mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-11-13 19:18:56 +00:00
220 lines
6.4 KiB
C
220 lines
6.4 KiB
C
/*
|
|
poly1305 implementation using 32 bit * 32 bit = 64 bit multiplication and 64 bit addition
|
|
*/
|
|
|
|
#if defined(_MSC_VER)
|
|
#define POLY1305_NOINLINE __declspec(noinline)
|
|
#elif defined(__GNUC__)
|
|
#define POLY1305_NOINLINE __attribute__((noinline))
|
|
#else
|
|
#define POLY1305_NOINLINE
|
|
#endif
|
|
|
|
#define poly1305_block_size 16
|
|
|
|
/* 17 + sizeof(size_t) + 14*sizeof(unsigned long) */
|
|
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;
|
|
|
|
/* interpret four 8 bit unsigned integers as a 32 bit unsigned integer in little endian */
|
|
static unsigned long
|
|
U8TO32(const unsigned char *p) {
|
|
return
|
|
(((unsigned long)(p[0] & 0xff) ) |
|
|
((unsigned long)(p[1] & 0xff) << 8) |
|
|
((unsigned long)(p[2] & 0xff) << 16) |
|
|
((unsigned long)(p[3] & 0xff) << 24));
|
|
}
|
|
|
|
/* store a 32 bit unsigned integer as four 8 bit unsigned integers in little endian */
|
|
static void
|
|
U32TO8(unsigned char *p, unsigned long v) {
|
|
p[0] = (v ) & 0xff;
|
|
p[1] = (v >> 8) & 0xff;
|
|
p[2] = (v >> 16) & 0xff;
|
|
p[3] = (v >> 24) & 0xff;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static void
|
|
poly1305_blocks(poly1305_state_internal_t *st, const unsigned char *m, size_t bytes) {
|
|
const unsigned long hibit = (st->final) ? 0 : (1UL << 24); /* 1 << 128 */
|
|
unsigned long r0,r1,r2,r3,r4;
|
|
unsigned long s1,s2,s3,s4;
|
|
unsigned long h0,h1,h2,h3,h4;
|
|
unsigned long long d0,d1,d2,d3,d4;
|
|
unsigned long c;
|
|
|
|
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 */
|
|
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);
|
|
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);
|
|
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);
|
|
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);
|
|
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 */
|
|
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;
|
|
}
|
|
|
|
POLY1305_NOINLINE 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 - (1UL << 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;
|
|
}
|
|
|