[stable-34.0] fix(macOS): Verify ability to access Local Network

cmake/modules/MacOSXBundleInfo.plist.in

@@ -45,6 +45,8 @@
     <true/>
     <key>NSRequiresAquaSystemAppearance</key>
     <false/>
+    <key>NSLocalNetworkUsageDescription</key>
+    <string>Nextcloud needs access to your local network to connect to Nextcloud servers hosted there.</string>
     <key>SUShowReleaseNotes</key>
     <false/>
     <key>SUPublicDSAKeyFile</key>

doc/local-network-permission.md

@@ -0,0 +1,262 @@
+<!--
+  - SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-License-Identifier: GPL-2.0-or-later
+-->
+
+# Local Network Permission Handling
+
+## Purpose
+
+On macOS 15 and later, the user can deny an application access to devices on
+the local network. A connection attempt affected by this setting otherwise
+looks much like an unreachable server to the desktop client. The local network
+permission check lets the client replace a generic connection error with an
+actionable message:
+
+> Local Network access is disabled. Enable it in System Settings → Privacy &
+> Security → Local Network.
+
+This check is diagnostic rather than proactive. It runs after a server
+connection has already failed or timed out. It does not request permission and
+does not report a global permission state. Apple does not provide a general API
+for querying that state; instead, the check observes the path of a connection
+to the server the user entered. See
+[TN3179: Understanding local network privacy](https://developer.apple.com/documentation/technotes/tn3179-understanding-local-network-privacy).
+
+The implementation was introduced in response to
+[nextcloud/desktop#10452](https://github.com/nextcloud/desktop/issues/10452).
+
+## Architecture
+
+### Platform boundary
+
+`LocalNetworkPermission` exposes two functions from
+`src/gui/localnetworkpermission.h`:
+
+- `checkDeniedForConnection()` reports through a callback whether local network
+  permission denied a specific failed connection.
+- `deniedError()` returns the platform-appropriate error shown to the user.
+
+CMake selects the implementation:
+
+- On macOS, `src/gui/macOS/localnetworkpermission.mm` uses Network.framework.
+- On other platforms, `src/gui/localnetworkpermission.cpp` reports `false`,
+  preserving the existing connection error.
+
+This keeps platform conditionals out of `ConnectionValidator` and
+`AccountWizardController`. A `false` result means that local network denial was
+not established; it does not prove that permission is enabled.
+
+### macOS connection probe
+
+The macOS implementation is available on macOS 15 and later. It performs the
+following steps:
+
+1. Extract the host and port from the failed URL. The default port is `443` for
+   HTTPS and `80` otherwise.
+2. Create a Network.framework TCP connection to that endpoint. The probe does
+   not perform an HTTP request or a TLS handshake.
+3. Set `prefer_no_proxy` on the connection parameters. This makes
+   Network.framework try the direct path first, so a VPN-provided local proxy
+   cannot immediately hide the local-network denial. Network.framework may
+   still try a configured proxy if the direct attempt fails.
+4. Observe connection path and state updates on the main dispatch queue.
+5. Finish with `true` when an unsatisfied path reports
+   `nw_path_unsatisfied_reason_local_network_denied`.
+6. Finish with `false` when the connection becomes ready.
+7. On a `waiting` or `failed` state, finish only if the current path explicitly
+   reports local-network denial. A path can be temporarily inconclusive, so
+   completing with `false` at this point would introduce a race with a later
+   path update.
+8. After two seconds, inspect the path once more and finish. This bounds the
+   diagnostic delay when the server is merely absent or unreachable.
+
+`ConnectionProbe` owns the Network.framework connection and callback. Its
+`completed` flag ensures exactly-once completion. Finishing cancels and
+releases the connection before dispatching the result back through Qt.
+
+The callback context is held as a `QPointer<QObject>`. The result is queued onto
+that context and is discarded if the context has been destroyed, preventing a
+callback into a deleted controller or validator.
+
+### Consumers
+
+`ConnectionValidator` invokes the check when:
+
+- the status request fails; or
+- its connection job times out.
+
+When denial is established, the permission message replaces the generic
+network error. The validator's status value is unchanged.
+
+`AccountWizardController` invokes the check after its server connection fails.
+When denial is established, it displays the permission message and does not
+offer secure-connection recovery, such as retrying without TLS. Otherwise, the
+existing recovery flow continues.
+
+The wizard also verifies that the account URL still matches the URL whose
+probe completed. This prevents a delayed result from an earlier attempt from
+changing the state of a newer attempt.
+
+### Test seam
+
+Both consumers store the permission check in a private `std::function`,
+initialized to `LocalNetworkPermission::checkDeniedForConnection`. Their test
+access classes are friends and replace that callable with a synchronous
+deterministic result.
+
+This keeps the production constructors and public API unchanged. It also tests
+the behavior of each consumer without subclassing production classes or
+making one-line methods virtual solely for tests.
+
+## Test plan
+
+### Automated coverage
+
+`AccountWizardControllerTest` covers:
+
+- An invalid URL produces a non-denied result.
+- A denied result displays `deniedError()` and suppresses secure-connection
