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/*
* Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/asn1t.h>
#define COPY_SIZE(a, b) (sizeof(a) < sizeof(b) ? sizeof(a) : sizeof(b))
/*
* Custom primitive type for long handling. This converts between an
* ASN1_INTEGER and a long directly.
*/
static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
static int long_i2c(const ASN1_VALUE **pval, unsigned char *cont, int *putype,
const ASN1_ITEM *it);
static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it);
static int long_print(BIO *out, const ASN1_VALUE **pval, const ASN1_ITEM *it,
int indent, const ASN1_PCTX *pctx);
static ASN1_PRIMITIVE_FUNCS long_pf = {
NULL, 0,
long_new,
long_free,
long_free, /* Clear should set to initial value */
long_c2i,
long_i2c,
long_print
};
ASN1_ITEM_start(LONG)
ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, ASN1_LONG_UNDEF, "LONG"
ASN1_ITEM_end(LONG)
ASN1_ITEM_start(ZLONG)
ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, 0, "ZLONG"
ASN1_ITEM_end(ZLONG)
static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
memcpy(pval, &it->size, COPY_SIZE(*pval, it->size));
return 1;
}
static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
memcpy(pval, &it->size, COPY_SIZE(*pval, it->size));
}
/*
* Originally BN_num_bits_word was called to perform this operation, but
* trouble is that there is no guarantee that sizeof(long) equals to
* sizeof(BN_ULONG). BN_ULONG is a configurable type that can be as wide
* as long, but also double or half...
*/
static int num_bits_ulong(unsigned long value)
{
size_t i;
unsigned long ret = 0;
/*
* It is argued that *on average* constant counter loop performs
* not worse [if not better] than one with conditional break or
* mask-n-table-lookup-style, because of branch misprediction
* penalties.
*/
for (i = 0; i < sizeof(value) * 8; i++) {
ret += (value != 0);
value >>= 1;
}
return (int)ret;
}
static int long_i2c(const ASN1_VALUE **pval, unsigned char *cont, int *putype,
const ASN1_ITEM *it)
{
long ltmp;
unsigned long utmp, sign;
int clen, pad, i;
memcpy(<mp, pval, COPY_SIZE(*pval, ltmp));
if (ltmp == it->size)
return -1;
/*
* Convert the long to positive: we subtract one if negative so we can
* cleanly handle the padding if only the MSB of the leading octet is
* set.
*/
if (ltmp < 0) {
sign = 0xff;
utmp = 0 - (unsigned long)ltmp - 1;
} else {
sign = 0;
utmp = ltmp;
}
clen = num_bits_ulong(utmp);
/* If MSB of leading octet set we need to pad */
if (!(clen & 0x7))
pad = 1;
else
pad = 0;
/* Convert number of bits to number of octets */
clen = (clen + 7) >> 3;
if (cont != NULL) {
if (pad)
*cont++ = (unsigned char)sign;
for (i = clen - 1; i >= 0; i--) {
cont[i] = (unsigned char)(utmp ^ sign);
utmp >>= 8;
}
}
return clen + pad;
}
static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it)
{
int i;
long ltmp;
unsigned long utmp = 0, sign = 0x100;
if (len > 1) {
/*
* Check possible pad byte. Worst case, we're skipping past actual
* content, but since that's only with 0x00 and 0xff and we set neg
* accordingly, the result will be correct in the end anyway.
*/
switch (cont[0]) {
case 0xff:
cont++;
len--;
sign = 0xff;
break;
case 0:
cont++;
len--;
sign = 0;
break;
}
}
if (len > (int)sizeof(long)) {
ERR_raise(ERR_LIB_ASN1, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
return 0;
}
if (sign == 0x100) {
/* Is it negative? */
if (len && (cont[0] & 0x80))
sign = 0xff;
else
sign = 0;
} else if (((sign ^ cont[0]) & 0x80) == 0) { /* same sign bit? */
ERR_raise(ERR_LIB_ASN1, ASN1_R_ILLEGAL_PADDING);
return 0;
}
utmp = 0;
for (i = 0; i < len; i++) {
utmp <<= 8;
utmp |= cont[i] ^ sign;
}
ltmp = (long)utmp;
if (ltmp < 0) {
ERR_raise(ERR_LIB_ASN1, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
return 0;
}
if (sign)
ltmp = -ltmp - 1;
if (ltmp == it->size) {
ERR_raise(ERR_LIB_ASN1, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
return 0;
}
memcpy(pval, <mp, COPY_SIZE(*pval, ltmp));
return 1;
}
static int long_print(BIO *out, const ASN1_VALUE **pval, const ASN1_ITEM *it,
int indent, const ASN1_PCTX *pctx)
{
long l;
memcpy(&l, pval, COPY_SIZE(*pval, l));
return BIO_printf(out, "%ld\n", l);
}
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