add d80211 from a recent wireless-dev checkout

[openwrt/openwrt.git] / package / d80211 / src / aes_ccm.c

diff --git a/package/d80211/src/aes_ccm.c b/package/d80211/src/aes_ccm.c
new file mode 100644 (file)
index 0000000..e3f5372
--- /dev/null
+++ b/package/d80211/src/aes_ccm.c
@@ -0,0 +1,155 @@
+/*
+ * Copyright 2003-2004, Instant802 Networks, Inc.
+ * Copyright 2005-2006, Devicescape Software, Inc.
+ *
+ * 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.
+ */
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+#include <linux/err.h>
+#include <asm/scatterlist.h>
+
+#include <net/d80211.h>
+#include "ieee80211_key.h"
+#include "aes_ccm.h"
+
+
+static void ieee80211_aes_encrypt(struct crypto_cipher *tfm,
+                                 const u8 pt[16], u8 ct[16])
+{
+       crypto_cipher_encrypt_one(tfm, ct, pt);
+}
+
+
+static inline void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *b_0, u8 *aad,
+                                  u8 *b, u8 *s_0, u8 *a)
+{
+       int i;
+
+       ieee80211_aes_encrypt(tfm, b_0, b);
+
+       /* Extra Authenticate-only data (always two AES blocks) */
+       for (i = 0; i < AES_BLOCK_LEN; i++)
+               aad[i] ^= b[i];
+       ieee80211_aes_encrypt(tfm, aad, b);
+
+       aad += AES_BLOCK_LEN;
+
+       for (i = 0; i < AES_BLOCK_LEN; i++)
+               aad[i] ^= b[i];
+       ieee80211_aes_encrypt(tfm, aad, a);
+
+       /* Mask out bits from auth-only-b_0 */
+       b_0[0] &= 0x07;
+
+       /* S_0 is used to encrypt T (= MIC) */
+       b_0[14] = 0;
+       b_0[15] = 0;
+       ieee80211_aes_encrypt(tfm, b_0, s_0);
+}
+
+
+void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch,
+                              u8 *b_0, u8 *aad, u8 *data, size_t data_len,
+                              u8 *cdata, u8 *mic)
+{
+       int i, j, last_len, num_blocks;
+       u8 *pos, *cpos, *b, *s_0, *e;
+
+       b = scratch;
+       s_0 = scratch + AES_BLOCK_LEN;
+       e = scratch + 2 * AES_BLOCK_LEN;
+
+       num_blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
+       last_len = data_len % AES_BLOCK_LEN;
+       aes_ccm_prepare(tfm, b_0, aad, b, s_0, b);
+
+       /* Process payload blocks */
+       pos = data;
+       cpos = cdata;
+       for (j = 1; j <= num_blocks; j++) {
+               int blen = (j == num_blocks && last_len) ?
+                       last_len : AES_BLOCK_LEN;
+
+               /* Authentication followed by encryption */
+               for (i = 0; i < blen; i++)
+                       b[i] ^= pos[i];
+               ieee80211_aes_encrypt(tfm, b, b);
+
+               b_0[14] = (j >> 8) & 0xff;
+               b_0[15] = j & 0xff;
+               ieee80211_aes_encrypt(tfm, b_0, e);
+               for (i = 0; i < blen; i++)
+                       *cpos++ = *pos++ ^ e[i];
+       }
+
+       for (i = 0; i < CCMP_MIC_LEN; i++)
+               mic[i] = b[i] ^ s_0[i];
+}
+
+
+int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
+                             u8 *b_0, u8 *aad, u8 *cdata, size_t data_len,
+                             u8 *mic, u8 *data)
+{
+       int i, j, last_len, num_blocks;
+       u8 *pos, *cpos, *b, *s_0, *a;
+
+       b = scratch;
+       s_0 = scratch + AES_BLOCK_LEN;
+       a = scratch + 2 * AES_BLOCK_LEN;
+
+       num_blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
+       last_len = data_len % AES_BLOCK_LEN;
+       aes_ccm_prepare(tfm, b_0, aad, b, s_0, a);
+
+       /* Process payload blocks */
+       cpos = cdata;
+       pos = data;
+       for (j = 1; j <= num_blocks; j++) {
+               int blen = (j == num_blocks && last_len) ?
+                       last_len : AES_BLOCK_LEN;
+
+               /* Decryption followed by authentication */
+               b_0[14] = (j >> 8) & 0xff;
+               b_0[15] = j & 0xff;
+               ieee80211_aes_encrypt(tfm, b_0, b);
+               for (i = 0; i < blen; i++) {
+                       *pos = *cpos++ ^ b[i];
+                       a[i] ^= *pos++;
+               }
+
+               ieee80211_aes_encrypt(tfm, a, a);
+       }
+
+       for (i = 0; i < CCMP_MIC_LEN; i++) {
+               if ((mic[i] ^ s_0[i]) != a[i])
+                       return -1;
+       }
+
+       return 0;
+}
+
+
+struct crypto_cipher * ieee80211_aes_key_setup_encrypt(const u8 key[])
+{
+       struct crypto_cipher *tfm;
+
+       tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
+       if (IS_ERR(tfm))
+               return NULL;
+
+       crypto_cipher_setkey(tfm, key, ALG_CCMP_KEY_LEN);
+
+       return tfm;
+}
+
+
+void ieee80211_aes_key_free(struct crypto_cipher *tfm)
+{
+       if (tfm)
+               crypto_free_cipher(tfm);
+}