+  recovery.
+- A non-denied result preserves the secure-connection recovery flow.
+
+`ConnectionValidatorTest` covers:
+
+- A denied result replaces the generic timeout text with `deniedError()`.
+
+Build and run the focused tests from the repository root:
+
+```sh
+cmake -S . -B build-testing
+cmake --build build-testing \
+    --target AccountWizardControllerTest ConnectionValidatorTest
+ctest --test-dir build-testing --output-on-failure \
+    -R '^(ConnectionValidator|AccountWizardController)Test$'
+```
+
+### Manual coverage
+
+The automated tests do not cover:
+
+- macOS Local Network privacy enforcement or its System Settings toggle;
+- Network.framework path-update ordering and unsatisfied reasons;
+- behavior with a real VPN or system proxy;
+- the direct-path preference and proxy fallback;
+- code-signing identity and executable UUID tracking;
+- differences between launching from Finder, Terminal, Xcode, or another
+  parent process;
+- the complete two-second probe against a real network.
+
+These behaviors depend on operating-system privacy state, routing, signing,
+and the active network environment. Checking only that a Network.framework
+parameter was set would test an implementation detail, not the intended VPN
+behavior. The native path therefore requires the manual regression test below.
+
+## Reproducing local-network denial
+
+### Requirements
+
+- macOS 15 or later.
+- A validly signed application with a stable Apple-issued identity.
+- A unique UUID in the main executable.
+- `NSLocalNetworkUsageDescription` in the application `Info.plist`.
+- A target address on a network directly attached through Wi-Fi or Ethernet.
+  A private address routed elsewhere is not necessarily a local-network
+  address for this privacy feature.
+
+The target does not need to run a Nextcloud server. Using an unused address on
+the directly attached subnet is useful because it isolates privacy diagnosis
+from server behavior.
+
+Verify the application before testing:
+
+```sh
+codesign --verify --deep --strict --verbose=2 /path/to/Nextcloud.app
+/usr/bin/dwarfdump --uuid /path/to/Nextcloud.app/Contents/MacOS/Nextcloud
+```
+
+Both commands must succeed, and the UUID output must not be empty.
+
+### Launch the application correctly
+
+Quit all running instances and launch the tested application by
+double-clicking its bundle in Finder.
+
+Do not start the executable directly from Terminal or SSH. macOS automatically
+allows local-network access for command-line tools launched from those
+environments and for their child processes. In that situation,
+Network.framework can report the connection as ineligible for privacy
+enforcement even though the application's Local Network toggle is disabled.
+This produces a false-negative test.
+
+For the same reason, Finder launch is preferred for this regression test over
+developer launch mechanisms whose responsible process may affect privacy
+attribution.
+
+### Test procedure
+
+1. Determine the Mac's Wi-Fi or Ethernet address and subnet.
+2. Choose an unused address on that same directly attached subnet.
+3. Open **System Settings → Privacy & Security → Local Network**.
+4. Disable Local Network access for Nextcloud.
+5. Quit Nextcloud, then launch the tested app bundle from Finder.
+6. In the account wizard, enter the unused address, for example
+   `https://192.168.0.64`.
+7. Start the connection.
+
+Expected result:
+
+- The wizard reports that Local Network access is disabled.
+- It does not show the secure-connection recovery dialog.
+
+Repeat with a VPN active. The expected result is the same. The permission probe
+should try the direct local route before a VPN-provided proxy can handle the
+connection.
+
+As a comparison, enable Local Network access and repeat. Because the chosen
+address has no server, the result should now be an ordinary timeout or
+connection failure rather than the permission message.
+
+## Troubleshooting
+
+### The result is a timeout or TLS recovery dialog
+
+Confirm all of the following:
+
+- The application was launched from Finder, not by executing its binary in a
+  shell.
+- The tested bundle has a valid signature.
+- The running process belongs to the bundle just verified.
+- The target address is on a directly attached Wi-Fi or Ethernet subnet.
+- The Local Network toggle for the tested application is disabled.
+
+### Inspect Network.framework activity
+
+The following command reads the relevant unified logs for a bounded test
+interval:
+
+```sh
+/usr/bin/log show \
+    --start '2026-07-27 22:20:45' \
+    --end '2026-07-27 22:22:35' \
+    --style compact --info --debug \
+    --predicate 'process == "Nextcloud" AND subsystem BEGINSWITH "com.apple.network"'
+```
+
+Replace the timestamps with the actual test interval. Useful evidence includes:
+
+- `prefer no proxy`, confirming that the direct path preference is active;
+- `local network denied` or an unsatisfied local-network-denial reason;
+- a proxy endpoint such as `127.0.0.1`, showing proxy fallback;
+- `Privacy Stance: Not Eligible`, which indicates that the operation was not
+  subject to normal Local Network privacy enforcement and commonly points to
+  the launch or identity conditions described above.
+
+### VPN interpretation
+
+A VPN can install a system proxy even when the local target remains routed over
+Wi-Fi. `prefer_no_proxy` means “try direct first,” not “prohibit all proxies.”
+Seeing a later proxy attempt is therefore expected when the direct attempt
+fails. What matters for this feature is that macOS has an opportunity to
+evaluate the direct local path and report denial before proxy fallback masks
+the original condition.

