crypto/blake2b: put architecture-dependent features behind build-tag …

crypto/blake2b/blake2b_f_fuzz_test.go

@@ -0,0 +1,75 @@
+// Only enable fuzzer on platforms with AVX enabled
+//go:build go1.7 && amd64 && !gccgo && !appengine
+// +build go1.7,amd64,!gccgo,!appengine
+
+package blake2b
+
+import (
+	"encoding/binary"
+	"testing"
+)
+
+func Fuzz(f *testing.F) {
+	f.Fuzz(func(t *testing.T, data []byte) {
+		fuzz(data)
+	})
+}
+
+func fuzz(data []byte) {
+	// Make sure the data confirms to the input model
+	if len(data) != 211 {
+		return
+	}
+	// Parse everything and call all the implementations
+	var (
+		rounds = binary.BigEndian.Uint16(data[0:2])
+
+		h [8]uint64
+		m [16]uint64
+		t [2]uint64
+		f uint64
+	)
+
+	for i := 0; i < 8; i++ {
+		offset := 2 + i*8
+		h[i] = binary.LittleEndian.Uint64(data[offset : offset+8])
+	}
+	for i := 0; i < 16; i++ {
+		offset := 66 + i*8
+		m[i] = binary.LittleEndian.Uint64(data[offset : offset+8])
+	}
+	t[0] = binary.LittleEndian.Uint64(data[194:202])
+	t[1] = binary.LittleEndian.Uint64(data[202:210])
+
+	if data[210]%2 == 1 { // Avoid spinning the fuzzer to hit 0/1
+		f = 0xFFFFFFFFFFFFFFFF
+	}
+
+	// Run the blake2b compression on all instruction sets and cross reference
+	want := h
+	fGeneric(&want, &m, t[0], t[1], f, uint64(rounds))
+
+	have := h
+	if useSSE4 {
+		fSSE4(&have, &m, t[0], t[1], f, uint64(rounds))
+		if have != want {
+			panic("SSE4 mismatches generic algo")
+		}
+	}
+
+	if useAVX {
+		have = h
+		fAVX(&have, &m, t[0], t[1], f, uint64(rounds))
+		if have != want {
+			panic("AVX mismatches generic algo")
+		}
+	}
+
+	if useAVX2 {
+		have = h
+		fAVX2(&have, &m, t[0], t[1], f, uint64(rounds))
+		if have != want {
+			panic("AVX2 mismatches generic algo")
+		}
+	}
+}