DAR-Encryption

.gitignore

@@ -1,3 +1,4 @@
 /target
 /data
 /.env
+/result

Cargo.toml

@@ -6,18 +6,23 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-tokio = { version = "1.27.0", features = ["full"] }
+tokio = { version = "1.33", features = ["full"] }
-tokio-util = { version="0.7"}
+tokio-util = { version="0.7", features = ["io"]}
 futures-util = "0.3"
 axum = {version="0.6", features=["macros", "headers"]}
 serde = "1.0"
-serde_cbor = "0.11"
+toml = "0.8"
 render = { git="https://github.com/render-rs/render.rs" }
-thiserror = "1.0.40"
+thiserror = "1.0"
-rand = "0.8.5"
+rand = "0.8"
 dotenvy = "0.15"
-markdown = "0.3.0"
+markdown = "0.3"
 axum_oidc = {git="https://git2.zettoit.eu/pfz4/axum_oidc"}
-rust-s3 = { version="0.33.0", features=["tokio-rustls-tls", "tags"], default_features=false }
+log = "0.4"
-log = "0.4.18"
+env_logger = "0.10"
-pretty_env_logger = "0.5.0"
+
+chacha20 = "0.9"
+sha3 = "0.10"
+hex = "0.4"
+bytes = "1.5"
+pin-project-lite = "0.2"

Dockerfile

@@ -1,4 +0,0 @@
-FROM debian:stable-slim as final
-WORKDIR /app
-COPY ./target/release/bin ./bin
-CMD ["/app/bin"]

flake.lock

@@ -0,0 +1,129 @@
+{
+  "nodes": {
+    "crane": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "rust-overlay": [
+          "rust-overlay"
+        ]
+      },
+      "locked": {
+        "lastModified": 1697513493,
+        "narHash": "sha256-Kjidf29+ahcsQE7DICxI4g4tjMSY76BfhKFANnkQhk0=",
+        "owner": "ipetkov",
+        "repo": "crane",
+        "rev": "eb5034b6ee36d523bf1d326ab990811ac2ceb870",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ipetkov",
+        "repo": "crane",
+        "type": "github"
+      }
+    },
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1696267196,
+        "narHash": "sha256-AAQ/2sD+0D18bb8hKuEEVpHUYD1GmO2Uh/taFamn6XQ=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "4f910c9827911b1ec2bf26b5a062cd09f8d89f85",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1694529238,
+        "narHash": "sha256-zsNZZGTGnMOf9YpHKJqMSsa0dXbfmxeoJ7xHlrt+xmY=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "ff7b65b44d01cf9ba6a71320833626af21126384",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1697059129,
+        "narHash": "sha256-9NJcFF9CEYPvHJ5ckE8kvINvI84SZZ87PvqMbH6pro0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "5e4c2ada4fcd54b99d56d7bd62f384511a7e2593",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "crane": "crane",
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1697508761,
+        "narHash": "sha256-QKWiXUlnke+EiJw3pek1l7xyJ4YsxYXZeQJt/YLgjvA=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "6f74c92caaf2541641b50ec623676430101d1fd4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,69 @@
+{
+  description = "bin service";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+      };
+    };
+    crane = {
+      url = "github:ipetkov/crane";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+        rust-overlay.follows = "rust-overlay";
+      };
+    };
+  };
+
+  outputs = { self, nixpkgs, flake-utils, rust-overlay, crane}:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+
+        rustToolchain = pkgs.rust-bin.stable.latest.default;
+
+        markdownFilter = path: _type: builtins.match ".*md$" path != null;
+        markdownOrCargo = path: type: (markdownFilter path type) || (craneLib.filterCargoSources path type);
+
+        craneLib = (crane.mkLib pkgs).overrideToolchain rustToolchain;
+        src = pkgs.lib.cleanSourceWith {
+          src = craneLib.path ./.;
+          filter = markdownOrCargo;
+        };
+
+        nativeBuildInputs = with pkgs; [ rustToolchain pkg-config ];
+        buildInputs = with pkgs; [ ];
+
+        commonArgs = {
+          inherit src buildInputs nativeBuildInputs;
+        };
+        cargoArtifacts = craneLib.buildDepsOnly commonArgs;
+
+        bin = craneLib.buildPackage (commonArgs // {
+          inherit cargoArtifacts;
+        });
+
+      in
+      with pkgs;
+      {
+        packages = {
+          inherit bin;
+          default = bin;
+        };
+        devShells.default = mkShell {
+          inputsFrom = [ bin ];
+        };
+
+        hydraJobs."build" = bin;
+      }
+    );
+}

