diff --git a/winpr/libwinpr/sspi/CredSSP/credssp.c b/winpr/libwinpr/sspi/CredSSP/credssp.c
index f6d5e2579..091f6d9e7 100644
--- a/winpr/libwinpr/sspi/CredSSP/credssp.c
+++ b/winpr/libwinpr/sspi/CredSSP/credssp.c
@@ -28,24 +28,25 @@
 
 #include "../sspi.h"
 
-char* CREDSSP_PACKAGE_NAME = "CredSSP";
+static const char* CREDSSP_PACKAGE_NAME = "CredSSP";
 
-SECURITY_STATUS SEC_ENTRY credssp_InitializeSecurityContextW(PCredHandle phCredential, PCtxtHandle phContext,
-		SEC_WCHAR* pszTargetName, ULONG fContextReq, ULONG Reserved1, ULONG TargetDataRep,
-		PSecBufferDesc pInput, ULONG Reserved2, PCtxtHandle phNewContext,
-		PSecBufferDesc pOutput, PULONG pfContextAttr, PTimeStamp ptsExpiry)
+static SECURITY_STATUS SEC_ENTRY credssp_InitializeSecurityContextW(PCredHandle phCredential,
+        PCtxtHandle phContext,
+        SEC_WCHAR* pszTargetName, ULONG fContextReq, ULONG Reserved1, ULONG TargetDataRep,
+        PSecBufferDesc pInput, ULONG Reserved2, PCtxtHandle phNewContext,
+        PSecBufferDesc pOutput, PULONG pfContextAttr, PTimeStamp ptsExpiry)
 {
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_InitializeSecurityContextA(PCredHandle phCredential, PCtxtHandle phContext,
-		SEC_CHAR* pszTargetName, ULONG fContextReq, ULONG Reserved1, ULONG TargetDataRep,
-		PSecBufferDesc pInput, ULONG Reserved2, PCtxtHandle phNewContext,
-		PSecBufferDesc pOutput, PULONG pfContextAttr, PTimeStamp ptsExpiry)
+static SECURITY_STATUS SEC_ENTRY credssp_InitializeSecurityContextA(PCredHandle phCredential,
+        PCtxtHandle phContext,
+        SEC_CHAR* pszTargetName, ULONG fContextReq, ULONG Reserved1, ULONG TargetDataRep,
+        PSecBufferDesc pInput, ULONG Reserved2, PCtxtHandle phNewContext,
+        PSecBufferDesc pOutput, PULONG pfContextAttr, PTimeStamp ptsExpiry)
 {
 	CREDSSP_CONTEXT* context;
 	SSPI_CREDENTIALS* credentials;
-
 	context = (CREDSSP_CONTEXT*) sspi_SecureHandleGetLowerPointer(phContext);
 
 	if (!context)
@@ -57,6 +58,12 @@ SECURITY_STATUS SEC_ENTRY credssp_InitializeSecurityContextA(PCredHandle phCrede
 
 		credentials = (SSPI_CREDENTIALS*) sspi_SecureHandleGetLowerPointer(phCredential);
 
+		if (!credentials)
+		{
+			credssp_ContextFree(context);
+			return SEC_E_INVALID_HANDLE;
+		}
+
 		sspi_SecureHandleSetLowerPointer(phNewContext, context);
 		sspi_SecureHandleSetUpperPointer(phNewContext, (void*) CREDSSP_PACKAGE_NAME);
 	}
@@ -64,10 +71,9 @@ SECURITY_STATUS SEC_ENTRY credssp_InitializeSecurityContextA(PCredHandle phCrede
 	return SEC_E_OK;
 }
 
