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#include "sha1.h"
#include "platform.h"
#include <string.h>
/* code adapted from https://git.figboot.dev/l2su/tree/src/digest/sha1.c */
#define SHA1_H0 UINT32_C(0x67452301)
#define SHA1_H1 UINT32_C(0xEFCDAB89)
#define SHA1_H2 UINT32_C(0x98BADCFE)
#define SHA1_H3 UINT32_C(0x10325476)
#define SHA1_H4 UINT32_C(0xC3D2E1F0)
#define SHA1_K0 UINT32_C(0x5A827999)
#define SHA1_K1 UINT32_C(0x6ED9EBA1)
#define SHA1_K2 UINT32_C(0x8F1BBCDC)
#define SHA1_K3 UINT32_C(0xCA62C1D6)
void vl_sha1_init(vl_sha1_st *st)
{
st->vl_state[0] = SHA1_H0;
st->vl_state[1] = SHA1_H1;
st->vl_state[2] = SHA1_H2;
st->vl_state[3] = SHA1_H3;
st->vl_state[4] = SHA1_H4;
memset(st->vl_chunk, 0, VL_SHA1_CHUNKLEN_BYTES);
st->vl_nchunk = 0;
st->vl_total = 0;
}
static uint32_t rol(uint32_t in, uint32_t v)
{
return (in << v) | (in >> (32 - v));
}
static void sha1_upd(vl_sha1_st *st)
{
uint32_t w[80];
uint32_t a, b, c, d, e, f, k, temp;
unsigned i;
memcpy(w, st->vl_chunk, VL_SHA1_CHUNKLEN_BYTES);
for (i = 0; i < 16; ++i) {
w[i] = vl_htobe32(w[i]);
}
for (i = 16; i < 80; ++i) {
w[i] = rol(w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16], 1);
}
a = st->vl_state[0];
b = st->vl_state[1];
c = st->vl_state[2];
d = st->vl_state[3];
e = st->vl_state[4];
#define OP(_start, _end, _k, _e) \
for (i = _start; i < _end; ++i) { \
f = _e; \
k = _k; \
temp = rol(a, 5) + f + e + k + w[i]; \
e = d; \
d = c; \
c = rol(b, 30); \
b = a; \
a = temp; \
}
OP( 0, 20, SHA1_K0, (b & c) ^ ((~b) & d))
OP(20, 40, SHA1_K1, b ^ c ^ d)
OP(40, 60, SHA1_K2, (b & c) ^ (b & d) ^ (c & d))
OP(60, 80, SHA1_K3, b ^ c ^ d)
#undef OP
#undef UP
st->vl_state[0] += a;
st->vl_state[1] += b;
st->vl_state[2] += c;
st->vl_state[3] += d;
st->vl_state[4] += e;
}
void vl_sha1_update(vl_sha1_st *st, const void *data, size_t sz)
{
const uint8_t *dbytes = data;
size_t rem;
st->vl_total += sz;
while (sz >= (rem = (VL_SHA1_CHUNKLEN_BYTES - st->vl_nchunk))) {
memcpy(st->vl_chunk + st->vl_nchunk, dbytes, rem);
sha1_upd(st);
st->vl_nchunk = 0;
dbytes += rem;
sz -= rem;
}
if (sz > 0) {
memcpy(st->vl_chunk + st->vl_nchunk, dbytes, sz);
st->vl_nchunk += sz;
}
}
void vl_sha1_finalize(vl_sha1_st *st, vl_sha1 out)
{
/* SHA1 specifies a 1 bit to follow the data */
st->vl_chunk[st->vl_nchunk] = UINT8_C(0x80);
++st->vl_nchunk;
if (st->vl_nchunk > (VL_SHA1_CHUNKLEN_BYTES - 8)) {
/* must pad the rest of the way */
memset(st->vl_chunk + st->vl_nchunk, 0, VL_SHA1_CHUNKLEN_BYTES - st->vl_nchunk);
sha1_upd(st);
st->vl_nchunk = 0;
}
size_t rem = (VL_SHA1_CHUNKLEN_BYTES - st->vl_nchunk) - 8;
