return correct mime types, improve web security

init-db.sql

@@ -10,3 +10,5 @@ CREATE TABLE IF NOT EXISTS files (
 ALTER TABLE files ADD COLUMN IF NOT EXISTS delete_on_download boolean;
 ALTER TABLE files ALTER COLUMN delete_on_download set not null;
 ALTER TABLE files ALTER COLUMN valid_till TYPE timestamptz;
+ALTER TABLE files DROP COLUMN IF EXISTS kind;
+ALTER TABLE files ADD COLUMN IF NOT EXISTS content_type varchar(255);

src/deleter.rs

@@ -1,9 +1,9 @@
 use futures_util::TryStreamExt;
-use time::OffsetDateTime;
 use sqlx::{postgres::PgPool, Row};
 use std::cmp::max;
 use std::path::{Path, PathBuf};
 use time::ext::NumericalStdDuration;
+use time::OffsetDateTime;
 use tokio::fs;
 use tokio::sync::mpsc::Receiver;
 use tokio::time::timeout;

src/download.rs

@@ -5,18 +5,18 @@ use actix_web::{
     error,
     http::header::{
         Accept, Charset, ContentDisposition, DispositionParam, DispositionType, ExtendedValue,
-        Header,
+        Header, HeaderValue, CONTENT_TYPE, VARY, X_CONTENT_TYPE_OPTIONS,
     },
     web, Error, HttpRequest, HttpResponse,
 };
-use mime::{Mime, TEXT_HTML};
+use mime::{Mime, APPLICATION_OCTET_STREAM, TEXT_HTML};
 use sqlx::postgres::PgPool;
 use std::path::Path;
 use tokio::fs;
 use url::Url;
 
+use crate::config::Config;
 use crate::deleter;
-use crate::{config::Config, file_kind::FileKind};
 
 const TEXT_VIEW_HTML: &str = include_str!("../template/text-view.html");
 const URL_VIEW_HTML: &str = include_str!("../template/url-view.html");
@@ -35,14 +35,14 @@ pub async fn download(
     config: web::Data<Config>,
 ) -> Result<HttpResponse, Error> {
     let id = req.match_info().query("id");
-    let (file_id, file_name, file_kind, delete) = load_file_info(id, &db).await?;
+    let (file_id, file_name, content_type, delete) = load_file_info(id, &db).await?;
     let mut path = config.files_dir.clone();
     path.push(&file_id);
 
-    let file_mime = get_content_type(&path);
+    let mime = Mime::from_str(&content_type).unwrap_or(APPLICATION_OCTET_STREAM);
-    let response = match get_view_type(&req, &file_kind, &file_mime, &path, delete).await {
+    let response = match get_view_type(&req, &mime, &path, delete).await {
-        ViewType::Raw => build_file_response(false, &file_name, path, file_mime, &req),
+        ViewType::Raw => build_file_response(false, &file_name, path, mime, &req),
-        ViewType::Download => build_file_response(true, &file_name, path, file_mime, &req),
+        ViewType::Download => build_file_response(true, &file_name, path, mime, &req),
         ViewType::Html => build_text_response(&path).await,
     };
     if delete {
@@ -61,7 +61,7 @@ async fn load_file_info(
     db: &web::Data<sqlx::Pool<sqlx::Postgres>>,
 ) -> Result<(String, String, String, bool), Error> {
     sqlx::query_as(
-        "SELECT file_id, file_name, kind, delete_on_download from files WHERE file_id = $1",
+        "SELECT file_id, file_name, content_type, delete_on_download from files WHERE file_id = $1",
     )
     .bind(id)
     .fetch_optional(db.as_ref())
@@ -73,18 +73,9 @@ async fn load_file_info(
     .ok_or_else(|| error::ErrorNotFound("file does not exist or has expired"))
 }
 