src/error.rs

@@ -0,0 +1,45 @@
+use axum::{http::StatusCode, response::IntoResponse};
+use log::error;
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("io error: {:?}", 0)]
+    Io(#[from] std::io::Error),
+    #[error("time error: {:?}", 0)]
+    Time(#[from] std::time::SystemTimeError),
+    #[error("metadata error: {:?}", 0)]
+    MetadataDe(#[from] toml::de::Error),
+    #[error("metadata error: {:?}", 0)]
+    MetadataSer(#[from] toml::ser::Error),
+    #[error("phrase is not valid")]
+    PhraseInvalid,
+    #[error("bin could not be found")]
+    BinNotFound,
+    #[error("file exists")]
+    DataFileExists,
+
+    #[error("hex error: {:?}", 0)]
+    Hex(#[from] hex::FromHexError),
+
+    #[error("could not parse ttl")]
+    ParseTtl,
+
+    #[error("encryption error")]
+    ChaCha,
+}
+
+impl IntoResponse for Error {
+    fn into_response(self) -> axum::response::Response {
+        match self {
+            Self::PhraseInvalid => (StatusCode::BAD_REQUEST, "phrase is not valid"),
+            Self::BinNotFound => (StatusCode::NOT_FOUND, "bin does not exist"),
+            Self::DataFileExists => (StatusCode::CONFLICT, "bin already has data"),
+            Self::ParseTtl => (StatusCode::BAD_REQUEST, "invalid ttl class"),
+            _ => {
+                error!("{:?}", self);
+                (StatusCode::INTERNAL_SERVER_ERROR, "internal server error")
+            }
+        }
+        .into_response()
+    }
+}

src/garbage_collector.rs

@@ -0,0 +1,108 @@
+use std::{
+    collections::BinaryHeap,
+    sync::Arc,
+    time::{Duration, SystemTime, UNIX_EPOCH},
+};
+
+use log::{debug, info, warn};
+use tokio::{fs, sync::Mutex};
+
+use crate::{metadata::Metadata, util::Id};
+
+#[derive(Clone)]
+pub(crate) struct GarbageCollector {
+    heap: Arc<Mutex<BinaryHeap<GarbageCollectorItem>>>,
+    path: String,
+}
+
+impl GarbageCollector {
+    pub(crate) async fn new(path: String) -> Self {
+        let mut heap = BinaryHeap::new();
+        let mut dir = fs::read_dir(&path).await.expect("readable data dir");
+        while let Ok(Some(entry)) = dir.next_entry().await {
+            let file_name = entry.file_name();
+            let file_name = file_name.to_string_lossy();
+            if let Some(id) = file_name.strip_suffix(".toml") {
+                if let Ok(metadata) = Metadata::from_file(&format!("./data/{}.toml", id)).await {
+                    heap.push(GarbageCollectorItem {
+                        expires_at: metadata.expires_at,
+                        id: Id::from_str(id),
+                    })
+                }
+            }
+        }
+        Self {
+            heap: Arc::new(Mutex::new(heap)),
+            path,
+        }
+    }
+
+    pub(crate) async fn schedule(&self, id: &Id, expires_at: u64) {
+        self.heap.lock().await.push(GarbageCollectorItem {
+            id: id.clone(),
+            expires_at,
+        })
+    }
+
+    pub(crate) async fn run(&self) {
+        let mut heap = self.heap.lock().await;
+
+        let now = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .expect("time after EPOCH")
+            .as_secs();
+
+        // skip if first item is not old enough to be deleted
+        if let Some(true) = heap.peek().map(|x| x.expires_at > now) {
+            return;
+        }
+        if let Some(item) = heap.pop() {
+            if let Ok(metadata) =
+                Metadata::from_file(&format!("{}/{}.toml", self.path, item.id)).await
+            {
+                // check metadata if the item is really ready for deletion (needed for reschedule
+                // population of bin with data)
+                if metadata.expires_at <= now {
+                    debug!("deleting bin {}", item.id);
+                    let res_meta =
+                        fs::remove_file(&format!("{}/{}.toml", self.path, item.id)).await;
+                    let res_data = fs::remove_file(&format!("{}/{}.dat", self.path, item.id)).await;
+
+                    if res_meta.is_err() || res_data.is_err() {
+                        warn!("failed to delete bin {} for gc", item.id);
+                    }
+                }
+            } else {
+                info!("cant open metadata file for bin {} for gc", item.id);
+            }
+        }
+    }
+
+    pub(crate) fn spawn(&self) {
+        let gc = self.clone();
+        tokio::spawn(async move {
+            loop {
+                tokio::time::sleep(Duration::from_secs(10)).await;
+                gc.run().await;
+            }
+        });
+    }
+}
+
+#[derive(PartialEq, Eq)]
+struct GarbageCollectorItem {
+    id: Id,
+    expires_at: u64,
+}
+
+impl PartialOrd for GarbageCollectorItem {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for GarbageCollectorItem {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.expires_at.cmp(&other.expires_at).reverse()
+    }
+}

src/item_explanation.md

@@ -2,9 +2,7 @@
 An empty bin was created for you. The first HTTP POST or PUT request can upload data.
 All following requests can only read the uploaded data.
 
-To use the build-in link-shortener functionality you have to POST or PUT the URL with Content-Type: text/x-uri or Content-Type: text/uri-list.
+To change the default expiration date, you can use the `?ttl=<seconds_to_live>` parameter.  
-
-To change the default expiration date, you can use the `?ttl=` parameter. The following expiry classes are defined: <lifecycle_classes>.  
 