uint64_t lenbe = vl_htobe64(st->vl_total * 8);
memset(st->vl_chunk + st->vl_nchunk, 0, rem);
st->vl_nchunk += rem;
memcpy(st->vl_chunk + st->vl_nchunk, (uint8_t *)&lenbe, 8);
sha1_upd(st);
uint32_t pout_i[VL_SHA1_STATELEN_32];
pout_i[0] = vl_htobe32(st->vl_state[0]);
pout_i[1] = vl_htobe32(st->vl_state[1]);
pout_i[2] = vl_htobe32(st->vl_state[2]);
pout_i[3] = vl_htobe32(st->vl_state[3]);
pout_i[4] = vl_htobe32(st->vl_state[4]);
memcpy(out, pout_i, sizeof(vl_sha1));
}
/* shortcut for hashing a buffer */
void vl_sha1_buffer(vl_sha1 odigest, const void *data, size_t sz)
{
vl_sha1_st st;
vl_sha1_init(&st);
vl_sha1_update(&st, data, sz);
vl_sha1_finalize(&st, odigest);
}
static const char nibs[] = "0123456789abcdef";
/* converts digest bytes to a hex string (does NOT place a NUL byte) */
void vl_sha1_encode(const vl_sha1 dig, char hex[VL_SHA1_DIGEST_HEX_STRLEN])
{
for (unsigned i = 0; i < VL_SHA1_DIGEST_BYTES; ++i) {
hex[i * 2] = nibs[dig[i] >> 4]; /* unsigned shift, dig[i] is 8 bytes */
hex[i * 2 + 1] = nibs[dig[i] & 0xf];
}
}
#define NIB_BAD (~0u)
static unsigned decode_nib(char c)
{
switch (c) {
case '0': return 0;
case '1': return 1;
case '2': return 2;
case '3': return 3;
case '4': return 4;
case '5': return 5;
case '6': return 6;
case '7': return 7;
case '8': return 8;
case '9': return 9;
case 'a': case 'A': return 10;
case 'b': case 'B': return 11;
case 'c': case 'C': return 12;
case 'd': case 'D': return 13;
case 'e': case 'E': return 14;
case 'f': case 'F': return 15;
default: return NIB_BAD;
}
}
/* converts a hex string to digest bytes */
int vl_sha1_decode(vl_sha1 odigest, const char hex[VL_SHA1_DIGEST_HEX_STRLEN])
{
for (unsigned i = 0; i < VL_SHA1_DIGEST_BYTES; ++i) {
unsigned nibhi = decode_nib(hex[i * 2]);
unsigned niblo = decode_nib(hex[i * 2 + 1]);
if ((nibhi | niblo) == NIB_BAD) return -1;
odigest[i] = (uint8_t)((nibhi << 4) | niblo);
}
return 0;
}
#ifdef SHA1_STANDALONE_TEST
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
int main(void)
{
unsigned char chunk[4096];
char dig[VL_SHA1_DIGEST_HEX_STRLEN + 1];
vl_sha1_st st;
dig[VL_SHA1_DIGEST_HEX_STRLEN] = '\0';
vl_sha1_init(&st);
while (1) {
ssize_t nread = read(0, chunk, 4096);
if (nread < 0) {
fprintf(stderr, "read: %s\n", strerror(errno));
return 1;
} else if (nread == 0) {
break;
}
vl_sha1_update(&st, chunk, nread);
}
vl_sha1 o;
vl_sha1_finalize(&st, o);
vl_sha1_encode(o, dig);
printf("%s\n", dig);
vl_sha1 o2;
vl_sha1_decode(o2, dig);
printf("cmp: %d\n", memcmp(o, o2, sizeof(vl_sha1)));
return 0;
}
#endif
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