aboutsummaryrefslogtreecommitdiff
path: root/net/mac80211/aes_ccm.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/mac80211/aes_ccm.c')
-rw-r--r--net/mac80211/aes_ccm.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/net/mac80211/aes_ccm.c b/net/mac80211/aes_ccm.c
new file mode 100644
index 00000000000..e55569bee7d
--- /dev/null
+++ b/net/mac80211/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/mac80211.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);
+}