From ec1c458bb72bc666a27f40170459c926ba0648f0 Mon Sep 17 00:00:00 2001
From: stefiosif <si.iosifidis@gmail.com>
Date: Sat, 6 Jun 2026 17:50:36 +0300
Subject: [PATCH] feat(backend): rate limit auth routes with tower_governor

---
 backend/Cargo.lock  | 218 +++++++++++++++++++++++++++++++++++++++++---
 backend/Cargo.toml  |   1 +
 backend/src/main.rs |  34 ++++++-
 3 files changed, 239 insertions(+), 14 deletions(-)

diff --git a/backend/Cargo.lock b/backend/Cargo.lock
index cbff620..9cad17a 100644
--- a/backend/Cargo.lock
+++ b/backend/Cargo.lock
@@ -202,6 +202,7 @@ dependencies = [
  "tokio",
  "tower-cookies",
  "tower-http",
+ "tower_governor",
  "tracing",
  "tracing-subscriber",
 ]
@@ -464,6 +465,20 @@ version = "0.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "52560adf09603e58c9a7ee1fe1dcb95a16927b17c127f0ac02d6e768a0e25bc1"
 
+[[package]]
+name = "dashmap"
+version = "6.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6361d5c062261c78a176addb82d4c821ae42bed6089de0e12603cd25de2059c"
+dependencies = [
+ "cfg-if",
+ "crossbeam-utils",
+ "hashbrown 0.14.5",
+ "lock_api",
+ "once_cell",
+ "parking_lot_core",
+]
+
 [[package]]
 name = "der"
 version = "0.7.10"
@@ -629,7 +644,7 @@ dependencies = [
  "regex",
  "serde",
  "serde_json",
- "thiserror",
+ "thiserror 2.0.18",
  "typetag",
  "uuid",
 ]
@@ -674,6 +689,12 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d9c4f5dac5e15c24eb999c26181a6ca40b39fe946cbe4c263c7209467bc83af2"
 
+[[package]]
+name = "foldhash"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77ce24cb58228fbb8aa041425bb1050850ac19177686ea6e0f41a70416f56fdb"
+
 [[package]]
 name = "form_urlencoded"
 version = "1.2.2"
@@ -683,6 +704,16 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "forwarded-header-value"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8835f84f38484cc86f110a805655697908257fb9a7af005234060891557198e9"
+dependencies = [
+ "nonempty",
+ "thiserror 1.0.69",
+]
+
 [[package]]
 name = "fs_extra"
 version = "1.3.0"
@@ -771,6 +802,12 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "037711b3d59c33004d3856fbdc83b99d4ff37a24768fa1be9ce3538a1cde4393"
 
+[[package]]
+name = "futures-timer"
+version = "3.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af43fadb8a98512d547e37b4e92e0ced13e205c061b87b4623eff01d918d6968"
+
 [[package]]
 name = "futures-util"
 version = "0.3.32"
@@ -851,6 +888,35 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "governor"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9efcab3c1958580ff1f25a2a41be1668f7603d849bb63af523b208a3cc1223b8"
+dependencies = [
+ "cfg-if",
+ "dashmap",
+ "futures-sink",
+ "futures-timer",
+ "futures-util",
+ "getrandom 0.3.4",
+ "hashbrown 0.16.1",
+ "nonzero_ext",
+ "parking_lot",
+ "portable-atomic",
+ "quanta",
+ "rand 0.9.4",
+ "smallvec",
+ "spinning_top",
+ "web-time",
+]
+
+[[package]]
+name = "hashbrown"
+version = "0.14.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
+
 [[package]]
 name = "hashbrown"
 version = "0.15.5"
@@ -859,7 +925,7 @@ checksum = "9229cfe53dfd69f0609a49f65461bd93001ea1ef889cd5529dd176593f5338a1"
 dependencies = [
  "allocator-api2",
  "equivalent",
- "foldhash",
+ "foldhash 0.1.5",
 ]
 