-CREDSSP_CONTEXT* credssp_ContextNew()
+CREDSSP_CONTEXT* credssp_ContextNew(void)
 {
 	CREDSSP_CONTEXT* context;
-
 	context = (CREDSSP_CONTEXT*) calloc(1, sizeof(CREDSSP_CONTEXT));
 
 	if (!context)
@@ -81,7 +87,9 @@ void credssp_ContextFree(CREDSSP_CONTEXT* context)
 	free(context);
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_QueryContextAttributes(PCtxtHandle phContext, ULONG ulAttribute, void* pBuffer)
+static SECURITY_STATUS SEC_ENTRY credssp_QueryContextAttributes(PCtxtHandle phContext,
+        ULONG ulAttribute,
+        void* pBuffer)
 {
 	if (!phContext)
 		return SEC_E_INVALID_HANDLE;
@@ -92,16 +100,18 @@ SECURITY_STATUS SEC_ENTRY credssp_QueryContextAttributes(PCtxtHandle phContext,
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_AcquireCredentialsHandleW(SEC_WCHAR* pszPrincipal, SEC_WCHAR* pszPackage,
-		ULONG fCredentialUse, void* pvLogonID, void* pAuthData, SEC_GET_KEY_FN pGetKeyFn,
-		void* pvGetKeyArgument, PCredHandle phCredential, PTimeStamp ptsExpiry)
+SECURITY_STATUS SEC_ENTRY credssp_AcquireCredentialsHandleW(SEC_WCHAR* pszPrincipal,
+        SEC_WCHAR* pszPackage,
+        ULONG fCredentialUse, void* pvLogonID, void* pAuthData, SEC_GET_KEY_FN pGetKeyFn,
+        void* pvGetKeyArgument, PCredHandle phCredential, PTimeStamp ptsExpiry)
 {
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_AcquireCredentialsHandleA(SEC_CHAR* pszPrincipal, SEC_CHAR* pszPackage,
-		ULONG fCredentialUse, void* pvLogonID, void* pAuthData, SEC_GET_KEY_FN pGetKeyFn,
-		void* pvGetKeyArgument, PCredHandle phCredential, PTimeStamp ptsExpiry)
+static SECURITY_STATUS SEC_ENTRY credssp_AcquireCredentialsHandleA(SEC_CHAR* pszPrincipal,
+        SEC_CHAR* pszPackage,
+        ULONG fCredentialUse, void* pvLogonID, void* pAuthData, SEC_GET_KEY_FN pGetKeyFn,
+        void* pvGetKeyArgument, PCredHandle phCredential, PTimeStamp ptsExpiry)
 {
 	SSPI_CREDENTIALS* credentials;
 	SEC_WINNT_AUTH_IDENTITY* identity;
@@ -114,30 +124,30 @@ SECURITY_STATUS SEC_ENTRY credssp_AcquireCredentialsHandleA(SEC_CHAR* pszPrincip
 			return SEC_E_INSUFFICIENT_MEMORY;
 
 		identity = (SEC_WINNT_AUTH_IDENTITY*) pAuthData;
-
 		CopyMemory(&(credentials->identity), identity, sizeof(SEC_WINNT_AUTH_IDENTITY));
-
 		sspi_SecureHandleSetLowerPointer(phCredential, (void*) credentials);
 		sspi_SecureHandleSetUpperPointer(phCredential, (void*) CREDSSP_PACKAGE_NAME);
-
 		return SEC_E_OK;
 	}
 
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_QueryCredentialsAttributesW(PCredHandle phCredential, ULONG ulAttribute, void* pBuffer)
+static SECURITY_STATUS SEC_ENTRY credssp_QueryCredentialsAttributesW(PCredHandle phCredential,
+        ULONG ulAttribute, void* pBuffer)
 {
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_QueryCredentialsAttributesA(PCredHandle phCredential, ULONG ulAttribute, void* pBuffer)
+static SECURITY_STATUS SEC_ENTRY credssp_QueryCredentialsAttributesA(PCredHandle phCredential,
+        ULONG ulAttribute, void* pBuffer)
 {
 	if (ulAttribute == SECPKG_CRED_ATTR_NAMES)
 	{
-		SSPI_CREDENTIALS* credentials;
+		SSPI_CREDENTIALS* credentials = (SSPI_CREDENTIALS*) sspi_SecureHandleGetLowerPointer(phCredential);
 
