From 6e5b9924b172be4f33c7fc264a8ff1d6109b79fe Mon Sep 17 00:00:00 2001 From: Frediano Ziglio Date: Sun, 20 Sep 2020 08:05:37 +0100 Subject: [PATCH vd_agent_linux 12/17] Avoids unlimited agent connections 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 --- 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