 [[package]]
@@ -867,6 +933,11 @@ name = "hashbrown"
 version = "0.16.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "841d1cc9bed7f9236f321df977030373f4a4163ae1a7dbfe1a51a2c1a51d9100"
+dependencies = [
+ "allocator-api2",
+ "equivalent",
+ "foldhash 0.2.0",
+]
 
 [[package]]
 name = "hashlink"
@@ -1247,7 +1318,7 @@ dependencies = [
  "jni-sys",
  "log",
  "simd_cesu8",
- "thiserror",
+ "thiserror 2.0.18",
  "walkdir",
  "windows-link",
 ]
@@ -1495,6 +1566,18 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "nonempty"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e9e591e719385e6ebaeb5ce5d3887f7d5676fceca6411d1925ccc95745f3d6f7"
+
+[[package]]
+name = "nonzero_ext"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38bf9645c8b145698bb0b18a4637dcacbc421ea49bef2317e4fd8065a387cf21"
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.50.3"
@@ -1786,6 +1869,26 @@ version = "2.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
+[[package]]
+name = "pin-project"
+version = "1.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2466b2336ed02bcdca6b294417127b90ec92038d1d5c4fbeac971a922e0e0924"
+dependencies = [
+ "pin-project-internal",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "1.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c96395f0a926bc13b1c17622aaddda1ecb55d49c8f1bf9777e4d877800a43f8b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.17"
@@ -1893,6 +1996,21 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "quanta"
+version = "0.12.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3ab5a9d756f0d97bdc89019bd2e4ea098cf9cde50ee7564dde6b81ccc8f06c7"
+dependencies = [
+ "crossbeam-utils",
+ "libc",
+ "once_cell",
+ "raw-cpuid",
+ "wasi",
+ "web-sys",
+ "winapi",
+]
+
 [[package]]
 name = "quick-xml"
 version = "0.38.4"
@@ -1917,7 +2035,7 @@ dependencies = [
  "rustc-hash",
  "rustls",
  "socket2",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tracing",
  "web-time",
@@ -1939,7 +2057,7 @@ dependencies = [
  "rustls",
  "rustls-pki-types",
  "slab",
- "thiserror",
+ "thiserror 2.0.18",
  "tinyvec",
  "tracing",
  "web-time",
@@ -2056,6 +2174,15 @@ version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c8d0fd677905edcbeedbf2edb6494d676f0e98d54d5cf9bda0b061cb8fb8aba"
 
+[[package]]
+name = "raw-cpuid"
+version = "11.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "498cd0dc59d73224351ee52a95fee0f1a617a2eae0e7d9d720cc622c73a54186"
+dependencies = [
+ "bitflags",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.18"
@@ -2169,7 +2296,7 @@ version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94070964579245eb2f76e62a7668fe87bd9969ed6c41256f3bf614e3323dd3cc"
 dependencies = [
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -2218,7 +2345,7 @@ dependencies = [
  "http",
  "mime",
  "rand 0.10.1",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -2604,6 +2731,15 @@ dependencies = [
  "lock_api",
 ]
 
+[[package]]
+name = "spinning_top"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d96d2d1d716fb500937168cc09353ffdc7a012be8475ac7308e1bdf0e3923300"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "spki"
 version = "0.7.3"
@@ -2656,7 +2792,7 @@ dependencies = [
  "serde_json",
  "sha2",
  "smallvec",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tokio-stream",
  "tracing",
@@ -2741,7 +2877,7 @@ dependencies = [
  "smallvec",
  "sqlx-core",
  "stringprep",
- "thiserror",
+ "thiserror 2.0.18",
  "tracing",
  "uuid",
  "whoami",
@@ -2780,7 +2916,7 @@ dependencies = [
  "smallvec",
  "sqlx-core",
  "stringprep",
- "thiserror",
+ "thiserror 2.0.18",
  "tracing",
  "uuid",
  "whoami",
@@ -2806,7 +2942,7 @@ dependencies = [
  "serde",
  "serde_urlencoded",
  "sqlx-core",
- "thiserror",
+ "thiserror 2.0.18",
  "tracing",
  "url",
  "uuid",
@@ -2866,13 +3002,33 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
+dependencies = [
+ "thiserror-impl 1.0.69",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
 dependencies = [
- "thiserror-impl",
+ "thiserror-impl 2.0.18",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -3085,6 +3241,22 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8df9b6e13f2d32c91b9bd719c00d1958837bc7dec474d94952798cc8e69eeec3"
 