 ## Upload a link
 `$ curl -H "Content-Type: text/x-uri" --data "https://example.com" <bin_url>`
@@ -27,4 +25,3 @@ $ curl <bin_url> | gpg -d - | tar -xzf
 
 ## Accessing the data
 After uploading data you can access it by accessing <bin_url> with an optional file extension that suits the data that you uploaded.
-If the bin is a link you will get redirected.

src/main.rs

@@ -1,13 +1,13 @@
+#![deny(clippy::unwrap_used)]
 use std::{
-    collections::HashSet,
+    borrow::Borrow,
     env,
-    io::ErrorKind,
+    str::FromStr,
-    task::{Context, Poll},
+    time::{SystemTime, UNIX_EPOCH},
-    time::Duration,
 };
 
 use axum::{
-    body::{Bytes, StreamBody},
+    body::StreamBody,
     debug_handler,
     extract::{BodyStream, FromRef, Path, Query, State},
     headers::ContentType,
@@ -16,62 +16,49 @@ use axum::{
     routing::get,
     Router, TypedHeader,
 };
-use axum_oidc::{ClaimsExtractor, EmptyAdditionalClaims, Key, OidcApplication};
+use axum_oidc::oidc::{self, EmptyAdditionalClaims, OidcApplication, OidcExtractor};
-use futures_util::{Stream, StreamExt, TryStreamExt};
+use chacha20::{
-use log::{info, warn};
+    cipher::{KeyIvInit, StreamCipher},
-use rand::{distributions::Alphanumeric, Rng};
+    ChaCha20,
+};
+use futures_util::StreamExt;
+use garbage_collector::GarbageCollector;
+use log::debug;
 use render::{html, raw};
-use s3::{creds::Credentials, error::S3Error, request::ResponseDataStream, Bucket};
 use serde::Deserialize;
-use tokio_util::io::StreamReader;
+use sha3::{Digest, Sha3_256};
+use tokio::{
+    fs::File,
+    io::{AsyncWriteExt, BufReader, BufWriter},
+};
+use util::{IdSalt, KeySalt};
 
-// RFC 7230 section 3.1.1
+use crate::{
-// It is RECOMMENDED that all HTTP senders and recipients
+    error::Error,
-// support, at a minimum, request-line lengths of 8000 octets.
+    metadata::Metadata,
-const HTTP_URL_MAXLENGTH: i64 = 8000;
+    util::{Id, Key, Nonce, Phrase},
+    web_util::DecryptingStream,
+};
+mod error;
+mod garbage_collector;
+mod metadata;
+mod util;
+mod web_util;
 
-// support the RFC2483 with text/uri-list and the inofficial text/x-uri mimetype
+/// length of the "phrase" that is used to access the bin (https://example.com/<phrase>)
-const HTTP_URL_MIMETYPES: [&str; 2] = ["text/x-uri", "text/uri-list"];
+const PHRASE_LENGTH: usize = 16;
+/// length of the salts that are used to generate the key for chacha and id for the files
+const SALT_LENGTH: usize = 256 - PHRASE_LENGTH;
 
-#[derive(Debug, thiserror::Error)]
-enum Error {
-    #[error("s3 error: {:?}", 1)]
-    S3(#[from] S3Error),
-    #[error("url is invalid utf8")]
-    UrlUtf8Invalid,
-    #[error("item could not be found")]
-    ItemNotFound,
-    #[error("file exists")]
-    DataFileExists,
-
-    #[error("could not parse ttl")]
-    ParseTtl,
-}
 type HandlerResult<T> = Result<T, Error>;
-
-impl IntoResponse for Error {
-    fn into_response(self) -> axum::response::Response {
-        match self {
-            Self::S3(e) => {
-                warn!("S3 Error: {:?}", e);
-                (StatusCode::INTERNAL_SERVER_ERROR, "s3 error")
-            }
-            Self::UrlUtf8Invalid => (StatusCode::INTERNAL_SERVER_ERROR, "url is not valid utf8"),
-            Self::ItemNotFound => (StatusCode::NOT_FOUND, "bin could not be found"),
-            Self::DataFileExists => (StatusCode::CONFLICT, "bin already has data"),
-            Self::ParseTtl => (StatusCode::BAD_REQUEST, "invalid ttl class"),
-        }
-        .into_response()
-    }
-}
-
 #[derive(Clone)]
 pub struct AppState {
     application_base: String,
     oidc_application: OidcApplication<EmptyAdditionalClaims>,
-    bucket: Bucket,
+    data: String,
-    lifecycle_classes: HashSet<String>,
+    key_salt: KeySalt,
-    default_lifecycle_class: String,
+    id_salt: IdSalt,
+    garbage_collector: GarbageCollector,
 }
 
 impl FromRef<AppState> for OidcApplication<EmptyAdditionalClaims> {
@@ -80,10 +67,16 @@ impl FromRef<AppState> for OidcApplication<EmptyAdditionalClaims> {
     }
 }
 
+#[derive(PartialEq, Eq, PartialOrd, Ord, Debug)]
+pub struct ExpiryHeapItem {
+    pub expires_at: u64,
+    pub id: String,
+}
+
 #[tokio::main]
 async fn main() {
     dotenvy::dotenv().ok();
-    pretty_env_logger::init();
+    env_logger::init();
 
     let application_base = env::var("APPLICATION_BASE").expect("APPLICATION_BASE env var");
     let issuer = env::var("ISSUER").expect("ISSUER env var");
@@ -96,204 +89,167 @@ async fn main() {
         .collect::<Vec<_>>();
 
     let oidc_application = OidcApplication::<EmptyAdditionalClaims>::create(
-        application_base.parse().unwrap(),
+        application_base
+            .parse()
+            .expect("valid APPLICATION_BASE url"),
         issuer.to_string(),
         client_id.to_string(),
         client_secret.to_owned(),
         scopes.clone(),
-        Key::generate(),
+        oidc::Key::generate(),
     )
     .await
-    .unwrap();
+    .expect("Oidc Authentication Client");
 
