1 files changed, 225 insertions, 0 deletions
diff --git a/poly1305-donna64.c b/poly1305-donna64.c
new file mode 100644
index 0000000..ca35f5e
--- /dev/null
+++ b/poly1305-donna64.c
@@ -0,0 +1,225 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is based in part on Andrew Moon's poly1305-donna, which is in the
+ * public domain.
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <asm/unaligned.h>
+
+enum {
+	POLY1305_BLOCK_SIZE = 16,
+	POLY1305_KEY_SIZE = 32,
+	POLY1305_MAC_SIZE = 16
+};
+
+struct poly1305_ctx {
+	u8 opaque[24 * sizeof(u64)];
+	u32 nonce[4];
+	u8 data[POLY1305_BLOCK_SIZE];
+	size_t num;
+} __aligned(8);
+
+
+typedef __uint128_t u128;
+
+struct poly1305_internal {
+	u64 r[3];
+	u64 h[3];
+};
+
+static void poly1305_init_generic(void *ctx, const u8 key[16])
+{
+	struct poly1305_internal *st = (struct poly1305_internal *)ctx;
+	u64 t0, t1;
+
+	/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+	t0 = get_unaligned_le64(&key[0]);
+	t1 = get_unaligned_le64(&key[8]);
+
+	/* wiped after finalization */
+	st->r[0] = (t0) &0xffc0fffffff;
+	st->r[1] = ((t0 >> 44) | (t1 << 20)) & 0xfffffc0ffff;
+	st->r[2] = ((t1 >> 24)) & 0x00ffffffc0f;
+
+	/* h = 0 */
+	st->h[0] = 0;
+	st->h[1] = 0;
+	st->h[2] = 0;
+}
+
+static void poly1305_blocks_generic(void *ctx, const u8 *input, size_t len,
+				    const u32 padbit)
+{
+	struct poly1305_internal *st = (struct poly1305_internal *)ctx;
+	const u64 hibit = padbit ? (1ULL << 40) : 0;
+	u64 r0, r1, r2;
+	u64 s1, s2;
+	u64 h0, h1, h2;
+	u64 c;
+	u128 d0, d1, d2, d;
+
+	r0 = st->r[0];
+	r1 = st->r[1];
+	r2 = st->r[2];
+
+	h0 = st->h[0];
+	h1 = st->h[1];
+	h2 = st->h[2];
+
+	s1 = r1 * (5 << 2);
+	s2 = r2 * (5 << 2);
+
+	while (len >= POLY1305_BLOCK_SIZE) {
+		u64 t0, t1;
+
+		/* h += m[i] */
+		t0 = get_unaligned_le64(&input[0]);
+		t1 = get_unaligned_le64(&input[8]);
+
+		h0 += ((t0) &0xfffffffffff);
+		h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffff);
+		h2 += (((t1 >> 24)) & 0x3ffffffffff) | hibit;
+
+		/* h *= r */
+		d0 = ((u128)h0 * r0);
+		d = ((u128)h1 * s2);
+		d0 += d;
+		d = ((u128)h2 * s1);
+		d0 += d;
+		d1 = ((u128)h0 * r1);
+		d = ((u128)h1 * r0);
+		d1 += d;
+		d = ((u128)h2 * s2);
+		d1 += d;
+		d2 = ((u128)h0 * r2);
+		d = ((u128)h1 * r1);
+		d2 += d;
+		d = ((u128)h2 * r0);
+		d2 += d;
+
+		/* (partial) h %= p */
+		c = (u64)(d0 >> 44);
+		h0 = (u64)d0 & 0xfffffffffff;
+		d1 += c;
+		c = (u64)(d1 >> 44);
+		h1 = (u64)d1 & 0xfffffffffff;
+		d2 += c;
+		c = (u64)(d2 >> 42);
+		h2 = (u64)d2 & 0x3ffffffffff;
