
+                return -1;
+
+        if (aeskey != NULL && keylen >= CCMP_TK_LEN)
+                memcpy(aeskey, key->key, CCMP_TK_LEN);
+
+        pos = skb_push(skb, CCMP_HDR_LEN);
+        memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
+        pos += hdr_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];
+
+        return CCMP_HDR_LEN;
+}
+
+static int lib80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
+{
+        struct lib80211_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_tailroom(skb) < CCMP_MIC_LEN || skb->len < hdr_len)
+                return -1;
+
+        data_len = skb->len - hdr_len;
+        len = lib80211_ccmp_hdr(skb, hdr_len, NULL, 0, priv);
+        if (len < 0)
+                return -1;
+
+        pos = skb->data + hdr_len + CCMP_HDR_LEN;
+        mic = skb_put(skb, CCMP_MIC_LEN);
+        hdr = (struct ieee80211_hdr *)skb->data;
+        ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
+
+        blocks = DIV_ROUND_UP(data_len, 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);
+                lib80211_ccmp_aes_encrypt(key->tfm, b, b);
+                /* Encryption, with counter */
+                b0[14] = (i >> 8) & 0xff;
+                b0[15] = i & 0xff;
+                lib80211_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;
+}
+
+/*
+ * deal with seq counter wrapping correctly.
+ * refer to timer_after() for jiffies wrapping handling
+ */
+static inline int ccmp_replay_check(u8 *pn_n, u8 *pn_o)
+{
+        u32 iv32_n, iv16_n;
+        u32 iv32_o, iv16_o;
+
+        iv32_n = (pn_n[0] << 24) | (pn_n[1] << 16) | (pn_n[2] << 8) | pn_n[3];
+        iv16_n = (pn_n[4] << 8) | pn_n[5];
+
+        iv32_o = (pn_o[0] << 24) | (pn_o[1] << 16) | (pn_o[2] << 8) | pn_o[3];
+        iv16_o = (pn_o[4] << 8) | pn_o[5];
+
+        if ((s32)iv32_n - (s32)iv32_o < 0 ||
+            (iv32_n == iv32_o && iv16_n <= iv16_o))
+                return 1;
+        return 0;
+}
+
+static int lib80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
+{
+        struct lib80211_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 %pM\n", 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 %pM"
+                               " with keyid=%d that does not have a configured"
+                               " key\n", 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 (ccmp_replay_check(pn, key->rx_pn)) {
+                if (net_ratelimit()) {
+                        printk(KERN_DEBUG "CCMP: replay detected: STA=%pM "
+                                 "previous PN %02x%02x%02x%02x%02x%02x "
+                                 "received PN %02x%02x%02x%02x%02x%02x\n",
+                                 hdr->addr2,
+                                 key->rx_pn[0], key->rx_pn[1], key->rx_pn[2],
+                                 key->rx_pn[3], key->rx_pn[4], key->rx_pn[5],
+                                 pn[0], pn[1], pn[2], pn[3], pn[4], pn[5]);
+                }
+                key->dot11RSNAStatsCCMPReplays++;
+                return -4;
+        }
+
+        ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
+        xor_block(mic, b, CCMP_MIC_LEN);
+
+        blocks = DIV_ROUND_UP(data_len, 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;
+                lib80211_ccmp_aes_encrypt(key->tfm, b0, b);
+                xor_block(pos, b, len);
+                /* Authentication */
+                xor_block(a, pos, len);
+                lib80211_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="
+                               "%pM\n", 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 lib80211_ccmp_set_key(void *key, int len, u8 * seq, void *priv)
+{
+        struct lib80211_ccmp_data *data = priv;
+        int keyidx;
+        struct crypto_cipher *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 lib80211_ccmp_get_key(void *key, int len, u8 * seq, void *priv)
+{
+        struct lib80211_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 *lib80211_ccmp_print_stats(char *p, void *priv)
+{
+        struct lib80211_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,
+                     ccmp->tx_pn[0], ccmp->tx_pn[1], ccmp->tx_pn[2],
+                     ccmp->tx_pn[3], ccmp->tx_pn[4], ccmp->tx_pn[5],
+                     ccmp->rx_pn[0], ccmp->rx_pn[1], ccmp->rx_pn[2],
+                     ccmp->rx_pn[3], ccmp->rx_pn[4], ccmp->rx_pn[5],
+                     ccmp->dot11RSNAStatsCCMPFormatErrors,
+                     ccmp->dot11RSNAStatsCCMPReplays,
+                     ccmp->dot11RSNAStatsCCMPDecryptErrors);
+
+        return p;
+}
+
+static struct lib80211_crypto_ops lib80211_crypt_ccmp = {
+        .name = "CCMP",
+        .init = lib80211_ccmp_init,
+        .deinit = lib80211_ccmp_deinit,
+        .build_iv = lib80211_ccmp_hdr,
+        .encrypt_mpdu = lib80211_ccmp_encrypt,
+        .decrypt_mpdu = lib80211_ccmp_decrypt,
+        .encrypt_msdu = NULL,
+        .decrypt_msdu = NULL,
+        .set_key = lib80211_ccmp_set_key,
+        .get_key = lib80211_ccmp_get_key,
+        .print_stats = lib80211_ccmp_print_stats,
+        .extra_mpdu_prefix_len = CCMP_HDR_LEN,
+        .extra_mpdu_postfix_len = CCMP_MIC_LEN,
+        .owner = THIS_MODULE,
+};
+
+static int __init lib80211_crypto_ccmp_init(void)
+{
+        return lib80211_register_crypto_ops(&lib80211_crypt_ccmp);
+}
+
+static void __exit lib80211_crypto_ccmp_exit(void)
+{
+        lib80211_unregister_crypto_ops(&lib80211_crypt_ccmp);
+}
+
+module_init(lib80211_crypto_ccmp_init);
+module_exit(lib80211_crypto_ccmp_exit);