Benoît Knecht 0ec6e10bf2 util: Limit cryptsetup PBKDF memory usage
By default, `cryptsetup luksFormat` uses Argon2i as Password-Based Key
Derivation Function (PBKDF), which not only has a CPU cost, but also a memory
cost (to make brute-force attacks harder).

The memory cost is based on the available system memory by default, which in
the context of Ceph CSI can be a problem for two reasons:

1. Pods can have a memory limit (much lower that the memory available on the
   node, usually) which isn't taken into account by `cryptsetup`, so it can get
   OOM-killed when formating a new volume;
2. The amount of memory that was used during `cryptsetup luksFormat` will then
   be needed for `cryptsetup luksOpen`, so if the volume was formated on a node
   with a lot of memory, but then needs to be opened on a different node with
   less memory, `cryptsetup` will get OOM-killed.

This commit sets the PBKDF memory limit to a fixed value to ensure consistent
memory usage regardless of the specifications of the nodes where the volume
happens to be formatted in the first place.

The limit is set to a relatively low value (32 MiB) so that the `csi-rbdplugin`
container in the `nodeplugin` pod doesn't require an extravagantly high memory
limit in order to format/open volumes (particularly with operations happening
in parallel), while at the same time not being so low as to render it
completely pointless.

Signed-off-by: Benoît Knecht <bknecht@protonmail.ch>
(cherry picked from commit 1852e977f899ba509e86e71b1a3d35dcf068a7e1)
2023-04-27 16:47:12 +00:00
..
2023-02-02 14:53:59 +00:00
2022-03-27 19:24:26 +00:00
2023-02-02 14:53:59 +00:00
2023-02-03 08:55:43 +00:00