tls13 ocsp: suppot lazy cert loading with ocsp stapling

- Expose dynamic TLS certificate loading via WOLFSSL_CERT_SETUP_CB
- Expose OCSP Status Cb to load responses directly. This bypasses internal checks on the OCSP response which is desirable if the CA is not loaded on the server.
- Add `wc_InitOCSP`, `wc_FreeOCSP`, and `wc_CheckCertOcspResponse` as wrapper functions around existing OCSP functionality
- Add `wolfSSL_GetOcspStaple` to retrieve OCSP staple data in TLS 1.3
- Add test for OCSP cert callback
- Expose store_ctx functions
- Add cert-setup-cb to os-check

Co-Authored-By: Marco Oliverio <[email protected]>

Author: julek-wolfssl

.github/workflows/os-check.yml

@@ -60,6 +60,7 @@ jobs:
           '--disable-sys-ca-certs',
           '--enable-all CPPFLAGS=-DWOLFSSL_DEBUG_CERTS ',
           '--enable-all CFLAGS="-DWOLFSSL_CHECK_MEM_ZERO"',
+          '--enable-dtls --enable-dtls13 --enable-ocspstapling --enable-cert-setup-cb',
         ]
     name: make check
     if: github.repository_owner == 'wolfssl'

configure.ac

@@ -9782,6 +9782,13 @@ AC_ARG_ENABLE([rpk],
     [ ENABLED_RPK=no ]
     )
 
+# Allows dynamically loading the certificate
+AC_ARG_ENABLE([cert-setup-cb],
+    [AS_HELP_STRING([--enable-cert-setup-cb],[Enable support for dynamically loading TLS certificates (default: disabled)])],
+    [ ENABLED_CERT_SETUP_CB=$enableval ],
+    [ ENABLED_CERT_SETUP_CB=no ]
+    )
+
 # check if should run the trusted peer certs test
 # (for now checking both C_FLAGS and C_EXTRA_FLAGS)
 AS_CASE(["$CFLAGS $CPPFLAGS"],[*'WOLFSSL_TRUST_PEER_CERT'*],[ENABLED_TRUSTED_PEER_CERT=yes])
@@ -10203,6 +10210,9 @@ AS_IF([test "x$ENABLED_DUAL_ALG_CERTS" = "xyes"],
 AS_IF([test "x$ENABLED_RPK" = "xyes"],
       [AM_CFLAGS="$AM_CFLAGS -DHAVE_RPK"])
 
+AS_IF([test "x$ENABLED_CERT_SETUP_CB" = "xyes"],
+      [AM_CFLAGS="$AM_CFLAGS -DWOLFSSL_CERT_SETUP_CB"])
+
 AS_IF([test "x$ENABLED_ALTNAMES" = "xyes"],
       [AM_CFLAGS="$AM_CFLAGS -DWOLFSSL_ALT_NAMES"])
 

src/internal.c

@@ -6755,13 +6755,21 @@ int InitSSL_Suites(WOLFSSL* ssl)
             !havePSK && !haveAnon && !haveMcast) {
 
         /* server certificate must be loaded */
-        if (!ssl->buffers.certificate || !ssl->buffers.certificate->buffer) {
+        if ((!ssl->buffers.certificate || !ssl->buffers.certificate->buffer)
+#ifdef WOLFSSL_CERT_SETUP_CB
+                && ssl->ctx->certSetupCb == NULL
+#endif
+                ) {
             WOLFSSL_MSG("Server missing certificate");
             WOLFSSL_ERROR_VERBOSE(NO_PRIVATE_KEY);
             return NO_PRIVATE_KEY;
         }
 
-        if (!ssl->buffers.key || !ssl->buffers.key->buffer) {
+        if ((!ssl->buffers.key || !ssl->buffers.key->buffer)
+#ifdef WOLFSSL_CERT_SETUP_CB
+                && ssl->ctx->certSetupCb == NULL
+#endif
+                ) {
             /* allow no private key if using existing key */
         #ifdef WOLF_PRIVATE_KEY_ID
             if (ssl->devId != INVALID_DEVID
@@ -24359,10 +24367,9 @@ int CreateOcspRequest(WOLFSSL* ssl, OcspRequest* request,
 