-fn get_content_type(path: &Path) -> Mime {
-    let std_path = std::path::Path::new(path.as_os_str());
-    tree_magic_mini::from_filepath(std_path)
-        .unwrap_or("application/octet-stream")
-        .parse::<Mime>()
-        .expect("tree_magic_mini should not produce invalid mime")
-}
-
 async fn get_view_type(
     req: &HttpRequest,
-    file_kind: &str,
+    mime: &Mime,
-    file_mime: &Mime,
     file_path: &Path,
     delete_on_download: bool,
 ) -> ViewType {
@@ -94,9 +85,7 @@ async fn get_view_type(
     if req.query_string().contains("raw") {
         return ViewType::Raw;
     }
-    let is_text =
+    if mime.type_() != mime::TEXT {
-        FileKind::from_str(file_kind) == Ok(FileKind::Text) || file_mime.type_() == mime::TEXT;
-    if !is_text {
         return ViewType::Raw;
     }
     if get_file_size(file_path).await >= TEXT_VIEW_SIZE_LIMIT {
@@ -107,7 +96,7 @@ async fn get_view_type(
             if accept_mime == TEXT_HTML {
                 return ViewType::Html;
             }
-            if mime_matches(&accept_mime, file_mime) {
+            if mime_matches(&accept_mime, mime) {
                 break;
             }
         }
@@ -151,7 +140,7 @@ fn build_file_response(
     download: bool,
     file_name: &str,
     path: PathBuf,
-    content_type: Mime,
+    mime: Mime,
     req: &HttpRequest,
 ) -> Result<HttpResponse, Error> {
     let content_disposition = ContentDisposition {
@@ -167,9 +156,34 @@ fn build_file_response(
             log::error!("file could not be read {:?}", file_err);
             error::ErrorInternalServerError("this file should be here but could not be found")
         })?
-        .set_content_type(content_type)
+        .set_content_type(mime)
         .set_content_disposition(content_disposition);
-    Ok(file.into_response(req))
+    let mut response = file.into_response(req);
+    add_headers(req, download, &mut response);
+    Ok(response)
+}
+
+fn add_headers(req: &HttpRequest, download: bool, response: &mut HttpResponse) {
+    // if the browser is trying to fetch this resource in a secure context pretend the reponse is
+    // just binary data so it won't be executed
+    let sec_fetch_mode = req
+        .headers()
+        .get("sec-fetch-mode")
+        .and_then(|v| v.to_str().ok());
+    if !download && sec_fetch_mode.is_some() && sec_fetch_mode != Some("navigate") {
+        response.headers_mut().insert(
+            CONTENT_TYPE,
+            HeaderValue::from_str(&APPLICATION_OCTET_STREAM.to_string())
+                .expect("mime type can be encoded to header value"),
+        );
+        response
+            .headers_mut()
+            .insert(X_CONTENT_TYPE_OPTIONS, HeaderValue::from_static("nosniff"));
+    }
+    // the reponse varies based on these request headers
+    response
+        .headers_mut()
+        .append(VARY, HeaderValue::from_static("accept, sec-fetch-mode"));
 }
 
 fn get_disposition_params(filename: &str) -> Vec<DispositionParam> {

src/file_kind.rs

@@ -1,27 +0,0 @@
-use std::{fmt::Display, str::FromStr};
-
-#[derive(Debug, PartialEq)]
-pub(crate) enum FileKind {
-    Text,
-    Binary,
-}
-
-impl Display for FileKind {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            FileKind::Text => write!(f, "text"),
-            FileKind::Binary => write!(f, "binary"),
-        }
-    }
-}
-
-impl FromStr for FileKind {
-    type Err = String;
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s.to_lowercase().as_str() {
-            "text" => Ok(FileKind::Text),
-            "binary" => Ok(FileKind::Binary),
-            _ => Err(format!("unknown kind {}", s)),
-        }
-    }
-}

src/main.rs

@@ -2,14 +2,14 @@ mod config;
 mod db;
 mod deleter;
 mod download;
-mod file_kind;
 mod multipart;
 mod template;
 mod upload;
 
 use actix_files::Files;
 use actix_web::{
-    middleware::{self, Logger},
+    http::header::{HeaderName, CONTENT_SECURITY_POLICY},
+    middleware::{self, DefaultHeaders, Logger},
     web::{self, Data},
     App, Error, HttpResponse, HttpServer,
 };
@@ -18,6 +18,11 @@ use sqlx::postgres::PgPool;
 use std::env;
 use tokio::{sync::mpsc::channel, task};
 