-		credentials = (SSPI_CREDENTIALS*) sspi_SecureHandleGetLowerPointer(phCredential);
+		if (!credentials)
+			return SEC_E_INVALID_HANDLE;
 
 		return SEC_E_OK;
 	}
@@ -145,7 +155,7 @@ SECURITY_STATUS SEC_ENTRY credssp_QueryCredentialsAttributesA(PCredHandle phCred
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_FreeCredentialsHandle(PCredHandle phCredential)
+static SECURITY_STATUS SEC_ENTRY credssp_FreeCredentialsHandle(PCredHandle phCredential)
 {
 	SSPI_CREDENTIALS* credentials;
 
@@ -158,26 +168,31 @@ SECURITY_STATUS SEC_ENTRY credssp_FreeCredentialsHandle(PCredHandle phCredential
 		return SEC_E_INVALID_HANDLE;
 
 	sspi_CredentialsFree(credentials);
-
 	return SEC_E_OK;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_EncryptMessage(PCtxtHandle phContext, ULONG fQOP, PSecBufferDesc pMessage, ULONG MessageSeqNo)
+static SECURITY_STATUS SEC_ENTRY credssp_EncryptMessage(PCtxtHandle phContext, ULONG fQOP,
+        PSecBufferDesc pMessage, ULONG MessageSeqNo)
 {
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_DecryptMessage(PCtxtHandle phContext, PSecBufferDesc pMessage, ULONG MessageSeqNo, ULONG* pfQOP)
+static SECURITY_STATUS SEC_ENTRY credssp_DecryptMessage(PCtxtHandle phContext,
+        PSecBufferDesc pMessage,
+        ULONG MessageSeqNo, ULONG* pfQOP)
 {
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_MakeSignature(PCtxtHandle phContext, ULONG fQOP, PSecBufferDesc pMessage, ULONG MessageSeqNo)
+static SECURITY_STATUS SEC_ENTRY credssp_MakeSignature(PCtxtHandle phContext, ULONG fQOP,
+        PSecBufferDesc pMessage, ULONG MessageSeqNo)
 {
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
 
-SECURITY_STATUS SEC_ENTRY credssp_VerifySignature(PCtxtHandle phContext, PSecBufferDesc pMessage, ULONG MessageSeqNo, ULONG* pfQOP)
+static SECURITY_STATUS SEC_ENTRY credssp_VerifySignature(PCtxtHandle phContext,
+        PSecBufferDesc pMessage,
+        ULONG MessageSeqNo, ULONG* pfQOP)
 {
 	return SEC_E_UNSUPPORTED_FUNCTION;
 }
@@ -256,14 +271,14 @@ const SecPkgInfoA CREDSSP_SecPkgInfoA =
 	"Microsoft CredSSP Security Provider" /* Comment */
 };
 
-WCHAR CREDSSP_SecPkgInfoW_Name[] = { 'C','R','E','D','S','S','P','\0' };
+static WCHAR CREDSSP_SecPkgInfoW_Name[] = { 'C', 'R', 'E', 'D', 'S', 'S', 'P', '\0' };
 
-WCHAR CREDSSP_SecPkgInfoW_Comment[] =
+static WCHAR CREDSSP_SecPkgInfoW_Comment[] =
 {
-	'M','i','c','r','o','s','o','f','t',' ',
-	'C','r','e','d','S','S','P',' ',
-	'S','e','c','u','r','i','t','y',' ',
-	'P','r','o','v','i','d','e','r','\0'
+	'M', 'i', 'c', 'r', 'o', 's', 'o', 'f', 't', ' ',
+	'C', 'r', 'e', 'd', 'S', 'S', 'P', ' ',
+	'S', 'e', 'c', 'u', 'r', 'i', 't', 'y', ' ',
+	'P', 'r', 'o', 'v', 'i', 'd', 'e', 'r', '\0'
 };
 
 const SecPkgInfoW CREDSSP_SecPkgInfoW =