[pbs-devel] [PATCH v3 proxmox-backup 09/20] server/rest: add ApiAuth trait to make user auth generic

Wolfgang Bumiller w.bumiller at proxmox.com
Wed Mar 31 14:55:57 CEST 2021


LGTM but I'll suggest some quality-of-life improvements:

On Wed, Mar 31, 2021 at 12:21:51PM +0200, Stefan Reiter wrote:
> This allows switching the base user identification/authentication method
> in the rest server. Will initially be used for single file restore VMs,
> where authentication is based on a ticket file, not the PBS user
> backend (PAM/local).
> 
> To avoid putting generic types into the RestServer type for this, we
> merge the two calls "extract_auth_data" and "check_auth" into a single
> one, which can use whatever type it wants internally.
> 
> Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
> ---
> 
> v3:
> * merge both calls into one trait, that way it doesn't have to be generic
> 
>  src/bin/proxmox-backup-api.rs   |  13 ++-
>  src/bin/proxmox-backup-proxy.rs |   7 +-
>  src/server/auth.rs              | 192 +++++++++++++++++++-------------
>  src/server/config.rs            |  13 ++-
>  src/server/rest.rs              |  36 +++---
>  5 files changed, 159 insertions(+), 102 deletions(-)
> 
> diff --git a/src/bin/proxmox-backup-api.rs b/src/bin/proxmox-backup-api.rs
> index 7d800259..e514a801 100644
> --- a/src/bin/proxmox-backup-api.rs
> +++ b/src/bin/proxmox-backup-api.rs
> @@ -6,8 +6,11 @@ use proxmox::api::RpcEnvironmentType;
>  
>  //use proxmox_backup::tools;
>  //use proxmox_backup::api_schema::config::*;
> -use proxmox_backup::server::rest::*;
> -use proxmox_backup::server;
> +use proxmox_backup::server::{
> +    self,
> +    auth::default_api_auth,
> +    rest::*,
> +};
>  use proxmox_backup::tools::daemon;
>  use proxmox_backup::auth_helpers::*;
>  use proxmox_backup::config;
> @@ -53,7 +56,11 @@ async fn run() -> Result<(), Error> {
>      let _ = csrf_secret(); // load with lazy_static
>  
>      let mut config = server::ApiConfig::new(
> -        buildcfg::JS_DIR, &proxmox_backup::api2::ROUTER, RpcEnvironmentType::PRIVILEGED)?;
> +        buildcfg::JS_DIR,
> +        &proxmox_backup::api2::ROUTER,
> +        RpcEnvironmentType::PRIVILEGED,
> +        default_api_auth(),
> +    )?;
>  
>      let mut commando_sock = server::CommandoSocket::new(server::our_ctrl_sock());
>  
> diff --git a/src/bin/proxmox-backup-proxy.rs b/src/bin/proxmox-backup-proxy.rs
> index 541d34b5..7e026455 100644
> --- a/src/bin/proxmox-backup-proxy.rs
> +++ b/src/bin/proxmox-backup-proxy.rs
> @@ -14,6 +14,7 @@ use proxmox::api::RpcEnvironmentType;
>  use proxmox_backup::{
>      backup::DataStore,
>      server::{
> +        auth::default_api_auth,
>          WorkerTask,
>          ApiConfig,
>          rest::*,
> @@ -84,7 +85,11 @@ async fn run() -> Result<(), Error> {
>      let _ = csrf_secret(); // load with lazy_static
>  
>      let mut config = ApiConfig::new(
> -        buildcfg::JS_DIR, &proxmox_backup::api2::ROUTER, RpcEnvironmentType::PUBLIC)?;
> +        buildcfg::JS_DIR,
> +        &proxmox_backup::api2::ROUTER,
> +        RpcEnvironmentType::PUBLIC,
> +        default_api_auth(),
> +    )?;
>  
>      // Enable experimental tape UI if tape.cfg exists
>      if Path::new("/etc/proxmox-backup/tape.cfg").exists() {
> diff --git a/src/server/auth.rs b/src/server/auth.rs
> index 24151886..0a9a740c 100644
> --- a/src/server/auth.rs
> +++ b/src/server/auth.rs
> @@ -1,102 +1,140 @@
>  //! Provides authentication primitives for the HTTP server
> -use anyhow::{bail, format_err, Error};
> +use anyhow::{format_err, Error};
> +
> +use std::sync::Arc;
>  
> -use crate::tools::ticket::Ticket;
> -use crate::auth_helpers::*;
> -use crate::tools;
> -use crate::config::cached_user_info::CachedUserInfo;
>  use crate::api2::types::{Authid, Userid};
> +use crate::auth_helpers::*;
> +use crate::config::cached_user_info::CachedUserInfo;
> +use crate::tools;
> +use crate::tools::ticket::Ticket;
>  
>  use hyper::header;
>  use percent_encoding::percent_decode_str;
>  
> -pub struct UserAuthData {
> +pub enum AuthError {
> +    Generic(Error),
> +    NoData,
> +}
> +
> +impl From<Error> for AuthError {
> +    fn from(err: Error) -> Self {
> +        AuthError::Generic(err)
> +    }
> +}

