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e6b636779b
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 <berrange@redhat.com> [Use errx, not err. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
78 lines
2.1 KiB
Plaintext
78 lines
2.1 KiB
Plaintext
@example
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@c man begin SYNOPSIS
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usage: qemu-nbd [OPTION]... @var{filename}
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@c man end
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@end example
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@c man begin DESCRIPTION
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Export QEMU disk image using NBD protocol.
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@c man end
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@c man begin OPTIONS
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@table @option
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@item @var{filename}
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is a disk image filename
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@item -p, --port=@var{port}
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port to listen on (default @samp{1024})
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@item -o, --offset=@var{offset}
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offset into the image
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@item -b, --bind=@var{iface}
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interface to bind to (default @samp{0.0.0.0})
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@item -k, --socket=@var{path}
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Use a unix socket with path @var{path}
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@item -r, --read-only
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export read-only
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@item -P, --partition=@var{num}
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only expose partition @var{num}
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@item -s, --snapshot
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use snapshot file
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@item -n, --nocache
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@itemx --cache=@var{cache}
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set cache mode to be used with the file. See the documentation of
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the emulator's @code{-drive cache=...} option for allowed values.
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@item --aio=@var{aio}
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choose asynchronous I/O mode between @samp{threads} (the default)
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and @samp{native} (Linux only).
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@item --discard=@var{discard}
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toggles whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap})
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requests are ignored or passed to the filesystem. The default is no
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(@samp{--discard=ignore}).
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@item -c, --connect=@var{dev}
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connect @var{filename} to NBD device @var{dev}
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@item -d, --disconnect
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disconnect the specified device
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@item -e, --shared=@var{num}
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device can be shared by @var{num} clients (default @samp{1})
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@item -f, --format=@var{fmt}
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force block driver for format @var{fmt} instead of auto-detecting
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@item -t, --persistent
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don't exit on the last connection
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@item -v, --verbose
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display extra debugging information
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@item -h, --help
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display this help and exit
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@item -V, --version
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output version information and exit
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@end table
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@c man end
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@ignore
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@setfilename qemu-nbd
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@settitle QEMU Disk Network Block Device Server
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@c man begin AUTHOR
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Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.
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This is free software; see the source for copying conditions. There is NO
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warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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@c man end
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@c man begin SEEALSO
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qemu-img(1)
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@c man end
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@end ignore
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