From f3b7dcc5bdd5b2b02e12133a0d8e16a75844f766 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Wed, 22 Feb 2017 17:35:11 +0100
Subject: [PATCH] common/hexutil: reject big integer inputs > 256 bits
This follows the change to common/math big integer parsing in PR #3699.
---
common/hexutil/hexutil.go | 5 +++++
common/hexutil/hexutil_test.go | 8 ++++++++
common/hexutil/json.go | 12 +++++++++---
common/hexutil/json_test.go | 8 ++++++++
4 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/common/hexutil/hexutil.go b/common/hexutil/hexutil.go
index 4ec0ee8e6..16863f6c0 100644
--- a/common/hexutil/hexutil.go
+++ b/common/hexutil/hexutil.go
@@ -49,6 +49,7 @@ var (
ErrOddLength = errors.New("hex string has odd length")
ErrUint64Range = errors.New("hex number does not fit into 64 bits")
ErrUintRange = fmt.Errorf("hex number does not fit into %d bits", uintBits)
+ ErrBig256Range = errors.New("hex number does not fit into 256 bits")
)
// Decode decodes a hex string with 0x prefix.
@@ -126,11 +127,15 @@ func init() {
}
// DecodeBig decodes a hex string with 0x prefix as a quantity.
+// Numbers larger than 256 bits are not accepted.
func DecodeBig(input string) (*big.Int, error) {
raw, err := checkNumber(input)
if err != nil {
return nil, err
}
+ if len(raw) > 64 {
+ return nil, ErrBig256Range
+ }
words := make([]big.Word, len(raw)/bigWordNibbles+1)
end := len(raw)
for i := range words {
diff --git a/common/hexutil/hexutil_test.go b/common/hexutil/hexutil_test.go
index 324e9d348..68d8a40e0 100644
--- a/common/hexutil/hexutil_test.go
+++ b/common/hexutil/hexutil_test.go
@@ -83,6 +83,10 @@ var (
{input: `0x01`, wantErr: ErrLeadingZero},
{input: `0xx`, wantErr: ErrSyntax},
{input: `0x1zz01`, wantErr: ErrSyntax},
+ {
+ input: `0x10000000000000000000000000000000000000000000000000000000000000000`,
+ wantErr: ErrBig256Range,
+ },
// valid
{input: `0x0`, want: big.NewInt(0)},
{input: `0x2`, want: big.NewInt(0x2)},
@@ -99,6 +103,10 @@ var (
input: `0xffffffffffffffffffffffffffffffffffff`,
want: referenceBig("ffffffffffffffffffffffffffffffffffff"),
},
+ {
+ input: `0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff`,
+ want: referenceBig("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+ },
}
decodeUint64Tests = []unmarshalTest{
diff --git a/common/hexutil/json.go b/common/hexutil/json.go
index 7e4736dd6..6174d6256 100644
--- a/common/hexutil/json.go
+++ b/common/hexutil/json.go
@@ -91,9 +91,12 @@ func UnmarshalJSON(typname string, input, out []byte) error {
return nil
}
-// Big marshals/unmarshals as a JSON string with 0x prefix. The zero value marshals as
-// "0x0". Negative integers are not supported at this time. Attempting to marshal them
-// will return an error.
+// Big marshals/unmarshals as a JSON string with 0x prefix.
+// The zero value marshals as "0x0".
+//
+// Negative integers are not supported at this time. Attempting to marshal them will
+// return an error. Values larger than 256bits are rejected by Unmarshal but will be
+// marshaled without error.
type Big big.Int
// MarshalJSON implements json.Marshaler.
@@ -119,6 +122,9 @@ func (b *Big) UnmarshalJSON(input []byte) error {
if err != nil {
return err
}
+ if len(raw) > 64 {
+ return ErrBig256Range
+ }
words := make([]big.Word, len(raw)/bigWordNibbles+1)
end := len(raw)
for i := range words {
diff --git a/common/hexutil/json_test.go b/common/hexutil/json_test.go
index 290bf9ca2..c7fde0adb 100644
--- a/common/hexutil/json_test.go
+++ b/common/hexutil/json_test.go
@@ -130,6 +130,10 @@ var unmarshalBigTests = []unmarshalTest{
{input: `"0x01"`, wantErr: ErrLeadingZero},
{input: `"0xx"`, wantErr: ErrSyntax},
{input: `"0x1zz01"`, wantErr: ErrSyntax},
+ {
+ input: `"0x10000000000000000000000000000000000000000000000000000000000000000"`,
+ wantErr: ErrBig256Range,
+ },
// valid encoding
{input: `""`, want: big.NewInt(0)},
@@ -148,6 +152,10 @@ var unmarshalBigTests = []unmarshalTest{
input: `"0xffffffffffffffffffffffffffffffffffff"`,
want: referenceBig("ffffffffffffffffffffffffffffffffffff"),
},
+ {
+ input: `"0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"`,
+ want: referenceBig("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+ },
}
func TestUnmarshalBig(t *testing.T) {
--
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