|
| 1 | +package websocket |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "crypto/rand" |
| 6 | + "encoding/binary" |
| 7 | + "math/big" |
| 8 | + "math/bits" |
| 9 | + "testing" |
| 10 | + |
| 11 | + "nhooyr.io/websocket/internal/test/assert" |
| 12 | +) |
| 13 | + |
| 14 | +func basicMask(b []byte, key uint32) uint32 { |
| 15 | + for i := range b { |
| 16 | + b[i] ^= byte(key) |
| 17 | + key = bits.RotateLeft32(key, -8) |
| 18 | + } |
| 19 | + return key |
| 20 | +} |
| 21 | + |
| 22 | +func basicMask2(b []byte, key uint32) uint32 { |
| 23 | + keyb := binary.LittleEndian.AppendUint32(nil, key) |
| 24 | + pos := 0 |
| 25 | + for i := range b { |
| 26 | + b[i] ^= keyb[pos&3] |
| 27 | + pos++ |
| 28 | + } |
| 29 | + return bits.RotateLeft32(key, (pos&3)*-8) |
| 30 | +} |
| 31 | + |
| 32 | +func TestMask(t *testing.T) { |
| 33 | + t.Parallel() |
| 34 | + |
| 35 | + testMask(t, "basicMask", basicMask) |
| 36 | + testMask(t, "maskGo", maskGo) |
| 37 | + testMask(t, "basicMask2", basicMask2) |
| 38 | +} |
| 39 | + |
| 40 | +func testMask(t *testing.T, name string, fn func(b []byte, key uint32) uint32) { |
| 41 | + t.Run(name, func(t *testing.T) { |
| 42 | + t.Parallel() |
| 43 | + for i := 0; i < 9999; i++ { |
| 44 | + keyb := make([]byte, 4) |
| 45 | + _, err := rand.Read(keyb) |
| 46 | + assert.Success(t, err) |
| 47 | + key := binary.LittleEndian.Uint32(keyb) |
| 48 | + |
| 49 | + n, err := rand.Int(rand.Reader, big.NewInt(1<<16)) |
| 50 | + assert.Success(t, err) |
| 51 | + |
| 52 | + b := make([]byte, 1+n.Int64()) |
| 53 | + _, err = rand.Read(b) |
| 54 | + assert.Success(t, err) |
| 55 | + |
| 56 | + b2 := make([]byte, len(b)) |
| 57 | + copy(b2, b) |
| 58 | + b3 := make([]byte, len(b)) |
| 59 | + copy(b3, b) |
| 60 | + |
| 61 | + key2 := basicMask(b2, key) |
| 62 | + key3 := fn(b3, key) |
| 63 | + |
| 64 | + if key2 != key3 { |
| 65 | + t.Errorf("expected key %X but got %X", key2, key3) |
| 66 | + } |
| 67 | + if !bytes.Equal(b2, b3) { |
| 68 | + t.Error("bad bytes") |
| 69 | + return |
| 70 | + } |
| 71 | + } |
| 72 | + }) |
| 73 | +} |
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