From: Frediano Ziglio <freddy77@xxxxxxxxx>
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@xxxxxxxxx>
---
src/udscs.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/src/udscs.c b/src/udscs.c
index 7c99eed..3df67b3 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 _UdscsConnection {
VDAgentConnection parent_instance;
int debug;
@@ -254,6 +260,12 @@ static gboolean udscs_server_accept_cb(GSocketService *service,
struct udscs_server *server = user_data;
UdscsConnection *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;
--
2.26.2
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