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authorMartin Pitt <martin.pitt@ubuntu.com>2015-04-16 06:44:07 -0500
committerMartin Pitt <martin.pitt@ubuntu.com>2015-04-17 10:53:01 -0500
commit4eac277367d70e6126f53886f99043409a80195f (patch)
tree71784ac1dcf5cdc0648126a87cd469e678ac6f8b /man/crypttab.xml
parent18ae3d98d97ca35da106f66f547bce64b4be31ee (diff)
cryptsetup: Implement offset and skip options
These are useful for plain devices as they don't have any metadata by themselves. Instead of using an unreliable hardcoded device name in crypttab you can then put static metadata at the start of the partition for a stable UUID or label. https://bugs.freedesktop.org/show_bug.cgi?id=87717 https://bugs.debian.org/751707 https://launchpad.net/bugs/953875
Diffstat (limited to 'man/crypttab.xml')
-rw-r--r--man/crypttab.xml24
1 files changed, 24 insertions, 0 deletions
diff --git a/man/crypttab.xml b/man/crypttab.xml
index 3e249ad23e..d4ff760adc 100644
--- a/man/crypttab.xml
+++ b/man/crypttab.xml
@@ -146,6 +146,30 @@
</varlistentry>
<varlistentry>
+ <term><option>offset=</option></term>
+
+ <listitem><para>Start offset in the backend device, in 512-byte sectors.
+ This option is only relevant for plain devices.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>skip=</option></term>
+
+ <listitem><para>How many 512-byte sectors of the encrypted data to skip
+ at the beginning. This is different from the <option>--offset</option>
+ option with respect to the sector numbers used in initialization vector
+ (IV) calculation. Using <option>--offset</option> will shift the IV
+ calculation by the same negative amount. Hence, if <option>--offset n</option>,
+ sector n will get a sector number of 0 for the IV calculation.
+ Using <option>--skip</option> causes sector n to also be the first
+ sector of the mapped device, but with its number for IV generation is n.</para>
+
+ <para>This option is only relevant for plain devices.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><option>keyfile-offset=</option></term>
<listitem><para>Specifies the number of bytes to skip at the