-    let bucket = Bucket::new(
+    let garbage_collector = GarbageCollector::new("./data".to_string()).await;
-        &env::var("S3_BUCKET").expect("S3_BUCKET env var"),
+    garbage_collector.spawn();
-        env::var("S3_REGION")
-            .expect("S3_REGION env var")
-            .parse()
-            .unwrap(),
-        Credentials::new(
-            Some(&env::var("S3_ACCESS_KEY").expect("S3_ACCESS_KEY env var")),
-            Some(&env::var("S3_SECRET_KEY").expect("S3_SECRET_KEY env var")),
-            None,
-            None,
-            None,
-        )
-        .unwrap(),
-    )
-    .unwrap()
-    .with_path_style()
-    .with_request_timeout(Duration::from_secs(60 * 60 * 6));
-
-    let lifecycle_classes = std::env::var("LIFECYCLE_CLASSES")
-        .expect("LIFECYCLE_CLASSES env var")
-        .split(',')
-        .map(|x| x.to_string())
-        .collect::<HashSet<String>>();
-    let default_lifecycle_class =
-        std::env::var("DEFAULT_LIFECYCLE_CLASS").expect("DEFAULT_LIFECYCLE_CLASS env var");
-    if !lifecycle_classes.contains(&default_lifecycle_class) {
-        panic!("DEFAULT_LIFECYCLE_CLASS must be an element of LIFECYCLE_CLASSES");
-    }
 
     let state: AppState = AppState {
         application_base,
         oidc_application,
-        bucket,
+        data: "./data".to_string(),
-        lifecycle_classes,
+        key_salt: KeySalt::from_str(&env::var("KEY_SALT").expect("KEY_SALT env var"))
-        default_lifecycle_class,
+            .expect("KEY SALT valid hex"),
+        id_salt: IdSalt::from_str(&env::var("ID_SALT").expect("ID_SALT env var"))
+            .expect("ID_SALT valid hex"),
+        garbage_collector,
     };
 
+    // when the two salts are identical, the bin id and the bin key are also identical, this would
+    // make the encryption useless
+    assert_ne!(state.key_salt.raw(), state.id_salt.raw());
+
     let app = Router::new()
         .route("/", get(get_index))
         .route("/:id", get(get_item).post(post_item).put(post_item))
         .with_state(state);
-    axum::Server::bind(&"[::]:3000".parse().unwrap())
+    axum::Server::bind(&"[::]:8080".parse().expect("valid listen address"))
         .serve(app.into_make_service())
         .await
-        .unwrap();
+        .expect("Axum Server");
 }
 
 async fn get_index(
     State(app_state): State<AppState>,
-    ClaimsExtractor(claims): ClaimsExtractor<EmptyAdditionalClaims>,
+    OidcExtractor { claims, .. }: OidcExtractor<EmptyAdditionalClaims>,
 ) -> Result<impl IntoResponse, Error> {
     let subject = claims.subject().to_string();
 
-    //generate id
+    //generate phrase and derive id from it
-    let id = rand::thread_rng()
+    let phrase = Phrase::random();
-        .sample_iter(Alphanumeric)
+    let id = Id::from_phrase(&phrase, &app_state.id_salt);
-        .take(8)
-        .map(char::from)
-        .collect::<String>();
 
-    app_state.bucket.put_object(&id, &[]).await?;
+    let nonce = Nonce::random();
-    app_state
-        .bucket
-        .put_object_tagging(
-            &id,
-            &[
-                ("ttl".to_string(), app_state.default_lifecycle_class.clone()),
-                ("subject".to_string(), subject),
-            ],
-        )
-        .await?;
 
-    info!("created bin {id}");
+    let expires_at = SystemTime::now().duration_since(UNIX_EPOCH)?.as_secs() + 24 * 3600;
+
+    let metadata_path = format!("{}/{}.toml", app_state.data, id);
+    let metadata = Metadata {
+        subject,
+        nonce: nonce.to_hex(),
+        etag: None,
+        size: None,
+        content_type: None,
+        expires_at,
+    };
+    metadata.to_file(&metadata_path).await?;
+
+    app_state.garbage_collector.schedule(&id, expires_at).await;
+
+    debug!("created bin {id}");
 
     Ok(Redirect::temporary(&format!(
         "{}{}",
-        app_state.application_base, id
+        app_state.application_base, phrase
     )))
 }
 
 #[derive(Deserialize)]
 pub struct PostQuery {
-    ttl: Option<String>,
+    ttl: Option<u64>,
 }
 
 async fn post_item(
-    Path(id): Path<String>,
+    Path(phrase): Path<String>,
     Query(params): Query<PostQuery>,
     State(app_state): State<AppState>,
     content_type: Option<TypedHeader<ContentType>>,
-    stream: BodyStream,
+    mut stream: BodyStream,
 ) -> HandlerResult<impl IntoResponse> {
-    let id = sanitize_id(id);
+    let phrase = Phrase::from_str(&phrase)?;
+    let id = Id::from_phrase(&phrase, &app_state.id_salt);
 
