strongSwan VPN Client for Android

Increased target SDK to Android 14 and fixed compatibility issues

Due to a bug in Android 14+, a new permission (SYSTEM_ALERT_WINDOW) is necessary to start a VPN profile in the background from the status tile. If necessary, the app opens the settings dialog where users have to search the app and then grant the permission manually (Google disabled the possibility to directly ask for this permission some versions ago)

Fix a crash when listing installed apps for new profiles

Fix for existing shortcuts and automation via Intents

Support for managed configurations via enterprise mobility management (EMM)

Increased target SDK to Android 13 and ask for permission to show status notification

Enable hardware acceleration in OpenSSL

Use a more stable approach to determine source IP

Changed the order of KE methods so that ecp256 is again proposed first and in the KE payload instead of curve25519. This avoids issues with Zyxel Firewalls that can’t handle KE payloads with an identifier larger than 21 (ecp521) — the identifier for curve25519 is 31 — and just silently drop such IKE_SA_INIT requests.

Switched from BoringSSL to OpenSSL, which adds the following algorithms: Curve448 ECDH, AES-CCM, Camellia (CBC/CTR/XCBC), SHA-3 (HMAC/PKCS#1)

Fixed an issue that caused file descriptor leaks when fetching OCSP/CRLs

Improved translation for simplified Chinese

Correctly included Ukrainian translation

Increased minimum SDK version to 21 (Android 5.0)

Adds a button to install user certificates (newer Android releases don’t provide one in the selection dialog anymore - if no certs are installed, the dialog doesn’t even show up).

DNS servers are now explicitly applied whenever a TUN device is created (instead of only when the IKE_SA is established), this ensures that the correct DNS servers are used if the CHILD_SA gets explicitly deleted by the server and recreated by the client.

Requests a new permission on Android 11 to get a list of all installed apps in order to exclude/include them from VPNs (and for the EAP-TNC use case).

Don’t mark VPN connections as metered. The default changed when targeting Android 10 with the last release.

Adds support to use IPv6 transport addresses for IKE and ESP. This can only be enabled if UDP encapsulation for IPv6 is supported by the server. Note that the Linux kernel only supports this since version 5.8, so many servers will not support it yet.

Shows a proper error message if the UUID in a profile is invalid (e.g. contains no dashes).

Fixes a potential crash with the power whitelist dialog and handles rotation and other Activity restarts better if the information dialog is shown

Fixes the port scanning IMC (was broken since about 1.6.1).

Several changes try to improve reachability even in Android’s deep sleep phases.

Fixes the app icon on Android < 5.0.

Fixes a possible crash via QuickSettings tile on some devices

Fixes loading CRL/OCSP via HTTP on Android 9, which defaults to HTTPs only.

Makes the client identity configurable (via advanced settings and profiles) also when using EAP authentication.

Fixes an issue with ECDSA certificate selection on Android 10.

Fixes an issue with break-before-make reauthentication (used if MOBIKE is not supported) if the server concurrently deletes the IKE_SA.

Uses a different API (ConnectivityManager.registerNetworkCallback instead of the deprecated ConnectivityManager.CONNECTIVITY_ACTION) to detect network changes on Android 7 and newer.

Fixes a potential crash on Huawei devices

Authentication via EAP-MSCHPv2 now supports UTF-8 encoded passwords.

Fixes an issue with upgrades from older versions.

Adds a copy command to duplicate an existing VPN profile.

Allows configuring custom DNS servers for each VPN profile.

Fixes potential DNS leaks caused by a bug in Android 9.

Fixes clicking some buttons (certificate selection, app selection) with keyboard navigation (also affects e.g. Fire TV sticks) when running on Android < 8.

Fixes an issue with the QuickSettings tile on some devices where the callback is called even if no tile is available.

Fixes profile selection/edit when the device is rotated.

Removes support for EAP-PEAP/TTLS as it caused major issues with commercial VPN services (one issue was that the server identity was initially enforced as AAA identity, but changing that revealed that some providers use self-signed AAA server certificates - not sure what clients accept that), hopefully proper support can be added in a future version.

Fixes a possible crash related to Android 8’s optional Autofill feature (the bug that causes it was apparently fixed with Android 8.1 but has not been backported).

Supports the Always-on VPN feature on Android 7+.

Adds a Quick Settings tile on Android 7+ to quickly initiate/terminate the VPN connection.

The new settings activity allows specifying a default VPN profile used for the two features above (the default is to initiate the most recently used profile).

The app automatically tries to reconnect the VPN profile if fatal errors occur (e.g. authentication failures). The retries are delayed by an exponential backoff which is currently capped at 2 minutes.

On Android 5+ a dummy VPN interface is installed while connecting to a VPN profile or recovering from errors, to block unencrypted traffic while taking excluded subnets/apps configured in the profile into account.

Errors are not shown in a modal dialog anymore in the main activity but in a banner directly above the status information (with buttons to view the log and retry connecting).

Uses a separate activity to initiate/terminate/retry VPN profiles which avoids having to bring the main Activity to the foreground for these actions.

Adds options to disable OCSP/CRL fetching (e.g. if it’s known the server is not available, or if CRLs are too large).