+const DEFAULT_CSP: (HeaderName, &str) = (
+    CONTENT_SECURITY_POLICY,
+    "default-src 'none'; connect-src 'self'; img-src 'self'; media-src 'self'; font-src 'self'; script-src 'self'; style-src 'self'; object-src 'none'; base-uri 'self'; frame-src 'none'; frame-ancestors 'none'; form-action 'self';"
+);
+
 async fn not_found() -> Result<HttpResponse, Error> {
     Ok(HttpResponse::NotFound()
         .content_type("text/plain")
@@ -51,6 +56,7 @@ async fn main() -> std::io::Result<()> {
         move || {
             App::new()
                 .wrap(Logger::new(r#"%{r}a "%r" =%s %bbytes %Tsec"#))
+                .wrap(DefaultHeaders::new().add(DEFAULT_CSP))
                 .wrap(middleware::Compress::default())
                 .app_data(db.clone())
                 .app_data(expiry_watch_sender.clone())

src/multipart.rs

@@ -1,7 +1,8 @@
-use crate::{config, file_kind::FileKind};
+use crate::config;
 use actix_multipart::{Field, Multipart};
 use actix_web::{error, http::header::DispositionParam, Error};
 use futures_util::{StreamExt, TryStreamExt};
+use mime::{Mime, TEXT_PLAIN};
 use std::path::Path;
 use time::OffsetDateTime;
 use time::{ext::NumericalDuration, Duration};
@@ -11,21 +12,20 @@ const MAX_UPLOAD_SECONDS: i64 = 31 * 24 * 60 * 60;
 const DEFAULT_UPLOAD_SECONDS: u32 = 30 * 60;
 
 pub(crate) struct UploadConfig {
-    pub original_name: String,
+    pub original_name: Option<String>,
+    pub content_type: Mime,
     pub valid_till: OffsetDateTime,
-    pub kind: FileKind,
     pub delete_on_download: bool,
 }
 
 pub(crate) async fn parse_multipart(
     mut payload: Multipart,
-    file_id: &str,
+    file_path: &Path,
-    file_name: &Path,
     config: &config::Config,
 ) -> Result<UploadConfig, error::Error> {
     let mut original_name: Option<String> = None;
+    let mut content_type: Option<Mime> = None;
     let mut keep_for: Option<String> = None;
-    let mut kind: Option<FileKind> = None;
     let mut delete_on_download = false;
     let mut password = None;
     let mut size = 0;
@@ -38,22 +38,20 @@ pub(crate) async fn parse_multipart(
                 keep_for = Some(parse_string(name, field).await?);
             }
             "file" => {
-                let file_original_name = get_original_filename(&field);
+                let (mime, uploaded_name) = get_file_metadata(&field);
-                if file_original_name == None || file_original_name.map(|f| f.as_str()) == Some("")
+                if uploaded_name == None || uploaded_name.map(|f| f.as_str()) == Some("") {
-                {
                     continue;
                 }
-                original_name = file_original_name.map(|f| f.to_string());
+                original_name = uploaded_name.map(|f| f.to_string());
-                kind = Some(FileKind::Binary);
+                content_type = Some(mime.clone());
-                size = create_file(file_name, field, config.max_file_size).await?;
+                size = create_file(file_path, field, config.max_file_size).await?;
             }
             "text" => {
                 if original_name.is_some() {
                     continue;
                 }
-                original_name = Some(format!("{}.txt", file_id));
+                size = create_file(file_path, field, config.max_file_size).await?;
-                kind = Some(FileKind::Text);
+                content_type = Some(get_content_type(file_path));
-                size = create_file(file_name, field, config.max_file_size).await?;
             }
             "delete_on_download" => {
                 delete_on_download = parse_string(name, field).await? != "false";
@@ -65,8 +63,8 @@ pub(crate) async fn parse_multipart(
         };
     }
 
-    let original_name = original_name.ok_or_else(|| error::ErrorBadRequest("no content found"))?;
+    let content_type =
-    let kind = kind.ok_or_else(|| error::ErrorBadRequest("no content found"))?;
+        content_type.ok_or_else(|| error::ErrorBadRequest("no content type found"))?;
     let keep_for: u32 = keep_for
         .map(|k| k.parse())
         .transpose()
@@ -77,8 +75,8 @@ pub(crate) async fn parse_multipart(
 
     let upload_config = UploadConfig {
         original_name,
+        content_type,
         valid_till,
-        kind,
         delete_on_download,
     };
 
