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

[Fiona Ebner]

Am 13.03.24 um 16:42 schrieb Stefan Sterz:
> 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.
>>

Technically, it's two changes, so could be two patches, but can be fine
like this too, since both touch the same check.

>> [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 at 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:
> 

If you already touch the same line, you can also adapt style in one go.
But since the style change is also done in a second place, which is not
touched by this patch, it's fine like Max did it too.

> Tested-by: Stefan Sterz <s.sterz at proxmox.com>
> 
>> +    if (!(defined($monhash->{$monid}) ||
>> +	  grep { exists($_->{name}) && $_->{name} eq $monid } @$monlist))

While I suppose we do not expect an entry with undef value here, you do
not want to compare against undef (just leads to an ugly Perl warning),
so this should be a definedness check, not an existence check.

>>      {
>>  	die "no such monitor id '$monid'\n"
>>      }
> 
> 
> 
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