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-rw-r--r--crypto/michael_mic.c181
1 files changed, 181 insertions, 0 deletions
diff --git a/crypto/michael_mic.c b/crypto/michael_mic.c
new file mode 100644
index 0000000..a470bcb
--- /dev/null
+++ b/crypto/michael_mic.c
@@ -0,0 +1,181 @@
+/*
+ * Cryptographic API
+ *
+ * Michael MIC (IEEE 802.11i/TKIP) keyed digest
+ *
+ * Copyright (c) 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.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/crypto.h>
+
+
+struct michael_mic_ctx {
+ u8 pending[4];
+ size_t pending_len;
+
+ u32 l, r;
+};
+
+
+static inline u32 xswap(u32 val)
+{
+ return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
+}
+
+
+#define michael_block(l, r) \
+do { \
+ r ^= rol32(l, 17); \
+ l += r; \
+ r ^= xswap(l); \
+ l += r; \
+ r ^= rol32(l, 3); \
+ l += r; \
+ r ^= ror32(l, 2); \
+ l += r; \
+} while (0)
+
+
+static inline u32 get_le32(const u8 *p)
+{
+ return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
+}
+
+
+static inline void put_le32(u8 *p, u32 v)
+{
+ p[0] = v;
+ p[1] = v >> 8;
+ p[2] = v >> 16;
+ p[3] = v >> 24;
+}
+
+
+static void michael_init(void *ctx)
+{
+ struct michael_mic_ctx *mctx = ctx;
+ mctx->pending_len = 0;
+}
+
+
+static void michael_update(void *ctx, const u8 *data, unsigned int len)
+{
+ struct michael_mic_ctx *mctx = ctx;
+
+ if (mctx->pending_len) {
+ int flen = 4 - mctx->pending_len;
+ if (flen > len)
+ flen = len;
+ memcpy(&mctx->pending[mctx->pending_len], data, flen);
+ mctx->pending_len += flen;
+ data += flen;
+ len -= flen;
+
+ if (mctx->pending_len < 4)
+ return;
+
+ mctx->l ^= get_le32(mctx->pending);
+ michael_block(mctx->l, mctx->r);
+ mctx->pending_len = 0;
+ }
+
+ while (len >= 4) {
+ mctx->l ^= get_le32(data);
+ michael_block(mctx->l, mctx->r);
+ data += 4;
+ len -= 4;
+ }
+
+ if (len > 0) {
+ mctx->pending_len = len;
+ memcpy(mctx->pending, data, len);
+ }
+}
+
+
+static void michael_final(void *ctx, u8 *out)
+{
+ struct michael_mic_ctx *mctx = ctx;
+ u8 *data = mctx->pending;
+
+ /* Last block and padding (0x5a, 4..7 x 0) */
+ switch (mctx->pending_len) {
+ case 0:
+ mctx->l ^= 0x5a;
+ break;
+ case 1:
+ mctx->l ^= data[0] | 0x5a00;
+ break;
+ case 2:
+ mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
+ break;
+ case 3:
+ mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
+ 0x5a000000;
+ break;
+ }
+ michael_block(mctx->l, mctx->r);
+ /* l ^= 0; */
+ michael_block(mctx->l, mctx->r);
+
+ put_le32(out, mctx->l);
+ put_le32(out + 4, mctx->r);
+}
+
+
+static int michael_setkey(void *ctx, const u8 *key, unsigned int keylen,
+ u32 *flags)
+{
+ struct michael_mic_ctx *mctx = ctx;
+ if (keylen != 8) {
+ if (flags)
+ *flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
+ return -EINVAL;
+ }
+ mctx->l = get_le32(key);
+ mctx->r = get_le32(key + 4);
+ return 0;
+}
+
+
+static struct crypto_alg michael_mic_alg = {
+ .cra_name = "michael_mic",
+ .cra_flags = CRYPTO_ALG_TYPE_DIGEST,
+ .cra_blocksize = 8,
+ .cra_ctxsize = sizeof(struct michael_mic_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(michael_mic_alg.cra_list),
+ .cra_u = { .digest = {
+ .dia_digestsize = 8,
+ .dia_init = michael_init,
+ .dia_update = michael_update,
+ .dia_final = michael_final,
+ .dia_setkey = michael_setkey } }
+};
+
+
+static int __init michael_mic_init(void)
+{
+ return crypto_register_alg(&michael_mic_alg);
+}
+
+
+static void __exit michael_mic_exit(void)
+{
+ crypto_unregister_alg(&michael_mic_alg);
+}
+
+
+module_init(michael_mic_init);
+module_exit(michael_mic_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Michael MIC");
+MODULE_AUTHOR("Jouni Malinen <jkmaline@cc.hut.fi>");
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