On Fri, May 18, 2012 at 6:22 PM, Matthew Monaco
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