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fix #433: EC privateD octetstring may need leading zeros

This commit is contained in:
Viktor Tarasov 2015-04-12 13:35:20 +02:00
parent 6caa85f238
commit 96556dea7b
1 changed files with 22 additions and 9 deletions
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31
src/libopensc/pkcs15-prkey.c
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@ -681,6 +681,7 @@ sc_pkcs15_convert_prkey(struct sc_pkcs15_prkey *pkcs15_key, void *evp_key)
assert(EC_KEY_get0_public_key(src));
pkcs15_key->algorithm = SC_ALGORITHM_EC;
if (!sc_pkcs15_convert_bignum(&dst->privateD, EC_KEY_get0_private_key(src)))
return SC_ERROR_INCOMPATIBLE_KEY;
@ -696,17 +697,29 @@ sc_pkcs15_convert_prkey(struct sc_pkcs15_prkey *pkcs15_key, void *evp_key)
/* Decode EC_POINT from a octet string */
buflen = EC_POINT_point2oct(grp, (const EC_POINT *) EC_KEY_get0_public_key(src),
POINT_CONVERSION_UNCOMPRESSED, buf, buflen, NULL);
if (!buflen)
return SC_ERROR_INCOMPATIBLE_KEY;
/* copy the public key */
if (buflen > 0) {
dst->ecpointQ.value = malloc(buflen);
memcpy(dst->ecpointQ.value, buf, buflen);
dst->ecpointQ.len = buflen;
/* calculate the field length */
dst->params.field_length = (buflen - 1) / 2 * 8;
}
else {
return SC_ERROR_INCOMPATIBLE_KEY;
dst->ecpointQ.value = malloc(buflen);
memcpy(dst->ecpointQ.value, buf, buflen);
dst->ecpointQ.len = buflen;
/* calculate the field length */
dst->params.field_length = (buflen - 1) / 2 * 8;
/* Octetstring may need leading zeros if BN is to short */
if (dst->privateD.len < dst->params.field_length/8) {
size_t d = dst->params.field_length/8 - dst->privateD.len;
dst->privateD.data = realloc(dst->privateD.data, dst->privateD.len + d);
if (!dst->privateD.data)
return SC_ERROR_OUT_OF_MEMORY;
memmove(dst->privateD.data + d, dst->privateD.data, dst->privateD.len);
memset(dst->privateD.data, 0, d);
dst->privateD.len += d;
}
break;