Merge pull request yuin#332 from tongson/fix_select

Detect invalid argument indexing.

Author: yuin

_glua-tests/issues.lua

@@ -330,4 +330,33 @@ function test()
 	t6.sec = "5"
 	assert(os.time(t1) == os.time(t6))
 end
-test()
+test()
+
+--issue #331
+function test()
+	local select_a = function()
+		return select(3, "1")
+	end
+	assert(true == pcall(select_a))
+	local select_b = function()
+		return select(0)
+	end
+	assert(false == pcall(select_b))
+	local select_c = function()
+		return select(1/9)
+	end
+	assert(false == pcall(select_c))
+	local select_d = function()
+		return select(1, "a")
+	end
+	assert("a" == select_d())
+	local select_e = function()
+		return select(3, "a", "b", "c")
+	end
+	assert("c" == select_e())
+	local select_f = function()
+		return select(0)(select(1/9))
+	end
+	assert(false == pcall(select_f))
+end
+test()

baselib.go

@@ -321,11 +321,16 @@ func baseSelect(L *LState) int {
 	switch lv := L.Get(1).(type) {
 	case LNumber:
 		idx := int(lv)
-		num := L.reg.Top() - L.indexToReg(int(lv)) - 1
+		num := L.GetTop()
 		if idx < 0 {
-			num++
+			idx = num + idx
+		} else if idx > num {
+			idx = num
 		}
-		return num
+		if 1 > idx {
+			L.ArgError(1, "index out of range")
+		}
+		return num - idx
 	case LString:
 		if string(lv) != "#" {
 			L.ArgError(1, "invalid string '"+string(lv)+"'")