usign/sha512.c
Jo-Philipp Wich 5a52b37990 sha512: fix bad hardcoded constant in sha512_final()
The SHA512 implementation shipped with usign uses a wrong hardcoded
numeric constant in the final block padding code.

An additional transform step must be done when there are at least
SHA512_BLOCK_SIZE - 16 = 112 bytes in the state buffer, however the
existing code incorrectly transformed buffer data larger than or
equal to 110 bytes as well, resulting in invalid hash calculations
when exactly 110 or 111 remaining bytes were left in the buffer.

To reproduce the issue, sign a plaintext file with a size of exactly
128 * N + 64 + 110 or 128 * N + 64 + 111 bytes using signify-openbsd
and attempt to verify the signature using usign:

    $ signify-openbsd -G -n -p test.pub -s test.key
    $ dd if=/dev/zero of=test.msg bs=1 count=$((64 + 110))
    $ signify-openbsd -S -x test.sig -s test.key -m test.msg
    $ usign -V -p test.pub -x test.sig -m test.msg

Fix this issue by replacing the bad numeric constanct with a macro
expression resulting in the proper value.

The fix has been verified by cross checking the intermedia hash
results with results from OpenSSL's SHA512 implementation and by
comparing the usign SHA512 code with the hashing code shipped with
signify-openbsd.

Ref: https://forum.openwrt.org/t/signature-check-failed/41945
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
2019-08-06 20:17:33 +02:00

