151 lines
3.8 KiB
C
151 lines
3.8 KiB
C
/***********************************************************************
|
|
* Copyright (c) 2015 Pieter Wuille *
|
|
* Distributed under the MIT software license, see the accompanying *
|
|
* file COPYING or https://www.opensource.org/licenses/mit-license.php.*
|
|
***********************************************************************/
|
|
|
|
#include <string.h>
|
|
|
|
#include "lax_der_parsing.h"
|
|
extern int rustsecp256k1_v0_9_0_ecdsa_signature_parse_compact(
|
|
const rustsecp256k1_v0_9_0_context *ctx,
|
|
rustsecp256k1_v0_9_0_ecdsa_signature *sig, const unsigned char *input64);
|
|
int rustsecp256k1_v0_9_0_ecdsa_signature_parse_der_lax(const rustsecp256k1_v0_9_0_context* ctx, rustsecp256k1_v0_9_0_ecdsa_signature* sig, const unsigned char *input, size_t inputlen) {
|
|
size_t rpos, rlen, spos, slen;
|
|
size_t pos = 0;
|
|
size_t lenbyte;
|
|
unsigned char tmpsig[64] = {0};
|
|
int overflow = 0;
|
|
|
|
/* Hack to initialize sig with a correctly-parsed but invalid signature. */
|
|
rustsecp256k1_v0_9_0_ecdsa_signature_parse_compact(ctx, sig, tmpsig);
|
|
|
|
/* Sequence tag byte */
|
|
if (pos == inputlen || input[pos] != 0x30) {
|
|
return 0;
|
|
}
|
|
pos++;
|
|
|
|
/* Sequence length bytes */
|
|
if (pos == inputlen) {
|
|
return 0;
|
|
}
|
|
lenbyte = input[pos++];
|
|
if (lenbyte & 0x80) {
|
|
lenbyte -= 0x80;
|
|
if (lenbyte > inputlen - pos) {
|
|
return 0;
|
|
}
|
|
pos += lenbyte;
|
|
}
|
|
|
|
/* Integer tag byte for R */
|
|
if (pos == inputlen || input[pos] != 0x02) {
|
|
return 0;
|
|
}
|
|
pos++;
|
|
|
|
/* Integer length for R */
|
|
if (pos == inputlen) {
|
|
return 0;
|
|
}
|
|
lenbyte = input[pos++];
|
|
if (lenbyte & 0x80) {
|
|
lenbyte -= 0x80;
|
|
if (lenbyte > inputlen - pos) {
|
|
return 0;
|
|
}
|
|
while (lenbyte > 0 && input[pos] == 0) {
|
|
pos++;
|
|
lenbyte--;
|
|
}
|
|
if (lenbyte >= sizeof(size_t)) {
|
|
return 0;
|
|
}
|
|
rlen = 0;
|
|
while (lenbyte > 0) {
|
|
rlen = (rlen << 8) + input[pos];
|
|
pos++;
|
|
lenbyte--;
|
|
}
|
|
} else {
|
|
rlen = lenbyte;
|
|
}
|
|
if (rlen > inputlen - pos) {
|
|
return 0;
|
|
}
|
|
rpos = pos;
|
|
pos += rlen;
|
|
|
|
/* Integer tag byte for S */
|
|
if (pos == inputlen || input[pos] != 0x02) {
|
|
return 0;
|
|
}
|
|
pos++;
|
|
|
|
/* Integer length for S */
|
|
if (pos == inputlen) {
|
|
return 0;
|
|
}
|
|
lenbyte = input[pos++];
|
|
if (lenbyte & 0x80) {
|
|
lenbyte -= 0x80;
|
|
if (lenbyte > inputlen - pos) {
|
|
return 0;
|
|
}
|
|
while (lenbyte > 0 && input[pos] == 0) {
|
|
pos++;
|
|
lenbyte--;
|
|
}
|
|
if (lenbyte >= sizeof(size_t)) {
|
|
return 0;
|
|
}
|
|
slen = 0;
|
|
while (lenbyte > 0) {
|
|
slen = (slen << 8) + input[pos];
|
|
pos++;
|
|
lenbyte--;
|
|
}
|
|
} else {
|
|
slen = lenbyte;
|
|
}
|
|
if (slen > inputlen - pos) {
|
|
return 0;
|
|
}
|
|
spos = pos;
|
|
|
|
/* Ignore leading zeroes in R */
|
|
while (rlen > 0 && input[rpos] == 0) {
|
|
rlen--;
|
|
rpos++;
|
|
}
|
|
/* Copy R value */
|
|
if (rlen > 32) {
|
|
overflow = 1;
|
|
} else if (rlen) {
|
|
memcpy(tmpsig + 32 - rlen, input + rpos, rlen);
|
|
}
|
|
|
|
/* Ignore leading zeroes in S */
|
|
while (slen > 0 && input[spos] == 0) {
|
|
slen--;
|
|
spos++;
|
|
}
|
|
/* Copy S value */
|
|
if (slen > 32) {
|
|
overflow = 1;
|
|
} else if (slen) {
|
|
memcpy(tmpsig + 64 - slen, input + spos, slen);
|
|
}
|
|
|
|
if (!overflow) {
|
|
overflow = !rustsecp256k1_v0_9_0_ecdsa_signature_parse_compact(ctx, sig, tmpsig);
|
|
}
|
|
if (overflow) {
|
|
memset(tmpsig, 0, 64);
|
|
rustsecp256k1_v0_9_0_ecdsa_signature_parse_compact(ctx, sig, tmpsig);
|
|
}
|
|
return 1;
|
|
}
|
|
|