^ When you define an Error type you should immediately also derive Debug
and implement `std::fmt::Display`. While you only "display" it once, I
don't think the error message should be left up to the caller (see
further down below).

In order to make this shorter and easier, I'd propose the inclusion of
the `thiserror` helper crate, then we'd need only as little code as:

    #[derive(thiserror::Error, Debug)]
    pub enum AuthError {
        #[error(transparent)]
        Generic(#[from] Error),

        #[error("no authentication credentials provided")]
        NoData,
    }

And the manual `From<anyhow::Error>` impl can simply be dropped ;-)

That is *unless* you explicitly want this to *not* be convertible to
`anyhow::Error` automagically. Then you don't want this to impl
`std::error::Error`, but then you should add a comment for this ;-)
Which would be a valid way to go given that you're already wrapping
`anyhow::Error` in there... OTOH all the token parsing errors could be
combined into a single `AuthError::BadToken` instead of multiple
"slightly different" `format_err!` messages where the minor difference
in the error message doesn't really provide much value anyway (IMO).

Anyway, this can easily be left as is and updated up in a later series.

> +
> +pub trait ApiAuth {
> +    fn check_auth(
> +        &self,
> +        headers: &http::HeaderMap,
> +        method: &hyper::Method,
> +        user_info: &CachedUserInfo,
> +    ) -> Result<Authid, AuthError>;
> +}
> +
> +struct UserAuthData {
>      ticket: String,
>      csrf_token: Option<String>,
>  }
>  
> -pub enum AuthData {
> +enum AuthData {
>      User(UserAuthData),
>      ApiToken(String),
>  }
>  
> -pub fn extract_auth_data(headers: &http::HeaderMap) -> Option<AuthData> {
> -    if let Some(raw_cookie) = headers.get(header::COOKIE) {
> -        if let Ok(cookie) = raw_cookie.to_str() {
> -            if let Some(ticket) = tools::extract_cookie(cookie, "PBSAuthCookie") {
> -                let csrf_token = match headers.get("CSRFPreventionToken").map(|v| v.to_str()) {
> -                    Some(Ok(v)) => Some(v.to_owned()),
> -                    _ => None,
> -                };
> -                return Some(AuthData::User(UserAuthData {
> -                    ticket,
> -                    csrf_token,
> -                }));
> -            }
> -        }
> -    }
> -
> -    match headers.get(header::AUTHORIZATION).map(|v| v.to_str()) {
> -        Some(Ok(v)) => {
> -            if v.starts_with("PBSAPIToken ") || v.starts_with("PBSAPIToken=") {
> -                Some(AuthData::ApiToken(v["PBSAPIToken ".len()..].to_owned()))
> -            } else {
> -                None
> -            }
> -        },
> -        _ => None,
> -    }
> +pub struct UserApiAuth {}
> +pub fn default_api_auth() -> Arc<UserApiAuth> {
> +    Arc::new(UserApiAuth {})
>  }
>  
> -pub fn check_auth(
> -    method: &hyper::Method,
> -    auth_data: &AuthData,
> -    user_info: &CachedUserInfo,
> -) -> Result<Authid, Error> {
> -    match auth_data {
> -        AuthData::User(user_auth_data) => {
> -            let ticket = user_auth_data.ticket.clone();
> -            let ticket_lifetime = tools::ticket::TICKET_LIFETIME;
> -
> -            let userid: Userid = Ticket::<super::ticket::ApiTicket>::parse(&ticket)?
> -                .verify_with_time_frame(public_auth_key(), "PBS", None, -300..ticket_lifetime)?
> -                .require_full()?;
> -
> -            let auth_id = Authid::from(userid.clone());
> -            if !user_info.is_active_auth_id(&auth_id) {
> -                bail!("user account disabled or expired.");
> -            }
> -
> -            if method != hyper::Method::GET {
> -                if let Some(csrf_token) = &user_auth_data.csrf_token {
> -                    verify_csrf_prevention_token(csrf_secret(), &userid, &csrf_token, -300, ticket_lifetime)?;
> -                } else {
> -                    bail!("missing CSRF prevention token");
> +impl UserApiAuth {
> +    fn extract_auth_data(headers: &http::HeaderMap) -> Option<AuthData> {
> +        if let Some(raw_cookie) = headers.get(header::COOKIE) {
