[Qemu-devel] [6121] Properly handle the case of SetPixelEncodings with a length of zero.

[Anthony Liguori]

Revision: 6121
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6121
Author:   aliguori
Date:     2008-12-22 21:06:23 +0000 (Mon, 22 Dec 2008)

Log Message:
-----------
Properly handle the case of SetPixelEncodings with a length of zero.

This commit addresses CORE-2008-1210/CVE-2008-2382.

Signed-off-by: Anthony Liguori <address@hidden>

Modified Paths:
--------------
    trunk/vnc.c

Modified: trunk/vnc.c
===================================================================
--- trunk/vnc.c 2008-12-22 20:33:55 UTC (rev 6120)
+++ trunk/vnc.c 2008-12-22 21:06:23 UTC (rev 6121)
@@ -1503,10 +1503,13 @@
        if (len == 1)
            return 4;
 
-       if (len == 4)
-           return 4 + (read_u16(data, 2) * 4);
+       if (len == 4) {
+            limit = read_u16(data, 2);
+            if (limit > 0)
+                return 4 + (limit * 4);
+        } else
+            limit = read_u16(data, 2);
 
-       limit = read_u16(data, 2);
        for (i = 0; i < limit; i++) {
            int32_t val = read_s32(data, 4 + (i * 4));
            memcpy(data + 4 + (i * 4), &val, sizeof(val));