crypto: import zinc

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 289 insertions, 0 deletions

diff --git a/src/crypto/zinc/poly1305/poly1305.c b/src/crypto/zinc/poly1305/poly1305.c
new file mode 100644
index 0000000..4b90523
--- /dev/null
+++ b/src/crypto/zinc/poly1305/poly1305.c
@@ -0,0 +1,289 @@
+/* SPDX-License-Identifier: OpenSSL OR (BSD-3-Clause OR GPL-2.0)
+ *
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Implementation of the Poly1305 message authenticator.
+ *
+ * Information: https://cr.yp.to/mac.html
+ */
+
+#include <zinc/poly1305.h>
+
+#include <asm/unaligned.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+
+#ifndef HAVE_POLY1305_ARCH_IMPLEMENTATION
+static inline bool poly1305_init_arch(void *ctx,
+				      const u8 key[POLY1305_KEY_SIZE],
+				      simd_context_t simd_context)
+{
+	return false;
+}
+static inline bool poly1305_blocks_arch(void *ctx, const u8 *inp,
+					const size_t len, const u32 padbit,
+					simd_context_t simd_context)
+{
+	return false;
+}
+static inline bool poly1305_emit_arch(void *ctx, u8 mac[POLY1305_MAC_SIZE],
+				      const u32 nonce[4],
+				      simd_context_t simd_context)
+{
+	return false;
+}
+void __init poly1305_fpu_init(void)
+{
+}
+#endif
+
+struct poly1305_internal {
+	u32 h[5];
+	u32 r[4];
+};
+
+static void poly1305_init_generic(void *ctx, const u8 key[16])
+{
+	struct poly1305_internal *st = (struct poly1305_internal *)ctx;
+
+	/* h = 0 */
+	st->h[0] = 0;
+	st->h[1] = 0;
+	st->h[2] = 0;
+	st->h[3] = 0;
+	st->h[4] = 0;
+
+	/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+	st->r[0] = get_unaligned_le32(&key[ 0]) & 0x0fffffff;
+	st->r[1] = get_unaligned_le32(&key[ 4]) & 0x0ffffffc;
+	st->r[2] = get_unaligned_le32(&key[ 8]) & 0x0ffffffc;
+	st->r[3] = get_unaligned_le32(&key[12]) & 0x0ffffffc;
+}
+
+static void poly1305_blocks_generic(void *ctx, const u8 *inp, size_t len,
+				    const u32 padbit)
+{
+#define CONSTANT_TIME_CARRY(a, b)                                              \
+	((a ^ ((a ^ b) | ((a - b) ^ b))) >> (sizeof(a) * 8 - 1))
+	struct poly1305_internal *st = (struct poly1305_internal *)ctx;
+	u32 r0, r1, r2, r3;
+	u32 s1, s2, s3;
+	u32 h0, h1, h2, h3, h4, c;
+	u64 d0, d1, d2, d3;
+
+	r0 = st->r[0];
+	r1 = st->r[1];
+	r2 = st->r[2];
+	r3 = st->r[3];
+
+	s1 = r1 + (r1 >> 2);
+	s2 = r2 + (r2 >> 2);
+	s3 = r3 + (r3 >> 2);
+
+	h0 = st->h[0];
+	h1 = st->h[1];
+	h2 = st->h[2];
+	h3 = st->h[3];
+	h4 = st->h[4];
+
+	while (len >= POLY1305_BLOCK_SIZE) {
+		/* h += m[i] */
+		h0 = (u32)(d0 = (u64)h0 + (0       ) + get_unaligned_le32(&inp[ 0]));
+		h1 = (u32)(d1 = (u64)h1 + (d0 >> 32) + get_unaligned_le32(&inp[ 4]));
