[pbs-devel] [PATCH proxmox-backup 3/4] access: ldap check connection on creation and change

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

this commit makes the ldap realm endpoints check whether a new or
updated configuration works correctly. it uses the new
`check_connection` function to make sure that a configuration can be
successfully used to connect to and query an ldap directory.

doing so allows us to significantly relax the ldap domain regex.
instead of relying on a regex to make sure that a given distinguished
name (dn) could be correct, we simply let the ldap directory tell us
whether it accepts it. this should also aid with usability as a dn
that looks correct could still be invalid.

the chosen regex still tries to make sure that what is provided as a
dn resembles one structurally. however, it does not impose strict
limits on what attribute values or types can look like.

this also implicitly removes unauthenticated binds, since the new
`ccheck_connection` function does not support those. it will simply
bail out of the check if a `bind_dn` but no password is configured.
therefore, this is a breaking change.

Signed-off-by: Stefan Sterz <s.sterz@proxmox.com>
---
 pbs-api-types/src/ldap.rs      |  6 +++---
 src/api2/config/access/ldap.rs | 26 +++++++++++++++++++++-----
 src/auth.rs                    | 12 +++++++++++-
 3 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/pbs-api-types/src/ldap.rs b/pbs-api-types/src/ldap.rs
index 762f560a..bc164a06 100644
--- a/pbs-api-types/src/ldap.rs
+++ b/pbs-api-types/src/ldap.rs
@@ -144,15 +144,15 @@ pub enum RemoveVanished {
 
 macro_rules! DOMAIN_PART_REGEX {
     () => {
-        r#"("[^"]+"|[^ ,+"/<>;=#][^,+"/<>;=]*[^ ,+"/<>;=]|[^ ,+"/<>;=#])"#
+        r#"[^\s,\+=]+=(?:"[^"]+"|(?:\\[,\+=]|[^,\+=])+)"#
     };
 }
 
 const_regex! {
     pub LDAP_DOMAIN_REGEX = concat!(
-        r#"^\w+="#,
+        r#"^"#,
         DOMAIN_PART_REGEX!(),
-        r#"(,\s*\w+="#,
+        r#"(?:[,\+]\s*"#,
         DOMAIN_PART_REGEX!(),
         ")*$"
     );
diff --git a/src/api2/config/access/ldap.rs b/src/api2/config/access/ldap.rs
index 90cd43c9..911142a0 100644
--- a/src/api2/config/access/ldap.rs
+++ b/src/api2/config/access/ldap.rs
@@ -1,8 +1,10 @@
+use crate::auth::LdapAuthenticator;
 use ::serde::{Deserialize, Serialize};
-use anyhow::Error;
+use anyhow::{format_err, Error};
 use hex::FromHex;
 use serde_json::Value;
 
+use proxmox_ldap::Connection;
 use proxmox_router::{http_bail, Permission, Router, RpcEnvironment};
 use proxmox_schema::{api, param_bail};
 
@@ -70,6 +72,11 @@ pub fn create_ldap_realm(config: LdapRealmConfig, password: Option<String>) -> R
         param_bail!("realm", "realm '{}' already exists.", config.realm);
     }
 
+    let ldap_config =
+        LdapAuthenticator::api_type_to_config_with_password(&config, password.clone())?;
+    let conn = Connection::new(ldap_config);
+    proxmox_async::runtime::block_on(conn.check_connection()).map_err(|e| format_err!("{e:#}"))?;
+
     if let Some(password) = password {
         auth_helpers::store_ldap_bind_password(&config.realm, &password, &domain_config_lock)?;
     }
@@ -317,10 +324,6 @@ pub fn update_ldap_realm(
         config.bind_dn = Some(bind_dn);
     }
 
-    if let Some(password) = password {
-        auth_helpers::store_ldap_bind_password(&realm, &password, &domain_config_lock)?;
-    }
-
     if let Some(filter) = update.filter {
         config.filter = Some(filter);
     }
@@ -334,6 +337,19 @@ pub fn update_ldap_realm(
         config.user_classes = Some(user_classes);
     }
 
+    let ldap_config = if let Some(_) = password {
+        LdapAuthenticator::api_type_to_config_with_password(&config, password.clone())?
+    } else {
+        LdapAuthenticator::api_type_to_config(&config)?
+    };
+
+    let conn = Connection::new(ldap_config);
+    proxmox_async::runtime::block_on(conn.check_connection()).map_err(|e| format_err!("{e:#}"))?;
+
+    if let Some(password) = password {
+        auth_helpers::store_ldap_bind_password(&realm, &password, &domain_config_lock)?;
+    }
+
     domains.set_data(&realm, "ldap", &config)?;
 
     domains::save_config(&domains)?;
diff --git a/src/auth.rs b/src/auth.rs
index e8d8d2da..318d1ff2 100644
--- a/src/auth.rs
+++ b/src/auth.rs
@@ -170,6 +170,16 @@ impl Authenticator for LdapAuthenticator {
 
 impl LdapAuthenticator {
     pub fn api_type_to_config(config: &LdapRealmConfig) -> Result<Config, Error> {
+        Self::api_type_to_config_with_password(
+            config,
+            auth_helpers::get_ldap_bind_password(&config.realm)?,
+        )
+    }
+
+    pub fn api_type_to_config_with_password(
+        config: &LdapRealmConfig,
+        password: Option<String>,
+    ) -> Result<Config, Error> {
         let mut servers = vec![config.server1.clone()];
         if let Some(server) = &config.server2 {
             servers.push(server.clone());
@@ -198,7 +208,7 @@ impl LdapAuthenticator {
             user_attr: config.user_attr.clone(),
             base_dn: config.base_dn.clone(),
             bind_dn: config.bind_dn.clone(),
-            bind_password: auth_helpers::get_ldap_bind_password(&config.realm)?,
+            bind_password: password,
             tls_mode,
             verify_certificate: config.verify.unwrap_or_default(),
             additional_trusted_certificates: trusted_cert,
-- 
2.39.2