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http2: consider 0-length non-end DATA frames an error
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This is intended to mitigate CVE-2019-9518.

PR-URL: #29122
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: James M Snell <[email protected]>
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addaleax authored and targos committed Aug 15, 2019
1 parent 23b0db5 commit ba332df
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Showing 3 changed files with 10 additions and 5 deletions.
12 changes: 8 additions & 4 deletions src/node_http2.cc
Original file line number Diff line number Diff line change
Expand Up @@ -979,8 +979,7 @@ int Http2Session::OnFrameReceive(nghttp2_session* handle,
frame->hd.type);
switch (frame->hd.type) {
case NGHTTP2_DATA:
session->HandleDataFrame(frame);
break;
return session->HandleDataFrame(frame);
case NGHTTP2_PUSH_PROMISE:
// Intentional fall-through, handled just like headers frames
case NGHTTP2_HEADERS:
Expand Down Expand Up @@ -1372,13 +1371,18 @@ void Http2Session::HandlePriorityFrame(const nghttp2_frame* frame) {
// Called by OnFrameReceived when a complete DATA frame has been received.
// If we know that this was the last DATA frame (because the END_STREAM flag
// is set), then we'll terminate the readable side of the StreamBase.
void Http2Session::HandleDataFrame(const nghttp2_frame* frame) {
int Http2Session::HandleDataFrame(const nghttp2_frame* frame) {
int32_t id = GetFrameID(frame);
Debug(this, "handling data frame for stream %d", id);
Http2Stream* stream = FindStream(id);

if (!stream->IsDestroyed() && frame->hd.flags & NGHTTP2_FLAG_END_STREAM)
if (!stream->IsDestroyed() && frame->hd.flags & NGHTTP2_FLAG_END_STREAM) {
stream->EmitRead(UV_EOF);
} else if (frame->hd.length == 0 &&
!IsReverted(SECURITY_REVERT_CVE_2019_9518)) {
return 1; // Consider 0-length frame without END_STREAM an error.
}
return 0;
}


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2 changes: 1 addition & 1 deletion src/node_http2.h
Original file line number Diff line number Diff line change
Expand Up @@ -877,7 +877,7 @@ class Http2Session : public AsyncWrap, public StreamListener {
size_t maxPayloadLen);

// Frame Handler
void HandleDataFrame(const nghttp2_frame* frame);
int HandleDataFrame(const nghttp2_frame* frame);
void HandleGoawayFrame(const nghttp2_frame* frame);
void HandleHeadersFrame(const nghttp2_frame* frame);
void HandlePriorityFrame(const nghttp2_frame* frame);
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1 change: 1 addition & 0 deletions src/node_revert.h
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ namespace node {
#define SECURITY_REVERSIONS(XX) \
XX(CVE_2019_9514, "CVE-2019-9514", "HTTP/2 Reset Flood") \
XX(CVE_2019_9516, "CVE-2019-9516", "HTTP/2 0-Length Headers Leak") \
XX(CVE_2019_9518, "CVE-2019-9518", "HTTP/2 Empty DATA Frame Flooding") \
// XX(CVE_2016_PEND, "CVE-2016-PEND", "Vulnerability Title")
// TODO(addaleax): Remove all of the above before Node.js 13 as the comment
// at the start of the file indicates.
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