> +            if let Ok(cookie) = raw_cookie.to_str() {
> +                if let Some(ticket) = tools::extract_cookie(cookie, "PBSAuthCookie") {
> +                    let csrf_token = match headers.get("CSRFPreventionToken").map(|v| v.to_str()) {
> +                        Some(Ok(v)) => Some(v.to_owned()),
> +                        _ => None,
> +                    };
> +                    return Some(AuthData::User(UserAuthData { ticket, csrf_token }));
>                  }
>              }
> +        }
>  
> -            Ok(auth_id)
> -        },
> -        AuthData::ApiToken(api_token) => {
> -            let mut parts = api_token.splitn(2, ':');
> -            let tokenid = parts.next()
> -                .ok_or_else(|| format_err!("failed to split API token header"))?;
> -            let tokenid: Authid = tokenid.parse()?;
> -
> -            if !user_info.is_active_auth_id(&tokenid) {
> -                bail!("user account or token disabled or expired.");
> +        match headers.get(header::AUTHORIZATION).map(|v| v.to_str()) {
> +            Some(Ok(v)) => {
> +                if v.starts_with("PBSAPIToken ") || v.starts_with("PBSAPIToken=") {
> +                    Some(AuthData::ApiToken(v["PBSAPIToken ".len()..].to_owned()))
> +                } else {
> +                    None
> +                }
>              }
> -
> -            let tokensecret = parts.next()
> -                .ok_or_else(|| format_err!("failed to split API token header"))?;
> -            let tokensecret = percent_decode_str(tokensecret)
> -                .decode_utf8()
> -                .map_err(|_| format_err!("failed to decode API token header"))?;
> -
> -            crate::config::token_shadow::verify_secret(&tokenid, &tokensecret)?;
> -
> -            Ok(tokenid)
> +            _ => None,
>          }
>      }
>  }
>  
> +impl ApiAuth for UserApiAuth {
> +    fn check_auth(
> +        &self,
> +        headers: &http::HeaderMap,
> +        method: &hyper::Method,
> +        user_info: &CachedUserInfo,
> +    ) -> Result<Authid, AuthError> {
> +        let auth_data = Self::extract_auth_data(headers);
> +        match auth_data {
> +            Some(AuthData::User(user_auth_data)) => {
> +                let ticket = user_auth_data.ticket.clone();
> +                let ticket_lifetime = tools::ticket::TICKET_LIFETIME;
> +
> +                let userid: Userid = Ticket::<super::ticket::ApiTicket>::parse(&ticket)?
> +                    .verify_with_time_frame(public_auth_key(), "PBS", None, -300..ticket_lifetime)?
> +                    .require_full()?;
> +
> +                let auth_id = Authid::from(userid.clone());
> +                if !user_info.is_active_auth_id(&auth_id) {
> +                    return Err(format_err!("user account disabled or expired.").into());
> +                }
> +
> +                if method != hyper::Method::GET {
> +                    if let Some(csrf_token) = &user_auth_data.csrf_token {
> +                        verify_csrf_prevention_token(
> +                            csrf_secret(),
> +                            &userid,
> +                            &csrf_token,
> +                            -300,
> +                            ticket_lifetime,
> +                        )?;
> +                    } else {
> +                        return Err(format_err!("missing CSRF prevention token").into());
> +                    }
> +                }
> +
> +                Ok(auth_id)
> +            }
> +            Some(AuthData::ApiToken(api_token)) => {
> +                let mut parts = api_token.splitn(2, ':');
> +                let tokenid = parts
> +                    .next()
> +                    .ok_or_else(|| format_err!("failed to split API token header"))?;
> +                let tokenid: Authid = tokenid.parse()?;
> +
> +                if !user_info.is_active_auth_id(&tokenid) {
> +                    return Err(format_err!("user account or token disabled or expired.").into());
> +                }
> +
> +                let tokensecret = parts
> +                    .next()
> +                    .ok_or_else(|| format_err!("failed to split API token header"))?;
