[pbs-devel] applied: [PATCH v3 proxmox-backup 1/2] access: limit editing pam credentials to superuser

["Fabian Grünbichler" <f.gruenbichler@proxmox.com>]

with fixup removing unnecessary ref/deref and moving the realm lookup 
back before saving the config, as it is our safeguard against bogus 
realms:

diff --git a/src/api2/access/user.rs b/src/api2/access/user.rs
index d9458524..f03389f8 100644
--- a/src/api2/access/user.rs
+++ b/src/api2/access/user.rs
@@ -236,17 +236,20 @@ pub fn create_user(
 
     config.set_data(user.userid.as_str(), "user", &user)?;
 
+    let realm = user.userid.realm();
+
+    // Fails if realm does not exist!
+    let authenticator = crate::auth::lookup_authenticator(realm)?;
+
     user::save_config(&config)?;
 
     if let Some(password) = password {
         let user_info = CachedUserInfo::new()?;
         let current_auth_id: Authid = rpcenv.get_auth_id().unwrap().parse()?;
-        let target_realm = &userZZ.userid.realm();
-        if *target_realm == "pam" && !user_info.is_superuser(&current_auth_id) {
+        if realm == "pam" && !user_info.is_superuser(&current_auth_id) {
             bail!("only superuser can edit pam credentials!");
         }
-        let authenticator = crate::auth::lookup_authenticator(target_realm)?;
-        authenticator.store_password(&user.userid.name(), &password)?;
+        authenticator.store_password(user.userid.name(), &password)?;
     }
 
     Ok(())

On January 13, 2021 5:26 pm, Oguz Bektas wrote:
> modifying @pam users credentials should be only possible for root@pam,
> otherwise it can have unintended consequences.
> 
> also enforce the same limit on user creation (except self_service check,
> since it makes no sense during user creation)
> 
> Signed-off-by: Oguz Bektas <o.bektas@proxmox.com>
> ---
> v2->v3:
> * apply restrictions for 'create_user' as well
> * make if condition more readable with variables
> * fix issue with regular pam users being unable to edit their own
> passwords (self_service)
> 
> 
>  src/api2/access/user.rs | 25 +++++++++++++++++++++----
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/src/api2/access/user.rs b/src/api2/access/user.rs
> index 484919bf..d9458524 100644
> --- a/src/api2/access/user.rs
> +++ b/src/api2/access/user.rs
> @@ -218,7 +218,11 @@ pub fn list_users(
>      },
>  )]
>  /// Create new user.
> -pub fn create_user(password: Option<String>, param: Value) -> Result<(), Error> {
> +pub fn create_user(
> +    password: Option<String>,
> +    param: Value,
> +    rpcenv: &mut dyn RpcEnvironment
> +) -> Result<(), Error> {
>  
>      let _lock = open_file_locked(user::USER_CFG_LOCKFILE, std::time::Duration::new(10, 0), true)?;
>  
> @@ -230,14 +234,19 @@ pub fn create_user(password: Option<String>, param: Value) -> Result<(), Error>
>          bail!("user '{}' already exists.", user.userid);
>      }
>  
> -    let authenticator = crate::auth::lookup_authenticator(&user.userid.realm())?;
> -
>      config.set_data(user.userid.as_str(), "user", &user)?;
>  
>      user::save_config(&config)?;
>  
>      if let Some(password) = password {
> -        authenticator.store_password(user.userid.name(), &password)?;
> +        let user_info = CachedUserInfo::new()?;
> +        let current_auth_id: Authid = rpcenv.get_auth_id().unwrap().parse()?;
> +        let target_realm = &user.userid.realm();
> +        if *target_realm == "pam" && !user_info.is_superuser(&current_auth_id) {
> +            bail!("only superuser can edit pam credentials!");
> +        }
> +        let authenticator = crate::auth::lookup_authenticator(target_realm)?;
> +        authenticator.store_password(&user.userid.name(), &password)?;
>      }
>  
>      Ok(())
> @@ -350,6 +359,7 @@ pub fn update_user(
>      email: Option<String>,
>      delete: Option<Vec<DeletableProperty>>,
>      digest: Option<String>,
> +    rpcenv: &mut dyn RpcEnvironment,
>  ) -> Result<(), Error> {
>  
>      let _lock = open_file_locked(user::USER_CFG_LOCKFILE, std::time::Duration::new(10, 0), true)?;
> @@ -392,6 +402,13 @@ pub fn update_user(
>      }
>  
>      if let Some(password) = password {
> +        let user_info = CachedUserInfo::new()?;
> +        let current_auth_id: Authid = rpcenv.get_auth_id().unwrap().parse()?;
> +        let self_service = current_auth_id.user() == &userid;
> +        let target_realm = userid.realm();
> +        if !self_service && target_realm == "pam" && !user_info.is_superuser(&current_auth_id) {
> +            bail!("only superuser can edit pam credentials!");
> +        }
>          let authenticator = crate::auth::lookup_authenticator(userid.realm())?;
>          authenticator.store_password(userid.name(), &password)?;
>      }
> -- 
> 2.20.1
> 
> 
> _______________________________________________
> pbs-devel mailing list
> pbs-devel@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel
> 
> 
>