+		h2 = (u32)(d2 = (u64)h2 + (d1 >> 32) + get_unaligned_le32(&inp[ 8]));
+		h3 = (u32)(d3 = (u64)h3 + (d2 >> 32) + get_unaligned_le32(&inp[12]));
+		h4 += (u32)(d3 >> 32) + padbit;
+
+		/* h *= r "%" p, where "%" stands for "partial remainder" */
+		d0 = ((u64)h0 * r0) +
+		     ((u64)h1 * s3) +
+		     ((u64)h2 * s2) +
+		     ((u64)h3 * s1);
+		d1 = ((u64)h0 * r1) +
+		     ((u64)h1 * r0) +
+		     ((u64)h2 * s3) +
+		     ((u64)h3 * s2) +
+		     (h4 * s1);
+		d2 = ((u64)h0 * r2) +
+		     ((u64)h1 * r1) +
+		     ((u64)h2 * r0) +
+		     ((u64)h3 * s3) +
+		     (h4 * s2);
+		d3 = ((u64)h0 * r3) +
+		     ((u64)h1 * r2) +
+		     ((u64)h2 * r1) +
+		     ((u64)h3 * r0) +
+		     (h4 * s3);
+		h4 = (h4 * r0);
+
+		/* last reduction step: */
+		/* a) h4:h0 = h4<<128 + d3<<96 + d2<<64 + d1<<32 + d0 */
+		h0 = (u32)d0;
+		h1 = (u32)(d1 += d0 >> 32);
+		h2 = (u32)(d2 += d1 >> 32);
+		h3 = (u32)(d3 += d2 >> 32);
+		h4 += (u32)(d3 >> 32);
+		/* b) (h4:h0 += (h4:h0>>130) * 5) %= 2^130 */
+		c = (h4 >> 2) + (h4 & ~3U);
+		h4 &= 3;
+		h0 += c;
+		h1 += (c = CONSTANT_TIME_CARRY(h0, c));
+		h2 += (c = CONSTANT_TIME_CARRY(h1, c));
+		h3 += (c = CONSTANT_TIME_CARRY(h2, c));
+		h4 += CONSTANT_TIME_CARRY(h3, c);
+		/*
+		 * Occasional overflows to 3rd bit of h4 are taken care of
+		 * "naturally". If after this point we end up at the top of
+		 * this loop, then the overflow bit will be accounted for
+		 * in next iteration. If we end up in poly1305_emit, then
+		 * comparison to modulus below will still count as "carry
+		 * into 131st bit", so that properly reduced value will be
+		 * picked in conditional move.
+		 */
+
+		inp += POLY1305_BLOCK_SIZE;
+		len -= POLY1305_BLOCK_SIZE;
+	}
+
+	st->h[0] = h0;
+	st->h[1] = h1;
+	st->h[2] = h2;
+	st->h[3] = h3;
+	st->h[4] = h4;
+#undef CONSTANT_TIME_CARRY
+}
+
+static void poly1305_emit_generic(void *ctx, u8 mac[16], const u32 nonce[4])
+{
+	struct poly1305_internal *st = (struct poly1305_internal *)ctx;
+	u32 h0, h1, h2, h3, h4;
+	u32 g0, g1, g2, g3, g4;
+	u64 t;
+	u32 mask;
+
+	h0 = st->h[0];
+	h1 = st->h[1];
+	h2 = st->h[2];
+	h3 = st->h[3];
+	h4 = st->h[4];
+
+	/* compare to modulus by computing h + -p */
+	g0 = (u32)(t = (u64)h0 + 5);
+	g1 = (u32)(t = (u64)h1 + (t >> 32));
+	g2 = (u32)(t = (u64)h2 + (t >> 32));
+	g3 = (u32)(t = (u64)h3 + (t >> 32));
+	g4 = h4 + (u32)(t >> 32);
+
+	/* if there was carry into 131st bit, h3:h0 = g3:g0 */
+	mask = 0 - (g4 >> 2);
+	g0 &= mask;
+	g1 &= mask;
+	g2 &= mask;
+	g3 &= mask;
+	mask = ~mask;
+	h0 = (h0 & mask) | g0;
+	h1 = (h1 & mask) | g1;
+	h2 = (h2 & mask) | g2;
+	h3 = (h3 & mask) | g3;
+
+	/* mac = (h + nonce) % (2^128) */
+	h0 = (u32)(t = (u64)h0 + nonce[0]);
