[pve-devel] [PATCH container] config: allow empty environment variables

[pve-devel] [PATCH container] config: allow empty environment variables

[Filip Schauer]

This fixes a problem with the docker.io/httpd OCI image which specifies
an empty environment variable. This violated the pattern of the `env`
property, causing `pct config <vmid>` to fail with:
```
env: value does not match the regex pattern
```

Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
 src/PVE/LXC/Config.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
index cd3a172..b6fc9a8 100644
--- a/src/PVE/LXC/Config.pm
+++ b/src/PVE/LXC/Config.pm
@@ -671,7 +671,7 @@ my $confdesc = {
         description => 'The container runtime environment as NUL-separated list.'
             . ' Replaces any lxc.environment.runtime entries in the config.',
         optional => 1,
-        pattern => qr/(?:\w+=[^\x00-\x1F\x7F]+)(?:\0\w+=[^\x00-\x1F\x7F]+)*/,
+        pattern => qr/(?:\w+=[^\x00-\x1F\x7F]*)(?:\0\w+=[^\x00-\x1F\x7F]*)*/,
     },
     hookscript => {
         optional => 1,
-- 
2.47.3



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Re: [pve-devel] [PATCH container] config: allow empty environment variables

[Fabian Grünbichler]

On November 17, 2025 1:49 pm, Filip Schauer wrote:
> This fixes a problem with the docker.io/httpd OCI image which specifies
> an empty environment variable. This violated the pattern of the `env`
> property, causing `pct config <vmid>` to fail with:

shouldn't we handle this and drop that environment variable entry
instead?

> ```
> env: value does not match the regex pattern
> ```
> 
> Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
> ---
>  src/PVE/LXC/Config.pm | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
> index cd3a172..b6fc9a8 100644
> --- a/src/PVE/LXC/Config.pm
> +++ b/src/PVE/LXC/Config.pm
> @@ -671,7 +671,7 @@ my $confdesc = {
>          description => 'The container runtime environment as NUL-separated list.'
>              . ' Replaces any lxc.environment.runtime entries in the config.',
>          optional => 1,
> -        pattern => qr/(?:\w+=[^\x00-\x1F\x7F]+)(?:\0\w+=[^\x00-\x1F\x7F]+)*/,
> +        pattern => qr/(?:\w+=[^\x00-\x1F\x7F]*)(?:\0\w+=[^\x00-\x1F\x7F]*)*/,
>      },
>      hookscript => {
>          optional => 1,
> -- 
> 2.47.3
> 
> 
> 
> _______________________________________________
> pve-devel mailing list
> pve-devel@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
> 
> 
> 


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Re: [pve-devel] [PATCH container] config: allow empty environment variables

[Fabian Grünbichler]

On November 17, 2025 2:59 pm, Fabian Grünbichler wrote:
> On November 17, 2025 1:49 pm, Filip Schauer wrote:
>> This fixes a problem with the docker.io/httpd OCI image which specifies
>> an empty environment variable. This violated the pattern of the `env`
>> property, causing `pct config <vmid>` to fail with:
> 
> shouldn't we handle this and drop that environment variable entry
> instead?

hmm, thinking about this some more - I guess an empty string and not
being set are worth disambiguating?

> 
>> ```
>> env: value does not match the regex pattern
>> ```
>> 
>> Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
>> ---
>>  src/PVE/LXC/Config.pm | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
>> index cd3a172..b6fc9a8 100644
>> --- a/src/PVE/LXC/Config.pm
>> +++ b/src/PVE/LXC/Config.pm
>> @@ -671,7 +671,7 @@ my $confdesc = {
>>          description => 'The container runtime environment as NUL-separated list.'
>>              . ' Replaces any lxc.environment.runtime entries in the config.',
>>          optional => 1,
>> -        pattern => qr/(?:\w+=[^\x00-\x1F\x7F]+)(?:\0\w+=[^\x00-\x1F\x7F]+)*/,
>> +        pattern => qr/(?:\w+=[^\x00-\x1F\x7F]*)(?:\0\w+=[^\x00-\x1F\x7F]*)*/,
>>      },
>>      hookscript => {
>>          optional => 1,
>> -- 
>> 2.47.3
>> 
>> 
>> 
>> _______________________________________________
>> pve-devel mailing list
>> pve-devel@lists.proxmox.com
>> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
>> 
>> 
>> 
> 


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Re: [pve-devel] [PATCH container] config: allow empty environment variables

[Filip Schauer]

On 17/11/2025 14:59, Fabian Grünbichler wrote:
> shouldn't we handle this and drop that environment variable entry
> instead?

An empty environment variable is not the same as a missing one. The
entrypoint in the container might interpret it differently:

```
$ perl -e 'use Data::Dumper; print Dumper($ENV{A});'
$VAR1 = undef;
$ A= perl -e 'use Data::Dumper; print Dumper($ENV{A});'
$VAR1 = '';
```



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[pve-devel] applied: [PATCH container] config: allow empty environment variables

[Thomas Lamprecht]

On Mon, 17 Nov 2025 13:49:03 +0100, Filip Schauer wrote:
> This fixes a problem with the docker.io/httpd OCI image which specifies
> an empty environment variable. This violated the pattern of the `env`
> property, causing `pct config <vmid>` to fail with:
> ```
> env: value does not match the regex pattern
> ```
> 
> [...]

I actually wondered about that and had the frontend "allowBlank" check
initially such that the value was only required if the name field was set (as
the variable simply gets deleted otherwise), but I then changed it to both to
be required, as allowing something more is almost always easier to do in the
future compared to restricting it, especially if it involves API exposed schema.

Anyhow, the UI part would need now also adaption to make your change fully work
also there.

Applied, thanks!

[1/1] config: allow empty environment variables
      commit: 9a5f5ce5cfdbc85b2d40a4a20662065d18b85f6c


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