[Spice-devel] [spice-streaming-agent PATCH 1/2] start streaming: check num_codecs

[Uri Lublin]

The server sends StreamMsgStartStop to tell spice-streaming-agent
to start streaming and a list of available codecs.

The first uint8_t is the number of codecs.
Each following uint8_t is a codec.

This patch checks that the number of codecs in the message, as
reported by the server, is not too large.
---
 src/spice-streaming-agent.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
index a9baf4d..05a1761 100644
--- a/src/spice-streaming-agent.cpp
+++ b/src/spice-streaming-agent.cpp
@@ -91,6 +91,11 @@ static void handle_stream_start_stop(StreamPort &stream_port, uint32_t len)
     syslog(LOG_INFO, "GOT START_STOP message -- request to %s streaming",
            streaming_requested ? "START" : "STOP");
     client_codecs.clear();
+    const int mnc = len - 1; /* max num codecs, see struct StreamMsgStartStop */
+    if (msg[0] > mnc) {
+        throw std::runtime_error("num_codecs=" + std::to_string(msg[0]) +
+                                 " > max_num_codecs=(" + std::to_string(mnc));
+    }
     for (int i = 1; i <= msg[0]; ++i) {
         client_codecs.insert((SpiceVideoCodecType) msg[i]);
     }
-- 
2.17.1