libvncserver: check for invalid socket before FD_ISSET in httpd

bk138 · bk138 · commit 27617e141ed9 · 2024-08-30T09:39:04.000+02:00
A mere workaround/mitigation for when the socket is closed by another thread...
diff --git a/src/libvncserver/httpd.c b/src/libvncserver/httpd.c
@@ -203,7 +203,8 @@ rfbHttpCheckFds(rfbScreenInfoPtr rfbScreen)
 	httpProcessInput(rfbScreen);
     }
 
-    if (FD_ISSET(rfbScreen->httpListenSock, &fds) || FD_ISSET(rfbScreen->httpListen6Sock, &fds)) {
+    if ((rfbScreen->httpListenSock != RFB_INVALID_SOCKET && FD_ISSET(rfbScreen->httpListenSock, &fds))
+        || (rfbScreen->httpListen6Sock != RFB_INVALID_SOCKET && FD_ISSET(rfbScreen->httpListen6Sock, &fds))) {
 	if (rfbScreen->httpSock != RFB_INVALID_SOCKET) rfbCloseSocket(rfbScreen->httpSock);
 
 	if(FD_ISSET(rfbScreen->httpListenSock, &fds)) {

Original file line number	Diff line number	Diff line change
`@@ -203,7 +203,8 @@ rfbHttpCheckFds(rfbScreenInfoPtr rfbScreen)`
`203`	`203`	`httpProcessInput(rfbScreen);`
`204`	`204`	`}`
`205`	`205`
`206`		`- if (FD_ISSET(rfbScreen->httpListenSock, &fds) \|\| FD_ISSET(rfbScreen->httpListen6Sock, &fds)) {`
	`206`	`+ if ((rfbScreen->httpListenSock != RFB_INVALID_SOCKET && FD_ISSET(rfbScreen->httpListenSock, &fds))`
	`207`	`+ \|\| (rfbScreen->httpListen6Sock != RFB_INVALID_SOCKET && FD_ISSET(rfbScreen->httpListen6Sock, &fds))) {`
`207`	`208`	`if (rfbScreen->httpSock != RFB_INVALID_SOCKET) rfbCloseSocket(rfbScreen->httpSock);`
`208`	`209`
`209`	`210`	`if(FD_ISSET(rfbScreen->httpListenSock, &fds)) {`