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-rw-r--r--crypto/poly1305/poly1305.c531
1 files changed, 531 insertions, 0 deletions
diff --git a/crypto/poly1305/poly1305.c b/crypto/poly1305/poly1305.c
new file mode 100644
index 000000000000..1d182364aee4
--- /dev/null
+++ b/crypto/poly1305/poly1305.c
@@ -0,0 +1,531 @@
+/*
+ * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <openssl/crypto.h>
+
+#include "internal/poly1305.h"
+#include "poly1305_local.h"
+
+size_t Poly1305_ctx_size(void)
+{
+ return sizeof(struct poly1305_context);
+}
+
+/* pick 32-bit unsigned integer in little endian order */
+static unsigned int U8TOU32(const unsigned char *p)
+{
+ return (((unsigned int)(p[0] & 0xff)) |
+ ((unsigned int)(p[1] & 0xff) << 8) |
+ ((unsigned int)(p[2] & 0xff) << 16) |
+ ((unsigned int)(p[3] & 0xff) << 24));
+}
+
+/*
+ * Implementations can be classified by amount of significant bits in
+ * words making up the multi-precision value, or in other words radix
+ * or base of numerical representation, e.g. base 2^64, base 2^32,
+ * base 2^26. Complementary characteristic is how wide is the result of
+ * multiplication of pair of digits, e.g. it would take 128 bits to
+ * accommodate multiplication result in base 2^64 case. These are used
+ * interchangeably. To describe implementation that is. But interface
+ * is designed to isolate this so that low-level primitives implemented
+ * in assembly can be self-contained/self-coherent.
+ */
+#ifndef POLY1305_ASM
+/*
+ * Even though there is __int128 reference implementation targeting
+ * 64-bit platforms provided below, it's not obvious that it's optimal
+ * choice for every one of them. Depending on instruction set overall
+ * amount of instructions can be comparable to one in __int64
+ * implementation. Amount of multiplication instructions would be lower,
+ * but not necessarily overall. And in out-of-order execution context,
+ * it is the latter that can be crucial...
+ *
+ * On related note. Poly1305 author, D. J. Bernstein, discusses and
+ * provides floating-point implementations of the algorithm in question.
+ * It made a lot of sense by the time of introduction, because most
+ * then-modern processors didn't have pipelined integer multiplier.
+ * [Not to mention that some had non-constant timing for integer
+ * multiplications.] Floating-point instructions on the other hand could
+ * be issued every cycle, which allowed to achieve better performance.
+ * Nowadays, with SIMD and/or out-or-order execution, shared or
+ * even emulated FPU, it's more complicated, and floating-point
+ * implementation is not necessarily optimal choice in every situation,
+ * rather contrary...
+ *
+ * <appro@openssl.org>
+ */
+
+typedef unsigned int u32;
+
+/*
+ * poly1305_blocks processes a multiple of POLY1305_BLOCK_SIZE blocks
+ * of |inp| no longer than |len|. Behaviour for |len| not divisible by
+ * block size is unspecified in general case, even though in reference
+ * implementation the trailing chunk is simply ignored. Per algorithm
+ * specification, every input block, complete or last partial, is to be
+ * padded with a bit past most significant byte. The latter kind is then
+ * padded with zeros till block size. This last partial block padding
+ * is caller(*)'s responsibility, and because of this the last partial
+ * block is always processed with separate call with |len| set to
+ * POLY1305_BLOCK_SIZE and |padbit| to 0. In all other cases |padbit|
+ * should be set to 1 to perform implicit padding with 128th bit.
+ * poly1305_blocks does not actually check for this constraint though,
+ * it's caller(*)'s responsibility to comply.
+ *
+ * (*) In the context "caller" is not application code, but higher
+ * level Poly1305_* from this very module, so that quirks are
+ * handled locally.
