diff options
Diffstat (limited to 'p2p')
| -rw-r--r-- | p2p/rlpx.go | 31 | ||||
| -rw-r--r-- | p2p/rlpx_test.go | 1 |
2 files changed, 19 insertions, 13 deletions
diff --git a/p2p/rlpx.go b/p2p/rlpx.go index 761dc2ed9..a041bb314 100644 --- a/p2p/rlpx.go +++ b/p2p/rlpx.go @@ -62,12 +62,15 @@ func (rw *rlpxFrameRW) WriteMsg(msg Msg) error { putInt24(fsize, headbuf) // TODO: check overflow copy(headbuf[3:], zeroHeader) rw.enc.XORKeyStream(headbuf[:16], headbuf[:16]) // first half is now encrypted - copy(headbuf[16:], updateHeaderMAC(rw.egressMAC, rw.macCipher, headbuf[:16])) + + // write header MAC + copy(headbuf[16:], updateMAC(rw.egressMAC, rw.macCipher, headbuf[:16])) if _, err := rw.conn.Write(headbuf); err != nil { return err } - // write encrypted frame, updating the egress MAC while writing to conn. + // write encrypted frame, updating the egress MAC hash with + // the data written to conn. tee := cipher.StreamWriter{S: rw.enc, W: io.MultiWriter(rw.conn, rw.egressMAC)} if _, err := tee.Write(ptype); err != nil { return err @@ -81,9 +84,10 @@ func (rw *rlpxFrameRW) WriteMsg(msg Msg) error { } } - // write packet-mac. egress MAC is up to date because + // write frame MAC. egress MAC hash is up to date because // frame content was written to it as well. - mac := updateHeaderMAC(rw.egressMAC, rw.macCipher, rw.egressMAC.Sum(nil)) + fmacseed := rw.egressMAC.Sum(nil) + mac := updateMAC(rw.egressMAC, rw.macCipher, fmacseed) _, err := rw.conn.Write(mac) return err } @@ -95,8 +99,8 @@ func (rw *rlpxFrameRW) ReadMsg() (msg Msg, err error) { return msg, err } // verify header mac - shouldMAC := updateHeaderMAC(rw.ingressMAC, rw.macCipher, headbuf[:16]) - if !hmac.Equal(shouldMAC[:16], headbuf[16:]) { + shouldMAC := updateMAC(rw.ingressMAC, rw.macCipher, headbuf[:16]) + if !hmac.Equal(shouldMAC, headbuf[16:]) { return msg, errors.New("bad header MAC") } rw.dec.XORKeyStream(headbuf[:16], headbuf[:16]) // first half is now decrypted @@ -115,11 +119,12 @@ func (rw *rlpxFrameRW) ReadMsg() (msg Msg, err error) { // read and validate frame MAC. we can re-use headbuf for that. rw.ingressMAC.Write(framebuf) - if _, err := io.ReadFull(rw.conn, headbuf); err != nil { + fmacseed := rw.ingressMAC.Sum(nil) + if _, err := io.ReadFull(rw.conn, headbuf[:16]); err != nil { return msg, err } - shouldMAC = updateHeaderMAC(rw.ingressMAC, rw.macCipher, rw.ingressMAC.Sum(nil)) - if !hmac.Equal(shouldMAC, headbuf) { + shouldMAC = updateMAC(rw.ingressMAC, rw.macCipher, fmacseed) + if !hmac.Equal(shouldMAC, headbuf[:16]) { return msg, errors.New("bad frame MAC") } @@ -136,14 +141,16 @@ func (rw *rlpxFrameRW) ReadMsg() (msg Msg, err error) { return msg, nil } -func updateHeaderMAC(mac hash.Hash, block cipher.Block, header []byte) []byte { +// updateMAC reseeds the given hash with encrypted seed. +// it returns the first 16 bytes of the hash sum after seeding. +func updateMAC(mac hash.Hash, block cipher.Block, seed []byte) []byte { aesbuf := make([]byte, aes.BlockSize) block.Encrypt(aesbuf, mac.Sum(nil)) for i := range aesbuf { - aesbuf[i] ^= header[i] + aesbuf[i] ^= seed[i] } mac.Write(aesbuf) - return mac.Sum(nil) + return mac.Sum(nil)[:16] } func readInt24(b []byte) uint32 { diff --git a/p2p/rlpx_test.go b/p2p/rlpx_test.go index b3c2adf8d..077dd1309 100644 --- a/p2p/rlpx_test.go +++ b/p2p/rlpx_test.go @@ -29,7 +29,6 @@ func TestRlpxFrameFake(t *testing.T) { 01010101010101010101010101010101 ba628a4ba590cb43f7848f41c4382885 01010101010101010101010101010101 -01010101010101010101010101010101 `) // Check WriteMsg. This puts a message into the buffer. |