On Fri, May 18, 2012 at 6:22 PM, Matthew Monaco <dgbale...@0x01b.net> wrote:
> Currently in rc.sysinit we check that blkid returns 2 before running
> mkswap. This is a little bit stronger. Even without mkswap "cryptsetup
> create" can be dangerous, so do the blkid check for all plain (non-LUKS)
> mappings. Furthermore, just check for a non-zero return status, if this
> is too broad we can get more specific.
I think you reverted the check. It used to be "if blkid returns 2
overwrite the device" now you do "if blkid returns 0 we can overwrite
the device".
> Note: A user can still destroy her data if she enters the wrong password
> for a cryptsetup create. This we'll leave as the user's fault; she
> should be aware of the limitations of a plain mapping and the
> --verify-passphrase cryptsetup option.
> ---
> cryptmount.sh | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/cryptmount.sh b/cryptmount.sh
> index d602043..03699d0 100755
> --- a/cryptmount.sh
> +++ b/cryptmount.sh
> @@ -1,6 +1,6 @@
> #!/bin/sh
>
> -SHORTOPTS="LMUc:w:nqvho:O:"
> +SHORTOPTS="LMUc:fw:nqvho:O:"
> DEPS="cryptsetup blkid findmnt mkswap mktemp"
> UDEVRUNNING=0
>
> @@ -10,6 +10,7 @@ WAITTIME=10
> CRYPTTAB=/etc/crypttab
> OPTIONS=
> FILTER="!noauto"
> +FORCE=0
>
> ct_print_usage() {
> cat <<__EOF__
> @@ -32,6 +33,8 @@ usage: $0 [OPTIONS] [-L]
>
> options:
> -c FILE set the crypttab location (default: /etc/crypttab)
> + -f force destructive operations even when a block device appears to
> + contain data
As this is a bit dangerous stuff, it might be best to not have an -f
option, but rather advice the user to use wipefs manually. Or are
there situations where we really must force cryptsetup, but cannot run
wipefs first?
> -w NUM wait time (seconds) for a device if it is not already available
> -n dry run
> -q decrease verbosity
> @@ -115,6 +118,7 @@ ct_main() {
> M) set_action map;;
> U) set_action unmap;;
> c) CRYPTTAB="$OPTARG";;
> + f) FORCE=1;;
> w) WAITTIME=${OPTARG//[!0-9]};;
> n) DRYRUN=1;;
> q) LOGLEVEL=$(( LOGLEVEL - 1 ));;
> @@ -381,7 +385,14 @@ ct_map() {
>
> info "device '$dev' assumed to be plain"
>
> - if run cryptsetup create $key $args "$name" "$dev"; then
> + # cryptsetup 'create' can be destructive, don't do it if
> blkid can
> + # identify the device type
> + if [ $FORCE -ne 1 ] && blkid -p "$dev" &>/dev/null; then
> + error "Refusing to call 'cryptsetup create' on device
> that might"
> + error " have data. If you are sure this is what you
> want, use"
> + error " the -f option"
> + ret=1
> + elif run cryptsetup create $key $args "$name" "$dev"; then
> info "sucessfully mapped '$dev' to '/dev/mapper/$name'"
> if [ $swap -eq 1 ]; then
> if run mkswap -f -L "$name"
> "/dev/mapper/$name"; then
> --
> 1.7.10.2
>
