From d8b20291cba6aa9bb295885a34f2b5f05d59d1b2 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Thu, 21 Jun 2018 07:49:37 -0500 Subject: [PATCH] nbd/server: Reject 0-length block status request 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 Message-Id: <20180621124937.166549-1-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy --- nbd/server.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/nbd/server.c b/nbd/server.c index 9e1f227178..493a926e06 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,