From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57009) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fVz28-0006Ul-2S for qemu-devel@nongnu.org; Thu, 21 Jun 2018 08:49:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fVz27-0004LO-8R for qemu-devel@nongnu.org; Thu, 21 Jun 2018 08:49:52 -0400 From: Eric Blake Date: Thu, 21 Jun 2018 07:49:37 -0500 Message-Id: <20180621124937.166549-1-eblake@redhat.com> Subject: [Qemu-devel] [PATCH] nbd/server: Reject 0-length block status request List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: jsnow@redhat.com, vsementsov@virtuozzo.com, qemu-block@nongnu.org, qemu-stable@nongnu.org, Paolo Bonzini The NBD spec says that behavior is unspecified if the client requests 0 length for block status; but since the structured reply is documenting as returning a non-zero length, it's easier to just diagnose this with an EINVAL error than to figure out what to return. CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake --- nbd/server.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/nbd/server.c b/nbd/server.c index 9e1f2271784..493a926e063 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -2007,6 +2007,10 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, "discard failed", errp); case NBD_CMD_BLOCK_STATUS: + if (!request->len) { + return nbd_send_generic_reply(client, request->handle, -EINVAL, + "need non-zero length", errp); + } if (client->export_meta.valid && client->export_meta.base_allocation) { return nbd_co_send_block_status(client, request->handle, blk_bs(exp->blk), request->from, -- 2.14.4