[Qemu-devel] [PULL v1 08/11] io: Ignore websocket PING and PONG frames

["Daniel P. Berrange" <berrange@redhat.com>]

From: Brandon Carpenter <brandon.carpenter@cypherpath.com>

Keep pings and gratuitous pongs generated by web browsers from killing
websocket connections.

Signed-off-by: Brandon Carpenter <brandon.carpenter@cypherpath.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.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 b19b5d96da..bfe4008d83 100644
--- a/io/channel-websock.c
+++ b/io/channel-websock.c
@@ -115,6 +115,7 @@
 #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;
 
@@ -659,8 +660,11 @@ 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;
         }
     }
@@ -673,6 +677,9 @@ 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);
@@ -728,9 +735,15 @@ 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;
-- 
2.13.5