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http2: treat non-EOF empty frames like other invalid frames #37875

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54 changes: 46 additions & 8 deletions lib/internal/http2/core.js
Expand Up @@ -19,14 +19,16 @@ const {
Promise,
PromisePrototypeCatch,
ReflectApply,
ReflectGet,
ReflectGetPrototypeOf,
ReflectSet,
RegExpPrototypeTest,
SafeArrayIterator,
SafeMap,
SafeSet,
StringPrototypeSlice,
Symbol,
TypedArrayPrototypeSet,
TypedArrayPrototypeGetLength,
Uint32Array,
Uint8Array,
} = primordials;
Expand Down Expand Up @@ -960,6 +962,36 @@ const validateSettings = hideStackFrames((settings) => {
}
});

// Wrap a typed array in a proxy, and allow selectively copying the entries
// that have explicitly been set to another typed array.
function trackAssignmentsTypedArray(typedArray) {
const typedArrayLength = TypedArrayPrototypeGetLength(typedArray);
const modifiedEntries = new Uint8Array(typedArrayLength);

function copyAssigned(target) {
for (let i = 0; i < typedArrayLength; i++) {
if (modifiedEntries[i]) {
target[i] = typedArray[i];
}
}
}

return new Proxy(typedArray, {
get(obj, prop, receiver) {
if (prop === 'copyAssigned') {
return copyAssigned;
}
return ReflectGet(obj, prop, receiver);
},
set(obj, prop, value) {
if (`${+prop}` === prop) {
modifiedEntries[prop] = 1;
}
return ReflectSet(obj, prop, value);
}
});
}

// Creates the internal binding.Http2Session handle for an Http2Session
// instance. This occurs only after the socket connection has been
// established. Note: the binding.Http2Session will take over ownership
Expand Down Expand Up @@ -990,10 +1022,13 @@ function setupHandle(socket, type, options) {
handle.consume(socket._handle);

this[kHandle] = handle;
if (this[kNativeFields])
TypedArrayPrototypeSet(handle.fields, this[kNativeFields]);
else
this[kNativeFields] = handle.fields;
if (this[kNativeFields]) {
// If some options have already been set before the handle existed, copy
// those (and only those) that have manually been set over.
this[kNativeFields].copyAssigned(handle.fields);
}

this[kNativeFields] = handle.fields;

if (socket.encrypted) {
this[kAlpnProtocol] = socket.alpnProtocol;
Expand Down Expand Up @@ -1045,7 +1080,8 @@ function cleanupSession(session) {
session[kProxySocket] = undefined;
session[kSocket] = undefined;
session[kHandle] = undefined;
session[kNativeFields] = new Uint8Array(kSessionUint8FieldCount);
session[kNativeFields] = trackAssignmentsTypedArray(
new Uint8Array(kSessionUint8FieldCount));
if (handle)
handle.ondone = null;
if (socket) {
Expand Down Expand Up @@ -1213,8 +1249,10 @@ class Http2Session extends EventEmitter {
setupFn();
}

if (!this[kNativeFields])
this[kNativeFields] = new Uint8Array(kSessionUint8FieldCount);
if (!this[kNativeFields]) {
this[kNativeFields] = trackAssignmentsTypedArray(
new Uint8Array(kSessionUint8FieldCount));
}
this.on('newListener', sessionListenerAdded);
this.on('removeListener', sessionListenerRemoved);

Expand Down
6 changes: 5 additions & 1 deletion src/node_http2.cc
Expand Up @@ -1335,7 +1335,11 @@ int Http2Session::HandleDataFrame(const nghttp2_frame* frame) {
frame->hd.flags & NGHTTP2_FLAG_END_STREAM) {
stream->EmitRead(UV_EOF);
} else if (frame->hd.length == 0) {
return 1; // Consider 0-length frame without END_STREAM an error.
if (invalid_frame_count_++ > js_fields_->max_invalid_frames) {

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Should invalid_frame_count be reset if valid frames come through? Pertaining to #37849, if an end server is sending EOF frames after every valid frame, would this solution only allow for single requests in a session?

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So... I don't think we'd want to reset after every valid frame, or at least I think that would be a bit separate from this PR.

What would makes sense to me is to make this a ratio of invalid frames/total frames that is being limited, rather than the total # of invalid frames ... but that feels a bit out of scope here :/ In any case, users who do wish to allow for a large number of invalid frames can set the maxSessionInvalidFrames option to a large value, if they are connecting to problematic servers.

Debug(this, "rejecting empty-frame-without-END_STREAM flood\n");
// Consider a flood of 0-length frames without END_STREAM an error.
return 1;
}
}
return 0;
}
Expand Down
Binary file added test/fixtures/emptyframe.http2
Binary file not shown.
39 changes: 39 additions & 0 deletions test/parallel/test-http2-empty-frame-without-eof.js
@@ -0,0 +1,39 @@
'use strict';
const common = require('../common');
if (!common.hasCrypto)
common.skip('missing crypto');
const { readSync } = require('../common/fixtures');
const net = require('net');
const http2 = require('http2');
const { once } = require('events');

async function main() {
const blobWithEmptyFrame = readSync('emptyframe.http2');
const server = net.createServer((socket) => {
socket.end(blobWithEmptyFrame);
}).listen(0);
await once(server, 'listening');

for (const maxSessionInvalidFrames of [0, 2]) {
const client = http2.connect(`http://localhost:${server.address().port}`, {
maxSessionInvalidFrames
});
const stream = client.request({
':method': 'GET',
':path': '/'
});
if (maxSessionInvalidFrames) {
stream.on('error', common.mustNotCall());
client.on('error', common.mustNotCall());
} else {
stream.on('error', common.mustCall());
client.on('error', common.mustCall());
}
stream.resume();
await once(stream, 'end');
client.close();
}
server.close();
}

main().then(common.mustCall());