From 5f96b596353d73bdf4bb3cd2de61e48a7fd5b4c3 Mon Sep 17 00:00:00 2001
From: Frediano Ziglio <fziglio@redhat.com>
Date: Tue, 29 Nov 2016 16:46:56 +0000
Subject: [PATCH] main-channel: Prevent overflow reading messages from client

Caller is supposed the function return a buffer able to store
size bytes.

[Peter: fixes CVE-2016-9577]
Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Acked-by: Christophe Fergeau <cfergeau@redhat.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
 server/main_channel.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/server/main_channel.c b/server/main_channel.c
index 0ecc9df8..1fc39155 100644
--- a/server/main_channel.c
+++ b/server/main_channel.c
@@ -1026,6 +1026,9 @@ static uint8_t *main_channel_alloc_msg_rcv_buf(RedChannelClient *rcc,
 
     if (type == SPICE_MSGC_MAIN_AGENT_DATA) {
         return reds_get_agent_data_buffer(mcc, size);
+    } else if (size > sizeof(main_chan->recv_buf)) {
+        /* message too large, caller will log a message and close the connection */
+        return NULL;
     } else {
         return main_chan->recv_buf;
     }
-- 
2.11.0