From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48607) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDY6R-000753-MY for qemu-devel@nongnu.org; Thu, 16 Jun 2016 10:17:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDY6P-00037P-E0 for qemu-devel@nongnu.org; Thu, 16 Jun 2016 10:17:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54317) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDY6P-00037H-7t for qemu-devel@nongnu.org; Thu, 16 Jun 2016 10:17:01 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E36883B709 for ; Thu, 16 Jun 2016 14:17:00 +0000 (UTC) From: Paolo Bonzini Date: Thu, 16 Jun 2016 16:16:16 +0200 Message-Id: <1466086585-16526-22-git-send-email-pbonzini@redhat.com> In-Reply-To: <1466086585-16526-1-git-send-email-pbonzini@redhat.com> References: <1466086585-16526-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PULL 21/30] nbd: Reject unknown request flags List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org From: Eric Blake The NBD protocol says that clients should not send a command flag that has not been negotiated (whether by the client requesting an option during a handshake, or because we advertise support for the flag in response to NBD_OPT_EXPORT_NAME), and that servers should reject invalid flags with EINVAL. We were silently ignoring the flags instead. The client can't rely on our behavior, since it is their fault for passing the bad flag in the first place, but it's better to be robust up front than to possibly behave differently than the client was expecting with the attempted flag. Signed-off-by: Eric Blake Reviewed-by: Alex Bligh Message-Id: <1463006384-7734-6-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini --- nbd/server.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/nbd/server.c b/nbd/server.c index 0e71f78..b9c839e 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1072,6 +1072,11 @@ static ssize_t nbd_co_receive_request(NBDRequest *req, rc = command == NBD_CMD_WRITE ? -ENOSPC : -EINVAL; goto out; } + if (request->type & ~NBD_CMD_MASK_COMMAND & ~NBD_CMD_FLAG_FUA) { + LOG("unsupported flags (got 0x%x)", + request->type & ~NBD_CMD_MASK_COMMAND); + return -EINVAL; + } rc = 0; -- 2.5.5