> +                let tokensecret = percent_decode_str(tokensecret)
> +                    .decode_utf8()
> +                    .map_err(|_| format_err!("failed to decode API token header"))?;
> +
> +                crate::config::token_shadow::verify_secret(&tokenid, &tokensecret)?;
> +
> +                Ok(tokenid)
> +            }
> +            None => Err(AuthError::NoData),
> +        }
> +    }
> +}
> diff --git a/src/server/config.rs b/src/server/config.rs
> index 9094fa80..ad378b0a 100644
> --- a/src/server/config.rs
> +++ b/src/server/config.rs
> @@ -13,6 +13,7 @@ use proxmox::api::{ApiMethod, Router, RpcEnvironmentType};
>  use proxmox::tools::fs::{create_path, CreateOptions};
>  
>  use crate::tools::{FileLogger, FileLogOptions};
> +use super::auth::ApiAuth;
>  
>  pub struct ApiConfig {
>      basedir: PathBuf,
> @@ -23,11 +24,16 @@ pub struct ApiConfig {
>      template_files: RwLock<HashMap<String, (SystemTime, PathBuf)>>,
>      request_log: Option<Arc<Mutex<FileLogger>>>,
>      pub enable_tape_ui: bool,
> +    pub api_auth: Arc<dyn ApiAuth + Send + Sync>,
>  }
>  
>  impl ApiConfig {
> -
> -    pub fn new<B: Into<PathBuf>>(basedir: B, router: &'static Router, env_type: RpcEnvironmentType) -> Result<Self, Error> {
> +    pub fn new<B: Into<PathBuf>>(
> +        basedir: B,
> +        router: &'static Router,
> +        env_type: RpcEnvironmentType,
> +        api_auth: Arc<dyn ApiAuth + Send + Sync>,
> +    ) -> Result<Self, Error> {
>          Ok(Self {
>              basedir: basedir.into(),
>              router,
> @@ -37,7 +43,8 @@ impl ApiConfig {
>              template_files: RwLock::new(HashMap::new()),
>              request_log: None,
>              enable_tape_ui: false,
> -       })
> +            api_auth,
> +        })
>      }
>  
>      pub fn find_method(
> diff --git a/src/server/rest.rs b/src/server/rest.rs
> index 9a971890..2d033510 100644
> --- a/src/server/rest.rs
> +++ b/src/server/rest.rs
> @@ -14,7 +14,6 @@ use hyper::header::{self, HeaderMap};
>  use hyper::http::request::Parts;
>  use hyper::{Body, Request, Response, StatusCode};
>  use lazy_static::lazy_static;
> -use percent_encoding::percent_decode_str;
>  use regex::Regex;
>  use serde_json::{json, Value};
>  use tokio::fs::File;
> @@ -31,16 +30,15 @@ use proxmox::api::{
>  };
>  use proxmox::http_err;
>  
> +use super::auth::AuthError;
>  use super::environment::RestEnvironment;
>  use super::formatter::*;
>  use super::ApiConfig;
> -use super::auth::{check_auth, extract_auth_data};
>  
>  use crate::api2::types::{Authid, Userid};
>  use crate::auth_helpers::*;
>  use crate::config::cached_user_info::CachedUserInfo;
>  use crate::tools;
> -use crate::tools::ticket::Ticket;
>  use crate::tools::FileLogger;
>  
>  extern "C" {
> @@ -614,6 +612,7 @@ async fn handle_request(
>      rpcenv.set_client_ip(Some(*peer));
>  
>      let user_info = CachedUserInfo::new()?;
> +    let auth = &api.api_auth;
>  
>      let delay_unauth_time = std::time::Instant::now() + std::time::Duration::from_millis(3000);
>      let access_forbidden_time = std::time::Instant::now() + std::time::Duration::from_millis(500);
> @@ -639,13 +638,15 @@ async fn handle_request(
>              }
>  
>              if auth_required {
> -                let auth_result = match extract_auth_data(&parts.headers) {
> -                    Some(auth_data) => check_auth(&method, &auth_data, &user_info),
> -                    None => Err(format_err!("no authentication credentials provided.")),
> -                };
> -                match auth_result {
> +                match auth.check_auth(&parts.headers, &method, &user_info) {
>                      Ok(authid) => rpcenv.set_auth_id(Some(authid.to_string())),
> -                    Err(err) => {
> +                    Err(auth_err) => {
> +                        let err = match auth_err {
> +                            AuthError::Generic(err) => err,
> +                            AuthError::NoData => {
> +                                format_err!("no authentication credentials provided.")
> +                            }
> +                        };

