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path: root/drivers/nfc

Age	Commit message (Expand)	Author
2011-10-31	drivers/nfc: add module.h to nfcwilink.c	Paul Gortmaker
2011-09-21	nfc: NFC_WILINK depends on NFC_NCI	Randy Dunlap
2011-09-20	NFC: driver for TI shared transport	Ilan Elias
2011-09-20	NFC: move nfc.h from include/net to include/net/nfc	Ilan Elias
2011-09-20	NFC: Add dev_up and dev_down control operations	Ilan Elias
2011-08-24	NFC: Reserve tx head and tail room	Samuel Ortiz
2011-07-26	NFC: pn533: use after free in pn533_disconnect()	Dan Carpenter
2011-07-05	NFC: pn533: add NXP pn533 nfc device driver	Aloisio Almeida Jr
2011-07-05	NFC: add nfc subsystem core	Lauro Ramos Venancio
2011-02-25	drivers/nfc/pn544.c: add missing regulator	Matti J. Aaltonen
2011-02-25	drivers/nfc/Kconfig: use full form of the NFC acronym	Matti J. Aaltonen
2011-01-16	drivers/nfc/pn544.c: fix min_t warnings	Andrew Morton
2011-01-13	NFC: Driver for NXP Semiconductors PN544 NFC chip.	Matti J. Aaltonen

generated by cgit v1.2.3 (git 2.25.1) at 2024-09-09 16:56:15 +0000

/*
 * ChaCha20 256-bit cipher algorithm, RFC7539
 *
 * Copyright (C) 2015 Martin Willi
 *
 * 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/algapi.h>
#include <linux/crypto.h>
#include <linux/kernel.h>
#include <linux/module.h>

#define CHACHA20_NONCE_SIZE 16
#define CHACHA20_KEY_SIZE   32
#define CHACHA20_BLOCK_SIZE 64

struct chacha20_ctx {
	u32 key[8];
};

static inline u32 rotl32(u32 v, u8 n)
{
	return (v << n) | (v >> (sizeof(v) * 8 - n));
}

static inline u32 le32_to_cpuvp(const void *p)
{
	return le32_to_cpup(p);
}

static void chacha20_block(u32 *state, void *stream)
{
	u32 x[16], *out = stream;
	int i;

	for (i = 0; i < ARRAY_SIZE(x); i++)
		x[i] = state[i];

	for (i = 0; i < 20; i += 2) {
		x[0]  += x[4];    x[12] = rotl32(x[12] ^ x[0],  16);
		x[1]  += x[5];    x[13] = rotl32(x[13] ^ x[1],  16);
		x[2]  += x[6];    x[14] = rotl32(x[14] ^ x[2],  16);
		x[3]  += x[7];    x[15] = rotl32(x[15] ^ x[3],  16);

		x[8]  += x[12];   x[4]  = rotl32(x[4]  ^ x[8],  12);
		x[9]  += x[13];   x[5]  = rotl32(x[5]  ^ x[9],  12);
		x[10] += x[14];   x[6]  = rotl32(x[6]  ^ x[10], 12);
		x[11] += x[15];   x[7]  = rotl32(x[7]  ^ x[11], 12);

		x[0]  += x[4];    x[12] = rotl32(x[12] ^ x[0],   8);
		x[1]  += x[5];    x[13] = rotl32(x[13] ^ x[1],   8);
		x[2]  += x[6];    x[14] = rotl32(x[14] ^ x[2],   8);
		x[3]  += x[7];    x[15] = rotl32(x[15] ^ x[3],   8);

		x[8]  += x[12];   x[4]  = rotl32(x[4]  ^ x[8],   7);
		x[9]  += x[13];   x[5]  = rotl32(x[5]  ^ x[9],   7);
		x[10] += x[14];   x[6]  = rotl32(x[6]  ^ x[10],  7);
		x[11] += x[15];   x[7]  = rotl32(x[7]  ^ x[11],  7);

		x[0]  += x[5];    x[15] = rotl32(x[15] ^ x[0],  16);
		x[1]  += x[6];    x[12] = rotl32(x[12] ^ x[1],  16);
		x[2]  += x[7];    x[13] = rotl32(x[13] ^ x[2],  16);
		x[3]  += x[4];    x[14] = rotl32(x[14] ^ x[3],  16);

		x[10] += x[15];   x[5]  = rotl32(x[5]  ^ x[10], 12);
		x[11] += x[12];   x[6]  = rotl32(x[6]  ^ x[11], 12);
		x[8]  += x[13];   x[7]  = rotl32(x[7]  ^ x[8],  12);
		x[9]  += x[14];   x[4]  = rotl32(x[4]  ^ x[9],  12);

		x[0]  += x[5];    x[15] = rotl32(x[15] ^ x[0],   8);
		x[1]  += x[6];    x[12] = rotl32(x[12] ^ x[1],   8);
		x[2]  += x[7];    x[13] = rotl32(x[13] ^ x[2],   8);
		x[3]  += x[4];    x[14] = rotl32(x[14] ^ x[3],   8);

		x[10] += x[15];   x[5]  = rotl32(x[5]  ^ x[10],  7);
		x[11] += x[12];   x[6]  = rotl32(x[6]  ^ x[11],  7);
		x[8]  += x[13];   x[7]  = rotl32(x[7]  ^ x[8],   7);
		x[9]  += x[14];   x[4]  = rotl32(x[4]  ^ x[9],   7);
	}

	for (i = 0; i < ARRAY_SIZE(x); i++)
		out[i] = cpu_to_le32(x[i] + state[i]);

	state[12]++;
}

static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
			     unsigned int bytes)
{
	u8 stream[CHACHA20_BLOCK_SIZE];

	if (dst != src)
		memcpy(dst, src, bytes);

	while (bytes >= CHACHA20_BLOCK_SIZE) {
		chacha20_block(state, stream);
		crypto_xor(dst, stream, CHACHA20_BLOCK_SIZE);
		bytes -= CHACHA20_BLOCK_SIZE;
		dst += CHACHA20_BLOCK_SIZE;
	}
	if (bytes) {
		chacha20_block(state, stream);
		crypto_xor(dst, stream, bytes);
	}
}

static void chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv)
{
	static const char constant[16] = "expand 32-byte k";

	state[0]  = le32_to_cpuvp(constant +  0);
	state[1]  = le32_to_cpuvp(constant +  4);
	state[2]  = le32_to_cpuvp(constant +  8);
	state[3]  = le32_to_cpuvp(constant + 12);
	state[4]  = ctx->key[0];
	state[5]  = ctx->key[1];
	state[6]  = ctx->key[2];
	state[7]  = ctx->key[3];
	state[8]  = ctx->key[4];
	state[9]  = ctx->key[5];
	state[10] = ctx->key[6];
	state[11] = ctx->key[7];
	state[12] = le32_to_cpuvp(iv +  0);
	state[13] = le32_to_cpuvp(iv +  4);
	state[14] = le32_to_cpuvp(iv +  8);
	state[15] = le32_to_cpuvp(iv + 12);
}

static int chacha20_setkey(struct crypto_tfm *tfm, const u8 *key,
			   unsigned int keysize)
{
	struct chacha20_ctx *ctx = crypto_tfm_ctx(tfm);
	int i;

	if (keysize != CHACHA20_KEY_SIZE)
		return -EINVAL;

	for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
		ctx->key[i] = le32_to_cpuvp(key + i * sizeof(u32));