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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "secder.h"
#include <limits.h>
#include "secerr.h"
int
DER_LengthLength(PRUint32 len)
{
if (len > 127) {
if (len > 255) {
if (len > 65535L) {
if (len > 16777215L) {
return 5;
} else {
return 4;
}
} else {
return 3;
}
} else {
return 2;
}
} else {
return 1;
}
}
unsigned char *
DER_StoreHeader(unsigned char *buf, unsigned int code, PRUint32 len)
{
unsigned char b[4];
b[0] = (unsigned char)(len >> 24);
b[1] = (unsigned char)(len >> 16);
b[2] = (unsigned char)(len >> 8);
b[3] = (unsigned char)len;
if ((code & DER_TAGNUM_MASK) == DER_SET || (code & DER_TAGNUM_MASK) == DER_SEQUENCE)
code |= DER_CONSTRUCTED;
*buf++ = code;
if (len > 127) {
if (len > 255) {
if (len > 65535) {
if (len > 16777215) {
*buf++ = 0x84;
*buf++ = b[0];
*buf++ = b[1];
*buf++ = b[2];
*buf++ = b[3];
} else {
*buf++ = 0x83;
*buf++ = b[1];
*buf++ = b[2];
*buf++ = b[3];
}
} else {
*buf++ = 0x82;
*buf++ = b[2];
*buf++ = b[3];
}
} else {
*buf++ = 0x81;
*buf++ = b[3];
}
} else {
*buf++ = b[3];
}
return buf;
}
/*
* XXX This should be rewritten, generalized, to take a long instead
* of a PRInt32.
*/
SECStatus
DER_SetInteger(PLArenaPool *arena, SECItem *it, PRInt32 i)
{
unsigned char bb[4];
unsigned len;
bb[0] = (unsigned char)(i >> 24);
bb[1] = (unsigned char)(i >> 16);
bb[2] = (unsigned char)(i >> 8);
bb[3] = (unsigned char)(i);
/*
** Small integers are encoded in a single byte. Larger integers
** require progressively more space.
*/
if (i < -128) {
if (i < -32768L) {
if (i < -8388608L) {
len = 4;
} else {
len = 3;
}
} else {
len = 2;
}
} else if (i > 127) {
if (i > 32767L) {
if (i > 8388607L) {
len = 4;
} else {
len = 3;
}
} else {
len = 2;
}
} else {
len = 1;
}
it->data = (unsigned char *)PORT_ArenaAlloc(arena, len);
if (!it->data) {
return SECFailure;
}
it->len = len;
PORT_Memcpy(it->data, bb + (4 - len), len);
return SECSuccess;
}
/*
* XXX This should be rewritten, generalized, to take an unsigned long instead
* of a PRUint32.
*/
SECStatus
DER_SetUInteger(PLArenaPool *arena, SECItem *it, PRUint32 ui)
{
unsigned char bb[5];
int len;
bb[0] = 0;
bb[1] = (unsigned char)(ui >> 24);
bb[2] = (unsigned char)(ui >> 16);
bb[3] = (unsigned char)(ui >> 8);
bb[4] = (unsigned char)(ui);
/*
** Small integers are encoded in a single byte. Larger integers
** require progressively more space.
*/
if (ui > 0x7f) {
if (ui > 0x7fff) {
if (ui > 0x7fffffL) {
if (ui >= 0x80000000L) {
len = 5;
} else {
len = 4;
}
} else {
len = 3;
}
} else {
len = 2;
}
} else {
len = 1;
}
it->data = (unsigned char *)PORT_ArenaAlloc(arena, len);
if (it->data == NULL) {
return SECFailure;
}
it->len = len;
PORT_Memcpy(it->data, bb + (sizeof(bb) - len), len);
return SECSuccess;
}
/*
** Convert a der encoded *signed* integer into a machine integral value.
** If an underflow/overflow occurs, sets error code and returns min/max.
*/
long
DER_GetInteger(const SECItem *it)
{
unsigned long ival;
PRBool negative;
unsigned int len = it->len;
unsigned char *cp = it->data;
size_t lsize = sizeof(ival);
PORT_Assert(len);
if (!len) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
return 0;
}
negative = (PRBool)(*cp & 0x80);
ival = negative ? ~0 : 0;
/* Ignore leading zeros/ones. */
while (len && *cp == (unsigned char)ival) {
len--;
cp++;
}
/* Check for overflow/underflow. */
if (len > lsize || (len == lsize && (*cp & 0x80) != negative)) {
PORT_SetError(SEC_ERROR_BAD_DER);
return negative ? LONG_MIN : LONG_MAX;
}
while (len--) {
ival <<= 8;
ival |= *cp++;
}
return ival;
}
/*
** Convert a der encoded *unsigned* integer into a machine integral value.
** If an overflow occurs, sets error code and returns max.
*/
unsigned long
DER_GetUInteger(SECItem *it)
{
unsigned long ival = 0;
unsigned len = it->len;
unsigned char *cp = it->data;
unsigned long overflow = 0xffUL << ((sizeof(ival) - 1) * 8);
PORT_Assert(len);
if (!len) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
return 0;
}
/* Cannot put a negative value into an unsigned container. */
if (*cp & 0x80) {
PORT_SetError(SEC_ERROR_BAD_DER);
return 0;
}
while (len) {
if (ival & overflow) {
PORT_SetError(SEC_ERROR_BAD_DER);
return ULONG_MAX;
}
ival = ival << 8;
ival |= *cp++;
--len;
}
return ival;
}
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