@@ -94,9 +92,11 @@ fn check_requirements(
     valid_duration: &Duration,
     config: &config::Config,
 ) -> Result<(), error::Error> {
-    if upload_config.original_name.len() > 255 {
+    if let Some(original_name) = upload_config.original_name.as_ref() {
+        if original_name.len() > 255 {
             return Err(error::ErrorBadRequest("filename is too long"));
         }
+    }
 
     let valid_seconds = valid_duration.whole_seconds();
     if valid_seconds > MAX_UPLOAD_SECONDS {
@@ -181,13 +181,22 @@ async fn write_to_file(
     Ok(written_bytes)
 }
 
-fn get_original_filename(field: &actix_multipart::Field) -> Option<&String> {
+fn get_file_metadata(field: &actix_multipart::Field) -> (&Mime, Option<&String>) {
-    field
+    let mime = field.content_type();
+    let filename = field
         .content_disposition()
         .parameters
         .iter()
         .find_map(|param| match param {
             DispositionParam::Filename(filename) => Some(filename),
             _ => None,
-        })
+        });
+    (mime, filename)
+}
+
+fn get_content_type(path: &Path) -> Mime {
+    let std_path = std::path::Path::new(path.as_os_str());
+    tree_magic_mini::from_filepath(std_path)
+        .and_then(|mime| mime.parse().ok())
+        .unwrap_or(TEXT_PLAIN)
 }

src/upload.rs

@@ -1,7 +1,6 @@
 use std::io::ErrorKind;
 
 use crate::config::Config;
-use crate::file_kind::FileKind;
 use crate::multipart::UploadConfig;
 use crate::{multipart, template};
 use actix_files::NamedFile;
@@ -42,11 +41,11 @@ pub async fn upload(
         error::ErrorInternalServerError("could not create file")
     })?;
 
-    let parsed_multipart = multipart::parse_multipart(payload, &file_id, &file_name, &config).await;
+    let parsed_multipart = multipart::parse_multipart(payload, &file_name, &config).await;
     let UploadConfig {
         original_name,
+        content_type,
         valid_till,
-        kind,
         delete_on_download,
     } = match parsed_multipart {
         Ok(data) => data,
@@ -65,14 +64,17 @@ pub async fn upload(
         }
     };
 
+    let file_name = original_name
+        .clone()
+        .unwrap_or_else(|| format!("{}.txt", file_id));
     let db_insert = sqlx::query(
-        "INSERT INTO Files (file_id, file_name, valid_till, kind, delete_on_download) \
+        "INSERT INTO Files (file_id, file_name, content_type, valid_till, delete_on_download) \
         VALUES ($1, $2, $3, $4, $5)",
     )
     .bind(&file_id)
-    .bind(&original_name)
+    .bind(&file_name)
+    .bind(&content_type.to_string())
     .bind(valid_till)
-    .bind(kind.to_string())
     .bind(delete_on_download)
     .execute(db.as_ref())
     .await;
@@ -90,24 +92,24 @@ pub async fn upload(
     }
 
     log::info!(
-        "{} create new file {} (valid_till: {}, kind: {}, delete_on_download: {})",
+        "{} create new file {} (valid_till: {}, content_type: {}, delete_on_download: {})",
         req.connection_info().realip_remote_addr().unwrap_or("-"),
         file_id,
         valid_till,
-        kind,
+        content_type,
         delete_on_download
     );
 
     expiry_watch_sender.send(()).await.unwrap();
 
-    let redirect = if kind == FileKind::Binary {
+    let redirect = if let Some(original_name) = original_name.as_ref() {
-        let encoded_name = urlencoding::encode(&original_name);
+        let encoded_name = urlencoding::encode(original_name);
         format!("/upload/{}/{}", file_id, encoded_name)
     } else {
         format!("/upload/{}", file_id)
     };
 
-    let url = get_file_url(&req, &file_id, Some(&original_name));
+    let url = get_file_url(&req, &file_id, original_name.as_deref());
     Ok(HttpResponse::SeeOther()
         .insert_header((LOCATION, redirect))
         .body(format!("{}\n", url)))