Support blind key rotation (#399)

* Allow receiving objects with new unknown key

* Rotate key after sending Delete activity

* Do the right check

plume-models/src/users.rs

@@ -364,6 +364,10 @@ impl User {
                         .followers_string()?),
                     users::avatar_id.eq(avatar.map(|a| a.id)),
                     users::last_fetched_date.eq(Utc::now().naive_utc()),
+                    users::public_key.eq(json
+                        .custom_props
+                        .public_key_publickey()?
+                        .public_key_pem_string()?),
                 ))
                 .execute(conn)
                 .map(|_| ())
@@ -638,6 +642,30 @@ impl User {
         ).map_err(Error::from)
     }
 
+    pub fn rotate_keypair(&self, conn: &Connection) -> Result<PKey<Private>> {
+        if self.private_key.is_none() {
+            return Err(Error::InvalidValue)
+        }
+        if (Utc::now().naive_utc() - self.last_fetched_date).num_minutes() < 10 {
+            //rotated recently
+            self.get_keypair()
+        } else {
+            let (public_key, private_key) = gen_keypair();
+            let public_key = String::from_utf8(public_key).expect("NewUser::new_local: public key error");
+            let private_key = String::from_utf8(private_key).expect("NewUser::new_local: private key error");
+            let res = PKey::from_rsa(
+                Rsa::private_key_from_pem(private_key.as_ref())?
+                )?;
+            diesel::update(self)
+                .set((users::public_key.eq(public_key),
+                    users::private_key.eq(Some(private_key)),
+                    users::last_fetched_date.eq(Utc::now().naive_utc())))
+                .execute(conn)
+                .map_err(Error::from)
+                .map(|_| res)
+        }
+    }
+
     pub fn to_activity(&self, conn: &Connection) -> Result<CustomPerson> {
         let mut actor = Person::default();
         actor

src/routes/comments.rs

@@ -7,6 +7,8 @@ use rocket_i18n::I18n;
 use validator::Validate;
 use template_utils::Ructe;
 
+use std::time::Duration;
+
 use plume_common::{utils, activity_pub::{broadcast, ApRequest, 
     ActivityStream, inbox::Deletable}};
 use plume_models::{
@@ -104,7 +106,9 @@ pub fn delete(blog: String, slug: String, id: i32, user: User, conn: DbConn, wor
         if comment.author_id == user.id {
             let dest = User::one_by_instance(&*conn)?;
             let delete_activity = comment.delete(&*conn)?;
-            worker.execute(move || broadcast(&user, delete_activity, dest));
+            let user_c = user.clone();
+            worker.execute(move || broadcast(&user_c, delete_activity, dest));
+            worker.execute_after(Duration::from_secs(10*60), move || {user.rotate_keypair(&conn).expect("Failed to rotate keypair");});
         }
     }
     Ok(Redirect::to(uri!(super::posts::details: blog = blog, slug = slug, responding_to = _)))

src/routes/instance.rs

@@ -10,6 +10,7 @@ use plume_models::{
     admin::Admin,
     comments::Comment,
     db_conn::DbConn,
+    Error,
     headers::Headers,
     posts::Post,
     users::User,
@@ -180,16 +181,26 @@ pub fn ban(_admin: Admin, conn: DbConn, id: i32, searcher: Searcher) -> Result<R
 #[post("/inbox", data = "<data>")]
 pub fn shared_inbox(conn: DbConn, data: SignedJson<serde_json::Value>, headers: Headers, searcher: Searcher) -> Result<String, status::BadRequest<&'static str>> {
     let act = data.1.into_inner();
+    let sig = data.0;
 
     let activity = act.clone();
     let actor_id = activity["actor"].as_str()
         .or_else(|| activity["actor"]["id"].as_str()).ok_or(status::BadRequest(Some("Missing actor id for activity")))?;
 
