File 0225-ui-vnc-limit-client_cut_text-msg-pa.patch of Package qemu.5921

Overview Repositories Revisions Requests Users Attributes Meta

File 0225-ui-vnc-limit-client_cut_text-msg-pa.patch of Package qemu.5921

From 6bf68f4e026fe2fbb23f09a27bbd415e4fcc64c8 Mon Sep 17 00:00:00 2001
From: Peter Lieven <pl@kamp.de>
Date: Mon, 30 Jun 2014 10:07:54 +0200
Subject: [PATCH] ui/vnc: limit client_cut_text msg payload size

currently a malicious client could define a payload
size of 2^32 - 1 bytes and send up to that size of
data to the vnc server. The server would allocated
that amount of memory which could easily create an
out of memory condition.

This patch limits the payload size to 1MB max.

Please note that client_cut_text messages are currently
silently ignored.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit f9a70e79391f6d7c2a912d785239ee8effc1922d)
[CYL: BSC#944463 CVE-2015-5239]
Signed-off-by: Chunyan Liu <cyliu@suse.com>
---
 ui/vnc.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index 38a1dd0213..dbe3f2b2fa 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -2187,13 +2187,20 @@ static int protocol_client_msg(VncState *vs, uint8_t *data, size_t len)
         pointer_event(vs, read_u8(data, 1), read_u16(data, 2), read_u16(data, 4));
         break;
     case VNC_MSG_CLIENT_CUT_TEXT:
-        if (len == 1)
+        if (len == 1) {
             return 8;
-
+        }
         if (len == 8) {
             uint32_t dlen = read_u32(data, 4);
-            if (dlen > 0)
+            if (dlen > (1 << 20)) {
+                error_report("vnc: client_cut_text msg payload has %u bytes"
+                             " which exceeds our limit of 1MB.", dlen);
+                vnc_client_error(vs);
+                break;
+            }
+            if (dlen > 0) {
                 return 8 + dlen;
+            }
         }
 
         client_cut_text(vs, read_u32(data, 4), data + 8);

Places

File 0225-ui-vnc-limit-client_cut_text-msg-pa.patch of Package qemu.5921

Places