-    let metadata = app_state.bucket.head_object(&id).await?.0;
+    let metadata_path = format!("{}/{}.toml", app_state.data, id);
+    let mut metadata = Metadata::from_file(&metadata_path).await?;
 
-    if metadata.e_tag.is_none() {
+    let path = format!("{}/{}.dat", app_state.data, id);
-        return Err(Error::ItemNotFound);
+    let path = std::path::Path::new(&path);
-    }
+
-    if let Some(content_length) = metadata.content_length {
+    if !path.exists() {
-        if content_length > 0 {
+        let key = Key::from_phrase(&phrase, &app_state.key_salt);
-            return Err(Error::DataFileExists);
+        let nonce = Nonce::from_hex(&metadata.nonce)?;
-        }
+        let mut cipher = ChaCha20::new(key.borrow(), nonce.borrow());
+
+        let file = File::create(&path).await?;
+        let mut writer = BufWriter::new(file);
+
+        let mut etag_hasher = Sha3_256::new();
+        let mut size = 0;
+
+        while let Some(chunk) = stream.next().await {
+            let mut buf = chunk.unwrap_or_default().to_vec();
+            etag_hasher.update(&buf);
+            size += buf.len() as u64;
+            cipher.apply_keystream(&mut buf);
+            writer.write_all(&buf).await?;
         }
 
-    let ttl = if let Some(ttl) = &params.ttl {
+        writer.flush().await?;
-        if !app_state.lifecycle_classes.contains(ttl) {
+
-            return Err(Error::ParseTtl);
+        metadata.etag = Some(hex::encode(etag_hasher.finalize()));
-        }
+        metadata.size = Some(size);
-        ttl
+        metadata.content_type = match content_type {
-    } else {
+            Some(content_type) => Some(content_type.to_string()),
-        &app_state.default_lifecycle_class
+            None => Some("application/octet-stream".to_string()),
         };
+        metadata.expires_at = SystemTime::now().duration_since(UNIX_EPOCH)?.as_secs()
+            + params.ttl.unwrap_or(24 * 3600);
+        metadata.to_file(&metadata_path).await?;
 
-    let tags = app_state.bucket.get_object_tagging(&id).await?.0;
-
-    let mut reader =
-        StreamReader::new(stream.map_err(|e| std::io::Error::new(ErrorKind::Other, e.to_string())));
-    let status_code = match content_type {
-        Some(content_type) => {
         app_state
-                .bucket
+            .garbage_collector
-                .put_object_stream_with_content_type(&mut reader, &id, &content_type.to_string())
+            .schedule(&id, metadata.expires_at)
-                .await
+            .await;
+
+        debug!("bin {id} got filled");
+
+        Ok((StatusCode::OK, "ok\n"))
+    } else {
+        Err(Error::DataFileExists)
     }
-        None => app_state.bucket.put_object_stream(&mut reader, &id).await,
-    }?;
-
-    let status_code = StatusCode::from_u16(status_code).unwrap();
-
-    let subject = tags
-        .iter()
-        .find(|x| x.key() == "subject")
-        .map(|x| x.value())
-        .unwrap_or_default();
-
-    app_state
-        .bucket
-        .put_object_tagging(
-            &id,
-            &[
-                ("ttl".to_string(), ttl.to_string()),
-                ("subject".to_string(), subject),
-            ],
-        )
-        .await?;
-
-    info!("bin {id} is now read only");
-
-    Ok((
-        status_code,
-        format!(
-            "{}\n",
-            status_code
-                .canonical_reason()
-                .unwrap_or(&status_code.to_string())
-        ),
-    ))
 }
 
 #[debug_handler]
 async fn get_item(
-    Path(id): Path<String>,
+    Path(phrase): Path<String>,
     State(app_state): State<AppState>,
 ) -> HandlerResult<impl IntoResponse> {
-    let id = sanitize_id(id);
+    let phrase = Phrase::from_str(&phrase)?;
+    let id = Id::from_phrase(&phrase, &app_state.id_salt);
 
-    let metadata = app_state.bucket.head_object(&id).await?.0;
+    let metadata = Metadata::from_file(&format!("{}/{}.toml", app_state.data, id)).await?;
 
-    if metadata.e_tag.is_none() {
+    let path = format!("{}/{}.dat", app_state.data, id);
-        return Err(Error::ItemNotFound);
+
-    }
+    let key = Key::from_phrase(&phrase, &app_state.key_salt);
-    if metadata.content_length.is_none() || metadata.content_length == Some(0) {
+    let nonce = Nonce::from_hex(&metadata.nonce)?;
-        let body = include_str!("item_explanation.md")
+
-            .replace(
+    if std::fs::metadata(&path).is_err() {
+        let body = include_str!("item_explanation.md").replace(
             "<bin_url>",
-                &format!("{}{}", app_state.application_base, id),
+            &format!("{}{}", app_state.application_base, phrase),
-            )
-            .replace(
-                "<lifecycle_classes>",
-                &app_state
-                    .lifecycle_classes
-                    .iter()
-                    .map(|x| x.to_string())
-                    .reduce(|acc, e| acc + ", " + e.as_str())
-                    .unwrap_or_default(),
         );
+
         let body = markdown::to_html(&body);
         let body = html! {
             <html>
@@ -309,70 +265,32 @@ async fn get_item(
             </html>
         };
         Ok((StatusCode::ACCEPTED, Html(body)).into_response())
-    } else if let Some(content_length) = metadata.content_length {
-        if HTTP_URL_MIMETYPES.contains(&metadata.content_type.as_deref().unwrap_or(""))
-            && content_length <= HTTP_URL_MAXLENGTH
-        {
-            let file = app_state.bucket.get_object(&id).await?;
-            let url = String::from_utf8(file.to_vec()).map_err(|_| Error::UrlUtf8Invalid)?;
-
-            // Use the first line that doesn't start with a # to be compliant with RFC2483.
-            let url = url.lines().find(|x| !x.starts_with('#')).unwrap_or("");
-
-            Ok(Redirect::temporary(url).into_response())
     } else {
-            let file_stream = app_state.bucket.get_object_stream(&id).await.unwrap();
+        //TODO(pfz4): Maybe add link handling
+        let file = File::open(&path).await?;
+        let reader = BufReader::new(file);
 
