spice-vdagent/backport-0002-CVE-2020-25650.patch

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From 9d35d8a86fb310fc1f29d428c0a96995948d2357 Mon Sep 17 00:00:00 2001
From: Frediano Ziglio <freddy77@gmail.com>
Date: Fri, 2 Oct 2020 12:27:59 +0100
Subject: [PATCH] Avoids uncontrolled "active_xfers" allocations
Limit the number of active file transfers possibly causing DoSes
consuming memory in "active_xfers".
This issue was reported by SUSE security team.
Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Acked-by: Uri Lublin <uril@redhat.com>
---
src/vdagentd/vdagentd.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
--- a/src/vdagentd/vdagentd.c
+++ b/src/vdagentd/vdagentd.c
@@ -46,6 +46,14 @@
#define DEFAULT_UINPUT_DEVICE "/dev/uinput"
+// Maximum number of transfers active at any time.
+// Avoid DoS from client.
+// As each transfer could likely end up taking a file descriptor
+// it is good to have a limit less than the number of file descriptors
+// in the process (by default 1024). The daemon do not open file
+// descriptors for the transfers but the agents do.
+#define MAX_ACTIVE_TRANSFERS 128
+
struct agent_data {
char *session;
int width;
@@ -372,6 +380,12 @@ static void do_client_file_xfer(VirtioPo
"Cancelling client file-xfer request %u",
s->id, VD_AGENT_FILE_XFER_STATUS_SESSION_LOCKED, NULL, 0);
return;
+ } else if (g_hash_table_size(active_xfers) >= MAX_ACTIVE_TRANSFERS) {
+ send_file_xfer_status(vport,
+ "Too many transfers ongoing. "
+ "Cancelling client file-xfer request %u",
+ s->id, VD_AGENT_FILE_XFER_STATUS_ERROR, NULL, 0);
+ return;
}
msg_type = VDAGENTD_FILE_XFER_START;
id = s->id;
--
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