Forbid remote URLs for avatars/banners (fixes #1618)

crates/api/src/local_user.rs

@@ -5,6 +5,7 @@ use captcha::{gen, Difficulty};
 use chrono::Duration;
 use lemmy_api_common::{
   blocking,
+  check_image_has_local_domain,
   check_registration_application,
   get_local_user_view_from_jwt,
   is_admin,
@@ -176,6 +177,9 @@ impl Perform for SaveUserSettings {
     let local_user_view =
       get_local_user_view_from_jwt(&data.auth, context.pool(), context.secret()).await?;
 
+    check_image_has_local_domain(&data.avatar)?;
+    check_image_has_local_domain(&data.banner)?;
+
     let avatar = diesel_option_overwrite_to_url(&data.avatar)?;
     let banner = diesel_option_overwrite_to_url(&data.banner)?;
     let bio = diesel_option_overwrite(&data.bio);

crates/api_common/src/lib.rs

@@ -40,6 +40,7 @@ use lemmy_utils::{
   LemmyError,
   Sensitive,
 };
+use url::Url;
 
 pub async fn blocking<F, T>(pool: &DbPool, f: F) -> Result<T, LemmyError>
 where
@@ -629,3 +630,15 @@ pub async fn remove_user_data_in_community(
 
   Ok(())
 }
+
+pub fn check_image_has_local_domain(url: &Option<String>) -> Result<(), LemmyError> {
+  if let Some(url) = url {
+    let settings = Settings::get();
+    let url = Url::parse(url)?;
+    let domain = url.domain().expect("url has domain");
+    if domain != settings.hostname {
+      return Err(LemmyError::from_message("image_not_local"));
+    }
+  }
+  Ok(())
+}

crates/api_crud/src/community/update.rs

@@ -2,6 +2,7 @@ use crate::PerformCrud;
 use actix_web::web::Data;
 use lemmy_api_common::{
   blocking,
+  check_image_has_local_domain,
   community::{CommunityResponse, EditCommunity, HideCommunity},
   get_local_user_view_from_jwt,
   is_admin,
@@ -37,6 +38,8 @@ impl PerformCrud for EditCommunity {
 
     check_slurs_opt(&data.title, &context.settings().slur_regex())?;
     check_slurs_opt(&data.description, &context.settings().slur_regex())?;
+    check_image_has_local_domain(&data.icon)?;
+    check_image_has_local_domain(&data.banner)?;
 
     // Verify its a mod (only mods can edit it)
     let community_id = data.community_id;

crates/api_crud/src/site/update.rs

@@ -2,6 +2,7 @@ use crate::PerformCrud;
 use actix_web::web::Data;
 use lemmy_api_common::{
   blocking,
+  check_image_has_local_domain,
   get_local_user_view_from_jwt,
   is_admin,
   site::{EditSite, SiteResponse},
@@ -38,6 +39,8 @@ impl PerformCrud for EditSite {
 
     check_slurs_opt(&data.name, &context.settings().slur_regex())?;
     check_slurs_opt(&data.description, &context.settings().slur_regex())?;
+    check_image_has_local_domain(&data.icon)?;
+    check_image_has_local_domain(&data.banner)?;
 
     // Make sure user is an admin
     is_admin(&local_user_view)?;

crates/apub/src/objects/instance.rs

@@ -1,6 +1,6 @@
 use crate::{
   check_is_apub_id_valid,
-  objects::get_summary_from_string_or_source,
+  objects::{get_summary_from_string_or_source, verify_image_domain_matches},
   protocol::{objects::instance::Instance, ImageObject, Source},
 };
 use activitystreams_kinds::actor::ServiceType;
@@ -103,6 +103,8 @@ impl ApubObject for ApubSite {
   ) -> Result<(), LemmyError> {
     check_is_apub_id_valid(apub.id.inner(), true, &data.settings())?;
     verify_domains_match(expected_domain, apub.id.inner())?;
+    verify_image_domain_matches(expected_domain, &apub.icon)?;
+    verify_image_domain_matches(expected_domain, &apub.image)?;
 
     let slur_regex = &data.settings().slur_regex();
     check_slurs(&apub.name, slur_regex)?;

crates/apub/src/objects/mod.rs

@@ -1,5 +1,8 @@
-use crate::protocol::Source;
+use crate::protocol::{ImageObject, Source};
 use html2md::parse_html;
+use lemmy_apub_lib::verify::verify_domains_match;
+use lemmy_utils::LemmyError;
+use url::Url;
 
 pub mod comment;
 pub mod community;
@@ -19,6 +22,14 @@ pub(crate) fn get_summary_from_string_or_source(
   }
 }
 
+pub fn verify_image_domain_matches(a: &Url, b: &Option<ImageObject>) -> Result<(), LemmyError> {
+  if let Some(b) = b {
+    verify_domains_match(a, &b.url)
+  } else {
+    Ok(())
+  }
+}
+
 #[cfg(test)]
 pub(crate) mod tests {
   use actix::Actor;

crates/apub/src/objects/person.rs

@@ -1,7 +1,11 @@
 use crate::{
   check_is_apub_id_valid,
   generate_outbox_url,
-  objects::{get_summary_from_string_or_source, instance::fetch_instance_actor_for_object},
+  objects::{
+    get_summary_from_string_or_source,
+    instance::fetch_instance_actor_for_object,
+    verify_image_domain_matches,
+  },
   protocol::{
     objects::{
       person::{Person, UserTypes},
@@ -123,6 +127,8 @@ impl ApubObject for ApubPerson {
   ) -> Result<(), LemmyError> {
     verify_domains_match(person.id.inner(), expected_domain)?;
     check_is_apub_id_valid(person.id.inner(), false, &context.settings())?;
+    verify_image_domain_matches(expected_domain, &person.icon)?;
+    verify_image_domain_matches(expected_domain, &person.image)?;
 
     let slur_regex = &context.settings().slur_regex();
     check_slurs(&person.preferred_username, slur_regex)?;

crates/apub/src/protocol/objects/group.rs

@@ -4,7 +4,11 @@ use crate::{
     community_moderators::ApubCommunityModerators,
     community_outbox::ApubCommunityOutbox,
   },
-  objects::{community::ApubCommunity, get_summary_from_string_or_source},
+  objects::{
+    community::ApubCommunity,
+    get_summary_from_string_or_source,
+    verify_image_domain_matches,
+  },
   protocol::{objects::Endpoints, ImageObject, Source},
 };
 use activitystreams_kinds::actor::GroupType;
@@ -58,6 +62,8 @@ impl Group {
   ) -> Result<(), LemmyError> {
     check_is_apub_id_valid(self.id.inner(), true, &context.settings())?;
     verify_domains_match(expected_domain, self.id.inner())?;
+    verify_image_domain_matches(expected_domain, &self.icon)?;
+    verify_image_domain_matches(expected_domain, &self.image)?;
 
     let slur_regex = &context.settings().slur_regex();
     check_slurs(&self.preferred_username, slur_regex)?;