shithub: choc

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ref: f1a8d991aa8a14afcb605cf2f65cd15fda204c56
parent: 5bf73c4864fedb6b97b27bf302435a1168ba8f4c
author: Fabian Greffrath <[email protected]>
date: Wed Jun 24 08:45:03 EDT 2020

net: fix missing server-side num_players validation (CVE-2020-14983)

The server in Chocolate Doom 3.0.0 and Crispy Doom 5.8.0 doesn't
validate the user-controlled num_players value, leading to a buffer
overflow. A malicious user can overwrite the server's stack.

Fixes CVE-2020-14983, found by Michał Dardas from LogicalTrust.

Fixes: #1293.

--- a/src/net_structrw.c

+++ b/src/net_structrw.c

@@ -116,7 +116,7 @@

         return false;

     }

-    for (i = 0; i < settings->num_players; ++i)

+    for (i = 0; i < settings->num_players && i < NET_MAXPLAYERS; ++i)

     {

         if (!NET_ReadInt8(packet,

                           (unsigned int *) &settings->player_classes[i]))