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/*
* X.509 internal, common functions for writing
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#include "common.h"
#if defined(MBEDTLS_X509_CSR_WRITE_C) || defined(MBEDTLS_X509_CRT_WRITE_C)
#include "mbedtls/x509_crt.h"
#include "x509_internal.h"
#include "mbedtls/asn1write.h"
#include "mbedtls/error.h"
#include "mbedtls/oid.h"
#include "mbedtls/platform.h"
#include "mbedtls/platform_util.h"
#include <string.h>
#include <stdint.h>
#if defined(MBEDTLS_PEM_WRITE_C)
#include "mbedtls/pem.h"
#endif /* MBEDTLS_PEM_WRITE_C */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "psa/crypto.h"
#include "mbedtls/psa_util.h"
#include "md_psa.h"
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#define CHECK_OVERFLOW_ADD(a, b) \
do \
{ \
if (a > SIZE_MAX - (b)) \
{ \
return MBEDTLS_ERR_X509_BAD_INPUT_DATA; \
} \
a += b; \
} while (0)
int mbedtls_x509_write_set_san_common(mbedtls_asn1_named_data **extensions,
const mbedtls_x509_san_list *san_list)
{
int ret = 0;
const mbedtls_x509_san_list *cur;
unsigned char *buf;
unsigned char *p;
size_t len;
size_t buflen = 0;
/* Determine the maximum size of the SubjectAltName list */
for (cur = san_list; cur != NULL; cur = cur->next) {
/* Calculate size of the required buffer */
switch (cur->node.type) {
case MBEDTLS_X509_SAN_DNS_NAME:
case MBEDTLS_X509_SAN_UNIFORM_RESOURCE_IDENTIFIER:
case MBEDTLS_X509_SAN_IP_ADDRESS:
case MBEDTLS_X509_SAN_RFC822_NAME:
/* length of value for each name entry,
* maximum 4 bytes for the length field,
* 1 byte for the tag/type.
*/
CHECK_OVERFLOW_ADD(buflen, cur->node.san.unstructured_name.len);
CHECK_OVERFLOW_ADD(buflen, 4 + 1);
break;
case MBEDTLS_X509_SAN_DIRECTORY_NAME:
{
const mbedtls_asn1_named_data *chunk = &cur->node.san.directory_name;
while (chunk != NULL) {
// Max 4 bytes for length, +1 for tag,
// additional 4 max for length, +1 for tag.
// See x509_write_name for more information.
CHECK_OVERFLOW_ADD(buflen, 4 + 1 + 4 + 1);
CHECK_OVERFLOW_ADD(buflen, chunk->oid.len);
CHECK_OVERFLOW_ADD(buflen, chunk->val.len);
chunk = chunk->next;
}
CHECK_OVERFLOW_ADD(buflen, 4 + 1);
break;
}
default:
/* Not supported - return. */
return MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE;
}
}
/* Add the extra length field and tag */
CHECK_OVERFLOW_ADD(buflen, 4 + 1);
/* Allocate buffer */
buf = mbedtls_calloc(1, buflen);
if (buf == NULL) {
return MBEDTLS_ERR_ASN1_ALLOC_FAILED;
}
p = buf + buflen;
/* Write ASN.1-based structure */
cur = san_list;
len = 0;
while (cur != NULL) {
size_t single_san_len = 0;
switch (cur->node.type) {
case MBEDTLS_X509_SAN_DNS_NAME:
case MBEDTLS_X509_SAN_RFC822_NAME:
case MBEDTLS_X509_SAN_UNIFORM_RESOURCE_IDENTIFIER:
case MBEDTLS_X509_SAN_IP_ADDRESS:
{
const unsigned char *unstructured_name =
(const unsigned char *) cur->node.san.unstructured_name.p;
size_t unstructured_name_len = cur->node.san.unstructured_name.len;
MBEDTLS_ASN1_CHK_CLEANUP_ADD(single_san_len,
mbedtls_asn1_write_raw_buffer(
&p, buf,
unstructured_name, unstructured_name_len));
MBEDTLS_ASN1_CHK_CLEANUP_ADD(single_san_len, mbedtls_asn1_write_len(
&p, buf, unstructured_name_len));
MBEDTLS_ASN1_CHK_CLEANUP_ADD(single_san_len,
mbedtls_asn1_write_tag(
&p, buf,
MBEDTLS_ASN1_CONTEXT_SPECIFIC | cur->node.type));
}
break;
case MBEDTLS_X509_SAN_DIRECTORY_NAME:
MBEDTLS_ASN1_CHK_CLEANUP_ADD(single_san_len,
mbedtls_x509_write_names(&p, buf,
(mbedtls_asn1_named_data *) &
cur->node
.san.directory_name));
MBEDTLS_ASN1_CHK_CLEANUP_ADD(single_san_len,
mbedtls_asn1_write_len(&p, buf, single_san_len));
MBEDTLS_ASN1_CHK_CLEANUP_ADD(single_san_len,
mbedtls_asn1_write_tag(&p, buf,
MBEDTLS_ASN1_CONTEXT_SPECIFIC |
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_X509_SAN_DIRECTORY_NAME));
break;
default:
/* Error out on an unsupported SAN */
ret = MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE;
goto cleanup;
}
cur = cur->next;
/* check for overflow */
if (len > SIZE_MAX - single_san_len) {
ret = MBEDTLS_ERR_X509_BAD_INPUT_DATA;
goto cleanup;
}
len += single_san_len;
}
MBEDTLS_ASN1_CHK_CLEANUP_ADD(len, mbedtls_asn1_write_len(&p, buf, len));
MBEDTLS_ASN1_CHK_CLEANUP_ADD(len,
mbedtls_asn1_write_tag(&p, buf,
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE));
ret = mbedtls_x509_set_extension(extensions,
MBEDTLS_OID_SUBJECT_ALT_NAME,
MBEDTLS_OID_SIZE(MBEDTLS_OID_SUBJECT_ALT_NAME),
0,
buf + buflen - len, len);
/* If we exceeded the allocated buffer it means that maximum size of the SubjectAltName list
* was incorrectly calculated and memory is corrupted. */
if (p < buf) {
ret = MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
}
cleanup:
mbedtls_free(buf);
return ret;
}
#endif /* MBEDTLS_X509_CSR_WRITE_C || MBEDTLS_X509_CRT_WRITE_C */
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