update build and update NULL salt usecase

IDE/iotsafe-raspberrypi/Makefile

@@ -3,6 +3,9 @@ CINCS  := -I. -I/usr/local/wolfssl
 CLIBS  := -L/usr/local/lib
 CDEPS  := -lc -lg -lm -lwolfssl
 
+WOLFSSL_BUILD=build
+MKDIR_P = mkdir -p
+
 ENABLE_DEBUG_UART_IO       := off
 ENABLE_DEBUG_UART_IO_EXTRA := off
 ENABLE_SECRET_CALLBACK     := off
@@ -19,7 +22,7 @@ ifeq ($(ENABLE_SECRET_CALLBACK), on)
 	CFLAGS+=-DUSE_SECRET_CALLBACK
 endif
 
-OBJS:=main.o client-tls13.o
+OBJS:=$(WOLFSSL_BUILD)/main.o $(WOLFSSL_BUILD)/client-tls13.o
 
 .PHONY: all clean help
 
@@ -57,16 +60,22 @@ endef
 help:
 	@$(run-help)
 
-all: main.bin
+all: directories main.bin
+
+directories: $(WOLFSSL_BUILD)
+
+$(WOLFSSL_BUILD):
+	${MKDIR_P} $(WOLFSSL_BUILD)
 
 main.bin: $(OBJS)
 	$(CC) $(CFLAGS) $(CINCS) $(CLIBS) -o $@ $^ $(CDEPS)
 
-main.o: main.c
+$(WOLFSSL_BUILD)/main.o: main.c
 	$(CC) $(CFLAGS) $(CINCS) $(CLIBS) -c -o $@ $^ $(CDEPS)
 
-client-tls13.o: client-tls13.c
+$(WOLFSSL_BUILD)/client-tls13.o: client-tls13.c
 	$(CC) $(CFLAGS) $(CINCS) $(CLIBS) -c -o $@ $^ $(CDEPS)
 
 clean:
 	rm -f *.o *.bin
+	rm -rf build

IDE/iotsafe-raspberrypi/include.am

@@ -0,0 +1,9 @@
+# vim:ft=automake
+# All paths should be given relative to the root
+
+EXTRA_DIST += IDE/iotsafe-raspberrypi/README.md
+EXTRA_DIST += IDE/iotsafe-raspberrypi/Makefile
+EXTRA_DIST += IDE/iotsafe-raspberrypi/main.c
+EXTRA_DIST += IDE/iotsafe-raspberrypi/client-tls13.c
+
+DISTCLEANFILES+= IDE/iotsafe-raspberrypi/build

wolfcrypt/src/port/iotsafe/iotsafe.c

@@ -1047,25 +1047,29 @@ static int wolfIoT_hkdf_extract(byte* prk, const byte* salt, word32 saltLen,
 {
     (void)ctx;
     int ret;
+    const  byte* localSalt;  /* either points to user input or tmp */
+    byte tmp[WC_MAX_DIGEST_SIZE]; /* localSalt helper */
 
     WOLFSSL_MSG("IOTSAFE: Called wolfIoT_hkdf_extract\n");
 
-    if(saltLen != 0){
+    localSalt = salt;
-         ret = iotsafe_hkdf_extract(prk, salt, saltLen, ikm, ikmLen, digest);
-    }
-    else{
-         #ifdef DEBUG_IOTSAFE
-        printf("SALT is NULL, not supported by IoT Safe Applet, fallback to software implementation\n");
-        #endif
-        ret = wc_Tls13_HKDF_Extract(prk, salt, saltLen, ikm, ikmLen, digest);
-    }     
-    return ret;
 
+    if(saltLen == 0) {
+        ret = wc_HmacSizeByType(digest);
+            if (ret < 0)
+                return ret;
+            saltLen = ret;
+            if (localSalt == NULL) {
+                XMEMSET(tmp, 0, saltLen);
+                localSalt = tmp;
+            }
+    }
+    
+    ret = iotsafe_hkdf_extract(prk, localSalt, saltLen, ikm, ikmLen, digest);    
+    return ret;
 }       
 #endif
 
-
-
 static int wolfIoT_ecc_sign(WOLFSSL* ssl,
        const unsigned char* in, unsigned int inSz,
        unsigned char* out, word32* outSz,