+	h1 = (u32)(t = (u64)h1 + (t >> 32) + nonce[1]);
+	h2 = (u32)(t = (u64)h2 + (t >> 32) + nonce[2]);
+	h3 = (u32)(t = (u64)h3 + (t >> 32) + nonce[3]);
+
+	put_unaligned_le32(h0, &mac[ 0]);
+	put_unaligned_le32(h1, &mac[ 4]);
+	put_unaligned_le32(h2, &mac[ 8]);
+	put_unaligned_le32(h3, &mac[12]);
+}
+
+void poly1305_init(struct poly1305_ctx *ctx, const u8 key[POLY1305_KEY_SIZE],
+		   simd_context_t simd_context)
+{
+	ctx->nonce[0] = get_unaligned_le32(&key[16]);
+	ctx->nonce[1] = get_unaligned_le32(&key[20]);
+	ctx->nonce[2] = get_unaligned_le32(&key[24]);
+	ctx->nonce[3] = get_unaligned_le32(&key[28]);
+
+	if (!poly1305_init_arch(ctx->opaque, key, simd_context))
+		poly1305_init_generic(ctx->opaque, key);
+	ctx->num = 0;
+}
+EXPORT_SYMBOL(poly1305_init);
+
+static inline void poly1305_blocks(void *ctx, const u8 *inp, const size_t len,
+				   const u32 padbit,
+				   simd_context_t simd_context)
+{
+	if (!poly1305_blocks_arch(ctx, inp, len, padbit, simd_context))
+		poly1305_blocks_generic(ctx, inp, len, padbit);
+}
+
+static inline void poly1305_emit(void *ctx, u8 mac[POLY1305_KEY_SIZE],
+				 const u32 nonce[4],
+				 simd_context_t simd_context)
+{
+	if (!poly1305_emit_arch(ctx, mac, nonce, simd_context))
+		poly1305_emit_generic(ctx, mac, nonce);
+}
+
+void poly1305_update(struct poly1305_ctx *ctx, const u8 *inp, size_t len,
+		     simd_context_t simd_context)
+{
+	const size_t num = ctx->num % POLY1305_BLOCK_SIZE;
+	size_t rem;
+
+	if (num) {
+		rem = POLY1305_BLOCK_SIZE - num;
+		if (len >= rem) {
+			memcpy(ctx->data + num, inp, rem);
+			poly1305_blocks(ctx->opaque, ctx->data,
+					POLY1305_BLOCK_SIZE, 1, simd_context);
+			inp += rem;
+			len -= rem;
+		} else {
+			/* Still not enough data to process a block. */
+			memcpy(ctx->data + num, inp, len);
+			ctx->num = num + len;
+			return;
+		}
+	}
+
+	rem = len % POLY1305_BLOCK_SIZE;
+	len -= rem;
+
+	if (len >= POLY1305_BLOCK_SIZE) {
+		poly1305_blocks(ctx->opaque, inp, len, 1, simd_context);
+		inp += len;
+	}
+
+	if (rem)
+		memcpy(ctx->data, inp, rem);
+
+	ctx->num = rem;
+}
+EXPORT_SYMBOL(poly1305_update);
+
+void poly1305_finish(struct poly1305_ctx *ctx, u8 mac[POLY1305_MAC_SIZE],
+		     simd_context_t simd_context)
+{
+	size_t num = ctx->num % POLY1305_BLOCK_SIZE;
+
+	if (num) {
+		ctx->data[num++] = 1; /* pad bit */
+		while (num < POLY1305_BLOCK_SIZE)
+			ctx->data[num++] = 0;
+		poly1305_blocks(ctx->opaque, ctx->data, POLY1305_BLOCK_SIZE, 0,
+				simd_context);
+	}
+
+	poly1305_emit(ctx->opaque, mac, ctx->nonce, simd_context);
+
+	/* zero out the state */
+	memzero_explicit(ctx, sizeof(*ctx));
+}
+EXPORT_SYMBOL(poly1305_finish);
+
+#include "../selftest/poly1305.h"