Stop verifying composition signatures: the node applies only its own

ADR 0593 §6: a composition read from composed-<node> is a record never
applied, and the engine applies only what it composes itself, so no
composition carries a signature and nothing is verified. The agent's
trusted signers, its signed-composition test and the unused signing
helper of the integration bed go, so mesh-sdk can drop SignComposed,
VerifyComposed and Composed.Signature.

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

internal/agent/agent.go

@@ -15,7 +15,6 @@ package agent
 import (
 	"bytes"
 	"context"
-	"crypto/ed25519"
 	"encoding/json"
 	"fmt"
 	"sort"
@@ -120,10 +119,6 @@ type Env struct {
 	// whose have names a composition the bucket keeps runs from that composition, never from the kept declaration
 	// (issue 924): the kept declaration is older than every composition applied since the switch.
 	KeptFilled func() map[string][]string
-	// Trusted is the public keys a composition may be signed by: the controller's and the operator's (ADR 0539 §3). A
-	// composition unsigned, signed by another key, or changed after it was signed is refused and nothing of it is
-	// applied. Nil trusts no key, so nothing is applied.
-	Trusted func() []ed25519.PublicKey
 	// Recorded says the engine holds a record of every resource of the composition, so it was applied and not removed
 	// since; nil says yes. A composition the kept declaration or a have says runs is applied again when it says no.
 	Recorded func(ctx context.Context, c delivery.Composed) bool
@@ -686,26 +681,14 @@ func (a *Agent) takeComposition(u Update) string {
 	}
 	now := compNow{Raw: u.Value, Rev: u.Revision}
 	c, err := delivery.DecodeComposed(u.Value)
-	if err == nil && a.env.SelfComposed {
-		// The node composed it itself: nothing crossed the bus, so nothing is signed (ADR 0547 §2).
+	if err == nil {
+		// The node composed it itself: it is applied as composed, never verified against a signer, since no composition
+		// read from the bus is applied (novox/hq ADR 0547 §2, ADR 0593 §6).
 		now.C = c
 		now.Dig, err = delivery.ComposedDigestOf(c)
 		if err != nil {
 			now.C = delivery.Composed{}
 		}
-	} else if err == nil {
-		var trusted []ed25519.PublicKey
-		if a.env.Trusted != nil {
-			trusted = a.env.Trusted()
-		}
-		// The signature before anything of the composition is used: its digest is what the want names.
-		now.C = c
-		now.Dig, err = delivery.VerifyComposed(c, trusted)
-		if err != nil {
-			now.C = delivery.Composed{}
-			a.sayOnce("verify:"+u.Key, fmt.Sprintf("the composition %s is refused and nothing of it is applied: %v", u.Key, err))
-			err = fmt.Errorf("refused: %w", err)
-		}
 	} else {
 		a.sayOnce("decode:"+u.Key, fmt.Sprintf("the composition %s cannot be read, and nothing of it is applied: %v", u.Key, err))
 	}

internal/agent/agent_test.go

@@ -2,7 +2,6 @@ package agent
 
 import (
 	"context"
-	"crypto/ed25519"
 	"encoding/json"
 	"fmt"
 	"maps"
@@ -18,19 +17,6 @@ import (
 
 const node = "n1"
 
-// The keys of the tests: the controller's and the operator's are trusted, a stranger's is not.
-var controllerPub, controllerKey = newKey()
-var operatorPub, operatorKey = newKey()
-var _, strangerKey = newKey()
-
-func newKey() (ed25519.PublicKey, ed25519.PrivateKey) {
-	pub, key, err := ed25519.GenerateKey(nil)
-	if err != nil {
-		panic(err)
-	}
-	return pub, key
-}
-
 func fpOf(c string) string { return delivery.SourcePrefix2 + strings.Repeat(c, 64) }
 
 // A watcher the test writes to; it says Caught once the keys written before the watch began are out.
@@ -183,8 +169,7 @@ func newBed(t *testing.T) *bed {
 			b.settled = append(b.settled, m)
 			b.settledRan = append(b.settledRan, ran)
 		},
-		Kept:    func() map[string][]json.RawMessage { return b.kept },
-		Trusted: func() []ed25519.PublicKey { return []ed25519.PublicKey{controllerPub, operatorPub} },
+		Kept: func() map[string][]json.RawMessage { return b.kept },
 		Say: func(s string) {
 			t.Log(s)
 			b.mu.Lock()
@@ -223,21 +208,17 @@ func composition(t *testing.T, module, fp string, data bool, rs ...json.RawMessa
 	if err != nil {
 		t.Fatal(err)
 	}
-	return signedBy(t, c, key, controllerKey)
+	return encodedAs(t, c, key)
 }
 
