diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index a6dc22c..b1d0ca0 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -48,16 +48,6 @@
 #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)
-
 void mbedtls_x509write_crt_init(mbedtls_x509write_cert *ctx)
 {
     memset(ctx, 0, sizeof(mbedtls_x509write_cert));
@@ -166,136 +156,7 @@
 int mbedtls_x509write_crt_set_subject_alternative_name(mbedtls_x509write_cert *ctx,
                                                        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_x509write_crt_set_extension(
-        ctx,
-        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;
+    return mbedtls_x509_write_set_san_common(&ctx->extensions, san_list);
 }