Re: [PATCH common 0/2] ticket: sign RSA tickets with SHA-256

["Shannon Sterz" <s.sterz@proxmox.com>]

On Fri Oct 23, 2026 at 8:36 PM CEST, Mark Atwood wrote:
> RSA tickets are currently signed with SHA-1, because that is the
> Crypt::OpenSSL::RSA default. NIST SP 800-131A Rev. 2 disallows SHA-1 for
> creating signatures. With a FIPS provider that enforces this, such as
> wolfProvider or the OpenSSL FIPS provider with its signature digest
> check enabled, the signing call fails and nobody can log in.
>
> The change is split in two so that it can be staged for clusters with
> mixed versions, where an updated node forwards its tickets to nodes
> that are not updated yet:
>
> 1/2 makes verification accept SHA-256 as well as SHA-1. It changes no
>     issued ticket and can be applied right away.
> 2/2 switches signing to SHA-256. Nodes without 1/2 reject the new
>     tickets, so this should go in once 1/2 has been in a released
>     version for a while, for example with the next major release.
>
> The SHA-1 verification fallback can be dropped in a later major release,
> once no supported version signs with SHA-1 anymore. Tickets are only
> valid for two hours, so it does not need to cover old tickets, only
> nodes running old versions.
>
> Tested with "make check" on Debian trixie with the build dependencies
> from pve-no-subscription. The new test fails on master for the SHA-256
> cases and, with only 1/2 applied, for the signing checks of 2/2. I also
> checked a ticket issued with the series applied with
> "openssl dgst -sha256 -verify", which accepts it, and with -sha1, which
> rejects it.
>
> A separate patch for pve-access-control removes the leftover SHA-1 CSRF
> token fallback there.
>
> Mark Atwood (2):
>   ticket: accept RSA tickets signed with SHA-256
>   ticket: sign RSA tickets with SHA-256
>
>  src/PVE/Ticket.pm   |  19 ++++++++-
>  test/Makefile       |   1 +
>  test/ticket_test.pl | 102 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 121 insertions(+), 1 deletion(-)
>  create mode 100755 test/ticket_test.pl
>
>
> base-commit: d3e8405874f43e4a128a11d7ce829102fda2eefd


Hey Mark,

thank you for these patches, one small note up-front: these patches will
also affect PMG as it uses the `PVE::Ticket` module for its tickets as
well. This should maybe be mentioned in the commit messages.

Noted a few smaller things on the patches. IMO nothing that needs to
hold up at least the first patch here. The second patch could be
re-written so that we can possibly apply it sooner, too. See my comment
there.

Note that these patches no longer apply as a ticket test module has been
applied since.

Thanks again!