With the `fmt::Display` impl for `AuthError` the above match on
`auth_err` can be dropped as well and the `Err(auth_err)` case can
stay `Err(err)` with the code below still working fine as is.

>                          let peer = peer.ip();
>                          auth_logger()?.log(format!(
>                              "authentication failure; rhost={} msg={}",
> @@ -708,9 +709,9 @@ async fn handle_request(
>  
>          if comp_len == 0 {
>              let language = extract_lang_header(&parts.headers);
> -            if let Some(auth_data) = extract_auth_data(&parts.headers) {
> -                match check_auth(&method, &auth_data, &user_info) {
> -                    Ok(auth_id) if !auth_id.is_token() => {
> +            match auth.check_auth(&parts.headers, &method, &user_info) {
> +                Ok(auth_id) => {
> +                    if !auth_id.is_token() {
>                          let userid = auth_id.user();
>                          let new_csrf_token = assemble_csrf_prevention_token(csrf_secret(), userid);
>                          return Ok(get_index(
> @@ -721,14 +722,13 @@ async fn handle_request(
>                              parts,
>                          ));
>                      }
> -                    _ => {
> -                        tokio::time::sleep_until(Instant::from_std(delay_unauth_time)).await;
> -                        return Ok(get_index(None, None, language, &api, parts));
> -                    }
>                  }
> -            } else {
> -                return Ok(get_index(None, None, language, &api, parts));
> +                Err(AuthError::Generic(_)) => {
> +                    tokio::time::sleep_until(Instant::from_std(delay_unauth_time)).await;
> +                }
> +                Err(AuthError::NoData) => {}
>              }
> +            return Ok(get_index(None, None, language, &api, parts));
>          } else {
>              let filename = api.find_alias(&components);
>              return handle_static_file_download(filename).await;
> -- 
> 2.20.1





More information about the pbs-devel mailing list