From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45329) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UNl0G-0000Qp-5y for qemu-devel@nongnu.org; Thu, 04 Apr 2013 10:19:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UNl09-0006Ih-SZ for qemu-devel@nongnu.org; Thu, 04 Apr 2013 10:19:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48115) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UNl09-0006Hk-L3 for qemu-devel@nongnu.org; Thu, 04 Apr 2013 10:18:53 -0400 From: Stefan Hajnoczi Date: Thu, 4 Apr 2013 16:18:31 +0200 Message-Id: <1365085111-17027-5-git-send-email-stefanha@redhat.com> In-Reply-To: <1365085111-17027-1-git-send-email-stefanha@redhat.com> References: <1365085111-17027-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH stable-1.4 v2 4/4] chardev: clear O_NONBLOCK on SCM_RIGHTS file descriptors List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Markus Armbruster , Michael Roth , Stefan Hajnoczi , Luiz Capitulino When we receive a file descriptor over a UNIX domain socket the O_NONBLOCK flag is preserved. Clear the O_NONBLOCK flag and rely on QEMU file descriptor users like migration, SPICE, VNC, block layer, and others to set non-blocking only when necessary. This change ensures we don't accidentally expose O_NONBLOCK in the QMP API. QMP clients should not need to get the non-blocking state "correct". A recent real-world example was when libvirt passed a non-blocking TCP socket for migration where we expected a blocking socket. The source QEMU produced a corrupted migration stream since its code did not cope with non-blocking sockets. Signed-off-by: Stefan Hajnoczi (cherry picked from commit e374f7f816171f9783c1d9d00a041f26379f1ac6) Signed-off-by: Stefan Hajnoczi --- qemu-char.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/qemu-char.c b/qemu-char.c index d685139..1efca64 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -2252,6 +2252,9 @@ static void unix_process_msgfd(CharDriverState *chr, struct msghdr *msg) if (fd < 0) continue; + /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */ + qemu_set_block(fd); + #ifndef MSG_CMSG_CLOEXEC qemu_set_cloexec(fd); #endif -- 1.8.1.4