From 2847040b3f06586e0dd84e376d3532376405d665 Mon Sep 17 00:00:00 2001
From: Nutomic <me@nutomic.com>
Date: Wed, 29 Jan 2025 18:51:10 +0000
Subject: [PATCH] Deny unknown config fields (#5370)

---
 crates/utils/src/settings/mod.rs     | 27 +++++++++++++++++----------
 crates/utils/src/settings/structs.rs | 13 ++++++-------
 2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/crates/utils/src/settings/mod.rs b/crates/utils/src/settings/mod.rs
index ecd0a9b55..240632f8d 100644
--- a/crates/utils/src/settings/mod.rs
+++ b/crates/utils/src/settings/mod.rs
@@ -2,7 +2,7 @@ use crate::{error::LemmyResult, location_info};
 use anyhow::{anyhow, Context};
 use deser_hjson::from_str;
 use regex::Regex;
-use std::{env, fs, io::Error, sync::LazyLock};
+use std::{env, fs, sync::LazyLock};
 use structs::{PictrsConfig, Settings};
 use url::Url;
 
@@ -39,7 +39,10 @@ impl Settings {
   /// `lemmy_db_schema/src/lib.rs::get_database_url_from_env()`
   /// Warning: Only call this once.
   pub(crate) fn init() -> LemmyResult<Self> {
-    let config = from_str::<Settings>(&Self::read_config_file()?)?;
+    let path =
+      env::var("LEMMY_CONFIG_LOCATION").unwrap_or_else(|_| DEFAULT_CONFIG_FILE.to_string());
+    let plain = fs::read_to_string(path)?;
+    let config = from_str::<Settings>(&plain)?;
     if config.hostname == "unset" {
       Err(anyhow!("Hostname variable is not set!").into())
     } else {
@@ -55,14 +58,6 @@ impl Settings {
     }
   }
 
-  fn get_config_location() -> String {
-    env::var("LEMMY_CONFIG_LOCATION").unwrap_or_else(|_| DEFAULT_CONFIG_FILE.to_string())
-  }
-
-  fn read_config_file() -> Result<String, Error> {
-    fs::read_to_string(Self::get_config_location())
-  }
-
   /// Returns either "http" or "https", depending on tls_enabled setting
   pub fn get_protocol_string(&self) -> &'static str {
     if self.tls_enabled {
@@ -109,3 +104,15 @@ impl Settings {
 fn pictrs_placeholder_url() -> Url {
   Url::parse("http://localhost:8080").expect("parse pictrs url")
 }
+
+#[cfg(test)]
+mod tests {
+
+  use super::*;
+
+  #[test]
+  fn test_load_config() -> LemmyResult<()> {
+    Settings::init()?;
+    Ok(())
+  }
+}
diff --git a/crates/utils/src/settings/structs.rs b/crates/utils/src/settings/structs.rs
index 4577f4e60..01b73afd7 100644
--- a/crates/utils/src/settings/structs.rs
+++ b/crates/utils/src/settings/structs.rs
@@ -9,7 +9,7 @@ use std::{
 use url::Url;
 
 #[derive(Debug, Deserialize, Serialize, Clone, SmartDefault, Document)]
-#[serde(default)]
+#[serde(default, deny_unknown_fields)]
 pub struct Settings {
   /// settings related to the postgresql database
   pub database: DatabaseConfig,
@@ -109,7 +109,6 @@ pub struct PictrsConfig {
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, Default, Document, PartialEq)]
-#[serde(deny_unknown_fields)]
 pub enum PictrsImageMode {
   /// Leave images unchanged, don't generate any local thumbnails for post urls. Instead the
   /// Opengraph image is directly returned as thumbnail
@@ -132,7 +131,7 @@ pub enum PictrsImageMode {
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, SmartDefault, Document)]
-#[serde(default)]
+#[serde(default, deny_unknown_fields)]
 pub struct DatabaseConfig {
   /// Configure the database by specifying URI pointing to a postgres instance
   ///
@@ -153,7 +152,7 @@ pub struct DatabaseConfig {
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, Document, SmartDefault)]
-#[serde(deny_unknown_fields)]
+#[serde(default, deny_unknown_fields)]
 pub struct EmailConfig {
   /// Hostname and port of the smtp server
   #[doku(example = "localhost:25")]
@@ -180,7 +179,7 @@ impl EmailConfig {
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, Default, Document)]
-#[serde(deny_unknown_fields)]
+#[serde(default, deny_unknown_fields)]
 pub struct SetupConfig {
   /// Username for the admin user
   #[doku(example = "admin")]
@@ -197,7 +196,7 @@ pub struct SetupConfig {
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, SmartDefault, Document)]
-#[serde(deny_unknown_fields)]
+#[serde(default, deny_unknown_fields)]
 pub struct PrometheusConfig {
   // Address that the Prometheus metrics will be served on.
   #[default(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)))]
@@ -210,7 +209,7 @@ pub struct PrometheusConfig {
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, SmartDefault, Document)]
-#[serde(default)]
+#[serde(default, deny_unknown_fields)]
 // named federation"worker"config to disambiguate from the activitypub library configuration
 pub struct FederationWorkerConfig {
   /// Limit to the number of concurrent outgoing federation requests per target instance.