+[[package]]
+name = "tower_governor"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44de9b94d849d3c46e06a883d72d408c2de6403367b39df2b1c9d9e7b6736fe6"
+dependencies = [
+ "axum",
+ "forwarded-header-value",
+ "governor",
+ "http",
+ "pin-project",
+ "thiserror 2.0.18",
+ "tower",
+ "tracing",
+]
+
 [[package]]
 name = "tracing"
 version = "0.1.44"
@@ -3490,6 +3662,22 @@ dependencies = [
  "wasite",
 ]
 
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
 [[package]]
 name = "winapi-util"
 version = "0.1.11"
@@ -3499,6 +3687,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-core"
 version = "0.62.2"
diff --git a/backend/Cargo.toml b/backend/Cargo.toml
index d20da21..dbc8b62 100644
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -22,6 +22,7 @@ argon2 = "0.5.3"
 rand = "0.10.1"
 futures-util = "0.3.32"
 mime_guess = "2.0.5"
+tower_governor = { version = "0.8.0", default-features = false, features = ["axum", "tracing"] }
 
 [dev-dependencies]
 axum-test = "20.0.0"
diff --git a/backend/src/main.rs b/backend/src/main.rs
index 90e7da8..0051dd2 100644
--- a/backend/src/main.rs
+++ b/backend/src/main.rs
@@ -3,6 +3,8 @@ mod error;
 mod model;
 mod web;
 
+use std::{net::SocketAddr, time::Duration};
+
 use anyhow::Result;
 use axum::{
     Router,
@@ -13,6 +15,9 @@ use axum::{
 };
 use sqlx::PgPool;
 use tower_cookies::CookieManagerLayer;
+use tower_governor::{
+    GovernorLayer, governor::GovernorConfigBuilder, key_extractor::SmartIpKeyExtractor,
+};
 use tower_http::{
     cors::CorsLayer,
     services::{ServeDir, ServeFile},
@@ -44,6 +49,26 @@ async fn main() -> Result<()> {
 
     dotenvy::dotenv().ok();
 
+    let governor_conf_auth = GovernorConfigBuilder::default()
+        .per_second(4)
+        .burst_size(2)
+        .key_extractor(SmartIpKeyExtractor)
+        .finish()
+        .unwrap();
+    let governor_auth_limiter = governor_conf_auth.limiter().clone();
+    let interval = Duration::from_secs(60);
+
+    std::thread::spawn(move || {
+        loop {
+            std::thread::sleep(interval);
+            info!(
+                "rate limiting auth storage size: {}",
+                governor_auth_limiter.len()
+            );
+            governor_auth_limiter.retain_recent();
+        }
+    });
+
     let database_url = std::env::var("DATABASE_URL").expect("DATABASE_URL must be set");
     let pool = PgPool::connect(&database_url).await.unwrap();
     sqlx::migrate!().run(&pool).await?;
@@ -53,7 +78,8 @@ async fn main() -> Result<()> {
         .layer(DefaultBodyLimit::disable());
 
     let user_repository = UserRepository::new(pool)?;
-    let routes_auth = routes_auth(user_repository.clone());
+    let routes_auth =
+        routes_auth(user_repository.clone()).layer(GovernorLayer::new(governor_conf_auth));
 
     let app = Router::new()
         .nest("/api", routes_file)
@@ -80,7 +106,11 @@ async fn main() -> Result<()> {
     let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await?;
     info!("listening on {}", listener.local_addr().unwrap());
 
-    axum::serve(listener, app).await?;
+    axum::serve(
+        listener,
+        app.into_make_service_with_connect_info::<SocketAddr>(),
+    )
+    .await?;
 
     Ok(())
 }