-// signedBy is c signed with signer, as the writer's code signs it: its key, its bytes and its digest.
-func signedBy(t *testing.T, c delivery.Composed, key string, signer ed25519.PrivateKey) (string, []byte, string) {
+// encodedAs is c as the node's composer hands it: unsigned (ADR 0593 §6), its key, its bytes and its digest.
+func encodedAs(t *testing.T, c delivery.Composed, key string) (string, []byte, string) {
 	t.Helper()
-	signed, err := delivery.SignComposed(c, signer)
+	raw, err := delivery.EncodeComposed(c)
 	if err != nil {
 		t.Fatal(err)
 	}
-	raw, err := delivery.EncodeComposed(signed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	digest, err := delivery.ComposedDigestOf(signed)
+	digest, err := delivery.ComposedDigestOf(c)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -735,76 +716,6 @@ func TestTheNodesOwnCompositionComesBeforeAnyModules(t *testing.T) {
 	}
 }
 
-// R6-A AC9: a composition signed by either trusted key is applied; one signed by another key, one changed after it was
-// signed and one unsigned are refused and nothing of them is applied (ADR 0539 §3).
-func TestOnlyACompositionSignedByATrustedKeyIsApplied(t *testing.T) {
-	t.Run("with no trusted key", testWithNoTrustedKeyNothingIsApplied)
-	b := newBed(t)
-	stop := b.run()
-	defer stop()
-
-	plain := func(module, fp, content string) delivery.Composed {
-		return delivery.Composed{Node: node, Module: module, FP: fp, Resources: []json.RawMessage{file(module, "x", content)}}
-	}
-	put := func(c delivery.Composed, signer ed25519.PrivateKey, tamper func([]byte) []byte) {
-		key, _ := delivery.ComposedKey(node, c.Module, c.FP)
-		var raw []byte
-		var dig string
-		if signer == nil {
-			raw, _ = delivery.EncodeComposed(c)
-			dig, _ = delivery.ComposedDigestOf(c)
-		} else {
-			_, raw, dig = signedBy(t, c, key, signer)
-		}
-		if tamper != nil {
-			raw = tamper(raw)
-		}
-		b.comps.put(key, raw)
-		wk, wraw := wantFor(t, c.Module, c.FP, dig, "")
-		b.wants.put(wk, wraw)
-	}
-
-	// Refused: signed by a stranger, changed after signing, unsigned.
-	put(plain("stranger", fpOf("1"), "x"), strangerKey, nil)
-	put(plain("changed", fpOf("2"), "before"), controllerKey, func(raw []byte) []byte {
-		return []byte(strings.Replace(string(raw), "before", "after!", 1))
-	})
-	put(plain("unsigned", fpOf("3"), "x"), nil, nil)
-	time.Sleep(200 * time.Millisecond)
-	if got := b.appliedList(); len(got) != 0 {
-		t.Fatalf("a composition that is not signed by a trusted key was applied: %v", got)
-	}
-
-	// Applied: signed by the controller, signed by the operator.
-	put(plain("bycontroller", fpOf("4"), "x"), controllerKey, nil)
-	put(plain("byoperator", fpOf("5"), "x"), operatorKey, nil)
-	eventually(t, "the trusted signers' compositions were not applied", func() bool { return len(b.appliedList()) == 2 })
-	got := b.appliedList()
-	if !(got[0] == "bycontroller" && got[1] == "byoperator") && !(got[0] == "byoperator" && got[1] == "bycontroller") {
-		t.Fatalf("applied %v", got)
-	}
-	if h := b.haves.last("byoperator"); h.Phase != string(delivery.PhaseRunning) || h.FP != fpOf("5") {
-		t.Fatalf("the operator's module has no running have: %+v", h)
-	}
-}
-
-// With no key trusted, nothing is applied: a node that does not know its signers fails closed.
-func testWithNoTrustedKeyNothingIsApplied(t *testing.T) {
-	b := newBed(t)
-	b.env.Trusted = nil
-	stop := b.run()
-	defer stop()
-	fp := fpOf("a")
-	ck, craw, dig := composition(t, "web", fp, false, file("web", "x", "1"))
-	b.comps.put(ck, craw)
-	wk, wraw := wantFor(t, "web", fp, dig, "")
-	b.wants.put(wk, wraw)
-	time.Sleep(200 * time.Millisecond)
-	if got := b.appliedList(); len(got) != 0 {
-		t.Fatalf("applied with no trusted key: %v", got)
-	}
-}
-
 // What a module's apply must not take is every other module that runs, those the agent holds and those still running from
 // the kept declaration (ADR 0429 §4): the resources of the kept declaration reach Apply as the others.
 func TestApplyingOneModuleHoldsOutTheModulesStillRunningFromTheKeptDeclaration(t *testing.T) {
@@ -860,7 +771,7 @@ func TestEverythingIsWhatTheAgentRunsAndWhatIsKeptForTheRest(t *testing.T) {
 	// and is what runs from before the first composition is watched; an apply keeps, a removal forgets.
 	t.Run("what this engine applied is what runs before the node composes its own", func(t *testing.T) {
 		b := newBed(t)
-		b.env.SelfComposed, b.env.Trusted, b.kept = true, nil, nil
+		b.env.SelfComposed, b.kept = true, nil
 		store := &memApplied{kept: map[string][]byte{}}
 		b.env.Applied = store
 		// A folded module's resource in the node's own composition: its id names the module, as the controller folds it.
@@ -930,7 +841,7 @@ func TestEverythingIsWhatTheAgentRunsAndWhatIsKeptForTheRest(t *testing.T) {
 		h.Write(context.Background(), Have{Module: NodeModule, Composed: "sha256:" + strings.Repeat("c", 64)})
 		firstPass := func(kept map[string][]json.RawMessage) []delivery.Composed {
 			b := newBed(t)
-			b.env.SelfComposed, b.env.Trusted, b.kept, b.env.Applied, b.env.Haves = true, nil, kept, store, h
+			b.env.SelfComposed, b.kept, b.env.Applied, b.env.Haves = true, kept, store, h
 			firstCh := make(chan []delivery.Composed, 1)
 			comps := b.comps
 			var ag *Agent
@@ -1155,8 +1066,7 @@ func testARemovedModulesCompositionHoldsNothingBack(t *testing.T) {
 	}
 }
 
