char: fix missing return in error path for chardev TLS init

If the qio_channel_tls_new_(server|client) methods fail,
we disconnect the client. Unfortunately a missing return
means we then go on to try and run the TLS handshake on
a NULL I/O channel. This gives predictably segfaulty
results.

The main way to trigger this is to request a bogus TLS
priority string for the TLS credentials. e.g.

  -object tls-creds-x509,id=tls0,priority=wibble,...

Most other ways appear impossible to trigger except
perhaps if OOM conditions cause gnutls initialization
to fail.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
(cherry picked from commit 660a2d83e026496db6b3eaec2256a2cdd6c74de8)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/qemu-char.c b/qemu-char.c
index fdb23f52896643595ab7f3a33f2926e5744e53bc..90e96271dd7a8c4bb17f41f9386060c019c430f6 100644 (file)
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3096,6 +3096,7 @@ static void tcp_chr_tls_init(CharDriverState *chr)
     if (tioc == NULL) {
         error_free(err);
         tcp_chr_disconnect(chr);
+        return;
     }
     object_unref(OBJECT(s->ioc));
     s->ioc = QIO_CHANNEL(tioc);