Re: [pve-devel] [PATCH pve-manager 1/2] fix #5198: ceph: mon: fix mon existence check in mon removal assertion

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

On Wed Mar 13, 2024 at 3:53 PM CET, Max Carrara wrote:
> The Ceph monitor removal assertion contains a condition that checks
> whether the given mon ID actually exists and thus may be removed.
>
> The first part of the condition checks whether the hash returned by
> `get_services_info` [0] contains the key "mon.$monid". However, the
> hash's keys are never prefixed with "mon.", which makes this check
> incorrect.
>
> This is fixed by just using "$monid" directly.
>
> The second part checks whether the mon hashes returned by
> Ceph contain the "name" key before comparing the key with the given
> mon ID. This key existence check is also incorrect; in particular:
>   * If the lookup `$_->{name}` evaluates to e.g. "foo", the check
>     passes, because "foo" is truthy. [1]
>   * If the lookup `$_->{name}` evaluates to "0", the check fails,
>     because "0" is falsy (due to it being equivalent to the number 0,
>     according to Perl [1]).
>
> This is solved by using the inbuilt `exists()` instead of relying on
> Perl's definition of truthiness.
>
> [0]: https://git.proxmox.com/?p=pve-manager.git;a=blob;f=PVE/Ceph/Services.pm;h=e0f31e8eb6bc9b3777b3d0d548497276efaa5c41;hb=HEAD#l112
> [1]: https://perldoc.perl.org/perldata#Scalar-values
>
> Fixes: https://bugzilla.proxmox.com/show_bug.cgi?id=5198
> Signed-off-by: Max Carrara <m.carrara@proxmox.com>
> ---
>  PVE/API2/Ceph/MON.pm | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/PVE/API2/Ceph/MON.pm b/PVE/API2/Ceph/MON.pm
> index 1e959ef3..1737c294 100644
> --- a/PVE/API2/Ceph/MON.pm
> +++ b/PVE/API2/Ceph/MON.pm
> @@ -147,8 +147,8 @@ my $assert_mon_prerequisites = sub {
>  my $assert_mon_can_remove = sub {
>      my ($monhash, $monlist, $monid, $mondir) = @_;
>
> -    if (!(defined($monhash->{"mon.$monid"}) ||
> -	  grep { $_->{name} && $_->{name} eq $monid } @$monlist))

not sure if splitting the fix and the code style clean up makes sense
here but otherwise this works as advertised. So:

Tested-by: Stefan Sterz <s.sterz@proxmox.com>

> +    if (!(defined($monhash->{$monid}) ||
> +	  grep { exists($_->{name}) && $_->{name} eq $monid } @$monlist))
>      {
>  	die "no such monitor id '$monid'\n"
>      }