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[Qemu-devel] [PATCH v2 5/6] io: Ignore websocket PING and PONG frames

Brandon Carpenter posted 6 patches 8 years, 5 months ago
There is a newer version of this series
[Qemu-devel] [PATCH v2 5/6] io: Ignore websocket PING and PONG frames
Posted by Brandon Carpenter 8 years, 5 months ago 
Keep pings and gratuitous pongs generated by web browsers from killing
websocket connections.

Signed-off-by: Brandon Carpenter <brandon.carpenter@cypherpath.com>
---
 io/channel-websock.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/io/channel-websock.c b/io/channel-websock.c
index 3183aeff77..50387050d5 100644
--- a/io/channel-websock.c
+++ b/io/channel-websock.c
@@ -86,6 +86,7 @@
 #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_OPCODE 0x0f
 #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_HAS_MASK 0x80
 #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_PAYLOAD_LEN 0x7f
+#define QIO_CHANNEL_WEBSOCK_CONTROL_OPCODE_MASK 0x8
 
 typedef struct QIOChannelWebsockHeader QIOChannelWebsockHeader;
 
@@ -565,8 +566,11 @@ static int qio_channel_websock_decode_header(QIOChannelWebsock *ioc,
             return -1;
         }
     } else {
-        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME) {
-            error_setg(errp, "only binary websocket frames are supported");
+        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME &&
+                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PING &&
+                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PONG) {
+            error_setg(errp, "unsupported opcode: %#04x; only binary, ping, "
+                             "and pong websocket frames are supported", opcode);
             return -1;
         }
     }
@@ -579,6 +583,9 @@ static int qio_channel_websock_decode_header(QIOChannelWebsock *ioc,
         ioc->payload_remain = payload_len;
         header_size = QIO_CHANNEL_WEBSOCK_HEADER_LEN_7_BIT;
         ioc->mask = header->u.m;
+    } else if (opcode & QIO_CHANNEL_WEBSOCK_CONTROL_OPCODE_MASK) {
+        error_setg(errp, "websocket control frame is too large");
+        return -1;
     } else if (payload_len == QIO_CHANNEL_WEBSOCK_PAYLOAD_LEN_MAGIC_16_BIT &&
                ioc->encinput.offset >= QIO_CHANNEL_WEBSOCK_HEADER_LEN_16_BIT) {
         ioc->payload_remain = be16_to_cpu(header->u.s16.l16);
@@ -634,9 +641,15 @@ static int qio_channel_websock_decode_payload(QIOChannelWebsock *ioc,
         }
     }
 
+    /* Drop the payload of ping/pong packets */
+    if (ioc->opcode == QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME) {
+        if (payload_len) {
+            buffer_reserve(&ioc->rawinput, payload_len);
+            buffer_append(&ioc->rawinput, ioc->encinput.buffer, payload_len);
+        }
+    }
+
     if (payload_len) {
-        buffer_reserve(&ioc->rawinput, payload_len);
-        buffer_append(&ioc->rawinput, ioc->encinput.buffer, payload_len);
         buffer_advance(&ioc->encinput, payload_len);
     }
     return 0;
-- 
2.14.1


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Re: [Qemu-devel] [PATCH v2 5/6] io: Ignore websocket PING and PONG frames
Posted by Daniel P. Berrange 8 years, 5 months ago 
On Fri, Sep 08, 2017 at 10:38:00AM -0700, Brandon Carpenter wrote:
> Keep pings and gratuitous pongs generated by web browsers from killing
> websocket connections.
> 
> Signed-off-by: Brandon Carpenter <brandon.carpenter@cypherpath.com>
> ---
>  io/channel-websock.c | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/io/channel-websock.c b/io/channel-websock.c
> index 3183aeff77..50387050d5 100644
> --- a/io/channel-websock.c
> +++ b/io/channel-websock.c
> @@ -86,6 +86,7 @@
>  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_OPCODE 0x0f
>  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_HAS_MASK 0x80
>  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_PAYLOAD_LEN 0x7f
> +#define QIO_CHANNEL_WEBSOCK_CONTROL_OPCODE_MASK 0x8
>  
>  typedef struct QIOChannelWebsockHeader QIOChannelWebsockHeader;
>  
> @@ -565,8 +566,11 @@ static int qio_channel_websock_decode_header(QIOChannelWebsock *ioc,
>              return -1;
>          }
>      } else {
> -        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME) {
> -            error_setg(errp, "only binary websocket frames are supported");
> +        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME &&
> +                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PING &&
> +                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PONG) {

Why would we need to ignore PONG ?  A client should only send a PONG in
response to a PING that we send, and we never send PINGs.  So if we
received a PONG that would be a serious error by the client, which should
cause us to close the connection IMHO>


Regards,
Daniel
-- 
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Re: [Qemu-devel] [PATCH v2 5/6] io: Ignore websocket PING and PONG frames
Posted by Daniel P. Berrange 8 years, 5 months ago 
On Mon, Sep 11, 2017 at 09:38:46AM +0100, Daniel P. Berrange wrote:
> On Fri, Sep 08, 2017 at 10:38:00AM -0700, Brandon Carpenter wrote:
> > Keep pings and gratuitous pongs generated by web browsers from killing
> > websocket connections.
> > 
> > Signed-off-by: Brandon Carpenter <brandon.carpenter@cypherpath.com>
> > ---
> >  io/channel-websock.c | 21 +++++++++++++++++----
> >  1 file changed, 17 insertions(+), 4 deletions(-)
> > 
> > diff --git a/io/channel-websock.c b/io/channel-websock.c
> > index 3183aeff77..50387050d5 100644
> > --- a/io/channel-websock.c
> > +++ b/io/channel-websock.c
> > @@ -86,6 +86,7 @@
> >  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_OPCODE 0x0f
> >  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_HAS_MASK 0x80
> >  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_PAYLOAD_LEN 0x7f
> > +#define QIO_CHANNEL_WEBSOCK_CONTROL_OPCODE_MASK 0x8
> >  
> >  typedef struct QIOChannelWebsockHeader QIOChannelWebsockHeader;
> >  
> > @@ -565,8 +566,11 @@ static int qio_channel_websock_decode_header(QIOChannelWebsock *ioc,
> >              return -1;
> >          }
> >      } else {
> > -        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME) {
> > -            error_setg(errp, "only binary websocket frames are supported");
> > +        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME &&
> > +                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PING &&
> > +                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PONG) {
> 
> Why would we need to ignore PONG ?  A client should only send a PONG in
> response to a PING that we send, and we never send PINGs.  So if we
> received a PONG that would be a serious error by the client, which should
> cause us to close the connection IMHO>

Never mind, I've just seen that the RFC allows clients to send an
unsolicited PONG


Regards,
Daniel
-- 
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