--- /dev/null
+From ea5c290d605b2af7b10d6e5ce69aa3534f52385f Mon Sep 17 00:00:00 2001
+From: Eric Blankenhorn <eric@wolfssl.com>
+Date: Fri, 17 Jul 2020 08:37:02 -0500
+Subject: [PATCH] Fix CheckHostName matching
+
+---
+ src/internal.c | 18 ++++++++++++------
+ src/ssl.c | 5 +++++
+ tests/api.c | 30 ++++++++++++++++++++++++++++++
+ 3 files changed, 47 insertions(+), 6 deletions(-)
+
+diff --git a/src/internal.c b/src/internal.c
+index dc57df0242..cda815d875 100644
+--- a/src/internal.c
++++ b/src/internal.c
+@@ -9346,7 +9346,7 @@ int CheckForAltNames(DecodedCert* dCert, const char* domain, int* checkCN)
+ altName = dCert->altNames;
+
+ if (checkCN != NULL) {
+- *checkCN = altName == NULL;
++ *checkCN = (altName == NULL) ? 1 : 0;
+ }
+
+ while (altName) {
+@@ -9415,23 +9415,29 @@ int CheckForAltNames(DecodedCert* dCert, const char* domain, int* checkCN)
+ int CheckHostName(DecodedCert* dCert, const char *domainName, size_t domainNameLen)
+ {
+ int checkCN;
++ int ret = DOMAIN_NAME_MISMATCH;
+
+ /* Assume name is NUL terminated. */
+ (void)domainNameLen;
+
+ if (CheckForAltNames(dCert, domainName, &checkCN) != 1) {
+- WOLFSSL_MSG("DomainName match on alt names failed too");
+- return DOMAIN_NAME_MISMATCH;
++ WOLFSSL_MSG("DomainName match on alt names failed");
+ }
++ else {
++ ret = 0;
++ }
++
+ if (checkCN == 1) {
+ if (MatchDomainName(dCert->subjectCN, dCert->subjectCNLen,
+- domainName) == 0) {
++ domainName) == 1) {
++ ret = 0;
++ }
++ else {
+ WOLFSSL_MSG("DomainName match on common name failed");
+- return DOMAIN_NAME_MISMATCH;
+ }
+ }
+
+- return 0;
++ return ret;
+ }
+
+ int CheckIPAddr(DecodedCert* dCert, const char* ipasc)
+diff --git a/src/ssl.c b/src/ssl.c
+index 11bc08a3cb..59ad9bae60 100644
+--- a/src/ssl.c
++++ b/src/ssl.c
+@@ -43661,6 +43661,11 @@ int wolfSSL_X509_check_host(WOLFSSL_X509 *x, const char *chk, size_t chklen,
+ (void)flags;
+ (void)peername;
+
++ if ((x == NULL) || (chk == NULL)) {
++ WOLFSSL_MSG("Invalid parameter");
++ return WOLFSSL_FAILURE;
++ }
++
+ if (flags == WOLFSSL_NO_WILDCARDS) {
+ WOLFSSL_MSG("X509_CHECK_FLAG_NO_WILDCARDS not yet implemented");
+ return WOLFSSL_FAILURE;
+diff --git a/tests/api.c b/tests/api.c
+index 774a332968..db888952d4 100644
+--- a/tests/api.c
++++ b/tests/api.c
+@@ -23875,6 +23875,35 @@ static void test_wolfSSL_X509_issuer_name_hash(void)
+ #endif
+ }
+
++static void test_wolfSSL_X509_check_host(void)
++{
++#if defined(OPENSSL_EXTRA) && !defined(NO_CERTS) && !defined(NO_FILESYSTEM) \
++ && !defined(NO_SHA) && !defined(NO_RSA)
++
++ X509* x509;
++ const char altName[] = "example.com";
++
++ printf(testingFmt, "wolfSSL_X509_check_host()");
++
++ AssertNotNull(x509 = wolfSSL_X509_load_certificate_file(cliCertFile,
++ SSL_FILETYPE_PEM));
++
++ AssertIntEQ(X509_check_host(x509, altName, XSTRLEN(altName), 0, NULL),
++ WOLFSSL_SUCCESS);
++
++ AssertIntEQ(X509_check_host(x509, NULL, 0, 0, NULL),
++ WOLFSSL_FAILURE);
++
++ X509_free(x509);
++
++ AssertIntEQ(X509_check_host(NULL, altName, XSTRLEN(altName), 0, NULL),
++ WOLFSSL_FAILURE);
++
++ printf(resultFmt, passed);
++
++#endif
++}
++
+ static void test_wolfSSL_DES(void)
+ {
+ #if defined(OPENSSL_EXTRA) && !defined(NO_DES3)
+@@ -36407,6 +36436,7 @@ void ApiTest(void)
+ test_wolfSSL_X509_INFO();
+ test_wolfSSL_X509_subject_name_hash();
+ test_wolfSSL_X509_issuer_name_hash();
++ test_wolfSSL_X509_check_host();
+ test_wolfSSL_DES();
+ test_wolfSSL_certs();
+ test_wolfSSL_ASN1_TIME_print();