+ */
+static void
+poly1305_blocks(void *ctx, const unsigned char *inp, size_t len, u32 padbit);
+
+/*
+ * Type-agnostic "rip-off" from constant_time_locl.h
+ */
+# define CONSTANT_TIME_CARRY(a,b) ( \
+ (a ^ ((a ^ b) | ((a - b) ^ b))) >> (sizeof(a) * 8 - 1) \
+ )
+
+# if (defined(__SIZEOF_INT128__) && __SIZEOF_INT128__==16) && \
+ (defined(__SIZEOF_LONG__) && __SIZEOF_LONG__==8)
+
+typedef unsigned long u64;
+typedef __uint128_t u128;
+
+typedef struct {
+ u64 h[3];
+ u64 r[2];
+} poly1305_internal;
+
+/* pick 32-bit unsigned integer in little endian order */
+static u64 U8TOU64(const unsigned char *p)
+{
+ return (((u64)(p[0] & 0xff)) |
+ ((u64)(p[1] & 0xff) << 8) |
+ ((u64)(p[2] & 0xff) << 16) |
+ ((u64)(p[3] & 0xff) << 24) |
+ ((u64)(p[4] & 0xff) << 32) |
+ ((u64)(p[5] & 0xff) << 40) |
+ ((u64)(p[6] & 0xff) << 48) |
+ ((u64)(p[7] & 0xff) << 56));
+}
+
+/* store a 32-bit unsigned integer in little endian */
+static void U64TO8(unsigned char *p, u64 v)
+{
+ p[0] = (unsigned char)((v) & 0xff);
+ p[1] = (unsigned char)((v >> 8) & 0xff);
+ p[2] = (unsigned char)((v >> 16) & 0xff);
+ p[3] = (unsigned char)((v >> 24) & 0xff);
+ p[4] = (unsigned char)((v >> 32) & 0xff);
+ p[5] = (unsigned char)((v >> 40) & 0xff);
+ p[6] = (unsigned char)((v >> 48) & 0xff);
+ p[7] = (unsigned char)((v >> 56) & 0xff);
+}
+
+static void poly1305_init(void *ctx, const unsigned char key[16])
+{
+ poly1305_internal *st = (poly1305_internal *) ctx;
+
+ /* h = 0 */
+ st->h[0] = 0;
+ st->h[1] = 0;
+ st->h[2] = 0;
+
+ /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+ st->r[0] = U8TOU64(&key[0]) & 0x0ffffffc0fffffff;
+ st->r[1] = U8TOU64(&key[8]) & 0x0ffffffc0ffffffc;
+}
+
+static void
+poly1305_blocks(void *ctx, const unsigned char *inp, size_t len, u32 padbit)
+{
+ poly1305_internal *st = (poly1305_internal *)ctx;
+ u64 r0, r1;
+ u64 s1;
+ u64 h0, h1, h2, c;
+ u128 d0, d1;
+
+ r0 = st->r[0];
+ r1 = st->r[1];
+
+ s1 = r1 + (r1 >> 2);
+
+ h0 = st->h[0];
+ h1 = st->h[1];
+ h2 = st->h[2];
+
+ while (len >= POLY1305_BLOCK_SIZE) {
+ /* h += m[i] */
+ h0 = (u64)(d0 = (u128)h0 + U8TOU64(inp + 0));
+ h1 = (u64)(d1 = (u128)h1 + (d0 >> 64) + U8TOU64(inp + 8));
+ /*
+ * padbit can be zero only when original len was
+ * POLY1306_BLOCK_SIZE, but we don't check
+ */
+ h2 += (u64)(d1 >> 64) + padbit;
+
+ /* h *= r "%" p, where "%" stands for "partial remainder" */
+ d0 = ((u128)h0 * r0) +
+ ((u128)h1 * s1);
+ d1 = ((u128)h0 * r1) +
+ ((u128)h1 * r0) +
+ (h2 * s1);
+ h2 = (h2 * r0);
+
+ /* last reduction step: */
+ /* a) h2:h0 = h2<<128 + d1<<64 + d0 */
+ h0 = (u64)d0;
+ h1 = (u64)(d1 += d0 >> 64);
+ h2 += (u64)(d1 >> 64);
+ /* b) (h2:h0 += (h2:h0>>130) * 5) %= 2^130 */
+ c = (h2 >> 2) + (h2 & ~3UL);
+ h2 &= 3;
+ h0 += c;
+ h1 += (c = CONSTANT_TIME_CARRY(h0,c));
+ h2 += CONSTANT_TIME_CARRY(h1,c);
+ /*
+ * Occasional overflows to 3rd bit of h2 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;
+}
+
+static void poly1305_emit(void *ctx, unsigned char mac[16],
+ const u32 nonce[4])
+{
+ poly1305_internal *st = (poly1305_internal *) ctx;
+ u64 h0, h1, h2;
+ u64 g0, g1, g2;
+ u128 t;
+ u64 mask;
+
+ h0 = st->h[0];
+ h1 = st->h[1];
+ h2 = st->h[2];
+
+ /* compare to modulus by computing h + -p */
+ g0 = (u64)(t = (u128)h0 + 5);
+ g1 = (u64)(t = (u128)h1 + (t >> 64));
+ g2 = h2 + (u64)(t >> 64);
+
+ /* if there was carry into 131st bit, h1:h0 = g1:g0 */
+ mask = 0 - (g2 >> 2);
+ g0 &= mask;
+ g1 &= mask;
+ mask = ~mask;
+ h0 = (h0 & mask) | g0;
+ h1 = (h1 & mask) | g1;
+
+ /* mac = (h + nonce) % (2^128) */
+ h0 = (u64)(t = (u128)h0 + nonce[0] + ((u64)nonce[1]<<32));
+ h1 = (u64)(t = (u128)h1 + nonce[2] + ((u64)nonce[3]<<32) + (t >> 64));
+
+ U64TO8(mac + 0, h0);
+ U64TO8(mac + 8, h1);
+}
+
+# else
+
+# if defined(_WIN32) && !defined(__MINGW32__)