     InitDecodedCert(cert, certData, length, ssl->heap);
     /* TODO: Setup async support here */
-    ret = ParseCertRelative(cert, CERT_TYPE, VERIFY, SSL_CM(ssl), NULL);
-    if (ret != 0) {
+    ret = ParseCertRelative(cert, CERT_TYPE, NO_VERIFY, SSL_CM(ssl), NULL);
+    if (ret != 0)
         WOLFSSL_MSG("ParseCert failed");
-    }
     if (ret == 0)
         ret = InitOcspRequest(request, cert, 0, ssl->heap);
     if (ret == 0) {
@@ -25115,9 +25122,7 @@ static int BuildCertificateStatus(WOLFSSL* ssl, byte type, buffer* status,
 }
 #endif
 
-#if defined(HAVE_CERTIFICATE_STATUS_REQUEST) &&                                \
-    (defined(OPENSSL_ALL) || defined(WOLFSSL_NGINX) ||                         \
-    defined(WOLFSSL_HAPROXY))
+#if defined(HAVE_CERTIFICATE_STATUS_REQUEST)
 static int BuildCertificateStatusWithStatusCB(WOLFSSL* ssl)
 {
     WOLFSSL_OCSP *ocsp;
@@ -25137,7 +25142,7 @@ static int BuildCertificateStatusWithStatusCB(WOLFSSL* ssl)
     WOLFSSL_MSG("Calling ocsp->statusCb");
     ret = ocsp->statusCb(ssl, ioCtx);
     switch (ret) {
-        case SSL_TLSEXT_ERR_OK:
+        case WOLFSSL_OCSP_STATUS_CB_OK:
             if (ssl->ocspResp == NULL || ssl->ocspRespSz == 0) {
                 ret = 0;
                 break;
@@ -25146,20 +25151,19 @@ static int BuildCertificateStatusWithStatusCB(WOLFSSL* ssl)
             response.length = ssl->ocspRespSz;
             ret = BuildCertificateStatus(ssl, WOLFSSL_CSR_OCSP, &response, 1);
             break;
-        case SSL_TLSEXT_ERR_NOACK:
+        case WOLFSSL_OCSP_STATUS_CB_NOACK:
             /* No OCSP response to send */
             ret = 0;
             break;
-        case SSL_TLSEXT_ERR_ALERT_FATAL:
+        case WOLFSSL_OCSP_STATUS_CB_ALERT_FATAL:
         /* fall through */
         default:
             ret = WOLFSSL_FATAL_ERROR;
             break;
     }
     return ret;
 }
-#endif /* HAVE_CERTIFICATE_STATUS_REQUEST && (defined(OPENSSL_ALL) ||
-          defined(WOLFSSL_NGINX) || defined(WOLFSSL_HAPROXY)) */
+#endif /* HAVE_CERTIFICATE_STATUS_REQUEST */
 
 #endif /* NO_WOLFSSL_SERVER */
 
@@ -25185,9 +25189,7 @@ int SendCertificateStatus(WOLFSSL* ssl)
     status_type = status_type ? status_type : ssl->status_request_v2;
 #endif
 
-#if defined(HAVE_CERTIFICATE_STATUS_REQUEST) && \
-    (defined(OPENSSL_ALL) || defined(WOLFSSL_NGINX) || \
-    defined(WOLFSSL_HAPROXY))
+#if defined(HAVE_CERTIFICATE_STATUS_REQUEST)
     if (SSL_CM(ssl)->ocsp_stapling != NULL &&
             SSL_CM(ssl)->ocsp_stapling->statusCb != NULL) {
         if (ssl->status_request == WOLFSSL_CSR_OCSP)
@@ -31704,7 +31706,8 @@ static int HashSkeData(WOLFSSL* ssl, enum wc_HashType hashType,
         word16 len;
         word32 begin = *inOutIdx;
     #if defined(OPENSSL_EXTRA) || defined(OPENSSL_ALL) || \
-        defined(WOLFSSL_NGINX) || defined(HAVE_LIGHTY)
+        defined(WOLFSSL_NGINX) || defined(HAVE_LIGHTY) || \
+        defined(WOLFSSL_CERT_SETUP_CB)
         int ret;
     #endif
     #ifdef OPENSSL_EXTRA
@@ -31851,6 +31854,7 @@ static int HashSkeData(WOLFSSL* ssl, enum wc_HashType hashType,
             len -= (word16)(OPAQUE16_LEN) + dnSz;
         }
 
