From 5988e567fbf69bccfbcce5cea4d16e83ac3ccec1 Mon Sep 17 00:00:00 2001
From: siddontang <siddontang@gmail.com>
Date: Mon, 21 Sep 2015 12:30:15 +0800
Subject: [PATCH] types: check overflow for bit type

---
 util/types/convert.go      | 21 ++++++++++++++++++++-
 util/types/convert_test.go | 13 +++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/util/types/convert.go b/util/types/convert.go
index 3ef0470549..edf9ddc4ed 100644
--- a/util/types/convert.go
+++ b/util/types/convert.go
@@ -370,7 +370,26 @@ func Convert(val interface{}, target *FieldType) (v interface{}, err error) { //
 		}
 		return convertToInt(val, target)
 	case mysql.TypeBit:
-		return convertToUint(val, target)
+		x, err := convertToUint(val, target)
+		if err != nil {
+			return x, errors.Trace(err)
+		}
+
+		// check bit boundary, if bit has n width, the boundary is
+		// in [0, (1 << n) - 1]
+		width := target.Flen
+		if width == 0 {
+			width = mysql.MinBitWidth
+		} else if width == mysql.UnspecifiedBitWidth {
+			width = mysql.MaxBitWidth
+		}
+
+		maxValue := uint64(1)<<uint64(width) - 1
+
+		if x > maxValue {
+			return maxValue, overflow(val, tp)
+		}
+		return x, nil
 	case mysql.TypeDecimal, mysql.TypeNewDecimal:
 		x, err := ToDecimal(val)
 		if err != nil {
diff --git a/util/types/convert_test.go b/util/types/convert_test.go
index 89ace25281..ba8cabbe48 100644
--- a/util/types/convert_test.go
+++ b/util/types/convert_test.go
@@ -169,6 +169,7 @@ func (s *testTypeConvertSuite) TestConvertType(c *C) {
 
 	// For TypeBit
 	ft = NewFieldType(mysql.TypeBit)
+	ft.Flen = 8
 	v, err = Convert("100", ft)
 	c.Assert(err, IsNil)
 	c.Assert(v, Equals, uint64(100))
@@ -181,6 +182,18 @@ func (s *testTypeConvertSuite) TestConvertType(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(v, Equals, uint64(100))
 
+	ft.Flen = 1
+	v, err = Convert(1, ft)
+	c.Assert(err, IsNil)
+	c.Assert(v, Equals, uint64(1))
+
+	_, err = Convert(2, ft)
+	c.Assert(err, NotNil)
+
+	ft.Flen = 0
+	_, err = Convert(2, ft)
+	c.Assert(err, NotNil)
+
 	// For TypeNewDecimal
 	ft = NewFieldType(mysql.TypeNewDecimal)
 	ft.Decimal = 5