openssl/crypto/asn1/a_bitstr.c

217 lines
5.3 KiB
C

/*
* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (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 <limits.h>
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/asn1.h>
#include "asn1_local.h"
int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, unsigned char *d, int len)
{
return ASN1_STRING_set(x, d, len);
}
int i2c_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
{
int ret, j, bits, len;
unsigned char *p, *d;
if (a == NULL)
return 0;
len = a->length;
if (len > 0) {
if (a->flags & ASN1_STRING_FLAG_BITS_LEFT) {
bits = (int)a->flags & 0x07;
} else {
for (; len > 0; len--) {
if (a->data[len - 1])
break;
}
j = a->data[len - 1];
if (j & 0x01)
bits = 0;
else if (j & 0x02)
bits = 1;
else if (j & 0x04)
bits = 2;
else if (j & 0x08)
bits = 3;
else if (j & 0x10)
bits = 4;
else if (j & 0x20)
bits = 5;
else if (j & 0x40)
bits = 6;
else if (j & 0x80)
bits = 7;
else
bits = 0; /* should not happen */
}
} else
bits = 0;
ret = 1 + len;
if (pp == NULL)
return ret;
p = *pp;
*(p++) = (unsigned char)bits;
d = a->data;
if (len > 0) {
memcpy(p, d, len);
p += len;
p[-1] &= (0xff << bits);
}
*pp = p;
return ret;
}
ASN1_BIT_STRING *c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,
const unsigned char **pp, long len)
{
ASN1_BIT_STRING *ret = NULL;
const unsigned char *p;
unsigned char *s;
int i;
if (len < 1) {
i = ASN1_R_STRING_TOO_SHORT;
goto err;
}
if (len > INT_MAX) {
i = ASN1_R_STRING_TOO_LONG;
goto err;
}
if ((a == NULL) || ((*a) == NULL)) {
if ((ret = ASN1_BIT_STRING_new()) == NULL)
return NULL;
} else
ret = (*a);
p = *pp;
i = *(p++);
if (i > 7) {
i = ASN1_R_INVALID_BIT_STRING_BITS_LEFT;
goto err;
}
/*
* We do this to preserve the settings. If we modify the settings, via
* the _set_bit function, we will recalculate on output
*/
ret->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear */
ret->flags |= (ASN1_STRING_FLAG_BITS_LEFT | i); /* set */
if (len-- > 1) { /* using one because of the bits left byte */
s = OPENSSL_malloc((int)len);
if (s == NULL) {
i = ERR_R_MALLOC_FAILURE;
goto err;
}
memcpy(s, p, (int)len);
s[len - 1] &= (0xff << i);
p += len;
} else
s = NULL;
ret->length = (int)len;
OPENSSL_free(ret->data);
ret->data = s;
ret->type = V_ASN1_BIT_STRING;
if (a != NULL)
(*a) = ret;
*pp = p;
return ret;
err:
ASN1err(ASN1_F_C2I_ASN1_BIT_STRING, i);
if ((a == NULL) || (*a != ret))
ASN1_BIT_STRING_free(ret);
return NULL;
}
/*
* These next 2 functions from Goetz Babin-Ebell.
*/
int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value)
{
int w, v, iv;
unsigned char *c;
w = n / 8;
v = 1 << (7 - (n & 0x07));
iv = ~v;
if (!value)
v = 0;
if (a == NULL)
return 0;
a->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear, set on write */
if ((a->length < (w + 1)) || (a->data == NULL)) {
if (!value)
return 1; /* Don't need to set */
c = OPENSSL_clear_realloc(a->data, a->length, w + 1);
if (c == NULL) {
ASN1err(ASN1_F_ASN1_BIT_STRING_SET_BIT, ERR_R_MALLOC_FAILURE);
return 0;
}
if (w + 1 - a->length > 0)
memset(c + a->length, 0, w + 1 - a->length);
a->data = c;
a->length = w + 1;
}
a->data[w] = ((a->data[w]) & iv) | v;
while ((a->length > 0) && (a->data[a->length - 1] == 0))
a->length--;
return 1;
}
int ASN1_BIT_STRING_get_bit(const ASN1_BIT_STRING *a, int n)
{
int w, v;
w = n / 8;
v = 1 << (7 - (n & 0x07));
if ((a == NULL) || (a->length < (w + 1)) || (a->data == NULL))
return 0;
return ((a->data[w] & v) != 0);
}
/*
* Checks if the given bit string contains only bits specified by
* the flags vector. Returns 0 if there is at least one bit set in 'a'
* which is not specified in 'flags', 1 otherwise.
* 'len' is the length of 'flags'.
*/
int ASN1_BIT_STRING_check(const ASN1_BIT_STRING *a,
const unsigned char *flags, int flags_len)
{
int i, ok;
/* Check if there is one bit set at all. */
if (!a || !a->data)
return 1;
/*
* Check each byte of the internal representation of the bit string.
*/
ok = 1;
for (i = 0; i < a->length && ok; ++i) {
unsigned char mask = i < flags_len ? ~flags[i] : 0xff;
/* We are done if there is an unneeded bit set. */
ok = (a->data[i] & mask) == 0;
}
return ok;
}