diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go index 3ce779cd7c..83244f5849 100644 --- a/src/net/http/h2_bundle.go +++ b/src/net/http/h2_bundle.go @@ -2842,6 +2842,7 @@ func (fr *http2Framer) readMetaFrame(hf *http2HeadersFrame) (*http2MetaHeadersFr if size > remainSize { hdec.SetEmitEnabled(false) mh.Truncated = true + remainSize = 0 return } remainSize -= size @@ -2854,6 +2855,36 @@ func (fr *http2Framer) readMetaFrame(hf *http2HeadersFrame) (*http2MetaHeadersFr var hc http2headersOrContinuation = hf for { frag := hc.HeaderBlockFragment() + + // Avoid parsing large amounts of headers that we will then discard. + // If the sender exceeds the max header list size by too much, + // skip parsing the fragment and close the connection. + // + // "Too much" is either any CONTINUATION frame after we've already + // exceeded the max header list size (in which case remainSize is 0), + // or a frame whose encoded size is more than twice the remaining + // header list bytes we're willing to accept. + if int64(len(frag)) > int64(2*remainSize) { + if http2VerboseLogs { + log.Printf("http2: header list too large") + } + // It would be nice to send a RST_STREAM before sending the GOAWAY, + // but the struture of the server's frame writer makes this difficult. + return nil, http2ConnectionError(http2ErrCodeProtocol) + } + + // Also close the connection after any CONTINUATION frame following an + // invalid header, since we stop tracking the size of the headers after + // an invalid one. + if invalid != nil { + if http2VerboseLogs { + log.Printf("http2: invalid header: %v", invalid) + } + // It would be nice to send a RST_STREAM before sending the GOAWAY, + // but the struture of the server's frame writer makes this difficult. + return nil, http2ConnectionError(http2ErrCodeProtocol) + } + if _, err := hdec.Write(frag); err != nil { return nil, http2ConnectionError(http2ErrCodeCompression) }