FIX: prevent too many refinements in now function

fixes: Oldes/Rebol-issues#2286

Author: Oldes

src/core/f-stubs.c

@@ -269,6 +269,25 @@
 	return result;
 }
 
+/***********************************************************************
+**
+*/	void Assert_Max_Refines(REBVAL *ds, REBCNT limit)
+/*
+**		Scans the stack for function refinements
+**		and throw an error if exeeds given limit
+**
+***********************************************************************/
+{
+	REBINT n;
+	REBCNT count=0;
+	REBINT len = DS_ARGC;
+
+	for (n = 1; n <= len; n++) {
+		if (D_REF(n))
+			if(count++ == limit) Trap0(RE_BAD_REFINES);
+	}
+}
+
 
 /***********************************************************************
 **

src/core/n-io.c

@@ -237,6 +237,8 @@ static REBSER *Read_All_File(char *fname)
 	REBINT n = -1;
 	REBVAL *ret = D_RET;
 
+	Assert_Max_Refines(ds, D_REF(9) ? 2 : 1); // prevent too many refines like: now/year/month
+
 	OS_GET_TIME(&dat);
 	if (!D_REF(9)) dat.nano = 0; // Not /precise
 	Set_Date(ret, &dat);

src/tests/units/date-test.r3

@@ -151,4 +151,31 @@ Rebol [
 
 ===end-group===
 
+
+===start-group=== "NOW"
+	--test-- "now"
+ 		--assert integer? now/year
+        --assert integer? now/month
+        --assert integer? now/day
+        --assert time?    now/time
+        --assert time?    now/zone
+        --assert date?    now/date
+        --assert integer? now/weekday
+        --assert integer? now/yearday
+        --assert date?    now/utc
+        
+    --test-- "now/precise"
+    	--assert time?    now/time/precise
+    	--assert date?    now/utc/precise
+        --assert date?    now/precise
+        --assert integer? now/year/precise ; precise ignored
+
+	--test-- "now with too many refines"
+	;@@ https://github.com/Oldes/Rebol-issues/issues/2286
+		--assert error? try [now/time/day]
+		--assert error? try [now/time/day/precise]
+		--assert error? try [now/utc/month]
+
+===end-group===
+
 ~~~end-file~~~