-            let body = StreamBody::new(ResponseStream(std::sync::Mutex::new(file_stream)));
+        let body = StreamBody::new(DecryptingStream::new(reader, id, &metadata, &key, &nonce));
 
         let mut headers = HeaderMap::new();
         headers.insert(
             header::CONTENT_LENGTH,
-                metadata.content_length.unwrap().into(),
+            metadata.size.unwrap_or_default().into(),
         );
 
-            if let Some(content_type) = metadata.content_type {
+        if let Some(content_type) = metadata.content_type.and_then(|x| x.parse().ok()) {
-                headers.insert(header::CONTENT_TYPE, content_type.parse().unwrap());
+            headers.insert(header::CONTENT_TYPE, content_type);
         }
-            if let Some(etag) = metadata.e_tag {
+        if let Some(etag) = metadata.etag.clone().and_then(|x| x.parse().ok()) {
-                headers.insert(header::ETAG, etag.parse().unwrap());
+            headers.insert(header::ETAG, etag);
         }
-            if let Some(content_encoding) = metadata.content_encoding {
+        if let Some(digest) = metadata
-                headers.insert(header::CONTENT_ENCODING, content_encoding.parse().unwrap());
+            .etag
-            }
+            .and_then(|x| format!("sha3-256={x}").parse().ok())
-            if let Some(content_language) = metadata.content_language {
+        {
-                headers.insert(header::CONTENT_LANGUAGE, content_language.parse().unwrap());
+            headers.insert("Digest", digest);
-            }
-            if let Some(cache_control) = metadata.cache_control {
-                headers.insert(header::CACHE_CONTROL, cache_control.parse().unwrap());
         }
 
         Ok((StatusCode::OK, headers, body).into_response())
     }
-    } else {
-        // logically should not happen
-        panic!("logic contradiction");
-    }
 }
-
-fn sanitize_id(id: String) -> String {
-    id.chars()
-        .take_while(|c| *c != '.')
-        .filter(|c| c.is_ascii_alphanumeric())
-        .collect()
-}
-
-struct ResponseStream(std::sync::Mutex<ResponseDataStream>);
-impl Stream for ResponseStream {
-    type Item = Result<Bytes, Error>;
-
-    fn poll_next(self: std::pin::Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        self.0
-            .lock()
-            .unwrap()
-            .bytes()
-            .poll_next_unpin(cx)
-            .map(|x| x.map(Ok))
-    }
-}
-unsafe impl Send for ResponseStream {}

src/metadata.rs

@@ -0,0 +1,33 @@
+use std::{io::ErrorKind, time::Instant};
+
+use serde::{Deserialize, Serialize};
+use tokio::{fs::File, io::AsyncWriteExt};
+
+use crate::Error;
+
+#[derive(Deserialize, Serialize, Debug)]
+pub struct Metadata {
+    pub subject: String,
+    pub nonce: String,
+    pub etag: Option<String>,
+    pub size: Option<u64>,
+    pub content_type: Option<String>,
+    pub expires_at: u64, // seconds since UNIX_EPOCH
+}
+
+impl Metadata {
+    pub async fn from_file(path: &str) -> Result<Self, Error> {
+        let metadata = match tokio::fs::read_to_string(path).await {
+            Ok(x) => Ok(x),
+            Err(err) if err.kind() == ErrorKind::NotFound => Err(Error::BinNotFound),
+            Err(x) => Err(x.into()),
+        }?;
+        Ok(toml::from_str::<Self>(&metadata)?)
+    }
+    pub async fn to_file(&self, path: &str) -> Result<(), Error> {
+        let data = toml::to_string(&self)?;
+        let mut file = File::create(path).await?;
+        file.write_all(data.as_ref()).await?;
+        Ok(())
+    }
+}