doc/macOS-development.md

@@ -179,5 +179,6 @@ The way Transifex handles Xcode string catalogs creates a high risk of accidenta
 
 - **Direct `mac-crafter` CLI usage / branding builds** → [`admin/osx/mac-crafter/README.md`](../admin/osx/mac-crafter/README.md)
 - **Qt + macOS App Sandbox internals** → [`doc/macOS-Sandbox-Qt.md`](./macOS-Sandbox-Qt.md)
+- **Local Network permission diagnostics and testing** → [`doc/local-network-permission.md`](./local-network-permission.md)
 - **Finder integration (FinderSync) extension — verifying & troubleshooting loading** → [`doc/macOS-FinderSync-extension.md`](./macOS-FinderSync-extension.md)
 - **NextcloudFileProviderKit Swift package** → [`shell_integration/MacOSX/NextcloudFileProviderKit/README.md`](../shell_integration/MacOSX/NextcloudFileProviderKit/README.md)

src/gui/CMakeLists.txt

@@ -86,6 +86,7 @@ set(client_SRCS
     conflictsolver.cpp
     connectionvalidator.h
     connectionvalidator.cpp
+    localnetworkpermission.h
     editlocallyjob.h
     editlocallyjob.cpp
     editlocallymanager.h
@@ -294,6 +295,8 @@ IF( APPLE )
     list(APPEND client_SRCS cocoainitializer_mac.mm)
     list(APPEND client_SRCS systray_mac_common.mm)
     list(APPEND client_SRCS notificationsoundplayer_mac.mm)
+    list(APPEND client_SRCS
+        macOS/localnetworkpermission.mm)
     list(APPEND client_SRCS
         # macOS tray account popup: one type per header/implementation pair.
         # Shared foundation first, then the base hover view, rows, popups and the
@@ -391,7 +394,7 @@ IF( APPLE )
     endif()
 ENDIF()
 IF( NOT APPLE )
-    list(APPEND client_SRCS trayaccountpopup_qt.cpp)
+    list(APPEND client_SRCS trayaccountpopup_qt.cpp localnetworkpermission.cpp)
 ENDIF()
 
