Fixed MTP to work with TWRP

crypto/michael_mic.c

@@ -0,0 +1,187 @@
+/*
+ * Cryptographic API
+ *
+ * Michael MIC (IEEE 802.11i/TKIP) keyed digest
+ *
+ * Copyright (c) 2004 Jouni Malinen <j@w1.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 <crypto/internal/hash.h>
+#include <asm/byteorder.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+
+struct michael_mic_ctx {
+	u32 l, r;
+};
+
+struct michael_mic_desc_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 int michael_init(struct shash_desc *desc)
+{
+	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
+	struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);
+	mctx->pending_len = 0;
+	mctx->l = ctx->l;
+	mctx->r = ctx->r;
+
+	return 0;
+}
+
+
+static int michael_update(struct shash_desc *desc, const u8 *data,
+			   unsigned int len)
+{
+	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
+	const __le32 *src;
+
+	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 0;
+
+		src = (const __le32 *)mctx->pending;
+		mctx->l ^= le32_to_cpup(src);
+		michael_block(mctx->l, mctx->r);
+		mctx->pending_len = 0;
+	}
+
+	src = (const __le32 *)data;
+
+	while (len >= 4) {
+		mctx->l ^= le32_to_cpup(src++);
+		michael_block(mctx->l, mctx->r);
+		len -= 4;
+	}
+
+	if (len > 0) {
+		mctx->pending_len = len;
+		memcpy(mctx->pending, src, len);
+	}
+
+	return 0;
+}
+
+
+static int michael_final(struct shash_desc *desc, u8 *out)
+{
+	struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
+	u8 *data = mctx->pending;
+	__le32 *dst = (__le32 *)out;
+
+	/* 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);
+
+	dst[0] = cpu_to_le32(mctx->l);
+	dst[1] = cpu_to_le32(mctx->r);
+
+	return 0;
+}
+
+
+static int michael_setkey(struct crypto_shash *tfm, const u8 *key,
+			  unsigned int keylen)
+{
+	struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);
+
+	const __le32 *data = (const __le32 *)key;
+
+	if (keylen != 8) {
+		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return -EINVAL;
+	}
+
+	mctx->l = le32_to_cpu(data[0]);
+	mctx->r = le32_to_cpu(data[1]);
+	return 0;
+}
+
+static struct shash_alg alg = {
+	.digestsize		=	8,
+	.setkey			=	michael_setkey,
+	.init			=	michael_init,
+	.update			=	michael_update,
+	.final			=	michael_final,
+	.descsize		=	sizeof(struct michael_mic_desc_ctx),
+	.base			=	{
+		.cra_name		=	"michael_mic",
+		.cra_blocksize		=	8,
+		.cra_alignmask		=	3,
+		.cra_ctxsize		=	sizeof(struct michael_mic_ctx),
+		.cra_module		=	THIS_MODULE,
+	}
+};
+
+static int __init michael_mic_init(void)
+{
+	return crypto_register_shash(&alg);
+}
+
+
+static void __exit michael_mic_exit(void)
+{
+	crypto_unregister_shash(&alg);
+}
+
+
+module_init(michael_mic_init);
+module_exit(michael_mic_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Michael MIC");
+MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");
+MODULE_ALIAS_CRYPTO("michael_mic");