From 3a6e26b844a8a552efbc0763796a72f431010826 Mon Sep 17 00:00:00 2001 From: Martin Holst Swende Date: Fri, 13 Nov 2020 09:27:57 +0100 Subject: [PATCH] crypto/bn256: improve bn256 fuzzer (#21815) * crypto/cloudflare: fix nil deref in random G1/G2 reading * crypto/bn256: improve fuzzer * crypto/bn256: fix some flaws in fuzzer --- crypto/bn256/bn256_fuzz.go | 117 ++++++++++++++----------------- crypto/bn256/cloudflare/bn256.go | 2 +- 2 files changed, 53 insertions(+), 66 deletions(-) diff --git a/crypto/bn256/bn256_fuzz.go b/crypto/bn256/bn256_fuzz.go index eec08584666ba..c3e1833ef2df7 100644 --- a/crypto/bn256/bn256_fuzz.go +++ b/crypto/bn256/bn256_fuzz.go @@ -20,42 +20,52 @@ package bn256 import ( "bytes" + "fmt" + "io" "math/big" cloudflare "github.com/XinFinOrg/XDPoSChain/crypto/bn256/cloudflare" google "github.com/XinFinOrg/XDPoSChain/crypto/bn256/google" ) -// FuzzAdd fuzzez bn256 addition between the Google and Cloudflare libraries. -func FuzzAdd(data []byte) int { - // Ensure we have enough data in the first place - if len(data) != 128 { - return 0 +func getG1Points(input io.Reader) (*cloudflare.G1, *google.G1) { + _, xc, err := cloudflare.RandomG1(input) + if err != nil { + // insufficient input + return nil, nil } - // Ensure both libs can parse the first curve point - xc := new(cloudflare.G1) - _, errc := xc.Unmarshal(data[:64]) - xg := new(google.G1) - _, errg := xg.Unmarshal(data[:64]) - - if (errc == nil) != (errg == nil) { - panic("parse mismatch") - } else if errc != nil { - return 0 + if _, err := xg.Unmarshal(xc.Marshal()); err != nil { + panic(fmt.Sprintf("Could not marshal cloudflare -> google:", err)) } - // Ensure both libs can parse the second curve point - yc := new(cloudflare.G1) - _, errc = yc.Unmarshal(data[64:]) + return xc, xg +} - yg := new(google.G1) - _, errg = yg.Unmarshal(data[64:]) +func getG2Points(input io.Reader) (*cloudflare.G2, *google.G2) { + _, xc, err := cloudflare.RandomG2(input) + if err != nil { + // insufficient input + return nil, nil + } + xg := new(google.G2) + if _, err := xg.Unmarshal(xc.Marshal()); err != nil { + panic(fmt.Sprintf("Could not marshal cloudflare -> google:", err)) + } + return xc, xg +} - if (errc == nil) != (errg == nil) { - panic("parse mismatch") - } else if errc != nil { +// FuzzAdd fuzzez bn256 addition between the Google and Cloudflare libraries. +func FuzzAdd(data []byte) int { + input := bytes.NewReader(data) + xc, xg := getG1Points(input) + if xc == nil { return 0 } + yc, yg := getG1Points(input) + if yc == nil { + return 0 + } + // Ensure both libs can parse the second curve point // Add the two points and ensure they result in the same output rc := new(cloudflare.G1) rc.Add(xc, yc) @@ -66,73 +76,50 @@ func FuzzAdd(data []byte) int { if !bytes.Equal(rc.Marshal(), rg.Marshal()) { panic("add mismatch") } - return 0 + return 1 } // FuzzMul fuzzez bn256 scalar multiplication between the Google and Cloudflare // libraries. func FuzzMul(data []byte) int { - // Ensure we have enough data in the first place - if len(data) != 96 { + input := bytes.NewReader(data) + pc, pg := getG1Points(input) + if pc == nil { return 0 } - // Ensure both libs can parse the curve point - pc := new(cloudflare.G1) - _, errc := pc.Unmarshal(data[:64]) - - pg := new(google.G1) - _, errg := pg.Unmarshal(data[:64]) - - if (errc == nil) != (errg == nil) { - panic("parse mismatch") - } else if errc != nil { + // Add the two points and ensure they result in the same output + remaining := input.Len() + if remaining == 0 { return 0 } - // Add the two points and ensure they result in the same output + buf := make([]byte, remaining) + input.Read(buf) + rc := new(cloudflare.G1) - rc.ScalarMult(pc, new(big.Int).SetBytes(data[64:])) + rc.ScalarMult(pc, new(big.Int).SetBytes(buf)) rg := new(google.G1) - rg.ScalarMult(pg, new(big.Int).SetBytes(data[64:])) + rg.ScalarMult(pg, new(big.Int).SetBytes(buf)) if !bytes.Equal(rc.Marshal(), rg.Marshal()) { panic("scalar mul mismatch") } - return 0 + return 1 } func FuzzPair(data []byte) int { - // Ensure we have enough data in the first place - if len(data) != 192 { + input := bytes.NewReader(data) + pc, pg := getG1Points(input) + if pc == nil { return 0 } - // Ensure both libs can parse the curve point - pc := new(cloudflare.G1) - _, errc := pc.Unmarshal(data[:64]) - - pg := new(google.G1) - _, errg := pg.Unmarshal(data[:64]) - - if (errc == nil) != (errg == nil) { - panic("parse mismatch") - } else if errc != nil { - return 0 - } - // Ensure both libs can parse the twist point - tc := new(cloudflare.G2) - _, errc = tc.Unmarshal(data[64:]) - - tg := new(google.G2) - _, errg = tg.Unmarshal(data[64:]) - - if (errc == nil) != (errg == nil) { - panic("parse mismatch") - } else if errc != nil { + tc, tg := getG2Points(input) + if tc == nil { return 0 } // Pair the two points and ensure thet result in the same output if cloudflare.PairingCheck([]*cloudflare.G1{pc}, []*cloudflare.G2{tc}) != google.PairingCheck([]*google.G1{pg}, []*google.G2{tg}) { panic("pair mismatch") } - return 0 + return 1 } diff --git a/crypto/bn256/cloudflare/bn256.go b/crypto/bn256/cloudflare/bn256.go index 38822a76bfecb..a6dd972ba8b23 100644 --- a/crypto/bn256/cloudflare/bn256.go +++ b/crypto/bn256/cloudflare/bn256.go @@ -23,7 +23,7 @@ import ( func randomK(r io.Reader) (k *big.Int, err error) { for { k, err = rand.Int(r, Order) - if k.Sign() > 0 || err != nil { + if err != nil || k.Sign() > 0 { return } }