-// The node's own composition is not applied while a module's composition in the node's bucket cannot be read or is not
-// signed by a trusted key: what that one carries may be what left the node's own, and the node's own apply would remove
+// The node's own composition is not applied while a module's composition in the node's bucket cannot be read: what that one carries may be what left the node's own, and the node's own apply would remove
 // it (issue 1945, the review's gap 2). It is said, naming the composition, and applied once that one reads.
 func TestTheNodesOwnWaitsWhileAModulesCompositionCannotBeRead(t *testing.T) {
 	b := newBed(t)
@@ -1284,11 +1194,11 @@ func TestWhatRunsBeforeTheAgentTakesAModuleNamesItsFilledPaths(t *testing.T) {
 	ck, _ := delivery.ComposedKey(node, "power", fp)
 	applied := delivery.Composed{Node: node, Module: "power", FP: fp, Filled: []string{old, added}, Data: true,
 		Resources: []json.RawMessage{filledFile("settings"), filledFile("bound")}}
-	_, appliedRaw, appliedDig := signedBy(t, applied, ck, controllerKey)
+	_, appliedRaw, appliedDig := encodedAs(t, applied, ck)
 	newer := applied
 	newer.Resources = append([]json.RawMessage{}, applied.Resources...)
 	newer.Resources = append(newer.Resources, file("power", "later", "1"))
-	_, newerRaw, _ := signedBy(t, newer, ck, controllerKey)
+	_, newerRaw, _ := encodedAs(t, newer, ck)
 	for _, tc := range []struct {
 		name string
 		// have is the module's have; bucket the value its composition key holds now, history the revisions kept.
@@ -1371,7 +1281,7 @@ func TestWhatRunsBeforeTheAgentTakesAModuleNamesItsFilledPaths(t *testing.T) {
 // the yes for that composition, and is then applied.
 func TestTheNodesOwnCompositionIsAppliedWhenItDiffersAndARecordMoveWaitsForAYes(t *testing.T) {
 	b := newBed(t)
-	b.env.SelfComposed, b.env.Trusted = true, nil
+	b.env.SelfComposed = true
 	b.env.Policy = func(_ context.Context, m string) string {
 		if m == "db" || m == "rec" {
 			return catalogue.PolicyRecord

