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ZeroTierOne/core/Poly1305.cpp
Adam Ierymenko 91556d0c55
Build fixes.
2021-04-26 18:11:01 -04:00

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/*
20080912
D. J. Bernstein
Public domain.
*/
// Small modifications have been made for ZeroTier, but this code remains in the public domain.
#include "Constants.hpp"
#include "Poly1305.hpp"
#include "Utils.hpp"
#ifdef __WINDOWS__
#pragma warning(disable : 4146)
#endif
#define U8TO64(p) Utils::loadLittleEndian<uint64_t>(p)
#define U64TO8(p, v) Utils::storeLittleEndian<uint64_t>(p, v)
#define U8TO32(p) Utils::loadLittleEndian<uint32_t>(p)
#define U32TO8(p, v) Utils::storeLittleEndian<uint32_t>(p, v)
namespace ZeroTier {
namespace {
typedef struct poly1305_context {
size_t aligner;
unsigned char opaque[136];
} poly1305_context;
#ifdef ZT_HAVE_UINT128
#define MUL(out, x, y) out = ((uint128_t)x * y)
#define ADD(out, in) out += in
#define ADDLO(out, in) out += in
#define SHR(in, shift) (unsigned long long)(in >> (shift))
#define LO(in) (unsigned long long)(in)
#define poly1305_block_size 16
typedef struct poly1305_state_internal_t {
unsigned long long r[3];
unsigned long long h[3];
unsigned long long pad[2];
size_t leftover;
unsigned char buffer[poly1305_block_size];
unsigned char final;
} poly1305_state_internal_t;
ZT_INLINE void poly1305_init(poly1305_context* ctx, const unsigned char key[32])
{
poly1305_state_internal_t* st = (poly1305_state_internal_t*)ctx;
unsigned long long t0, t1;
/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
t0 = U8TO64(&key[0]);
t1 = U8TO64(&key[8]);
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;
/* save pad for later */
st->pad[0] = U8TO64(&key[16]);
st->pad[1] = U8TO64(&key[24]);
st->leftover = 0;
st->final = 0;
}
void poly1305_blocks(poly1305_state_internal_t* st, const unsigned char* m, size_t bytes)
{
const unsigned long long hibit = (st->final) ? 0 : ((unsigned long long)1 << 40); /* 1 << 128 */
unsigned long long r0, r1, r2;
unsigned long long s1, s2;
unsigned long long h0, h1, h2;
uint128_t 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 (bytes >= poly1305_block_size) {
unsigned long long t0, t1;
/* h += m[i] */
t0 = U8TO64(&m[0]);
t1 = U8TO64(&m[8]);
h0 += ((t0)&0xfffffffffff);
h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffff);
h2 += (((t1 >> 24)) & 0x3ffffffffff) | hibit;
/* h *= r */
MUL(d0, h0, r0);
MUL(d, h1, s2);
ADD(d0, d);
MUL(d, h2, s1);
ADD(d0, d);
MUL(d1, h0, r1);
MUL(d, h1, r0);
ADD(d1, d);
MUL(d, h2, s2);
ADD(d1, d);
MUL(d2, h0, r2);
MUL(d, h1, r1);
ADD(d2, d);
MUL(d, h2, r0);
ADD(d2, d);
/* (partial) h %= p */
unsigned long long c = SHR(d0, 44);
h0 = LO(d0) & 0xfffffffffff;
ADDLO(d1, c);
c = SHR(d1, 44);
h1 = LO(d1) & 0xfffffffffff;
ADDLO(d2, c);
c = SHR(d2, 42);
h2 = LO(d2) & 0x3ffffffffff;
h0 += c * 5;
c = (h0 >> 44);
h0 = h0 & 0xfffffffffff;
h1 += c;
m += poly1305_block_size;
bytes -= poly1305_block_size;
}
st->h[0] = h0;
st->h[1] = h1;
st->h[2] = h2;
}
ZT_INLINE void poly1305_finish(poly1305_context* ctx, unsigned char mac[16])
{
poly1305_state_internal_t* st = (poly1305_state_internal_t*)ctx;
unsigned long long h0, h1, h2, c;
unsigned long long g0, g1, g2;
unsigned long long t0, t1;
/* process the remaining block */
if (st->leftover) {
size_t i = st->leftover;
st->buffer[i] = 1;
for (i = i + 1; i < poly1305_block_size; i++)
st->buffer[i] = 0;
st->final = 1;
poly1305_blocks(st, st->buffer, poly1305_block_size);
}
/* 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 - ((unsigned long long)1 << 42);
/* select h if h < p, or h + -p if h >= p */
c = (g2 >> ((sizeof(unsigned long long) * 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 + pad) */