+    #ifdef WOLFSSL_CERT_SETUP_CB
     #ifdef OPENSSL_EXTRA
         /* call client cert callback if no cert has been loaded */
         if ((ssl->ctx->CBClientCert != NULL) &&
@@ -31872,6 +31876,7 @@ static int HashSkeData(WOLFSSL* ssl, enum wc_HashType hashType,
                 return WOLFSSL_ERROR_WANT_X509_LOOKUP;
             }
         }
+    #endif
         if ((ret = CertSetupCbWrapper(ssl)) != 0)
             return ret;
     #endif
@@ -38698,7 +38703,7 @@ static int DoSessionTicket(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
     #endif
 #endif
 
-#ifdef OPENSSL_EXTRA
+#ifdef WOLFSSL_CERT_SETUP_CB
         /* Give user last chance to provide a cert for cipher selection */
         if (ret == 0 && ssl->ctx->certSetupCb != NULL)
             ret = CertSetupCbWrapper(ssl);

src/ocsp.c

@@ -45,6 +45,52 @@
 #endif
 
 
+int  wc_InitOCSP(WOLFSSL_OCSP* ocsp, WOLFSSL_CERT_MANAGER* cm)
+{
+    return InitOCSP(ocsp, cm);
+}
+
+void wc_FreeOCSP(WOLFSSL_OCSP* ocsp)
+{
+    FreeOCSP(ocsp, 0);
+}
+
+int wc_CheckCertOcspResponse(WOLFSSL_OCSP *ocsp, DecodedCert *cert,
+        byte *response, int responseSz, void* heap)
+{
+    int ret = WC_NO_ERR_TRACE(ASN_OCSP_CONFIRM_E);
+
+#ifdef WOLFSSL_SMALL_STACK
+    OcspRequest* ocspRequest;
+#else
+    OcspRequest ocspRequest[1];
+#endif
+
+
+#ifdef WOLFSSL_SMALL_STACK
+    ocspRequest = (OcspRequest*)XMALLOC(sizeof(OcspRequest), NULL,
+                                                       DYNAMIC_TYPE_TMP_BUFFER);
+    if (ocspRequest == NULL) {
+        WOLFSSL_LEAVE("CheckCertOCSP", MEMORY_ERROR);
+        return MEMORY_E;
+    }
+#endif
+
+    if (InitOcspRequest(ocspRequest, cert, ocsp->cm->ocspSendNonce,
+                                                         ocsp->cm->heap) == 0) {
+        ret = CheckOcspResponse(ocsp, response, responseSz, NULL, NULL, NULL,
+                ocspRequest, heap);
+        FreeOcspRequest(ocspRequest);
+    }
+
+#ifdef WOLFSSL_SMALL_STACK
+    XFREE(ocspRequest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
+#endif
+
+    WOLFSSL_LEAVE("CheckCertOCSP", ret);
+    return ret;
+}
+
 int InitOCSP(WOLFSSL_OCSP* ocsp, WOLFSSL_CERT_MANAGER* cm)
 {
     WOLFSSL_ENTER("InitOCSP");
@@ -375,7 +421,7 @@ int CheckOcspResponse(WOLFSSL_OCSP *ocsp, byte *response, int responseSz,
         ocspResponse->single->status->next = status->next;
         XMEMCPY(status, ocspResponse->single->status, sizeof(CertStatus));
     }
-    else {
+    else if (entry != NULL) {
         /* Save new certificate entry */
         status = (CertStatus*)XMALLOC(sizeof(CertStatus),
                                       ocsp->cm->heap, DYNAMIC_TYPE_OCSP_STATUS);