libvncclient: prevent acting on ExtendedDesktopSize with 0 dimensions

Christian Beier · Christian Beier · commit 5b4be28e1082 · 2022-08-09T15:43:55.000+02:00
This is sent by UltraVNC 1.3.2 at least.
diff --git a/libvncclient/rfbproto.c b/libvncclient/rfbproto.c
@@ -1914,7 +1914,7 @@ HandleRFBServerMessage(rfbClient* client)
           if (!ReadFromRFBServer(client, ((char *)&screen), sz_rfbExtDesktopScreen)) {
             return FALSE;
           }
-          if (screen.id != 0) {
+          if (screen.id != 0 && screen.width && screen.height) {
             client->screen = screen;
           } else {
             invalidScreen = TRUE;

Original file line number	Diff line number	Diff line change
`@@ -1914,7 +1914,7 @@ HandleRFBServerMessage(rfbClient* client)`
`1914`	`1914`	`if (!ReadFromRFBServer(client, ((char *)&screen), sz_rfbExtDesktopScreen)) {`
`1915`	`1915`	`return FALSE;`
`1916`	`1916`	`}`
`1917`		`- if (screen.id != 0) {`
	`1917`	`+ if (screen.id != 0 && screen.width && screen.height) {`
`1918`	`1918`	`client->screen = screen;`
`1919`	`1919`	`} else {`
`1920`	`1920`	`invalidScreen = TRUE;`