t0 = st->pad[0];
t1 = st->pad[1];
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));
U64TO8(&mac[0], h0);
U64TO8(&mac[8], h1);
/* zero out the state */
st->h[0] = 0;
st->h[1] = 0;
st->h[2] = 0;
st->r[0] = 0;
st->r[1] = 0;
st->r[2] = 0;
st->pad[0] = 0;
st->pad[1] = 0;
}
#else // no uint128_t
#define poly1305_block_size 16
typedef struct poly1305_state_internal_t {
unsigned long r[5];
unsigned long h[5];
unsigned long pad[4];
size_t leftover;
unsigned char buffer[poly1305_block_size];
unsigned char final;
} poly1305_state_internal_t;
ZT_INLINE void poly1305_init(poly1305_context* ctx, const unsigned char key[32])
{
poly1305_state_internal_t* st = (poly1305_state_internal_t*)ctx;
/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
st->r[0] = (U8TO32(&key[0])) & 0x3ffffff;
st->r[1] = (U8TO32(&key[3]) >> 2) & 0x3ffff03;
st->r[2] = (U8TO32(&key[6]) >> 4) & 0x3ffc0ff;
st->r[3] = (U8TO32(&key[9]) >> 6) & 0x3f03fff;
st->r[4] = (U8TO32(&key[12]) >> 8) & 0x00fffff;
/* h = 0 */
st->h[0] = 0;
st->h[1] = 0;
st->h[2] = 0;
st->h[3] = 0;
st->h[4] = 0;
/* save pad for later */
st->pad[0] = U8TO32(&key[16]);
st->pad[1] = U8TO32(&key[20]);
st->pad[2] = U8TO32(&key[24]);
st->pad[3] = U8TO32(&key[28]);
st->leftover = 0;
st->final = 0;
}
void poly1305_blocks(poly1305_state_internal_t* st, const unsigned char* m, size_t bytes)
{
const unsigned long hibit = (st->final) ? 0 : (1 << 24); /* 1 << 128 */
unsigned long r0, r1, r2, r3, r4;
unsigned long s1, s2, s3, s4;
unsigned long h0, h1, h2, h3, h4;
r0 = st->r[0];
r1 = st->r[1];
r2 = st->r[2];
r3 = st->r[3];
r4 = st->r[4];
s1 = r1 * 5;
s2 = r2 * 5;
s3 = r3 * 5;
s4 = r4 * 5;
h0 = st->h[0];
h1 = st->h[1];
h2 = st->h[2];
h3 = st->h[3];
h4 = st->h[4];
while (bytes >= poly1305_block_size) {
/* h += m[i] */
h0 += (U8TO32(m + 0)) & 0x3ffffff;
h1 += (U8TO32(m + 3) >> 2) & 0x3ffffff;
h2 += (U8TO32(m + 6) >> 4) & 0x3ffffff;
h3 += (U8TO32(m + 9) >> 6) & 0x3ffffff;
h4 += (U8TO32(m + 12) >> 8) | hibit;
/* h *= r */
unsigned long long d0 = ((unsigned long long)h0 * r0) + ((unsigned long long)h1 * s4)
+ ((unsigned long long)h2 * s3) + ((unsigned long long)h3 * s2)
+ ((unsigned long long)h4 * s1);
unsigned long long d1 = ((unsigned long long)h0 * r1) + ((unsigned long long)h1 * r0)
+ ((unsigned long long)h2 * s4) + ((unsigned long long)h3 * s3)
+ ((unsigned long long)h4 * s2);
unsigned long long d2 = ((unsigned long long)h0 * r2) + ((unsigned long long)h1 * r1)
+ ((unsigned long long)h2 * r0) + ((unsigned long long)h3 * s4)
+ ((unsigned long long)h4 * s3);
unsigned long long d3 = ((unsigned long long)h0 * r3) + ((unsigned long long)h1 * r2)
+ ((unsigned long long)h2 * r1) + ((unsigned long long)h3 * r0)
+ ((unsigned long long)h4 * s4);
unsigned long long d4 = ((unsigned long long)h0 * r4) + ((unsigned long long)h1 * r3)
+ ((unsigned long long)h2 * r2) + ((unsigned long long)h3 * r1)
+ ((unsigned long long)h4 * r0);
/* (partial) h %= p */
unsigned long c = (unsigned long)(d0 >> 26);
h0 = (unsigned long)d0 & 0x3ffffff;
d1 += c;
c = (unsigned long)(d1 >> 26);
h1 = (unsigned long)d1 & 0x3ffffff;
d2 += c;
c = (unsigned long)(d2 >> 26);
h2 = (unsigned long)d2 & 0x3ffffff;
d3 += c;
c = (unsigned long)(d3 >> 26);
h3 = (unsigned long)d3 & 0x3ffffff;
d4 += c;
c = (unsigned long)(d4 >> 26);
h4 = (unsigned long)d4 & 0x3ffffff;
h0 += c * 5;
c = (h0 >> 26);
h0 = h0 & 0x3ffffff;
h1 += c;
m += poly1305_block_size;
bytes -= poly1305_block_size;
}
st->h[0] = h0;
st->h[1] = h1;
st->h[2] = h2;
st->h[3] = h3;
st->h[4] = h4;
}
ZT_INLINE void poly1305_finish(poly1305_context* ctx, unsigned char mac[16])
{
poly1305_state_internal_t* st = (poly1305_state_internal_t*)ctx;