 IF( NOT WIN32 AND NOT APPLE )
@@ -751,7 +754,7 @@ if (APPLE)
     else()
         target_link_libraries(nextcloudCore PUBLIC "-framework UserNotifications")
     endif()
-    target_link_libraries(nextcloudCore PRIVATE "-framework AVFoundation" "-framework Foundation")
+    target_link_libraries(nextcloudCore PRIVATE "-framework AVFoundation" "-framework Foundation" "-framework Network")
     target_compile_definitions(nextcloudCore PRIVATE NEXTCLOUD_HAS_NATIVE_SOUND_BACKEND)
 endif()
 

src/gui/connectionvalidator.cpp

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #include <QJsonDocument>
 #include <QJsonObject>
 #include <QJsonArray>
 #include <QLoggingCategory>
@@ -18,6 +18,7 @@
 #include "userinfo.h"
 #include "networkjobs.h"
 #include "clientproxy.h"
+#include "localnetworkpermission.h"
 #include <creds/abstractcredentials.h>
 #include "systray.h"
 
@@ -35,6 +36,7 @@
     , _accountState(accountState)
     , _account(accountState->account())
     , _termsOfServiceChecker(_account)
+    , _localNetworkPermissionCheck(LocalNetworkPermission::checkDeniedForConnection)
 {
     connect(&_termsOfServiceChecker, &TermsOfServiceChecker::done,
             this, &ConnectionValidator::termsOfServiceCheckDone);
@@ -160,25 +162,30 @@
         return;
     }
 
+    QString error;
     if (!_account->credentials()->stillValid(reply)) {
         // Note: Why would this happen on a status.php request?
-        _errors.append(tr("Authentication error: Either username or password are wrong."));
+        error = tr("Authentication error: Either username or password are wrong.");
     } else {
         //_errors.append(tr("Unable to connect to %1").arg(_account->url().toString()));
-        _errors.append(job->errorString());
+        error = job->errorString();
     }
-    reportResult(StatusNotFound);
+
+    _localNetworkPermissionCheck(_account->url(), this, [this, error](const bool denied) {
+        _errors.append(denied ? LocalNetworkPermission::deniedError() : error);
+        reportResult(StatusNotFound);
+    });
 }
 
 void ConnectionValidator::slotJobTimeout(const QUrl &url)
 {
-    Q_UNUSED(url);
     //_errors.append(tr("Unable to connect to %1").arg(url.toString()));
-    _errors.append(tr("Timeout"));
-    reportResult(Timeout);
+    _localNetworkPermissionCheck(url, this, [this](const bool denied) {
+        _errors.append(denied ? LocalNetworkPermission::deniedError() : tr("Timeout"));
+        reportResult(Timeout);
+    });
 }
 
-
 void ConnectionValidator::checkAuthentication()
 {
     AbstractCredentials *creds = _account->credentials();

src/gui/connectionvalidator.h

@@ -7,7 +7,7 @@
 #ifndef CONNECTIONVALIDATOR_H
 #define CONNECTIONVALIDATOR_H
 
 #include "owncloudlib.h"
 #include <QObject>
 #include <QStringList>
 #include <QVariantMap>
@@ -15,6 +15,8 @@
 #include "accountfwd.h"
 #include "clientsideencryption.h"
 
+#include <functional>
+
 namespace OCC {
 
 /**
@@ -157,6 +159,10 @@
     void termsOfServiceCheckDone();
 
 private:
+    using LocalNetworkPermissionCheck = std::function<void(const QUrl &, QObject *, std::function<void(bool)>)>;
+
+    friend class ConnectionValidatorTestAccess;
+
 #ifndef TOKEN_AUTH_ONLY
     void reportConnected();
 #endif
@@ -177,6 +183,7 @@
     AccountStatePtr _accountState;
     AccountPtr _account;
     TermsOfServiceChecker _termsOfServiceChecker;
+    LocalNetworkPermissionCheck _localNetworkPermissionCheck;
     bool _isCheckingServerAndAuth = false;
 };
 }