From e6b636779b51c97e67694be740ee972c52460c59 Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Tue, 19 Mar 2013 11:20:20 +0000 Subject: Add -f FMT / --format FMT arg to qemu-nbd Currently the qemu-nbd program will auto-detect the format of any disk it is given. This behaviour is known to be insecure. For example, if qemu-nbd initially exposes a 'raw' file to an unprivileged app, and that app runs 'qemu-img create -f qcow2 -o backing_file=/etc/shadow /dev/nbd0' then the next time the app is started, the qemu-nbd will now detect it as a 'qcow2' file and expose /etc/shadow to the unprivileged app. The only way to avoid this is to explicitly tell qemu-nbd what disk format to use on the command line, completely disabling auto-detection. This patch adds a '-f' / '--format' arg for this purpose, mirroring what is already available via qemu-img and qemu commands. qemu-nbd --format raw -p 9000 evil.img will now always use raw, regardless of what format 'evil.img' looks like it contains Signed-off-by: Daniel P. Berrange [Use errx, not err. - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Anthony Liguori --- qemu-nbd.texi | 2 ++ 1 file changed, 2 insertions(+) (limited to 'qemu-nbd.texi') diff --git a/qemu-nbd.texi b/qemu-nbd.texi index 5f3f3e3276..6055ec693b 100644 --- a/qemu-nbd.texi +++ b/qemu-nbd.texi @@ -45,6 +45,8 @@ Export QEMU disk image using NBD protocol. disconnect the specified device @item -e, --shared=@var{num} device can be shared by @var{num} clients (default @samp{1}) +@item -f, --format=@var{fmt} + force block driver for format @var{fmt} instead of auto-detecting @item -t, --persistent don't exit on the last connection @item -v, --verbose -- cgit v1.2.1