Unify csr and crt san writing functions
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/x509write.c b/library/x509write.c
new file mode 100644
index 0000000..cd3c739
--- /dev/null
+++ b/library/x509write.c
@@ -0,0 +1,186 @@
+/*
+ * X.509 internal, common functions for writing
+ *
+ * Copyright The Mbed TLS Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "common.h"
+#if defined(MBEDTLS_X509_CSR_WRITE_C) || defined(MBEDTLS_X509_CRT_WRITE_C)
+
+#include "mbedtls/x509_crt.h"
+#include "mbedtls/asn1write.h"
+#include "mbedtls/error.h"
+#include "mbedtls/oid.h"
+#include "mbedtls/platform.h"
+#include "mbedtls/platform_util.h"
+#include "mbedtls/md.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 */