From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41945) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aIyRt-0004xK-JG for qemu-devel@nongnu.org; Tue, 12 Jan 2016 07:53:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aIyRp-0007s6-Cy for qemu-devel@nongnu.org; Tue, 12 Jan 2016 07:53:21 -0500 From: Wolfgang Bumiller Date: Tue, 12 Jan 2016 13:52:39 +0100 Message-Id: <1452603159-19782-1-git-send-email-w.bumiller@proxmox.com> Subject: [Qemu-devel] [PATCH] vnc: clear vs->tlscreds after unparenting it List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: qemu-trivial@nongnu.org, qemu-devel@nongnu.org This pointer should be cleared in vnc_display_close() otherwise a use-after-free can happen when when using the old style 'x509' and 'tls' options rather than a persistent tls-creds -object, by issuing monitor commands to change the vnc server like so: Start with: -vnc unix:test.socket,x509,tls Then use the following monitor command: change vnc unix:test.socket After this the pointer is still set but invalid and a crash can be triggered for instance by issuing the same command a second time which will try to object_unparent() the same pointer again. --- ui/vnc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/ui/vnc.c b/ui/vnc.c index 09756cd..35843b5 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -3134,6 +3134,7 @@ static void vnc_display_close(VncDisplay *vs) vs->subauth = VNC_AUTH_INVALID; if (vs->tlscreds) { object_unparent(OBJECT(vs->tlscreds)); + vs->tlscreds = NULL; } g_free(vs->tlsaclname); vs->tlsaclname = NULL; -- 2.1.4