     let actor = User::from_url(&conn, actor_id).expect("instance::shared_inbox: user error");
-    if !verify_http_headers(&actor, &headers.0, &data.0).is_secure() &&
+    if !verify_http_headers(&actor, &headers.0, &sig).is_secure() &&
         !act.clone().verify(&actor) {
-        println!("Rejected invalid activity supposedly from {}, with headers {:?}", actor.username, headers.0);
-        return Err(status::BadRequest(Some("Invalid signature")));
+        // maybe we just know an old key?
+        actor.refetch(&conn).and_then(|_| User::get(&conn, actor.id))
+            .and_then(|u| if verify_http_headers(&u, &headers.0, &sig).is_secure() ||
+                      act.clone().verify(&u) {
+                          Ok(())
+                      } else {
+                          Err(Error::Signature)
+                      })
+            .map_err(|_| {
+                println!("Rejected invalid activity supposedly from {}, with headers {:?}", actor.username, headers.0);
+                status::BadRequest(Some("Invalid signature"))})?;
     }
 
     if Instance::is_blocked(&*conn, actor_id).map_err(|_| status::BadRequest(Some("Can't tell if instance is blocked")))? {

src/routes/posts.rs

@@ -3,7 +3,10 @@ use heck::{CamelCase, KebabCase};
 use rocket::request::LenientForm;
 use rocket::response::{Redirect, Flash};
 use rocket_i18n::I18n;
-use std::{collections::{HashMap, HashSet}, borrow::Cow};
+use std::{
+    collections::{HashMap, HashSet},
+    borrow::Cow, time::Duration,
+};
 use validator::{Validate, ValidationError, ValidationErrors};
 
 use plume_common::activity_pub::{broadcast, ActivityStream, ApRequest, inbox::Deletable};
@@ -397,7 +400,9 @@ pub fn delete(blog_name: String, slug: String, conn: DbConn, user: User, worker:
         } else {
             let dest = User::one_by_instance(&*conn)?;
             let delete_activity = post.delete(&(&conn, &searcher))?;
-            worker.execute(move || broadcast(&user, delete_activity, dest));
+            let user_c = user.clone();
+            worker.execute(move || broadcast(&user_c, delete_activity, dest));
+            worker.execute_after(Duration::from_secs(10*60), move || {user.rotate_keypair(&conn).expect("Failed to rotate keypair");});
 
             Ok(Redirect::to(uri!(super::blogs::details: name = blog_name, page = _)))
         }

src/routes/user.rs

@@ -370,6 +370,7 @@ pub fn inbox(
 ) -> Result<String, Option<status::BadRequest<&'static str>>> {
     let user = User::find_local(&*conn, &name).map_err(|_| None)?;
     let act = data.1.into_inner();
+    let sig = data.0;
 
     let activity = act.clone();
     let actor_id = activity["actor"]
@@ -380,14 +381,21 @@ pub fn inbox(
         ))))?;
 
     let actor = User::from_url(&conn, actor_id).expect("user::inbox: user error");
-    if !verify_http_headers(&actor, &headers.0, &data.0).is_secure()
+    if !verify_http_headers(&actor, &headers.0, &sig).is_secure()
         && !act.clone().verify(&actor)
     {
-        println!(
-            "Rejected invalid activity supposedly from {}, with headers {:?}",
-            actor.username, headers.0
-        );
-        return Err(Some(status::BadRequest(Some("Invalid signature"))));
+        // maybe we just know an old key?
+        actor.refetch(&conn).and_then(|_| User::get(&conn, actor.id))
+            .and_then(|actor| if verify_http_headers(&actor, &headers.0, &sig).is_secure()
+                      || act.clone().verify(&actor)
+                    {
+                        Ok(())
+                    } else {
+                        Err(Error::Signature)
+                    })
+            .map_err(|_| {
+                println!("Rejected invalid activity supposedly from {}, with headers {:?}", actor.username, headers.0);
+                status::BadRequest(Some("Invalid signature"))})?;
     }
 
     if Instance::is_blocked(&*conn, actor_id).map_err(|_| None)? {