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#include "config.h"
#include "chacha.h"
#include "cryptobox.h"
#if defined(HAVE_INT32)
typedef uint32_t chacha_int32;
#else
typedef uint32_t chacha_int32;
#endif
/* interpret four 8 bit unsigned integers as a 32 bit unsigned integer in little endian */
static chacha_int32
U8TO32(const unsigned char *p)
{
return (((chacha_int32) (p[0])) |
((chacha_int32) (p[1]) << 8) |
((chacha_int32) (p[2]) << 16) |
((chacha_int32) (p[3]) << 24));
}
/* store a 32 bit unsigned integer as four 8 bit unsigned integers in little endian */
static void
U32TO8(unsigned char *p, chacha_int32 v)
{
p[0] = (v) &0xff;
p[1] = (v >> 8) & 0xff;
p[2] = (v >> 16) & 0xff;
p[3] = (v >> 24) & 0xff;
}
/* 32 bit left rotate */
static chacha_int32
ROTL32(chacha_int32 x, int k)
{
return ((x << k) | (x >> (32 - k))) & 0xffffffff;
}
/* "expand 32-byte k", as 4 little endian 32-bit unsigned integers */
static const chacha_int32 chacha_constants[4] = {
0x61707865, 0x3320646e, 0x79622d32, 0x6b206574};
void chacha_blocks_ref(chacha_state_internal *state, const unsigned char *in, unsigned char *out, size_t bytes)
{
chacha_int32 x[16], j[12];
chacha_int32 t;
unsigned char *ctarget = out, tmp[64];
size_t i, r;
if (!bytes) return;
j[0] = U8TO32(state->s + 0);
j[1] = U8TO32(state->s + 4);
j[2] = U8TO32(state->s + 8);
j[3] = U8TO32(state->s + 12);
j[4] = U8TO32(state->s + 16);
j[5] = U8TO32(state->s + 20);
j[6] = U8TO32(state->s + 24);
j[7] = U8TO32(state->s + 28);
j[8] = U8TO32(state->s + 32);
j[9] = U8TO32(state->s + 36);
j[10] = U8TO32(state->s + 40);
j[11] = U8TO32(state->s + 44);
r = state->rounds;
for (;;) {
if (bytes < 64) {
if (in) {
for (i = 0; i < bytes; i++) tmp[i] = in[i];
in = tmp;
}
ctarget = out;
out = tmp;
}
x[0] = chacha_constants[0];
x[1] = chacha_constants[1];
x[2] = chacha_constants[2];
x[3] = chacha_constants[3];
x[4] = j[0];
x[5] = j[1];
x[6] = j[2];
x[7] = j[3];
x[8] = j[4];
x[9] = j[5];
x[10] = j[6];
x[11] = j[7];
x[12] = j[8];
x[13] = j[9];
x[14] = j[10];
x[15] = j[11];
#define quarter(a, b, c, d) \
a += b; \
t = d ^ a; \
d = ROTL32(t, 16); \
c += d; \
t = b ^ c; \
b = ROTL32(t, 12); \
a += b; \
t = d ^ a; \
d = ROTL32(t, 8); \
c += d; \
t = b ^ c; \
b = ROTL32(t, 7);
#define doubleround() \
quarter(x[0], x[4], x[8], x[12]) \
quarter(x[1], x[5], x[9], x[13]) \
quarter(x[2], x[6], x[10], x[14]) \
quarter(x[3], x[7], x[11], x[15]) \
quarter(x[0], x[5], x[10], x[15]) \
quarter(x[1], x[6], x[11], x[12]) \
quarter(x[2], x[7], x[8], x[13]) \
quarter(x[3], x[4], x[9], x[14])
i = r;
do {
doubleround()
i -= 2;
} while (i);
x[0] += chacha_constants[0];
x[1] += chacha_constants[1];
x[2] += chacha_constants[2];
x[3] += chacha_constants[3];
x[4] += j[0];
x[5] += j[1];
x[6] += j[2];
x[7] += j[3];
x[8] += j[4];
x[9] += j[5];
x[10] += j[6];
x[11] += j[7];
x[12] += j[8];
x[13] += j[9];
x[14] += j[10];
x[15] += j[11];
if (in) {
U32TO8(out + 0, x[0] ^ U8TO32(in + 0));
U32TO8(out + 4, x[1] ^ U8TO32(in + 4));
U32TO8(out + 8, x[2] ^ U8TO32(in + 8));
U32TO8(out + 12, x[3] ^ U8TO32(in + 12));
U32TO8(out + 16, x[4] ^ U8TO32(in + 16));