unsigned long h0, h1, h2, h3, h4, c;
unsigned long g0, g1, g2, g3, g4;
unsigned long long f;
unsigned long mask;
/* process the remaining block */
if (st->leftover) {
size_t i = st->leftover;
st->buffer[i++] = 1;
for (; i < poly1305_block_size; i++)
st->buffer[i] = 0;
st->final = 1;
poly1305_blocks(st, st->buffer, poly1305_block_size);
}
/* fully carry h */
h0 = st->h[0];
h1 = st->h[1];
h2 = st->h[2];
h3 = st->h[3];
h4 = st->h[4];
c = h1 >> 26;
h1 = h1 & 0x3ffffff;
h2 += c;
c = h2 >> 26;
h2 = h2 & 0x3ffffff;
h3 += c;
c = h3 >> 26;
h3 = h3 & 0x3ffffff;
h4 += c;
c = h4 >> 26;
h4 = h4 & 0x3ffffff;
h0 += c * 5;
c = h0 >> 26;
h0 = h0 & 0x3ffffff;
h1 += c;
/* compute h + -p */
g0 = h0 + 5;
c = g0 >> 26;
g0 &= 0x3ffffff;
g1 = h1 + c;
c = g1 >> 26;
g1 &= 0x3ffffff;
g2 = h2 + c;
c = g2 >> 26;
g2 &= 0x3ffffff;
g3 = h3 + c;
c = g3 >> 26;
g3 &= 0x3ffffff;
g4 = h4 + c - (1 << 26);
/* select h if h < p, or h + -p if h >= p */
mask = (g4 >> ((sizeof(unsigned long) * 8) - 1)) - 1;
g0 &= mask;
g1 &= mask;
g2 &= mask;
g3 &= mask;
g4 &= mask;
mask = ~mask;
h0 = (h0 & mask) | g0;
h1 = (h1 & mask) | g1;
h2 = (h2 & mask) | g2;
h3 = (h3 & mask) | g3;
h4 = (h4 & mask) | g4;
/* h = h % (2^128) */
h0 = ((h0) | (h1 << 26)) & 0xffffffff;
h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff;
h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;
h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff;
/* mac = (h + pad) % (2^128) */
f = (unsigned long long)h0 + st->pad[0];
h0 = (unsigned long)f;
f = (unsigned long long)h1 + st->pad[1] + (f >> 32);
h1 = (unsigned long)f;
f = (unsigned long long)h2 + st->pad[2] + (f >> 32);
h2 = (unsigned long)f;
f = (unsigned long long)h3 + st->pad[3] + (f >> 32);
h3 = (unsigned long)f;
U32TO8(mac + 0, h0);
U32TO8(mac + 4, h1);
U32TO8(mac + 8, h2);
U32TO8(mac + 12, h3);
/* zero out the state */
st->h[0] = 0;
st->h[1] = 0;
st->h[2] = 0;
st->h[3] = 0;
st->h[4] = 0;
st->r[0] = 0;
st->r[1] = 0;
st->r[2] = 0;
st->r[3] = 0;
st->r[4] = 0;
st->pad[0] = 0;
st->pad[1] = 0;
st->pad[2] = 0;
st->pad[3] = 0;
}
#endif // uint128_t or portable version?
ZT_INLINE void poly1305_update(poly1305_context* ctx, const unsigned char* m, size_t bytes) noexcept
{
poly1305_state_internal_t* st = (poly1305_state_internal_t*)ctx;
size_t i;
/* handle leftover */
if (st->leftover) {
size_t want = (poly1305_block_size - st->leftover);
if (want > bytes)
want = bytes;
for (i = 0; i < want; i++)
st->buffer[st->leftover + i] = m[i];
bytes -= want;
m += want;
st->leftover += want;
if (st->leftover < poly1305_block_size)
return;
poly1305_blocks(st, st->buffer, poly1305_block_size);
st->leftover = 0;
}
/* process full blocks */
if (bytes >= poly1305_block_size) {
size_t want = (bytes & ~(poly1305_block_size - 1));
poly1305_blocks(st, m, want);
m += want;
bytes -= want;
}
/* store leftover */
if (bytes) {
for (i = 0; i < bytes; i++)
st->buffer[st->leftover + i] = m[i];
st->leftover += bytes;
}
}
} // anonymous namespace
void Poly1305::init(const void* key) noexcept
{
static_assert(sizeof(ctx) >= sizeof(poly1305_context), "buffer in class smaller than required structure size");
poly1305_init(reinterpret_cast<poly1305_context*>(&ctx), reinterpret_cast<const unsigned char*>(key));
}
void Poly1305::update(const void* data, unsigned int len) noexcept
{
poly1305_update(
reinterpret_cast<poly1305_context*>(&ctx),
reinterpret_cast<const unsigned char*>(data),
(size_t)len);
}
void Poly1305::finish(void* auth) noexcept
{
poly1305_finish(reinterpret_cast<poly1305_context*>(&ctx), reinterpret_cast<unsigned char*>(auth));
}
} // namespace ZeroTier
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