diff options
| -rw-r--r-- | man/man8/zfs-load-key.8 | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/man/man8/zfs-load-key.8 b/man/man8/zfs-load-key.8 index bf255d96d..158f69b0a 100644 --- a/man/man8/zfs-load-key.8 +++ b/man/man8/zfs-load-key.8 @@ -30,7 +30,7 @@ .\" Copyright 2018 Nexenta Systems, Inc. .\" Copyright 2019 Joyent, Inc. .\" -.Dd June 30, 2019 +.Dd January 13, 2020 .Dt ZFS-LOAD-KEY 8 .Os Linux .Sh NAME @@ -154,7 +154,7 @@ Unloads the keys for all encryption roots in all imported pools. .Op Fl l .Ar filesystem .Xc -Allows a user to change the encryption key used to access a dataset. This +Changes the user's key (e.g. a passphrase) used to access a dataset. This command requires that the existing key for the dataset is already loaded into ZFS. This command may also be used to change the .Sy keylocation , @@ -166,6 +166,29 @@ will become one. Alternatively, the .Fl i flag may be provided to cause an encryption root to inherit the parent's key instead. +.Pp +If the user's key is compromised, +.Nm zfs Cm change-key +does not necessarily protect existing or newly-written data from attack. +Newly-written data will continue to be encrypted with the same master key as +the existing data. The master key is compromised if an attacker obtains a +user key and the corresponding wrapped master key. Currently, +.Nm zfs Cm change-key +does not overwrite the previous wrapped master key on disk, so it is +accessible via forensic analysis for an indeterminate length of time. +.Pp +In the event of a master key compromise, ideally the drives should be securely +erased to remove all the old data (which is readable using the compromised +master key), a new pool created, and the data copied back. This can be +approximated in place by creating new datasets, copying the data +(e.g. using +.Nm zfs Cm send +| +.Nm zfs Cm recv Ns +), and then clearing the free space with +.Nm zpool Cm trim --secure +if supported by your hardware, otherwise +.Nm zpool Cm initialize Ns . .Bl -tag -width "-r" .It Fl l Ensures the key is loaded before attempting to change the key. This is |