U32TO8(out + 20, x[5] ^ U8TO32(in + 20));
U32TO8(out + 24, x[6] ^ U8TO32(in + 24));
U32TO8(out + 28, x[7] ^ U8TO32(in + 28));
U32TO8(out + 32, x[8] ^ U8TO32(in + 32));
U32TO8(out + 36, x[9] ^ U8TO32(in + 36));
U32TO8(out + 40, x[10] ^ U8TO32(in + 40));
U32TO8(out + 44, x[11] ^ U8TO32(in + 44));
U32TO8(out + 48, x[12] ^ U8TO32(in + 48));
U32TO8(out + 52, x[13] ^ U8TO32(in + 52));
U32TO8(out + 56, x[14] ^ U8TO32(in + 56));
U32TO8(out + 60, x[15] ^ U8TO32(in + 60));
in += 64;
}
else {
U32TO8(out + 0, x[0]);
U32TO8(out + 4, x[1]);
U32TO8(out + 8, x[2]);
U32TO8(out + 12, x[3]);
U32TO8(out + 16, x[4]);
U32TO8(out + 20, x[5]);
U32TO8(out + 24, x[6]);
U32TO8(out + 28, x[7]);
U32TO8(out + 32, x[8]);
U32TO8(out + 36, x[9]);
U32TO8(out + 40, x[10]);
U32TO8(out + 44, x[11]);
U32TO8(out + 48, x[12]);
U32TO8(out + 52, x[13]);
U32TO8(out + 56, x[14]);
U32TO8(out + 60, x[15]);
}
/* increment the 64 bit counter, split in to two 32 bit halves */
j[8]++;
if (!j[8])
j[9]++;
if (bytes <= 64) {
if (bytes < 64)
for (i = 0; i < bytes; i++) ctarget[i] = out[i];
/* store the counter back to the state */
U32TO8(state->s + 32, j[8]);
U32TO8(state->s + 36, j[9]);
goto cleanup;
}
bytes -= 64;
out += 64;
}
cleanup:
rspamd_explicit_memzero(j, sizeof(j));
}
void hchacha_ref(const unsigned char key[32], const unsigned char iv[16], unsigned char out[32], size_t rounds)
{
chacha_int32 x[16];
chacha_int32 t;
x[0] = chacha_constants[0];
x[1] = chacha_constants[1];
x[2] = chacha_constants[2];
x[3] = chacha_constants[3];
x[4] = U8TO32(key + 0);
x[5] = U8TO32(key + 4);
x[6] = U8TO32(key + 8);
x[7] = U8TO32(key + 12);
x[8] = U8TO32(key + 16);
x[9] = U8TO32(key + 20);
x[10] = U8TO32(key + 24);
x[11] = U8TO32(key + 28);
x[12] = U8TO32(iv + 0);
x[13] = U8TO32(iv + 4);
x[14] = U8TO32(iv + 8);
x[15] = U8TO32(iv + 12);
do {
doubleround()
rounds -= 2;
} while (rounds);
/* indices for the chacha constant */
U32TO8(out + 0, x[0]);
U32TO8(out + 4, x[1]);
U32TO8(out + 8, x[2]);
U32TO8(out + 12, x[3]);
/* indices for the iv */
U32TO8(out + 16, x[12]);
U32TO8(out + 20, x[13]);
U32TO8(out + 24, x[14]);
U32TO8(out + 28, x[15]);
}
void chacha_clear_state_ref(chacha_state_internal *state)
{
rspamd_explicit_memzero(state, 48);
}
void chacha_ref(const chacha_key *key, const chacha_iv *iv, const unsigned char *in, unsigned char *out, size_t inlen, size_t rounds)
{
chacha_state_internal state;
size_t i;
for (i = 0; i < 32; i++)
state.s[i + 0] = key->b[i];
for (i = 0; i < 8; i++)
state.s[i + 32] = 0;
for (i = 0; i < 8; i++)
state.s[i + 40] = iv->b[i];
state.rounds = rounds;
chacha_blocks_ref(&state, in, out, inlen);
chacha_clear_state_ref(&state);
}
void xchacha_ref(const chacha_key *key, const chacha_iv24 *iv, const unsigned char *in, unsigned char *out, size_t inlen, size_t rounds)
{
chacha_state_internal state;
size_t i;
hchacha_ref(key->b, iv->b, &state.s[0], rounds);
for (i = 0; i < 8; i++)
state.s[i + 32] = 0;
for (i = 0; i < 8; i++)
state.s[i + 40] = iv->b[i + 16];
state.rounds = rounds;
chacha_blocks_ref(&state, in, out, inlen);
chacha_clear_state_ref(&state);
}
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