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/*
* Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2019, Oracle and/or its affiliates. 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 <string.h>
#include <openssl/ebcdic.h>
#include <openssl/err.h>
#include <openssl/params.h>
/*
* When processing text to params, we're trying to be smart with numbers.
* Instead of handling each specific separate integer type, we use a bignum
* and ensure that it isn't larger than the expected size, and we then make
* sure it is the expected size... if there is one given.
* (if the size can be arbitrary, then we give whatever we have)
*/
static int prepare_from_text(const OSSL_PARAM *paramdefs, const char *key,
const char *value, size_t value_n,
/* Output parameters */
const OSSL_PARAM **paramdef, int *ishex,
size_t *buf_n, BIGNUM **tmpbn, int *found)
{
const OSSL_PARAM *p;
size_t buf_bits;
int r;
/*
* ishex is used to translate legacy style string controls in hex format
* to octet string parameters.
*/
*ishex = strncmp(key, "hex", 3) == 0;
if (*ishex)
key += 3;
p = *paramdef = OSSL_PARAM_locate_const(paramdefs, key);
if (found != NULL)
*found = p != NULL;
if (p == NULL)
return 0;
switch (p->data_type) {
case OSSL_PARAM_INTEGER:
case OSSL_PARAM_UNSIGNED_INTEGER:
if (*ishex)
r = BN_hex2bn(tmpbn, value);
else
r = BN_asc2bn(tmpbn, value);
if (r == 0 || *tmpbn == NULL)
return 0;
if (p->data_type == OSSL_PARAM_UNSIGNED_INTEGER
&& BN_is_negative(*tmpbn)) {
ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_INVALID_NEGATIVE_VALUE);
return 0;
}
/*
* 2's complement negate, part 1
*
* BN_bn2nativepad puts the absolute value of the number in the
* buffer, i.e. if it's negative, we need to deal with it. We do
* it by subtracting 1 here and inverting the bytes in
* construct_from_text() below.
* To subtract 1 from an absolute value of a negative number we
* actually have to add 1: -3 - 1 = -4, |-3| = 3 + 1 = 4.
*/
if (p->data_type == OSSL_PARAM_INTEGER && BN_is_negative(*tmpbn)
&& !BN_add_word(*tmpbn, 1)) {
return 0;
}
buf_bits = (size_t)BN_num_bits(*tmpbn);
/*
* Compensate for cases where the most significant bit in
* the resulting OSSL_PARAM buffer will be set after the
* BN_bn2nativepad() call, as the implied sign may not be
* correct after the second part of the 2's complement
* negation has been performed.
* We fix these cases by extending the buffer by one byte
* (8 bits), which will give some padding. The second part
* of the 2's complement negation will do the rest.
*/
if (p->data_type == OSSL_PARAM_INTEGER && buf_bits % 8 == 0)
buf_bits += 8;
*buf_n = (buf_bits + 7) / 8;
/*
* A zero data size means "arbitrary size", so only do the
* range checking if a size is specified.
*/
if (p->data_size > 0) {
if (buf_bits > p->data_size * 8) {
ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_TOO_SMALL_BUFFER);
/* Since this is a different error, we don't break */
return 0;
}
/* Change actual size to become the desired size. */
*buf_n = p->data_size;
}
break;
case OSSL_PARAM_UTF8_STRING:
if (*ishex) {
ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_INVALID_ARGUMENT);
return 0;
}
*buf_n = strlen(value) + 1;
break;
case OSSL_PARAM_OCTET_STRING:
if (*ishex) {
*buf_n = strlen(value) >> 1;
} else {
*buf_n = value_n;
}
break;
}
return 1;
}
static int construct_from_text(OSSL_PARAM *to, const OSSL_PARAM *paramdef,
const char *value, size_t value_n, int ishex,
void *buf, size_t buf_n, BIGNUM *tmpbn)
{
if (buf == NULL)
return 0;
if (buf_n > 0) {
switch (paramdef->data_type) {
case OSSL_PARAM_INTEGER:
case OSSL_PARAM_UNSIGNED_INTEGER:
/*
{
if ((new_value = OPENSSL_malloc(new_value_n)) == NULL) {
BN_free(a);
break;
}
*/
BN_bn2nativepad(tmpbn, buf, buf_n);
/*
* 2's complement negation, part two.
*
* Because we did the first part on the BIGNUM itself, we can just
* invert all the bytes here and be done with it.
*/
if (paramdef->data_type == OSSL_PARAM_INTEGER
&& BN_is_negative(tmpbn)) {
unsigned char *cp;
size_t i = buf_n;
for (cp = buf; i-- > 0; cp++)
*cp ^= 0xFF;
}
break;
case OSSL_PARAM_UTF8_STRING:
#ifdef CHARSET_EBCDIC
ebcdic2ascii(buf, value, buf_n);
#else
strncpy(buf, value, buf_n);
#endif
/* Don't count the terminating NUL byte as data */
buf_n--;
break;
case OSSL_PARAM_OCTET_STRING:
if (ishex) {
size_t l = 0;
if (!OPENSSL_hexstr2buf_ex(buf, buf_n, &l, value, ':'))
return 0;
} else {
memcpy(buf, value, buf_n);
}
break;
}
}
*to = *paramdef;
to->data = buf;
to->data_size = buf_n;
to->return_size = OSSL_PARAM_UNMODIFIED;
return 1;
}
int OSSL_PARAM_allocate_from_text(OSSL_PARAM *to,
const OSSL_PARAM *paramdefs,
const char *key, const char *value,
size_t value_n, int *found)
{
const OSSL_PARAM *paramdef = NULL;
int ishex = 0;
void *buf = NULL;
size_t buf_n = 0;
BIGNUM *tmpbn = NULL;
int ok = 0;
if (to == NULL || paramdefs == NULL)
return 0;
if (!prepare_from_text(paramdefs, key, value, value_n,
¶mdef, &ishex, &buf_n, &tmpbn, found))
goto err;
if ((buf = OPENSSL_zalloc(buf_n > 0 ? buf_n : 1)) == NULL) {
ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
goto err;
}
ok = construct_from_text(to, paramdef, value, value_n, ishex,
buf, buf_n, tmpbn);
BN_free(tmpbn);
if (!ok)
OPENSSL_free(buf);
return ok;
err:
BN_free(tmpbn);
return 0;
}
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