projects / pve-qemu.git / blame
| Commit | Line | Data |
|---|---|---|
| 3dcc8d3b | 1 | From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
| c53dfb57 WB |
2 | From: "Daniel P. Berrange" <berrange@redhat.com> |
| 3 | Date: Mon, 9 Oct 2017 14:43:42 +0100 | |
| 3dcc8d3b | 4 | Subject: [PATCH] io: monitor encoutput buffer size from websocket GSource |
| c53dfb57 WB |
5 | |
| 6 | The websocket GSource is monitoring the size of the rawoutput | |
| 7 | buffer to determine if the channel can accepts more writes. | |
| 8 | The rawoutput buffer, however, is merely a temporary staging | |
| 9 | buffer before data is copied into the encoutput buffer. Thus | |
| 10 | its size will always be zero when the GSource runs. | |
| 11 | ||
| 12 | This flaw causes the encoutput buffer to grow without bound | |
| 13 | if the other end of the underlying data channel doesn't | |
| 14 | read data being sent. This can be seen with VNC if a client | |
| 15 | is on a slow WAN link and the guest OS is sending many screen | |
| 16 | updates. A malicious VNC client can act like it is on a slow | |
| 17 | link by playing a video in the guest and then reading data | |
| 18 | very slowly, causing QEMU host memory to expand arbitrarily. | |
| 19 | ||
| 20 | This issue is assigned CVE-2017-15268, publically reported in | |
| 21 | ||
| 22 | https://bugs.launchpad.net/qemu/+bug/1718964 | |
| 23 | ||
| 24 | Reviewed-by: Eric Blake <eblake@redhat.com> | |
| 25 | Signed-off-by: Daniel P. Berrange <berrange@redhat.com> | |
| 26 | --- | |
| 27 | io/channel-websock.c | 4 ++-- | |
| 28 | 1 file changed, 2 insertions(+), 2 deletions(-) | |
| 29 | ||
| 30 | diff --git a/io/channel-websock.c b/io/channel-websock.c | |
| 31 | index 8fabadea2f..882bbb4cbc 100644 | |
| 32 | --- a/io/channel-websock.c | |
| 33 | +++ b/io/channel-websock.c | |
| 34 | @@ -26,7 +26,7 @@ | |
| 35 | #include "trace.h" | |
| 36 | ||
| 37 | ||
| 38 | -/* Max amount to allow in rawinput/rawoutput buffers */ | |
| 39 | +/* Max amount to allow in rawinput/encoutput buffers */ | |
| 40 | #define QIO_CHANNEL_WEBSOCK_MAX_BUFFER 8192 | |
| 41 | ||
| 42 | #define QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN 24 | |
| 43 | @@ -1006,7 +1006,7 @@ qio_channel_websock_source_prepare(GSource *source, | |
| 44 | if (wsource->wioc->rawinput.offset) { | |
| 45 | cond |= G_IO_IN; | |
| 46 | } | |
| 47 | - if (wsource->wioc->rawoutput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER) { | |
| 48 | + if (wsource->wioc->encoutput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER) { | |
| 49 | cond |= G_IO_OUT; | |
| 50 | } | |
| 51 | ||
| 52 | -- | |
| 53 | 2.11.0 | |
| 54 |