259 lines
6.4 KiB
C

/*
* Copyright (C) 2015 Felix Fietkau <nbd@openwrt.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* SHA512
* Daniel Beer <dlbeer@gmail.com>, 22 Apr 2014
*
* This file is in the public domain.
*/
#include "sha512.h"
static const uint64_t sha512_initial_state[8] = {
0x6a09e667f3bcc908LL, 0xbb67ae8584caa73bLL,
0x3c6ef372fe94f82bLL, 0xa54ff53a5f1d36f1LL,
0x510e527fade682d1LL, 0x9b05688c2b3e6c1fLL,
0x1f83d9abfb41bd6bLL, 0x5be0cd19137e2179LL,
};
static const uint64_t round_k[80] = {
0x428a2f98d728ae22LL, 0x7137449123ef65cdLL,
0xb5c0fbcfec4d3b2fLL, 0xe9b5dba58189dbbcLL,
0x3956c25bf348b538LL, 0x59f111f1b605d019LL,
0x923f82a4af194f9bLL, 0xab1c5ed5da6d8118LL,
0xd807aa98a3030242LL, 0x12835b0145706fbeLL,
0x243185be4ee4b28cLL, 0x550c7dc3d5ffb4e2LL,
0x72be5d74f27b896fLL, 0x80deb1fe3b1696b1LL,
0x9bdc06a725c71235LL, 0xc19bf174cf692694LL,
0xe49b69c19ef14ad2LL, 0xefbe4786384f25e3LL,
0x0fc19dc68b8cd5b5LL, 0x240ca1cc77ac9c65LL,
0x2de92c6f592b0275LL, 0x4a7484aa6ea6e483LL,
0x5cb0a9dcbd41fbd4LL, 0x76f988da831153b5LL,
0x983e5152ee66dfabLL, 0xa831c66d2db43210LL,
0xb00327c898fb213fLL, 0xbf597fc7beef0ee4LL,
0xc6e00bf33da88fc2LL, 0xd5a79147930aa725LL,
0x06ca6351e003826fLL, 0x142929670a0e6e70LL,
0x27b70a8546d22ffcLL, 0x2e1b21385c26c926LL,
0x4d2c6dfc5ac42aedLL, 0x53380d139d95b3dfLL,
0x650a73548baf63deLL, 0x766a0abb3c77b2a8LL,
0x81c2c92e47edaee6LL, 0x92722c851482353bLL,
0xa2bfe8a14cf10364LL, 0xa81a664bbc423001LL,
0xc24b8b70d0f89791LL, 0xc76c51a30654be30LL,
0xd192e819d6ef5218LL, 0xd69906245565a910LL,
0xf40e35855771202aLL, 0x106aa07032bbd1b8LL,
0x19a4c116b8d2d0c8LL, 0x1e376c085141ab53LL,
0x2748774cdf8eeb99LL, 0x34b0bcb5e19b48a8LL,
0x391c0cb3c5c95a63LL, 0x4ed8aa4ae3418acbLL,
0x5b9cca4f7763e373LL, 0x682e6ff3d6b2b8a3LL,
0x748f82ee5defb2fcLL, 0x78a5636f43172f60LL,
0x84c87814a1f0ab72LL, 0x8cc702081a6439ecLL,
0x90befffa23631e28LL, 0xa4506cebde82bde9LL,
0xbef9a3f7b2c67915LL, 0xc67178f2e372532bLL,
0xca273eceea26619cLL, 0xd186b8c721c0c207LL,
0xeada7dd6cde0eb1eLL, 0xf57d4f7fee6ed178LL,
0x06f067aa72176fbaLL, 0x0a637dc5a2c898a6LL,
0x113f9804bef90daeLL, 0x1b710b35131c471bLL,
0x28db77f523047d84LL, 0x32caab7b40c72493LL,
0x3c9ebe0a15c9bebcLL, 0x431d67c49c100d4cLL,
0x4cc5d4becb3e42b6LL, 0x597f299cfc657e2aLL,
0x5fcb6fab3ad6faecLL, 0x6c44198c4a475817LL,
};
static inline uint64_t load64(const uint8_t *x)
{
uint64_t r;
r = *(x++);
r = (r << 8) | *(x++);
r = (r << 8) | *(x++);
r = (r << 8) | *(x++);
r = (r << 8) | *(x++);
r = (r << 8) | *(x++);
r = (r << 8) | *(x++);
r = (r << 8) | *(x++);
return r;
}
static inline void store64(uint8_t *x, uint64_t v)
{
x += 7;
*(x--) = v;
v >>= 8;
*(x--) = v;
v >>= 8;
*(x--) = v;
v >>= 8;
*(x--) = v;
v >>= 8;
*(x--) = v;
v >>= 8;
*(x--) = v;
v >>= 8;
*(x--) = v;
v >>= 8;
*(x--) = v;
}
static inline uint64_t rot64(uint64_t x, int bits)
{
return (x >> bits) | (x << (64 - bits));
}
static void
sha512_block(struct sha512_state *s, const uint8_t *blk)
{
uint64_t w[16];
uint64_t a, b, c, d, e, f, g, h;
int i;
for (i = 0; i < 16; i++) {
w[i] = load64(blk);
blk += 8;
}
/* Load state */
a = s->h[0];
b = s->h[1];
c = s->h[2];
d = s->h[3];
e = s->h[4];
f = s->h[5];
g = s->h[6];
h = s->h[7];
for (i = 0; i < 80; i++) {
/* Compute value of w[i + 16]. w[wrap(i)] is currently w[i] */
const uint64_t wi = w[i & 15];
const uint64_t wi15 = w[(i + 1) & 15];
const uint64_t wi2 = w[(i + 14) & 15];
const uint64_t wi7 = w[(i + 9) & 15];
const uint64_t s0 =
rot64(wi15, 1) ^ rot64(wi15, 8) ^ (wi15 >> 7);
const uint64_t s1 =
rot64(wi2, 19) ^ rot64(wi2, 61) ^ (wi2 >> 6);
/* Round calculations */
const uint64_t S0 = rot64(a, 28) ^ rot64(a, 34) ^ rot64(a, 39);
const uint64_t S1 = rot64(e, 14) ^ rot64(e, 18) ^ rot64(e, 41);
const uint64_t ch = (e & f) ^ ((~e) & g);
const uint64_t temp1 = h + S1 + ch + round_k[i] + wi;
const uint64_t maj = (a & b) ^ (a & c) ^ (b & c);
const uint64_t temp2 = S0 + maj;
/* Update round state */
h = g;
g = f;
f = e;
e = d + temp1;
d = c;
c = b;
b = a;
a = temp1 + temp2;
/* w[wrap(i)] becomes w[i + 16] */
w[i & 15] = wi + s0 + wi7 + s1;
}
/* Store state */
s->h[0] += a;
s->h[1] += b;
s->h[2] += c;
s->h[3] += d;
s->h[4] += e;
s->h[5] += f;
s->h[6] += g;
s->h[7] += h;
}
void sha512_init(struct sha512_state *s)
{
memcpy(s->h, &sha512_initial_state, sizeof(s->h));
s->len = 0;
}
void sha512_add(struct sha512_state *s, const void *data, size_t len)
{
unsigned int partial = s->len & (SHA512_BLOCK_SIZE - 1);
if (partial) {
unsigned int cur = SHA512_BLOCK_SIZE - partial;
if (cur > len)
cur = len;
memcpy(&s->partial[partial], data, cur);
s->len += cur;
data += cur;
len -= cur;
partial = s->len & (SHA512_BLOCK_SIZE - 1);
if (!partial)
sha512_block(s, s->partial);
}
while (len >= SHA512_BLOCK_SIZE) {
sha512_block(s, data);
s->len += SHA512_BLOCK_SIZE;
data += SHA512_BLOCK_SIZE;
len -= SHA512_BLOCK_SIZE;
}
if (!len)
return;
memcpy(s->partial, data, len);
s->len += len;
}
void sha512_final(struct sha512_state *s, uint8_t *hash)
{
size_t last_size = s->len & (SHA512_BLOCK_SIZE - 1);
unsigned int len = SHA512_HASH_SIZE;
int i = 0;
s->partial[last_size++] = 0x80;
if (last_size < SHA512_BLOCK_SIZE)
memset(&s->partial[last_size], 0,
SHA512_BLOCK_SIZE - last_size);
if (last_size > (SHA512_BLOCK_SIZE - 16)) {
sha512_block(s, s->partial);
memset(s->partial, 0, sizeof(s->partial));
}
/* Note: we assume total_size fits in 61 bits */
store64(s->partial + SHA512_BLOCK_SIZE - 8, s->len << 3);
sha512_block(s, s->partial);
/* Read out whole words */
while (len >= 8) {
store64(hash, s->h[i++]);
hash += 8;
len -= 8;
}
/* Read out bytes */
if (len) {
uint8_t tmp[8];
store64(tmp, s->h[i]);
memcpy(hash, tmp, len);
}
}