internal/agent/composition.go

@@ -2,7 +2,6 @@ package agent
 
 import (
 	"context"
-	"crypto/ed25519"
 	"errors"
 	"fmt"
 
@@ -194,8 +193,8 @@ func (a *Agent) compositionKey(module, fp string) (string, error) {
 	return delivery.ComposedKey(a.env.Node, module, fp)
 }
 
-// revisionsOf is every revision of a composition key the bucket keeps, oldest first, each with its digest as this node
-// trusts it (its own unsigned with SelfComposed, else signed by a trusted key), or why it is refused. Nil Revisions
+// revisionsOf is every revision of a composition key the state keeps, oldest first, each with its digest (unsigned, ADR
+// 0593 §6), or why it is refused. Nil Revisions
 // reads none.
 func (a *Agent) revisionsOf(ctx context.Context, key string) ([]compNow, error) {
 	if a.env.Revisions == nil {
@@ -205,10 +204,6 @@ func (a *Agent) revisionsOf(ctx context.Context, key string) ([]compNow, error)
 	if err != nil {
 		return nil, err
 	}
-	var trusted []ed25519.PublicKey
-	if a.env.Trusted != nil {
-		trusted = a.env.Trusted()
-	}
 	var out []compNow
 	for _, u := range revs {
 		if u.Deleted || u.Key != key {
@@ -219,12 +214,7 @@ func (a *Agent) revisionsOf(ctx context.Context, key string) ([]compNow, error)
 			out = append(out, compNow{Raw: u.Value, Rev: u.Revision, Err: err})
 			continue
 		}
-		var dig string
-		if a.env.SelfComposed {
-			dig, err = delivery.ComposedDigestOf(c) // the node's own: unsigned (ADR 0547 §2)
-		} else {
-			dig, err = delivery.VerifyComposed(c, trusted)
-		}
+		dig, err := delivery.ComposedDigestOf(c) // unsigned: a record, never verified (ADR 0593 §6)
 		out = append(out, compNow{Raw: u.Value, C: c, Dig: dig, Rev: u.Revision, Err: err})
 	}
 	return out, nil

internal/compose/composed.go

@@ -21,8 +21,8 @@ import (
 // gets that one; but for a module the node runs inside its own composition (Node.InOwn, and the
 // private network's always), which fps names at no fingerprint of the new form: its resources go into the node's own,
 // their module taken off and their ids still naming it, and its filled paths with them, as the controller's composed
-// writer folds them (issue 1126). Each module's Data says whether its manifest declares data. The compositions are not
-// signed and not yet by digest: the writer does both (delivery.SignComposed, Composed.ByDigest).
+// writer folds them (issue 1126). Each module's Data says whether its manifest declares data. The compositions are unsigned
+// (ADR 0593 §6) and not yet by digest (Composed.ByDigest).
 func Compositions(in Input, node string, fps map[string]string, mode Mode) (out map[string]delivery.Composed, skipped []string, err error) {
 	out, skipped, _, err = compositions(in, node, fps, mode, false)
 	return out, skipped, err

internal/selfcompose/composedstate_test.go

@@ -123,7 +123,7 @@ func TestTheNodePublishesItsCompositions(t *testing.T) {
 	}
 	if raw := state.kv[lemursKey].Value; raw != nil {
 		comp, err := delivery.DecodeComposed(raw)
-		if err != nil || comp.Module != "lemurs" || comp.FP != fp || comp.Signature != nil || len(comp.Resources) == 0 {
+		if err != nil || comp.Module != "lemurs" || comp.FP != fp || len(comp.Resources) == 0 {
 			t.Errorf("the published composition of lemurs: %+v, %v", comp, err)
 		}
 	}