Check for community ban when parsing post/comment (fixes #1287)

lemmy_apub/src/inbox/community_inbox.rs

@@ -259,7 +259,7 @@ async fn handle_undo_follow(
   Ok(())
 }
 
-async fn check_community_or_site_ban(
+pub(crate) async fn check_community_or_site_ban(
   user: &User_,
   community: &Community,
   pool: &DbPool,

lemmy_apub/src/objects/comment.rs

@@ -7,6 +7,7 @@ use crate::{
   },
   objects::{
     check_object_domain,
+    check_object_for_community_or_site_ban,
     create_tombstone,
     get_object_from_apub,
     get_source_markdown_value,
@@ -101,6 +102,8 @@ impl FromApub for Comment {
     expected_domain: Option<Url>,
     request_counter: &mut i32,
   ) -> Result<Comment, LemmyError> {
+    check_object_for_community_or_site_ban(note, context, request_counter).await?;
+
     let comment: Comment =
       get_object_from_apub(note, context, expected_domain, request_counter).await?;
 

lemmy_apub/src/objects/mod.rs

@@ -1,4 +1,8 @@
-use crate::check_is_apub_id_valid;
+use crate::{
+  check_is_apub_id_valid,
+  fetcher::{get_or_fetch_and_upsert_community, get_or_fetch_and_upsert_user},
+  inbox::community_inbox::check_community_or_site_ban,
+};
 use activitystreams::{
   base::{AsBase, BaseExt, ExtendsExt},
   markers::Base,
@@ -205,3 +209,26 @@ where
     Ok(to)
   }
 }
+
+pub(in crate::objects) async fn check_object_for_community_or_site_ban<T, Kind>(
+  object: &T,
+  context: &LemmyContext,
+  request_counter: &mut i32,
+) -> Result<(), LemmyError>
+where
+  T: ObjectExt<Kind>,
+{
+  let user_id = object
+    .attributed_to()
+    .context(location_info!())?
+    .as_single_xsd_any_uri()
+    .context(location_info!())?;
+  let user = get_or_fetch_and_upsert_user(user_id, context, request_counter).await?;
+  let community_id = object
+    .to()
+    .context(location_info!())?
+    .as_single_xsd_any_uri()
+    .context(location_info!())?;
+  let community = get_or_fetch_and_upsert_community(community_id, context, request_counter).await?;
+  check_community_or_site_ban(&user, &community, context.pool()).await
+}

lemmy_apub/src/objects/post.rs

@@ -3,6 +3,7 @@ use crate::{
   fetcher::{get_or_fetch_and_upsert_community, get_or_fetch_and_upsert_user},
   objects::{
     check_object_domain,
+    check_object_for_community_or_site_ban,
     create_tombstone,
     get_object_from_apub,
     get_source_markdown_value,
@@ -112,6 +113,7 @@ impl FromApub for Post {
     expected_domain: Option<Url>,
     request_counter: &mut i32,
   ) -> Result<Post, LemmyError> {
+    check_object_for_community_or_site_ban(page, context, request_counter).await?;
     get_object_from_apub(page, context, expected_domain, request_counter).await
   }
 }