src/util.rs

@@ -0,0 +1,238 @@
+use std::{borrow::Borrow, fmt::Display, str::FromStr};
+
+use chacha20::cipher::{generic_array::GenericArray, ArrayLength};
+use rand::{distributions, Rng};
+use sha3::{Digest, Sha3_256};
+
+use crate::{error::Error, PHRASE_LENGTH, SALT_LENGTH};
+
+#[derive(Debug, PartialEq)]
+pub(crate) struct Phrase(String);
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub(crate) struct Id(String);
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) struct IdSalt(Vec<u8>);
+#[derive(Debug, PartialEq)]
+pub(crate) struct Key(Vec<u8>);
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) struct KeySalt(Vec<u8>);
+#[derive(Debug, PartialEq)]
+pub(crate) struct Nonce(Vec<u8>);
+
+impl Phrase {
+    pub(crate) fn random() -> Self {
+        let phrase = rand::thread_rng()
+            .sample_iter(distributions::Alphanumeric)
+            .take(PHRASE_LENGTH)
+            .map(char::from)
+            .collect::<String>();
+        Self(phrase)
+    }
+}
+impl FromStr for Phrase {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.chars().any(|x| !x.is_ascii_alphanumeric()) {
+            Err(Error::PhraseInvalid)
+        } else {
+            Ok(Self(s.to_string()))
+        }
+    }
+}
+impl Display for Phrase {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl Id {
+    pub(crate) fn from_phrase(phrase: &Phrase, salt: &IdSalt) -> Self {
+        let mut hasher = Sha3_256::new();
+        hasher.update(&phrase.0);
+        hasher.update(&salt.0);
+
+        let id = hex::encode(hasher.finalize());
+        Self(id)
+    }
+    pub(crate) fn from_str(s: &str) -> Self {
+        Self(s.to_string())
+    }
+    pub(crate) fn raw(&self) -> &str {
+        &self.0
+    }
+}
+impl Display for Id {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl IdSalt {
+    pub(crate) fn random() -> Self {
+        let salt = rand::thread_rng()
+            .sample_iter(distributions::Standard)
+            .take(SALT_LENGTH)
+            .collect();
+        Self(salt)
+    }
+    pub(crate) fn raw(&self) -> &[u8] {
+        &self.0
+    }
+}
+impl FromStr for IdSalt {
+    type Err = hex::FromHexError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(Self(hex::decode(s)?))
+    }
+}
+
+impl Key {
+    pub(crate) fn from_phrase(phrase: &Phrase, salt: &KeySalt) -> Self {
+        let mut hasher = Sha3_256::new();
+        hasher.update(&phrase.0);
+        hasher.update(&salt.0);
+        Self(hasher.finalize().to_vec())
+    }
+}
+
+impl<L: ArrayLength<u8>> Borrow<GenericArray<u8, L>> for Key {
+    fn borrow(&self) -> &GenericArray<u8, L> {
+        GenericArray::<u8, L>::from_slice(&self.0)
+    }
+}
+
+impl KeySalt {
+    pub(crate) fn random() -> Self {
+        let salt = rand::thread_rng()
+            .sample_iter(distributions::Standard)
+            .take(SALT_LENGTH)
+            .collect();
+        Self(salt)
+    }
+    pub(crate) fn raw(&self) -> &[u8] {
+        &self.0
+    }
+}
+impl FromStr for KeySalt {
+    type Err = hex::FromHexError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(Self(hex::decode(s)?))
+    }
+}
+
+impl Nonce {
+    pub(crate) fn random() -> Self {
+        // generate a 12 byte / 96 bit nonce for chacha20 as defined in rfc7539
+        let nonce = rand::thread_rng()
+            .sample_iter(distributions::Standard)
+            .take(12)
+            .collect();
+        Self(nonce)
+    }
+    pub(crate) fn from_hex(hex_value: &str) -> Result<Self, Error> {
+        Ok(Self(hex::decode(hex_value)?))
+    }
+    pub(crate) fn to_hex(&self) -> String {
+        hex::encode(&self.0)
+    }
+}
+
+impl<L: ArrayLength<u8>> Borrow<GenericArray<u8, L>> for Nonce {
+    fn borrow(&self) -> &GenericArray<u8, L> {
+        GenericArray::from_slice(&self.0)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::{
+        util::{Id, IdSalt, Key, KeySalt, Nonce, Phrase},
+        PHRASE_LENGTH, SALT_LENGTH,
+    };
+
+    #[test]
+    fn phrase() {
+        assert_eq!(PHRASE_LENGTH, Phrase::random().0.len());
+        assert_ne!(Phrase::random(), Phrase::random());
+    }
+
+    #[test]
+    fn id() {
+        let phrase = Phrase::random();
+        let salt = IdSalt::random();
+        let phrase2 = Phrase::random();
+        let salt2 = IdSalt::random();
+
+        assert_eq!(
+            Id::from_phrase(&phrase, &salt),
+            Id::from_phrase(&phrase, &salt)
+        );
+
+        assert_ne!(
+            Id::from_phrase(&phrase, &salt),
+            Id::from_phrase(&phrase, &salt2)
+        );
+
+        assert_ne!(
+            Id::from_phrase(&phrase, &salt),
+            Id::from_phrase(&phrase2, &salt)
+        );
+    }
+
+    #[test]
+    fn key() {
+        let phrase = Phrase::random();
+        let salt = KeySalt::random();
+        let phrase2 = Phrase::random();
+        let salt2 = KeySalt::random();
+
+        assert_eq!(
+            Key::from_phrase(&phrase, &salt),
+            Key::from_phrase(&phrase, &salt)
+        );
+
+        assert_ne!(
+            Key::from_phrase(&phrase, &salt),
+            Key::from_phrase(&phrase, &salt2)
+        );
+
+        assert_ne!(
+            Key::from_phrase(&phrase, &salt),
+            Key::from_phrase(&phrase2, &salt)
+        );
+    }
+
+    #[test]
+    #[allow(clippy::unwrap_used)]
+    fn key_id_collision() {
+        let phrase = Phrase::random();
+        let id_salt = IdSalt::random();
+        let key_salt = KeySalt::random();
+
+        assert_ne!(
+            hex::decode(Id::from_phrase(&phrase, &id_salt).0).unwrap(),
+            Key::from_phrase(&phrase, &key_salt).0
+        );
+    }
+
+    #[test]
+    fn id_salt() {
+        assert_eq!(SALT_LENGTH, IdSalt::random().0.len());
+        assert_ne!(IdSalt::random(), IdSalt::random());
+    }
+
+    #[test]
+    fn key_salt() {
+        assert_eq!(SALT_LENGTH, KeySalt::random().0.len());
+        assert_ne!(KeySalt::random(), KeySalt::random());
+    }
+
+    #[test]
+    fn nonce() {
+        assert_eq!(12, Nonce::random().0.len());
+        assert_ne!(Nonce::random(), Nonce::random());
+    }
+}

