asn1_lib.c
/*
* Copyright 1995-2021 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 <limits.h>
#include "internal/cryptlib.h"
#include <openssl/asn1.h>
#include "asn1_local.h"
static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
long max);
static void asn1_put_length(unsigned char **pp, int length);
static int _asn1_check_infinite_end(const unsigned char **p, long len)
{
/*
* If there is 0 or 1 byte left, the length check should pick things up
*/
if (len <= 0) {
return 1;
} else {
if ((len >= 2) && ((*p)[0] == 0) && ((*p)[1] == 0)) {
(*p) += 2;
return 1;
}
}
return 0;
}
int ASN1_check_infinite_end(unsigned char **p, long len)
{
return _asn1_check_infinite_end((const unsigned char **)p, len);
}
int ASN1_const_check_infinite_end(const unsigned char **p, long len)
{
return _asn1_check_infinite_end(p, len);
}
int ASN1_get_object(const unsigned char **pp, long *plength, int *ptag,
int *pclass, long omax)
{
int i, ret;
long len;
const unsigned char *p = *pp;
int tag, xclass, inf;
long max = omax;
if (omax <= 0) {
ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_SMALL);
return 0x80;
}
ret = (*p & V_ASN1_CONSTRUCTED);
xclass = (*p & V_ASN1_PRIVATE);
i = *p & V_ASN1_PRIMITIVE_TAG;
if (i == V_ASN1_PRIMITIVE_TAG) { /* high-tag */
p++;
if (--max == 0)
goto err;
len = 0;
while (*p & 0x80) {
len <<= 7L;
len |= *(p++) & 0x7f;
if (--max == 0)
goto err;
if (len > (INT_MAX >> 7L))
goto err;
}
len <<= 7L;
len |= *(p++) & 0x7f;
tag = (int)len;
if (--max == 0)
goto err;
} else {
tag = i;
p++;
if (--max == 0)
goto err;
}
*ptag = tag;
*pclass = xclass;
if (!asn1_get_length(&p, &inf, plength, max))
goto err;
if (inf && !(ret & V_ASN1_CONSTRUCTED))
goto err;
if (*plength > (omax - (p - *pp))) {
ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LONG);
/*
* Set this so that even if things are not long enough the values are
* set correctly
*/
ret |= 0x80;
}
*pp = p;
return ret | inf;
err:
ERR_raise(ERR_LIB_ASN1, ASN1_R_HEADER_TOO_LONG);
return 0x80;
}
/*
* Decode a length field.
* The short form is a single byte defining a length 0 - 127.
* The long form is a byte 0 - 127 with the top bit set and this indicates
* the number of following octets that contain the length. These octets
* are stored most significant digit first.
*/
static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
long max)
{
const unsigned char *p = *pp;
unsigned long ret = 0;
int i;
if (max-- < 1)
return 0;
if (*p == 0x80) {
*inf = 1;
p++;
} else {
*inf = 0;
i = *p & 0x7f;
if (*p++ & 0x80) {
if (max < i + 1)
return 0;
/* Skip leading zeroes */
while (i > 0 && *p == 0) {
p++;
i--;
}
if (i > (int)sizeof(long))
return 0;
while (i > 0) {
ret <<= 8;
ret |= *p++;
i--;
}
if (ret > LONG_MAX)
return 0;
} else {
ret = i;
}
}
*pp = p;
*rl = (long)ret;
return 1;
}
/*
* constructed == 2 for indefinite length constructed
*/
void ASN1_put_object(unsigned char **pp, int constructed, int length, int tag,
int xclass)
{
unsigned char *p = *pp;
int i, ttag;
i = (constructed) ? V_ASN1_CONSTRUCTED : 0;
i |= (xclass & V_ASN1_PRIVATE);
if (tag < 31) {
*(p++) = i | (tag & V_ASN1_PRIMITIVE_TAG);
} else {
*(p++) = i | V_ASN1_PRIMITIVE_TAG;
for (i = 0, ttag = tag; ttag > 0; i++)
ttag >>= 7;
ttag = i;
while (i-- > 0) {
p[i] = tag & 0x7f;
if (i != (ttag - 1))
p[i] |= 0x80;
tag >>= 7;
}
p += ttag;
}
if (constructed == 2)
*(p++) = 0x80;
else
asn1_put_length(&p, length);
*pp = p;
}
int ASN1_put_eoc(unsigned char **pp)
{
unsigned char *p = *pp;
*p++ = 0;
*p++ = 0;
*pp = p;
return 2;
}
static void asn1_put_length(unsigned char **pp, int length)
{
unsigned char *p = *pp;
int i, len;
if (length <= 127) {
*(p++) = (unsigned char)length;
} else {
len = length;
for (i = 0; len > 0; i++)
len >>= 8;
*(p++) = i | 0x80;
len = i;
while (i-- > 0) {
p[i] = length & 0xff;
length >>= 8;
}
p += len;
}
*pp = p;
}
int ASN1_object_size(int constructed, int length, int tag)
{
int ret = 1;
if (length < 0)
return -1;
if (tag >= 31) {
while (tag > 0) {
tag >>= 7;
ret++;
}
}
if (constructed == 2) {
ret += 3;
} else {
ret++;
if (length > 127) {
int tmplen = length;
while (tmplen > 0) {
tmplen >>= 8;
ret++;
}
}
}
if (ret >= INT_MAX - length)
return -1;
return ret + length;
}
void ossl_asn1_string_set_bits_left(ASN1_STRING *str, unsigned int num)
{
str->flags &= ~0x07;
str->flags |= ASN1_STRING_FLAG_BITS_LEFT | (num & 0x07);
}
int ASN1_STRING_copy(ASN1_STRING *dst, const ASN1_STRING *str)
{
if (str == NULL)
return 0;
dst->type = str->type;
if (!ASN1_STRING_set(dst, str->data, str->length))
return 0;
/* Copy flags but preserve embed value */
dst->flags &= ASN1_STRING_FLAG_EMBED;
dst->flags |= str->flags & ~ASN1_STRING_FLAG_EMBED;
return 1;
}
ASN1_STRING *ASN1_STRING_dup(const ASN1_STRING *str)
{
ASN1_STRING *ret;
if (!str)
return NULL;
ret = ASN1_STRING_new();
if (ret == NULL)
return NULL;
if (!ASN1_STRING_copy(ret, str)) {
ASN1_STRING_free(ret);
return NULL;
}
return ret;
}
int ASN1_STRING_set(ASN1_STRING *str, const void *_data, int len_in)
{
unsigned char *c;
const char *data = _data;
size_t len;
if (len_in < 0) {
if (data == NULL)
return 0;
len = strlen(data);
} else {
len = (size_t)len_in;
}
/*
* Verify that the length fits within an integer for assignment to
* str->length below. The additional 1 is subtracted to allow for the
* '\0' terminator even though this isn't strictly necessary.
