Various fixes for dual algorithm certificates (#7577)

This commit adds varios fixes for the implementation of hybrid
certificates with two algorithms:
* Support for Certificate Signing Requests (both creating hybrid ones
  and also verifying ones)
* Fix for SAN fields in the DecodedCert and PreTBS generation
* Fix related to WOLFSSL_SMALL_STACK

Signed-off-by: Tobias Frauenschläger <t.frauenschlaeger@me.com>

src/x509.c

@@ -7526,11 +7526,24 @@ int wolfSSL_i2d_X509(WOLFSSL_X509* x509, unsigned char** out)
 int wc_GeneratePreTBS(DecodedCert* cert, byte *der, int derSz) {
  int ret = 0;
  WOLFSSL_X509 *x = NULL;
+ byte certOwnsAltNames = 0;
+ byte certIsCSR = 0;
 
  if ((cert == NULL) || (der == NULL) || (derSz <= 0)) {
  return BAD_FUNC_ARG;
  }
 
+ /* The call to CopyDecodedToX509() transfers ownership of the altNames in
+ * the DecodedCert to the temporary X509 object, causing the list to be
+ * freed in wolfSSL_X509_free(). As this is an unintended side-effect, we
+ * have to save the ownerFlag here and transfer ownership back to the
+ * DecodedCert prior to freeing the X509 object. */
+ certOwnsAltNames = cert->weOwnAltNames;
+
+#ifdef WOLFSSL_CERT_REQ
+ certIsCSR = cert->isCSR;
+#endif
+
  x = wolfSSL_X509_new();
  if (x == NULL) {
  ret = MEMORY_E;
@@ -7539,6 +7552,9 @@ int wc_GeneratePreTBS(DecodedCert* cert, byte *der, int derSz) {
  ret = CopyDecodedToX509(x, cert);
  }
 
+ /* CopyDecodedToX509() clears cert->weOwnAltNames. Restore it. */
+ cert->weOwnAltNames = certOwnsAltNames;
+
  if (ret == 0) {
  /* Remove the altsigval extension. */
  XFREE(x->altSigValDer, x->heap, DYNAMIC_TYPE_X509_EXT);
@@ -7547,13 +7563,16 @@ int wc_GeneratePreTBS(DecodedCert* cert, byte *der, int derSz) {
  /* Remove sigOID so it won't be encoded. */
  x->sigOID = 0;
  /* We now have a PreTBS. Encode it. */
- ret = wolfssl_x509_make_der(x, 0, der, &derSz, 0);
+ ret = wolfssl_x509_make_der(x, certIsCSR, der, &derSz, 0);
  if (ret == WOLFSSL_SUCCESS) {
  ret = derSz;
  }
  }
 
  if (x != NULL) {
+ /* Safe the altNames list from being freed unitentionally. */
+ x->altNames = NULL;
+
  wolfSSL_X509_free(x);
  }
 

wolfcrypt/src/asn.c

@@ -23864,13 +23864,12 @@ int ParseCertRelative(DecodedCert* cert, int type, int verify, void* cm)
  #ifndef WOLFSSL_SMALL_STACK
  byte der[MAX_CERT_VERIFY_SZ];
  #else
- byte *der = (byte*)XMALLOC(MAX_CERT_VERIFY_SZ, ssl->heap,
+ byte *der = (byte*)XMALLOC(MAX_CERT_VERIFY_SZ, cert->heap,
  DYNAMIC_TYPE_DCERT);
  if (der == NULL) {
  ret = MEMORY_E;
  } else
  #endif /* ! WOLFSSL_SMALL_STACK */
-
  {
  ret = wc_GeneratePreTBS(cert, der, MAX_CERT_VERIFY_SZ);
 
@@ -23882,7 +23881,7 @@ int ParseCertRelative(DecodedCert* cert, int type, int verify, void* cm)
  NULL, 0, NULL);
  }
  #ifdef WOLFSSL_SMALL_STACK
- XFREE(der, ssl->heap, DYNAMIC_TYPE_DCERT);
+ XFREE(der, cert->heap, DYNAMIC_TYPE_DCERT);
  #endif /* WOLFSSL_SMALL_STACK */
 
  if (ret != 0) {
@@ -23912,6 +23911,7 @@ int ParseCertRelative(DecodedCert* cert, int type, int verify, void* cm)
  }
 #ifdef WOLFSSL_CERT_REQ
  else if (type == CERTREQ_TYPE) {
+ /* try to confirm/verify signature */
  if ((ret = ConfirmSignature(&cert->sigCtx,
  cert->source + cert->certBegin,
  cert->sigIndex - cert->certBegin,
@@ -23930,6 +23930,44 @@ int ParseCertRelative(DecodedCert* cert, int type, int verify, void* cm)
  WOLFSSL_ERROR_VERBOSE(ret);
  return ret;
  }
+
+ #ifdef WOLFSSL_DUAL_ALG_CERTS
+ if ((ret == 0) && cert->extAltSigAlgSet &&
+ cert->extAltSigValSet) {
+ #ifndef WOLFSSL_SMALL_STACK
+ byte der[MAX_CERT_VERIFY_SZ];
+ #else
+ byte *der = (byte*)XMALLOC(MAX_CERT_VERIFY_SZ, cert->heap,
+ DYNAMIC_TYPE_DCERT);
+ if (der == NULL) {
+ ret = MEMORY_E;
+ } else
+ #endif /* ! WOLFSSL_SMALL_STACK */
+ {
+ ret = wc_GeneratePreTBS(cert, der, MAX_CERT_VERIFY_SZ);
+
+ if (ret > 0) {
+ ret = ConfirmSignature(&cert->sigCtx, der, ret,
+ cert->sapkiDer, cert->sapkiLen,
+ cert->sapkiOID, cert->altSigValDer,
+ cert->altSigValLen, cert->altSigAlgOID,
+ NULL, 0, NULL);
+ }
+ #ifdef WOLFSSL_SMALL_STACK
+ XFREE(der, cert->heap, DYNAMIC_TYPE_DCERT);
+ #endif /* WOLFSSL_SMALL_STACK */
+
+ if (ret != 0) {
+ WOLFSSL_MSG("Confirm alternative signature failed");
+ WOLFSSL_ERROR_VERBOSE(ret);
+ return ret;
+ }
+ else {
+ WOLFSSL_MSG("Alt signature has been verified!");
+ }
+ }
+ }
+ #endif /* WOLFSSL_DUAL_ALG_CERTS */
  }
 #endif
  else {