Fixed MTP to work with TWRP

crypto/crc32c_generic.c

@@ -0,0 +1,175 @@
+/*
+ * Cryptographic API.
+ *
+ * CRC32C chksum
+ *
+ *@Article{castagnoli-crc,
+ * author =       { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
+ * title =        {{Optimization of Cyclic Redundancy-Check Codes with 24
+ *                 and 32 Parity Bits}},
+ * journal =      IEEE Transactions on Communication,
+ * year =         {1993},
+ * volume =       {41},
+ * number =       {6},
+ * pages =        {},
+ * month =        {June},
+ *}
+ * Used by the iSCSI driver, possibly others, and derived from the
+ * the iscsi-crc.c module of the linux-iscsi driver at
+ * http://linux-iscsi.sourceforge.net.
+ *
+ * Following the example of lib/crc32, this function is intended to be
+ * flexible and useful for all users.  Modules that currently have their
+ * own crc32c, but hopefully may be able to use this one are:
+ *  net/sctp (please add all your doco to here if you change to
+ *            use this one!)
+ *  <endoflist>
+ *
+ * Copyright (c) 2004 Cisco Systems, Inc.
+ * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <crypto/internal/hash.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/crc32.h>
+
+#define CHKSUM_BLOCK_SIZE	1
+#define CHKSUM_DIGEST_SIZE	4
+
+struct chksum_ctx {
+	u32 key;
+};
+
+struct chksum_desc_ctx {
+	u32 crc;
+};
+
+/*
+ * Steps through buffer one byte at at time, calculates reflected
+ * crc using table.
+ */
+
+static int chksum_init(struct shash_desc *desc)
+{
+	struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	ctx->crc = mctx->key;
+
+	return 0;
+}
+
+/*
+ * Setting the seed allows arbitrary accumulators and flexible XOR policy
+ * If your algorithm starts with ~0, then XOR with ~0 before you set
+ * the seed.
+ */
+static int chksum_setkey(struct crypto_shash *tfm, const u8 *key,
+			 unsigned int keylen)
+{
+	struct chksum_ctx *mctx = crypto_shash_ctx(tfm);
+
+	if (keylen != sizeof(mctx->key)) {
+		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return -EINVAL;
+	}
+	mctx->key = le32_to_cpu(*(__le32 *)key);
+	return 0;
+}
+
+static int chksum_update(struct shash_desc *desc, const u8 *data,
+			 unsigned int length)
+{
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	ctx->crc = __crc32c_le(ctx->crc, data, length);
+	return 0;
+}
+
+static int chksum_final(struct shash_desc *desc, u8 *out)
+{
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	*(__le32 *)out = ~cpu_to_le32p(&ctx->crc);
+	return 0;
+}
+
+static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
+{
+	*(__le32 *)out = ~cpu_to_le32(__crc32c_le(*crcp, data, len));
+	return 0;
+}
+
+static int chksum_finup(struct shash_desc *desc, const u8 *data,
+			unsigned int len, u8 *out)
+{
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	return __chksum_finup(&ctx->crc, data, len, out);
+}
+
+static int chksum_digest(struct shash_desc *desc, const u8 *data,
+			 unsigned int length, u8 *out)
+{
+	struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
+
+	return __chksum_finup(&mctx->key, data, length, out);
+}
+
+static int crc32c_cra_init(struct crypto_tfm *tfm)
+{
+	struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
+
+	mctx->key = ~0;
+	return 0;
+}
+
+static struct shash_alg alg = {
+	.digestsize		=	CHKSUM_DIGEST_SIZE,
+	.setkey			=	chksum_setkey,
+	.init		=	chksum_init,
+	.update		=	chksum_update,
+	.final		=	chksum_final,
+	.finup		=	chksum_finup,
+	.digest		=	chksum_digest,
+	.descsize		=	sizeof(struct chksum_desc_ctx),
+	.base			=	{
+		.cra_name		=	"crc32c",
+		.cra_driver_name	=	"crc32c-generic",
+		.cra_priority		=	100,
+		.cra_blocksize		=	CHKSUM_BLOCK_SIZE,
+		.cra_alignmask		=	3,
+		.cra_ctxsize		=	sizeof(struct chksum_ctx),
+		.cra_module		=	THIS_MODULE,
+		.cra_init		=	crc32c_cra_init,
+	}
+};
+
+static int __init crc32c_mod_init(void)
+{
+	return crypto_register_shash(&alg);
+}
+
+static void __exit crc32c_mod_fini(void)
+{
+	crypto_unregister_shash(&alg);
+}
+
+module_init(crc32c_mod_init);
+module_exit(crc32c_mod_fini);
+
+MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
+MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_CRYPTO("crc32c");
+MODULE_ALIAS_CRYPTO("crc32c-generic");
+MODULE_SOFTDEP("pre: crc32c");