src/web_util.rs

@@ -0,0 +1,133 @@
+use std::{
+    borrow::Borrow,
+    pin::Pin,
+    task::{Context, Poll},
+};
+
+use bytes::{Bytes, BytesMut};
+use chacha20::{
+    cipher::{KeyIvInit, StreamCipher},
+    ChaCha20,
+};
+use futures_util::Stream;
+use log::{debug, warn};
+use pin_project_lite::pin_project;
+use sha3::{Digest, Sha3_256};
+use tokio::io::AsyncRead;
+use tokio_util::io::poll_read_buf;
+
+use crate::{
+    metadata::Metadata,
+    util::{Id, Key, Nonce},
+};
+pin_project! {
+    pub(crate) struct DecryptingStream<R> {
+        #[pin]
+        reader: Option<R>,
+        buf: BytesMut,
+        // chunk size
+        capacity: usize,
+        // chacha20 cipher
+        cipher: ChaCha20,
+        // hasher to verify file integrity
+        hasher: Sha3_256,
+        // hash to verify against
+        target_hash: String,
+        // id of the file for logging purposes
+        id: Id,
+        // total file size
+        size: u64,
+        // current position of the "reading head"
+        progress: u64
+    }
+}
+impl<R: AsyncRead> DecryptingStream<R> {
+    pub(crate) fn new(reader: R, id: Id, metadata: &Metadata, key: &Key, nonce: &Nonce) -> Self {
+        let cipher = ChaCha20::new(key.borrow(), nonce.borrow());
+        Self {
+            reader: Some(reader),
+            buf: BytesMut::new(),
+            capacity: 1 << 22, // 4 MiB
+            cipher,
+            hasher: Sha3_256::new(),
+            target_hash: metadata.etag.clone().unwrap_or_default(),
+            id,
+            size: metadata.size.unwrap_or_default(),
+            progress: 0,
+        }
+    }
+}
+
+impl<R: AsyncRead> Stream for DecryptingStream<R> {
+    type Item = std::io::Result<Bytes>;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let mut this = self.as_mut().project();
+
+        let reader = match this.reader.as_pin_mut() {
+            Some(r) => r,
+            None => return Poll::Ready(None),
+        };
+
+        if this.buf.capacity() == 0 {
+            this.buf.reserve(*this.capacity);
+        }
+
+        match poll_read_buf(reader, cx, &mut this.buf) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(Err(err)) => {
+                debug!("failed to send bin {}", this.id);
+                self.project().reader.set(None);
+                Poll::Ready(Some(Err(err)))
+            }
+            Poll::Ready(Ok(0)) => {
+                if self.progress_check() == DecryptingStreamProgress::Failed {
+                    // The hash is invalid, the file has been tampered with. Close reader and stream causing the download to fail
+                    self.project().reader.set(None);
+                    return Poll::Ready(None);
+                };
+                self.project().reader.set(None);
+                Poll::Ready(None)
+            }
+            Poll::Ready(Ok(n)) => {
+                let mut chunk = this.buf.split();
+                // decrypt the chunk using chacha
+                this.cipher.apply_keystream(&mut chunk);
+                // update the sha3 hasher
+                this.hasher.update(&chunk);
+                // track progress
+                *this.progress += n as u64;
+                if self.progress_check() == DecryptingStreamProgress::Failed {
+                    // The hash is invalid, the file has been tampered with. Close reader and stream causing the download to fail
+                    warn!("bin {} is corrupted! transmission failed", self.id);
+                    self.project().reader.set(None);
+                    return Poll::Ready(None);
+                };
+                Poll::Ready(Some(Ok(chunk.freeze())))
+            }
+        }
+    }
+}
+
+impl<R: AsyncRead> DecryptingStream<R> {
+    /// checks if the hash is correct when the last byte has been read
+    fn progress_check(&self) -> DecryptingStreamProgress {
+        if self.progress >= self.size {
+            let hash = hex::encode(self.hasher.clone().finalize());
+            if hash != self.target_hash {
+                DecryptingStreamProgress::Failed
+            } else {
+                DecryptingStreamProgress::Finished
+            }
+        } else {
+            DecryptingStreamProgress::Running
+        }
+    }
+}
+
+#[derive(PartialEq, Eq)]
+enum DecryptingStreamProgress {
+    Finished,
+    Failed,
+    Running,
+}