76 lines
2.0 KiB
Go
76 lines
2.0 KiB
Go
|
//go:build gofuzz
|
||
|
|
// +build gofuzz
|
||
|
|
|
||
|
|
// How to run the fuzzer:
|
||
|
|
//
|
||
|
|
// $ go get -u github.com/dvyukov/go-fuzz/go-fuzz
|
||
|
|
// $ go get -u github.com/dvyukov/go-fuzz/go-fuzz-build
|
||
|
|
// $ go-fuzz-build -libfuzzer -func FuzzReduction -o lib.a
|
||
|
|
// $ clang -fsanitize=fuzzer lib.a -o fu.exe
|
||
|
|
// $ ./fu.exe
|
||
|
|
package fp448
|
||
|
|
|
||
|
|
import (
|
||
|
|
"encoding/binary"
|
||
|
|
"fmt"
|
||
|
|
"math/big"
|
||
|
|
|
||
|
|
"github.com/cloudflare/circl/internal/conv"
|
||
|
|
)
|
||
|
|
|
||
|
|
// FuzzReduction is a fuzzer target for red64 function, which reduces t
|
||
|
|
// (112 bits) to a number t' (56 bits) congruent modulo p448.
|
||
|
|
func FuzzReduction(data []byte) int {
|
||
|
|
if len(data) != 2*Size {
|
||
|
|
return -1
|
||
|
|
}
|
||
|
|
var got, want Elt
|
||
|
|
var lo, hi [7]uint64
|
||
|
|
a := data[:Size]
|
||
|
|
b := data[Size:]
|
||
|
|
lo[0] = binary.LittleEndian.Uint64(a[0*8 : 1*8])
|
||
|
|
lo[1] = binary.LittleEndian.Uint64(a[1*8 : 2*8])
|
||
|
|
lo[2] = binary.LittleEndian.Uint64(a[2*8 : 3*8])
|
||
|
|
lo[3] = binary.LittleEndian.Uint64(a[3*8 : 4*8])
|
||
|
|
lo[4] = binary.LittleEndian.Uint64(a[4*8 : 5*8])
|
||
|
|
lo[5] = binary.LittleEndian.Uint64(a[5*8 : 6*8])
|
||
|
|
lo[6] = binary.LittleEndian.Uint64(a[6*8 : 7*8])
|
||
|
|
|
||
|
|
hi[0] = binary.LittleEndian.Uint64(b[0*8 : 1*8])
|
||
|
|
hi[1] = binary.LittleEndian.Uint64(b[1*8 : 2*8])
|
||
|
|
hi[2] = binary.LittleEndian.Uint64(b[2*8 : 3*8])
|
||
|
|
hi[3] = binary.LittleEndian.Uint64(b[3*8 : 4*8])
|
||
|
|
hi[4] = binary.LittleEndian.Uint64(b[4*8 : 5*8])
|
||
|
|
hi[5] = binary.LittleEndian.Uint64(b[5*8 : 6*8])
|
||
|
|
hi[6] = binary.LittleEndian.Uint64(b[6*8 : 7*8])
|
||
|
|
|
||
|
|
red64(&got, &lo, &hi)
|
||
|
|
|
||
|
|
t := conv.BytesLe2BigInt(data[:2*Size])
|
||
|
|
|
||
|
|
two448 := big.NewInt(1)
|
||
|
|
two448.Lsh(two448, 448) // 2^448
|
||
|
|
mask448 := big.NewInt(1)
|
||
|
|
mask448.Sub(two448, mask448) // 2^448-1
|
||
|
|
two224plus1 := big.NewInt(1)
|
||
|
|
two224plus1.Lsh(two224plus1, 224)
|
||
|
|
two224plus1.Add(two224plus1, big.NewInt(1)) // 2^224+1
|
||
|
|
|
||
|
|
var loBig, hiBig big.Int
|
||
|
|
for t.Cmp(two448) >= 0 {
|
||
|
|
loBig.And(t, mask448)
|
||
|
|
hiBig.Rsh(t, 448)
|
||
|
|
t.Mul(&hiBig, two224plus1)
|
||
|
|
t.Add(t, &loBig)
|
||
|
|
}
|
||
|
|
conv.BigInt2BytesLe(want[:], t)
|
||
|
|
|
||
|
|
if got != want {
|
||
|
|
fmt.Printf("in: %v\n", conv.BytesLe2BigInt(data[:2*Size]))
|
||
|
|
fmt.Printf("got: %v\n", got)
|
||
|
|
fmt.Printf("want: %v\n", want)
|
||
|
|
panic("error found")
|
||
|
|
}
|
||
|
|
return 1
|
||
|
|
}
|