openssl/crypto/asn1/evp_asn1.c
Paul Dreik 0760d132da Avoid invoking memcpy if size is zero or the supplied buffer is NULL
This allows for passing a NULL pointer with zero max_len.

Invoking memcpy on NULL is undefined behaviour, even if the size is zero.

https://en.cppreference.com/w/c/string/byte/memcpy

The function can now be queried for the necessary buffer length.

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10541)
2021-08-25 17:02:37 +02:00

188 lines
4.7 KiB
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 "internal/cryptlib.h"
#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include "crypto/asn1.h"
int ASN1_TYPE_set_octetstring(ASN1_TYPE *a, unsigned char *data, int len)
{
ASN1_STRING *os;
if ((os = ASN1_OCTET_STRING_new()) == NULL)
return 0;
if (!ASN1_OCTET_STRING_set(os, data, len)) {
ASN1_OCTET_STRING_free(os);
return 0;
}
ASN1_TYPE_set(a, V_ASN1_OCTET_STRING, os);
return 1;
}
/* int max_len: for returned value
* if passing NULL in data, nothing is copied but the necessary length
* for it is returned.
*/
int ASN1_TYPE_get_octetstring(const ASN1_TYPE *a, unsigned char *data, int max_len)
{
int ret, num;
const unsigned char *p;
if ((a->type != V_ASN1_OCTET_STRING) || (a->value.octet_string == NULL)) {
ERR_raise(ERR_LIB_ASN1, ASN1_R_DATA_IS_WRONG);
return -1;
}
p = ASN1_STRING_get0_data(a->value.octet_string);
ret = ASN1_STRING_length(a->value.octet_string);
if (ret < max_len)
num = ret;
else
num = max_len;
if (num > 0 && data != NULL)
memcpy(data, p, num);
return ret;
}
static ossl_inline void asn1_type_init_oct(ASN1_OCTET_STRING *oct,
unsigned char *data, int len)
{
oct->data = data;
oct->type = V_ASN1_OCTET_STRING;
oct->length = len;
oct->flags = 0;
}
static int asn1_type_get_int_oct(ASN1_OCTET_STRING *oct, int32_t anum,
long *num, unsigned char *data, int max_len)
{
int ret = ASN1_STRING_length(oct), n;
if (num != NULL)
*num = anum;
if (max_len > ret)
n = ret;
else
n = max_len;
if (data != NULL)
memcpy(data, ASN1_STRING_get0_data(oct), n);
return ret;
}
typedef struct {
int32_t num;
ASN1_OCTET_STRING *oct;
} asn1_int_oct;
ASN1_SEQUENCE(asn1_int_oct) = {
ASN1_EMBED(asn1_int_oct, num, INT32),
ASN1_SIMPLE(asn1_int_oct, oct, ASN1_OCTET_STRING)
} static_ASN1_SEQUENCE_END(asn1_int_oct)
DECLARE_ASN1_ITEM(asn1_int_oct)
int ASN1_TYPE_set_int_octetstring(ASN1_TYPE *a, long num, unsigned char *data,
int len)
{
asn1_int_oct atmp;
ASN1_OCTET_STRING oct;
atmp.num = num;
atmp.oct = &oct;
asn1_type_init_oct(&oct, data, len);
if (ASN1_TYPE_pack_sequence(ASN1_ITEM_rptr(asn1_int_oct), &atmp, &a))
return 1;
return 0;
}
int ASN1_TYPE_get_int_octetstring(const ASN1_TYPE *a, long *num,
unsigned char *data, int max_len)
{
asn1_int_oct *atmp = NULL;
int ret = -1;
if ((a->type != V_ASN1_SEQUENCE) || (a->value.sequence == NULL)) {
goto err;
}
atmp = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(asn1_int_oct), a);
if (atmp == NULL)
goto err;
ret = asn1_type_get_int_oct(atmp->oct, atmp->num, num, data, max_len);
if (ret == -1) {
err:
ERR_raise(ERR_LIB_ASN1, ASN1_R_DATA_IS_WRONG);
}
M_ASN1_free_of(atmp, asn1_int_oct);
return ret;
}
typedef struct {
ASN1_OCTET_STRING *oct;
int32_t num;
} asn1_oct_int;
/*
* Defined in RFC 5084 -
* Section 2. "Content-Authenticated Encryption Algorithms"
*/
ASN1_SEQUENCE(asn1_oct_int) = {
ASN1_SIMPLE(asn1_oct_int, oct, ASN1_OCTET_STRING),
ASN1_EMBED(asn1_oct_int, num, INT32)
} static_ASN1_SEQUENCE_END(asn1_oct_int)
DECLARE_ASN1_ITEM(asn1_oct_int)
int ossl_asn1_type_set_octetstring_int(ASN1_TYPE *a, long num,
unsigned char *data, int len)
{
asn1_oct_int atmp;
ASN1_OCTET_STRING oct;
atmp.num = num;
atmp.oct = &oct;
asn1_type_init_oct(&oct, data, len);
if (ASN1_TYPE_pack_sequence(ASN1_ITEM_rptr(asn1_oct_int), &atmp, &a))
return 1;
return 0;
}
int ossl_asn1_type_get_octetstring_int(const ASN1_TYPE *a, long *num,
unsigned char *data, int max_len)
{
asn1_oct_int *atmp = NULL;
int ret = -1;
if ((a->type != V_ASN1_SEQUENCE) || (a->value.sequence == NULL))
goto err;
atmp = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(asn1_oct_int), a);
if (atmp == NULL)
goto err;
ret = asn1_type_get_int_oct(atmp->oct, atmp->num, num, data, max_len);
if (ret == -1) {
err:
ERR_raise(ERR_LIB_ASN1, ASN1_R_DATA_IS_WRONG);
}
M_ASN1_free_of(atmp, asn1_oct_int);
return ret;
}