+		h0 += c * 5;
+		c = (h0 >> 44);
+		h0 = h0 & 0xfffffffffff;
+		h1 += c;
+
+		input += POLY1305_BLOCK_SIZE;
+		len -= POLY1305_BLOCK_SIZE;
+	}
+
+	st->h[0] = h0;
+	st->h[1] = h1;
+	st->h[2] = h2;
+}
+
+static void poly1305_emit_generic(void *ctx, u8 mac[16], const u32 nonce[4])
+{
+	struct poly1305_internal *st = (struct poly1305_internal *)ctx;
+	u64 h0, h1, h2, c;
+	u64 g0, g1, g2;
+	u64 t0, t1;
+
+	/* fully carry h */
+	h0 = st->h[0];
+	h1 = st->h[1];
+	h2 = st->h[2];
+
+	c = (h1 >> 44);
+	h1 &= 0xfffffffffff;
+	h2 += c;
+	c = (h2 >> 42);
+	h2 &= 0x3ffffffffff;
+	h0 += c * 5;
+	c = (h0 >> 44);
+	h0 &= 0xfffffffffff;
+	h1 += c;
+	c = (h1 >> 44);
+	h1 &= 0xfffffffffff;
+	h2 += c;
+	c = (h2 >> 42);
+	h2 &= 0x3ffffffffff;
+	h0 += c * 5;
+	c = (h0 >> 44);
+	h0 &= 0xfffffffffff;
+	h1 += c;
+
+	/* compute h + -p */
+	g0 = h0 + 5;
+	c  = (g0 >> 44);
+	g0 &= 0xfffffffffff;
+	g1 = h1 + c;
+	c  = (g1 >> 44);
+	g1 &= 0xfffffffffff;
+	g2 = h2 + c - (1ULL << 42);
+
+	/* select h if h < p, or h + -p if h >= p */
+	c = (g2 >> ((sizeof(u64) * 8) - 1)) - 1;
+	g0 &= c;
+	g1 &= c;
+	g2 &= c;
+	c  = ~c;
+	h0 = (h0 & c) | g0;
+	h1 = (h1 & c) | g1;
+	h2 = (h2 & c) | g2;
+
+	/* h = (h + nonce) */
+	t0 = ((u64)nonce[1] << 32) | nonce[0];
+	t1 = ((u64)nonce[3] << 32) | nonce[2];
+
+	h0 += ((t0) &0xfffffffffff);
+	c = (h0 >> 44);
+	h0 &= 0xfffffffffff;
+	h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffff) + c;
+	c = (h1 >> 44);
+	h1 &= 0xfffffffffff;
+	h2 += (((t1 >> 24)) & 0x3ffffffffff) + c;
+	h2 &= 0x3ffffffffff;
+
+	/* mac = h % (2^128) */
+	h0 = (h0 | (h1 << 44));
+	h1 = ((h1 >> 20) | (h2 << 24));
+
+	put_unaligned_le64(h0, &mac[0]);
+	put_unaligned_le64(h1, &mac[8]);
+}
+
+void poly1305_donna64(unsigned char *out, const unsigned char *in, unsigned long long inlen, const unsigned char *k)
+{
+	size_t rem;
+	struct poly1305_ctx ctx;
+	ctx.nonce[0] = get_unaligned_le32(&k[16]);
+	ctx.nonce[1] = get_unaligned_le32(&k[20]);
+	ctx.nonce[2] = get_unaligned_le32(&k[24]);
+	ctx.nonce[3] = get_unaligned_le32(&k[28]);
+	poly1305_init_generic(ctx.opaque, k);
+	ctx.num = 0;
+
+	rem = inlen % POLY1305_BLOCK_SIZE;
+	inlen -= rem;
+
+	if (inlen >= POLY1305_BLOCK_SIZE) {
+		poly1305_blocks_generic(ctx.opaque, in, inlen, 1);
+		in += inlen;
+	}
+	if (rem) {
+		memcpy(ctx.data, in, rem);
+		ctx.data[rem++] = 1;   /* pad bit */
+		while (rem < POLY1305_BLOCK_SIZE)
+			ctx.data[rem++] = 0;
+		poly1305_blocks_generic(ctx.opaque, ctx.data, POLY1305_BLOCK_SIZE, 0);
+	}
+
+	poly1305_emit_generic(ctx.opaque, out, ctx.nonce);
+}