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RIN-02 Panic Due to Integer Overflow in Signature Size Calculation #401

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Merged
merged 5 commits into from
Feb 3, 2024
Merged

RIN-02 Panic Due to Integer Overflow in Signature Size Calculation #401

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4b44617
RIN-02 Panic Due to Integer Overflow in Signature Size Calculation
Jan 22, 2024
74db26a
assert the error
Jan 22, 2024
34d7343
simply overflow check
Jan 29, 2024
fdf9c08
simply overflow check
Jan 29, 2024
9033c2f
simply overflow check
Jan 29, 2024
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16 changes: 15 additions & 1 deletion core/vm/privacy/ringct.go
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Original file line number Diff line number Diff line change
Expand Up @@ -176,6 +176,20 @@ func (r *RingSignature) Serialize() ([]byte, error) {
}

func computeSignatureSize(numRing int, ringSize int) int {
const MaxInt = int(^uint(0) >> 1)

if numRing < 0 || ringSize < 0 {
return -1
}

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@gzliudan gzliudan Jan 26, 2024

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Both of numRing and ringSize must greater than zero:

	if numRing <= 0 || ringSize <= 0 {
		return -1
	}

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@liam-lai liam-lai Jan 28, 2024

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It can be zero right? based on the logic

	numRing := r[offset : offset+8]
	offset += 8
	size := r[offset : offset+8]
	offset += 8

	size_uint := binary.BigEndian.Uint64(size)
	size_int := int(size_uint)
	sig.Size = size_int

	size_uint = binary.BigEndian.Uint64(numRing)
	size_int = int(size_uint)
	sig.NumRing = size_int

// Calculate term and check for overflow

term := numRing * ringSize * 65

if term < 0 || term < numRing || term < ringSize {
return -1
}

return 8 + 8 + 32 + 32 + numRing*ringSize*32 + numRing*ringSize*33 + numRing*33
}

Expand All @@ -200,7 +214,7 @@ func Deserialize(r []byte) (*RingSignature, error) {
sig.NumRing = size_int

if len(r) != computeSignatureSize(sig.NumRing, sig.Size) {
return nil, errors.New("incorrect ring size")
return nil, fmt.Errorf("incorrect ring size, len r: %d, sig.NumRing: %d sig.Size: %d", len(r), sig.NumRing, sig.Size)
}

m := r[offset : offset+32]
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35 changes: 35 additions & 0 deletions core/vm/privacy/ringct_test.go
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Expand Up @@ -2,6 +2,7 @@ package privacy

import (
"bytes"
"encoding/binary"
"fmt"
"testing"

Expand Down Expand Up @@ -48,6 +49,40 @@ func TestSign(t *testing.T) {

}

func TestDeserialize(t *testing.T) {
numRing := 5
ringSize := 10
s := 5
rings, privkeys, m, err := GenerateMultiRingParams(numRing, ringSize, s)

ringSignature, err := Sign(m, rings, privkeys, s)
if err != nil {
t.Error("Failed to create Ring signature")
}

// A normal signature.
sig, err := ringSignature.Serialize()
if err != nil {
t.Error("Failed to Serialize input Ring signature")
}

// Modify the serialized signature s.t.
// the new signature passes the length check
// but triggers buffer overflow in Deserialize().
// ringSize: 10 -> 56759212534490939
// len(sig): 3495 -> 3804
// 80 + 5 * (56759212534490939*65 + 33) = 18446744073709551616 + 3804
bs := make([]byte, 8)
binary.BigEndian.PutUint64(bs, 56759212534490939)
for i := 0; i < 8; i++ {
sig[i+8] = bs[i]
}
tail := make([]byte, 3804-len(sig))
sig = append(sig, tail...)

_, err = Deserialize(sig)
assert.EqualError(t, err, "incorrect ring size, len r: 3804, sig.NumRing: 5 sig.Size: 56759212534490939")
}
func TestPadTo32Bytes(t *testing.T) {
arr := [44]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34}

Expand Down