+typedef unsigned __int64 u64;
+# elif defined(__arch64__)
+typedef unsigned long u64;
+# else
+typedef unsigned long long u64;
+# endif
+
+typedef struct {
+ u32 h[5];
+ u32 r[4];
+} poly1305_internal;
+
+/* store a 32-bit unsigned integer in little endian */
+static void U32TO8(unsigned char *p, unsigned int v)
+{
+ p[0] = (unsigned char)((v) & 0xff);
+ p[1] = (unsigned char)((v >> 8) & 0xff);
+ p[2] = (unsigned char)((v >> 16) & 0xff);
+ p[3] = (unsigned char)((v >> 24) & 0xff);
+}
+
+static void poly1305_init(void *ctx, const unsigned char key[16])
+{
+ poly1305_internal *st = (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] = U8TOU32(&key[0]) & 0x0fffffff;
+ st->r[1] = U8TOU32(&key[4]) & 0x0ffffffc;
+ st->r[2] = U8TOU32(&key[8]) & 0x0ffffffc;
+ st->r[3] = U8TOU32(&key[12]) & 0x0ffffffc;
+}
+
+static void
+poly1305_blocks(void *ctx, const unsigned char *inp, size_t len, u32 padbit)
+{
+ poly1305_internal *st = (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 + U8TOU32(inp + 0));
+ h1 = (u32)(d1 = (u64)h1 + (d0 >> 32) + U8TOU32(inp + 4));
+ h2 = (u32)(d2 = (u64)h2 + (d1 >> 32) + U8TOU32(inp + 8));
+ h3 = (u32)(d3 = (u64)h3 + (d2 >> 32) + U8TOU32(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;
+}
+
+static void poly1305_emit(void *ctx, unsigned char mac[16],
+ const u32 nonce[4])
+{
+ poly1305_internal *st = (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]);
+
+ U32TO8(mac + 0, h0);
+ U32TO8(mac + 4, h1);
+ U32TO8(mac + 8, h2);
+ U32TO8(mac + 12, h3);
+}
+# endif
+#else
+int poly1305_init(void *ctx, const unsigned char key[16], void *func);
+void poly1305_blocks(void *ctx, const unsigned char *inp, size_t len,
+ unsigned int padbit);
+void poly1305_emit(void *ctx, unsigned char mac[16],
+ const unsigned int nonce[4]);
+#endif
+
+void Poly1305_Init(POLY1305 *ctx, const unsigned char key[32])
+{
+ ctx->nonce[0] = U8TOU32(&key[16]);
+ ctx->nonce[1] = U8TOU32(&key[20]);
+ ctx->nonce[2] = U8TOU32(&key[24]);
+ ctx->nonce[3] = U8TOU32(&key[28]);
+
+#ifndef POLY1305_ASM
+ poly1305_init(ctx->opaque, key);
+#else
+ /*
+ * Unlike reference poly1305_init assembly counterpart is expected
+ * to return a value: non-zero if it initializes ctx->func, and zero
+ * otherwise. Latter is to simplify assembly in cases when there no
+ * multiple code paths to switch between.
+ */
+ if (!poly1305_init(ctx->opaque, key, &ctx->func)) {
+ ctx->func.blocks = poly1305_blocks;
+ ctx->func.emit = poly1305_emit;
+ }
+#endif
+
+ ctx->num = 0;
+
+}
+
+#ifdef POLY1305_ASM
+/*
+ * This "eclipses" poly1305_blocks and poly1305_emit, but it's
+ * conscious choice imposed by -Wshadow compiler warnings.
+ */
+# define poly1305_blocks (*poly1305_blocks_p)
+# define poly1305_emit (*poly1305_emit_p)
+#endif
+
+void Poly1305_Update(POLY1305 *ctx, const unsigned char *inp, size_t len)
+{
+#ifdef POLY1305_ASM
+ /*
+ * As documented, poly1305_blocks is never called with input
+ * longer than single block and padbit argument set to 0. This
+ * property is fluently used in assembly modules to optimize
+ * padbit handling on loop boundary.
+ */
+ poly1305_blocks_f poly1305_blocks_p = ctx->func.blocks;
+#endif
+ size_t rem, num;
+
+ if ((num = ctx->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);
+ 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);
+ inp += len;
+ }
+
+ if (rem)
+ memcpy(ctx->data, inp, rem);
+
+ ctx->num = rem;
+}
+
+void Poly1305_Final(POLY1305 *ctx, unsigned char mac[16])
+{
+#ifdef POLY1305_ASM
+ poly1305_blocks_f poly1305_blocks_p = ctx->func.blocks;
+ poly1305_emit_f poly1305_emit_p = ctx->func.emit;
+#endif
+ size_t num;
+
+ if ((num = ctx->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);
+ }
+
+ poly1305_emit(ctx->opaque, mac, ctx->nonce);
+
+ /* zero out the state */
+ OPENSSL_cleanse(ctx, sizeof(*ctx));
+}