*/
if (len > INT_MAX - 1) {
ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LARGE);
return 0;
}
if ((size_t)str->length <= len || str->data == NULL) {
c = str->data;
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
/* No NUL terminator in fuzzing builds */
str->data = OPENSSL_realloc(c, len != 0 ? len : 1);
#else
str->data = OPENSSL_realloc(c, len + 1);
#endif
if (str->data == NULL) {
str->data = c;
return 0;
}
}
str->length = len;
if (data != NULL) {
memcpy(str->data, data, len);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
/* Set the unused byte to something non NUL and printable. */
if (len == 0)
str->data[len] = '~';
#else
/*
* Add a NUL terminator. This should not be necessary - but we add it as
* a safety precaution
*/
str->data[len] = '\0';
#endif
}
return 1;
}
void ASN1_STRING_set0(ASN1_STRING *str, void *data, int len)
{
OPENSSL_free(str->data);
str->data = data;
str->length = len;
}
ASN1_STRING *ASN1_STRING_new(void)
{
return ASN1_STRING_type_new(V_ASN1_OCTET_STRING);
}
ASN1_STRING *ASN1_STRING_type_new(int type)
{
ASN1_STRING *ret;
ret = OPENSSL_zalloc(sizeof(*ret));
if (ret == NULL)
return NULL;
ret->type = type;
return ret;
}
void ossl_asn1_string_embed_free(ASN1_STRING *a, int embed)
{
if (a == NULL)
return;
if (!(a->flags & ASN1_STRING_FLAG_NDEF))
OPENSSL_free(a->data);
if (embed == 0)
OPENSSL_free(a);
}
void ASN1_STRING_free(ASN1_STRING *a)
{
if (a == NULL)
return;
ossl_asn1_string_embed_free(a, a->flags & ASN1_STRING_FLAG_EMBED);
}
void ASN1_STRING_clear_free(ASN1_STRING *a)
{
if (a == NULL)
return;
if (a->data && !(a->flags & ASN1_STRING_FLAG_NDEF))
OPENSSL_cleanse(a->data, a->length);
ASN1_STRING_free(a);
}
int ASN1_STRING_cmp(const ASN1_STRING *a, const ASN1_STRING *b)
{
int i;
i = (a->length - b->length);
if (i == 0) {
if (a->length != 0)
i = memcmp(a->data, b->data, a->length);
if (i == 0)
return a->type - b->type;
else
return i;
} else {
return i;
}
}
int ASN1_STRING_length(const ASN1_STRING *x)
{
return x->length;
}
#ifndef OPENSSL_NO_DEPRECATED_3_0
void ASN1_STRING_length_set(ASN1_STRING *x, int len)
{
x->length = len;
}
#endif
int ASN1_STRING_type(const ASN1_STRING *x)
{
return x->type;
}
const unsigned char *ASN1_STRING_get0_data(const ASN1_STRING *x)
{
return x->data;
}
#ifndef OPENSSL_NO_DEPRECATED_1_1_0
unsigned char *ASN1_STRING_data(ASN1_STRING *x)
{
return x->data;
}
#endif
/* |max_len| excludes NUL terminator and may be 0 to indicate no restriction */
char *ossl_sk_ASN1_UTF8STRING2text(STACK_OF(ASN1_UTF8STRING) *text,
const char *sep, size_t max_len)
{
int i;
ASN1_UTF8STRING *current;
size_t length = 0, sep_len;
char *result = NULL;
char *p;
if (sep == NULL)
sep = "";
sep_len = strlen(sep);
for (i = 0; i < sk_ASN1_UTF8STRING_num(text); i++) {
current = sk_ASN1_UTF8STRING_value(text, i);
if (i > 0)
length += sep_len;
length += ASN1_STRING_length(current);
if (max_len != 0 && length > max_len)
return NULL;
}
if ((result = OPENSSL_malloc(length + 1)) == NULL)
return NULL;
p = result;
for (i = 0; i < sk_ASN1_UTF8STRING_num(text); i++) {
current = sk_ASN1_UTF8STRING_value(text, i);
length = ASN1_STRING_length(current);
if (i > 0 && sep_len > 0) {
strncpy(p, sep, sep_len + 1); /* using + 1 to silence gcc warning */
p += sep_len;
}
strncpy(p, (const char *)ASN1_STRING_get0_data(current), length);
p += length;
}
*p = '\0';
return result;
}
