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authorEdgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>2018-01-10 18:39:24 +0300
committerDaniel P. Berrangé <berrange@redhat.com>2018-02-15 16:54:57 +0000
commita46ded1de5cf0edd6c780e071ddafb92601070b5 (patch)
tree7f538816906bd367ebd670932587d311ca573174 /io
parent28bb0a59f84c11c42117a7009646508256ed4475 (diff)
io/channel-websock: handle continuous reads without any data
According to the current implementation of websocket protocol in QEMU, qio_channel_websock_handshake_io tries to read handshake from the channel to start communication over socket. But this approach doesn't cover scenario when socket was closed while handshaking. Therefore, if G_IO_IN is caught and qio_channel_read returns zero, error has to be set and connection has to be done. Such behaviour causes 100% CPU load in main QEMU loop, because main loop poll continues to receive and handle G_IO_IN events from websocket. Step to reproduce 100% CPU load: 1) start qemu with the simplest configuration $ qemu -vnc [::1]:1,websocket=7500 2) open any vnc listener (which doesn't follow websocket protocol) $ vncviewer :7500 3) kill listener 4) qemu main thread eats 100% CPU Signed-off-by: Edgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'io')
-rw-r--r--io/channel-websock.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/io/channel-websock.c b/io/channel-websock.c
index 7fd6bb68ba..ec48a305f0 100644
--- a/io/channel-websock.c
+++ b/io/channel-websock.c
@@ -499,9 +499,12 @@ static int qio_channel_websock_handshake_read(QIOChannelWebsock *ioc,
error_setg(errp,
"End of headers not found in first 4096 bytes");
return 1;
- } else {
- return 0;
+ } else if (ret == 0) {
+ error_setg(errp,
+ "End of headers not found before connection closed");
+ return -1;
}
+ return 0;
}
*handshake_end = '\0';