chore: vendor

vendor/github.com/cloudflare/circl/math/fp448/fuzzer.go

@@ -0,0 +1,75 @@
+//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
+}