Confirm changes automatically from the client that made them

A change made over the network answers with a one-time confirm_token
and closes its connection (HTTP/2: a GOAWAY). The web UI and hc send the
token straight back to /confirm, which accepts it only for the newest
change, from the same user and API token, the same address, and over a
new connection: proof that the client can still reach the API through
the new ruleset (an established connection would get through anyway). A
change that cuts its client off can't be confirmed so, and rolls back by
itself. The setting manual_confirm (hc settings set --auto-confirm off)
and hc --no-confirm leave confirming to a person. Changes through the
local socket still need no confirmation. e2e: 136 checks, among them a
lockout change rolled back without anyone confirming.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/server/server_test.go

@@ -722,3 +722,76 @@ func TestQuotaResets(t *testing.T) {
 		t.Errorf("reset by hand: %d %v", code, e.fw.resets)
 	}
 }
+
+// TestAutoConfirm: the client that made a change confirms it by itself:
+// with its token, from the same address, over a new connection. Nobody
+// else can, an older token can't, and with manual_confirm there is none.
+func TestAutoConfirm(t *testing.T) {
+	e := newEnv(t)
+	e.srv.probationFor = 5 * time.Second
+	post := func(token, path string, body any) (*http.Response, []byte) {
+		b, _ := json.Marshal(body)
+		req, _ := http.NewRequest("POST", e.ts.URL+api.Prefix+path, bytes.NewReader(b))
+		req.Header.Set("Authorization", "Bearer "+token)
+		req.Header.Set("Content-Type", "application/json")
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer resp.Body.Close()
+		out, _ := io.ReadAll(resp.Body)
+		return resp, out
+	}
+	resp, body := post(e.token, "/zones", model.Zone{Name: "lan", Interfaces: []string{"eth1"}})
+	var mr api.MutationResponse
+	json.Unmarshal(body, &mr)
+	if mr.ConfirmToken == "" || !resp.Close {
+		t.Fatalf("no token, or the connection stays open: %+v close=%v", mr, resp.Close)
+	}
+	first := mr.ConfirmToken
+	// A newer change: only its token confirms now.
+	_, body = post(e.token, "/zones", model.Zone{Name: "dmz", Interfaces: []string{"eth2"}})
+	json.Unmarshal(body, &mr)
+	if resp, _ := post(e.token, "/confirm", api.ConfirmInput{Token: first}); resp.StatusCode != 409 {
+		t.Errorf("an older token: %d", resp.StatusCode)
+	}
+	// Another user can't use it.
+	ctx := context.Background()
+	other := &model.User{Username: "sam", Grants: auth.Roles["operator"]}
+	e.srv.store.CreateUser(ctx, other)
+	otok, pid, sh := auth.NewToken()
+	e.srv.store.CreateToken(ctx, &model.Token{UserID: other.ID, Name: "t", PublicID: pid, SecretHash: sh})
+	if resp, _ := post(otok, "/confirm", api.ConfirmInput{Token: mr.ConfirmToken}); resp.StatusCode != 403 {
+		t.Errorf("another user's confirmation: %d", resp.StatusCode)
+	}
+	// Not over the change's own connection, nor from elsewhere.
+	c := e.srv.probation.check
+	p := &auth.Principal{User: &model.User{ID: c.userID, Username: c.username}, Method: "token", Token: &model.Token{ID: c.tokenID}}
+	same := httptest.NewRequest("POST", "/", nil)
+	same.RemoteAddr = c.remote
+	if _, err := e.srv.confirmToken(same, p, c.token); err == nil || !strings.Contains(err.Error(), "new one") {
+		t.Errorf("over the same connection: %v", err)
+	}
+	elsewhere := httptest.NewRequest("POST", "/", nil)
+	elsewhere.RemoteAddr = "192.0.2.9:4444"
+	if _, err := e.srv.confirmToken(elsewhere, p, c.token); err == nil || !strings.Contains(err.Error(), "same place") {
+		t.Errorf("from elsewhere: %v", err)
+	}
+	// The client itself, over a new connection: confirmed.
+	resp, body = post(e.token, "/confirm", api.ConfirmInput{Token: mr.ConfirmToken})
+	if resp.StatusCode != 200 || !strings.Contains(string(body), `"confirmed":2`) {
+		t.Fatalf("auto-confirm: %d %s", resp.StatusCode, body)
+	}
+	if pr := e.srv.probationStatus(); len(pr.Pending) != 0 {
+		t.Errorf("still pending: %+v", pr)
+	}
+	// manual_confirm: no token; a person confirms.
+	e.call(e.token, "PATCH", "/settings", map[string]any{"manual_confirm": true}, nil)
+	e.call(e.token, "POST", "/confirm", nil, nil)
+	_, body = post(e.token, "/zones", model.Zone{Name: "guest", Interfaces: []string{"eth3"}})
+	mr = api.MutationResponse{}
+	json.Unmarshal(body, &mr)
+	if mr.ConfirmToken != "" || mr.ConfirmBy == nil {
+		t.Errorf("manual confirmation: %+v", mr)
+	}
+}