From 429828cd9205a8db0024652fd9da96cfbdaeae86 Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Wed, 4 Mar 2015 16:39:04 +0100 Subject: [PATCH] p2p: reject messages that cannot be written as simple RLPx frames Until chunked frames are implemented we cannot send messages with a size overflowing uint24. --- p2p/rlpx.go | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/p2p/rlpx.go b/p2p/rlpx.go index 166bbb5e6..6b533e275 100644 --- a/p2p/rlpx.go +++ b/p2p/rlpx.go @@ -19,6 +19,8 @@ var ( // sixteen zero bytes zero16 = make([]byte, 16) + + maxUint24 = ^uint32(0) >> 8 ) // rlpxFrameRW implements a simplified version of RLPx framing. @@ -64,6 +66,9 @@ func (rw *rlpxFrameRW) WriteMsg(msg Msg) error { // write header headbuf := make([]byte, 32) fsize := uint32(len(ptype)) + msg.Size + if fsize > maxUint24 { + return errors.New("message size overflows uint24") + } putInt24(fsize, headbuf) // TODO: check overflow copy(headbuf[3:], zeroHeader) rw.enc.XORKeyStream(headbuf[:16], headbuf[:16]) // first half is now encrypted