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From: "Shannon Sterz" <s.sterz@proxmox.com>
To: "Maximiliano Sandoval" <m.sandoval@proxmox.com>
Cc: pve-devel@lists.proxmox.com
Subject: Re: [PATCH docs v2 2/2] pveum: document that the pve realm now uses yescrypt
Date: Wed, 21 Oct 2026 16:39:46 +0200	[thread overview]
Message-ID: <DMALE4VQBDTS.3DTOENDCFVG6R@proxmox.com> (raw)
In-Reply-To: <s8ojynbtaum.fsf@toolbox>

On Wed Oct 21, 2026 at 3:57 PM CEST, Maximiliano Sandoval wrote:
-->8 snip 8<--

>> +`/etc/pve/priv/shadow.cfg`. Passwords are hashed and salted using the yescrypt
>> +algorithm footnote:[yescrypt https://www.openwall.com/yescrypt/]. It provides
>> +strong protections against offline password cracking attempts. This realm is the
>
> nit: Perhaps /protections/protection/?

No protections is right. It offers tunable hardness for all three the
runtime, memory usage and parallelism. So I'd say those are multiple
protections.

>
>> +most convenient realm for small-scale (or even mid-scale) installations, where
>> +users do not need access to anything outside of {pve}. In this case, users are
>> +fully managed by {pve} and are able to change their own passwords via the GUI.
>> +
>> +NOTE: Passwords created with older versions of Proxmox VE  used a hashing scheme
>
> nit: This should be '{pve}' rather than 'Proxmox VE '.

Yep will update this for a potential v3. Same for the related PMG patch.

>
>> +based on SHA-256 that is now considered insecure. If the file
>
> nit: By whom? Is there any good source to link here?
>

> The default processing cost parameter is 5000, which is too low  for  modern
> hardware.
>
> - man 5 crypt

We never modified the default of 5000. So technically if you want to
capture all nuances here, the function itself *could* still be fine.
However, the way we used it wasn't (incidentally, SHA-256 is still used
by yescrypt, just in a different construction).

I'll add that to the commit message of the first patch for more clarity,
but I think for the docs the text is fine as-is. What's important for
users is that if they see a `$5$` in that file, they should log in again
or, alternatively, set a new password (e.g. by having an admin account
set a new password for that account).

Note that PDM and PBS already use yescrypt for that reason [1].

[1]: https://lore.proxmox.com/all/20240306123609.164021-7-s.sterz@proxmox.com/

-->8 snip 8<--




  reply	other threads:[~2026-10-21 14:40 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-21 11:38 [PATCH access-control/docs v2 0/2] Update default password hash function to yescrypt Shannon Sterz
2026-10-21 11:38 ` [PATCH access-control v2 1/2] pam/pve: use yescrypt for new password hashes Shannon Sterz
2026-10-21 11:38 ` [PATCH docs v2 2/2] pveum: document that the pve realm now uses yescrypt Shannon Sterz
2026-10-21 13:57   ` Maximiliano Sandoval
2026-10-21 14:39     ` Shannon Sterz [this message]
2026-10-21 14:04 ` [PATCH access-control/docs v2 0/2] Update default password hash function to yescrypt Maximiliano Sandoval
2026-10-21 14:39   ` Shannon Sterz

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