From f2db469dd9380414ba11c573695f305c9b8c0b34 Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Sat, 7 Nov 2026 22:35:21 +0100
Subject: simtest: signed changes

Every change vouched for on every node within a second; a forged
signature vouches for nothing.

Auth plan M5.
---
 src/simtest/mod.rs        |   3 +-
 src/simtest/signatures.rs | 113 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+), 1 deletion(-)
 create mode 100644 src/simtest/signatures.rs

(limited to 'src/simtest')

diff --git a/src/simtest/mod.rs b/src/simtest/mod.rs
index 5acc886..cd0c2c7 100644
--- a/src/simtest/mod.rs
+++ b/src/simtest/mod.rs
@@ -16,6 +16,7 @@ mod identity;
 mod reach;
 mod relay;
 mod remakes;
+mod signatures;
 mod soak;
 mod timing;
 
@@ -403,7 +404,7 @@ pub(crate) fn sim_key(id: &str) -> NodeKey {
     NodeKey::from_seed(sha2::Sha256::digest(id.as_bytes()).into())
 }
 
-fn path(path: &str) -> Vec<String> {
+pub(crate) fn path(path: &str) -> Vec<String> {
     path.split('/').map(str::to_owned).collect()
 }
 
diff --git a/src/simtest/signatures.rs b/src/simtest/signatures.rs
new file mode 100644
index 0000000..2425a16
--- /dev/null
+++ b/src/simtest/signatures.rs
@@ -0,0 +1,113 @@
+//! Signed changes end to end (`document::signatures`, `swarm::signatures`): nodes under
+//! the identity layer, whose node keys sign, write through the API as a user would,
+//! and every node comes to see the writes verified, by signatures that came with sync
+//! messages or on their own.
+
+use std::time::Duration;
+
+use serde_json::json;
+
+use super::{Sim, path};
+use crate::document::ActorId;
+use crate::document::signatures::{Sign, SignEvery};
+use crate::document::store;
+use crate::state::AppState;
+use crate::swarm::bootstrap::Start;
+
+const SOON: Duration = Duration::from_secs(20);
+
+/// Writes `value` at `at` on `node` as a write through the API does, signed at once if
+/// `signed` (`?signed=true`); the change's actor and seq.
+async fn write_as_user(
+    node: &AppState,
+    at: &str,
+    value: serde_json::Value,
+    signed: bool,
+) -> (ActorId, u64) {
+    let at = path(at);
+    let sign = Sign::Write {
+        path: at.clone(),
+        asked: signed,
+    };
+    node.mutate_doc_for(Some("alice".to_owned()), sign, move |doc| {
+        store::write_path(doc, &at, &value)
+    })
+    .await
+    .expect("write");
+    let replica = node.doc.read().await;
+    let change = replica.doc.get_last_local_change().expect("the write");
+    (change.actor_id().clone(), change.seq())
+}
+
+/// Whether a signature vouches for `actor`'s change `seq` on `node`.
+async fn verified(node: &AppState, actor: &ActorId, seq: u64) -> bool {
+    node.doc.read().await.signatures.verified(actor, seq)
+}
+
+/// A write no rule signs is signed a while after it (`--sign-every`, 1 s by default),
+/// and the signature reaches every node on its own (SIGNATURES): the change went before
+/// it was signed.
+#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
+async fn unsigned_writes_are_verified_within_the_interval() {
+    let sim = Sim::with_identity(61);
+    let a = sim.start("a", &[], Start::Genesis);
+    let b = sim.start("b", &["a"], Start::Join);
+    let c = sim.start("c", &["a"], Start::Join);
+    sim.wait_ready(&[&a, &b, &c], SOON).await;
+
+    let (actor, seq) = write_as_user(&b, "metrics/cpu", json!(42), false).await;
+    sim.wait_converged(&[&a, &b, &c], SOON).await;
+    for node in [&a, &b, &c] {
+        let actor = actor.clone();
+        sim.wait_until("the write is verified", SOON, move || {
+            let actor = actor.clone();
+            async move { verified(node, &actor, seq).await }
+        })
+        .await;
+    }
+}
+
+/// With `--sign-every none`, a write no rule signs stays unverified; the node's next
+/// signed write vouches for it too, wherever its signature goes.
+#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
+async fn a_signed_write_vouches_for_the_writes_before() {
+    let sim = Sim::with_identity(62);
+    let a = sim.start("a", &[], Start::Genesis);
+    let b = sim.start_with("b", &["a"], Start::Join, |config| {
+        config.sign_every = SignEvery::Never;
+    });
+    let c = sim.start("c", &["a"], Start::Join);
+    sim.wait_ready(&[&a, &b, &c], SOON).await;
+
+    let (actor, first) = write_as_user(&b, "metrics/cpu", json!(42), false).await;
+    sim.wait_converged(&[&a, &b, &c], SOON).await;
+    // Signatures go within a second: none came for it. Unless b wrote protocol data
+    // since (always signed), whose signature vouches for it too.
+    tokio::time::sleep(Duration::from_secs(3)).await;
+    let latest = b
+        .doc
+        .read()
+        .await
+        .doc
+        .get_last_local_change()
+        .map(|change| change.seq());
+    if latest == Some(first) {
+        for node in [&a, &b, &c] {
+            assert!(!verified(node, &actor, first).await);
+        }
+    }
+
+    let (same, second) = write_as_user(&b, "config/mode", json!("fast"), true).await;
+    assert_eq!(same, actor);
+    sim.wait_converged(&[&a, &b, &c], SOON).await;
+    for node in [&a, &b, &c] {
+        let actor = actor.clone();
+        sim.wait_until("both writes are verified", SOON, move || {
+            let actor = actor.clone();
+            async move {
+                verified(node, &actor, first).await && verified(node, &actor, second).await
+            }
+        })
+        .await;
+    }
+}
-- 
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