Re: [pbs-devel] [PATCH proxmox 01/12] ldap: add method for retrieving root DSE attributes

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

On Tue, Aug 08, 2023 at 02:22:03PM +0200, Christoph Heiss wrote:
> The root DSE holds common attributes about the LDAP server itself.
> Needed to e.g. support Active Directory-based LDAP servers to retrieve
> the base DN from the server itself, based on an valid bind.
> 
> See also RFC 4512, Section 5.1 [0] for more information about this
> special object.
> 
> [0] https://www.rfc-editor.org/rfc/rfc4512#section-5.1
> 
> Signed-off-by: Christoph Heiss <c.heiss@proxmox.com>
> ---
>  proxmox-ldap/src/lib.rs              | 22 ++++++++++++++++++++++
>  proxmox-ldap/tests/assets/glauth.cfg |  1 +
>  proxmox-ldap/tests/glauth.rs         | 16 ++++++++++++++++
>  3 files changed, 39 insertions(+)
> 
> diff --git a/proxmox-ldap/src/lib.rs b/proxmox-ldap/src/lib.rs
> index b3b5d65..534c0c8 100644
> --- a/proxmox-ldap/src/lib.rs
> +++ b/proxmox-ldap/src/lib.rs
> @@ -198,6 +198,28 @@ impl Connection {
>          Ok(())
>      }
> 
> +    /// Retrieves an attribute from the root DSE according to RFC 4512, Section 5.1
> +    /// https://www.rfc-editor.org/rfc/rfc4512#section-5.1
> +    pub async fn retrieve_root_dse_attr(&self, attr: &str) -> Result<Vec<String>, Error> {
> +        let mut ldap = self.create_connection().await?;
> +
> +        let (entries, _res) = ldap
> +            .search("", Scope::Base, "(objectClass=*)", vec![attr])

The last parameter of `search` is an `impl AsRef<[impl AsRef<str>]>`, so
you can just pass `&[attr]` here.
The 2 other existing search calls in the crate should also be adapted,
there's no point in the extra allocation.

> +            .await?
> +            .success()?;
> +
> +        if entries.len() > 1 {
> +            bail!("found multiple root DSEs with attribute '{attr}'");
> +        }
> +
> +        entries
> +            .into_iter()
> +            .next()
> +            .map(SearchEntry::construct)
> +            .and_then(|e| e.attrs.get(attr).cloned())
> +            .ok_or_else(|| format_err!("failed to retrieve root DSE attribute '{attr}'"))
> +    }
> +
>      /// Retrive port from LDAP configuration, otherwise use the correct default
>      fn port_from_config(&self) -> u16 {
>          self.config.port.unwrap_or_else(|| {