File Avoids-unlimited-agent-connections.patch of Package spice-vdagent

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File Avoids-unlimited-agent-connections.patch of Package spice-vdagent

From e7cb988419bc4bba88083938a5d99e2b42d6034f Mon Sep 17 00:00:00 2001
From: Frediano Ziglio <freddy77@gmail.com>
Date: Sun, 20 Sep 2020 08:05:37 +0100
Subject: [PATCH 15/20] Avoids unlimited agent connections

Git-commit: 09ae6b76669dff47ec877c18f087c287c2e0e887
References: bsc#1173749

Limit the number of agents that can be connected.
Avoids reaching the maximum number of files in a process.
Beside one file descriptor per agent the daemon open just some
other fixed number of files.

This issue was reported by SUSE security team.

Signed-off-by: Frediano Ziglio <freddy77@gmail.com>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 src/udscs.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/udscs.c b/src/udscs.c
index f5dcc1b..4944948 100644
--- a/src/udscs.c
+++ b/src/udscs.c
@@ -30,6 +30,12 @@
 #include "vdagentd-proto-strings.h"
 #include "vdagent-connection.h"
 
+// Maximum number of connected agents.
+// Avoid DoS from agents.
+// As each connection end up taking a file descriptor is good to have a limit
+// less than the number of file descriptors in the process (by default 1024).
+#define MAX_CONNECTED_AGENTS 128
+
 struct udscs_connection {
     VDAgentConnection parent_instance;
 
@@ -257,6 +263,12 @@ static gboolean udscs_server_accept_cb(GSocketService    *service,
     struct udscs_server *server = user_data;
     struct udscs_connection *new_conn;
 
+    /* prevents DoS having too many agents attached */
+    if (g_list_length(server->connections) >= MAX_CONNECTED_AGENTS) {
+        syslog(LOG_ERR, "Too many agents connected");
+        return TRUE;
+    }
+
     new_conn = g_object_new(UDSCS_TYPE_CONNECTION, NULL);
     new_conn->debug = server->debug;
     new_conn->read_callback = server->read_callback;
-- 
2.29.0

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File Avoids-unlimited-agent-connections.patch of Package spice-vdagent

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