Adds an option to enable strict revocation checking via OCSP/CRL. If enabled, the authentication will fail if the revocation status of the server certificate is unknown (e.g. because no valid CRL is available).

Fetching OCSP/CRL can now be aborted immediately (e.g. to cancel connecting if an OCSP server is not reachable).

Basic support for EAP-TTLS/EAP-PEAP has been added but had to be removed again with 2.0.1.

Adds an option to use PSS encoding for RSA signatures instead of the classic PKCS#1 encoding.

The explicit ESP proposals for the deprecated Suite B have been removed.

Adds more clear error messages if permission for VPNs can’t be acquired (e.g. because another app has the Always-on VPN feature enabled).

The date/time/thread is shown in the log view if enough space is available (e.g. on tablets or even in landscape orientation on phones). It should also be more efficient when displaying large logs.

Removes the MIME-type filter when importing trusted certificates, allowing the import of certificates even if they don’t have an X.509 related MIME-type set.

All VPN profiles now have a random UUID assigned (its value may be copied from the profile editor e.g. to initiate/terminate a VPN profile via explicit Intent).

Always sends the client certificate (if applicable) instead of only after receiving a certificate request (allows servers that accept certificates from a lot of CAs to avoid sending certificate requests).

Makes the IKE and/or ESP algorithms configurable.

Removes modp1024 from the default IKEv2 proposal. If the server only allows this DH group, a custom IKE proposal has to be configured in the VPN profile.

Adds support for delta CRLs.

Fixes issues with fragmented IP packets (pull request #80).

Ensures expires are triggered for the correct IPsec SA.

Fixes an issue with multicast addresses when using split tunneling on older Android releases.

Does not consider a DH group mismatch as failure anymore as responder of a CHILD_SA rekeying (commit e7276f78aa).

Adds support to verify server certificates via OCSP (Online Certificate Status Protocol).

Caches CRLs in the app directory.

The CRL cache may be cleared via main menu.

Adds a button to reconnect the VPN profile to the "currently connected" dialog.

Don’t apply/configure app selection on Android < 5 (the API is not supported there).

Initiator SPIs are reset when retrying while reconnecting which might avoid issues with INVALID_KE_PAYLOAD notifies.

Catches some random exceptions (as seen in Play Console)

Fixes a crash on Android ⇐ 5.

Fixes database update when updating from app versions < 1.8.0.

Fixes a crash with pre-existing profiles.

Adds support for split-tunneling on the client (only route specific traffic via VPN and/or exclude specific traffic from the VPN).

Adds support for per-app VPN (either allow only specific apps to use the VPN or exclude certain apps from using it).

Sending of certificate requests may be disabled (while this allows reducing the size of the IKE_AUTH message, e.g. if fragmentation is not supported. It only works if the server also sends its certificate if it didn’t receive any certificate requests).

NAT-T keepalive interval is now configurable.

VPN profiles may be imported via SAF (Storage Access Framework) and allow the configuration of the new settings.

CRLs are now fetched with a simple Android-specific HTTP[S] fetcher.

Adds a disconnect button in the permanent notification.

The log view should now be more efficient.

Fixes the handling of backslashes in usernames.

Adds a Traditional Chinese translation.

Fixes an issue while disconnecting on certain devices.

Adds Simplified Chinese translation.

Adds support to import VPN profiles from JSON-encoded files.

Re-adds support for the ECC Brainpool DH groups (BoringSSL doesn’t provide these).

Fixes a crash (regarding libtpmtss.so) on older Android systems.

Adds a permanent notification while connected (or connecting) that shows the current status and which allows running the VpnService instance as foreground service. This in turn should prevent Android from terminating it when low on memory.

Supports the ChaCha20/Poly1305 AEAD and Curve25519 DH algorithms.

Properly validates entered server port and MTU values in the GUI.

Logs the installed DNS servers.

Uses BoringSSL instead of OpenSSL.

Based on strongSwan version 5.5.1.

Fixes a crash when importing CA/server certificates via SAF (Storage Access Framework).

Fixes an interoperability issue with Windows Server. strongSwan version 5.4.0 changed the order of the algorithms in the default IKE proposal. Algorithms that provide a security of less than 128-bit were moved to the end of the list. Now Windows Server 2012 R2 (in its default configuration at least) only supports modp1024. The problem is that Microsoft’s IKEv2 implementation only seems to consider the first fifteen algorithms of a specific transform type in the proposal. Because strongSwan supports quite a lot of DH groups and due to the reordering, modp1024 was now at position 17 in the proposal. This meant that Microsoft Server rejected the IKE_SA_INIT message with a NO_PROPOSAL_CHOSEN error. This has been fixed by removing some of the weaker and rarely used DH groups from the default proposal (commit fae18fd201).

Also corrects the label for the password field in the login dialog.

Based on version:5.4.0, which e.g. adds support for IKEv2 redirection.

Configuration of the server identity. If it is set the identity is sent as IDr during authentication and must match the server’s identity exactly (i.e. it disables loose identity matching against all subjectAltNames).

Selection of the client identity if certificate authentication is used.

GUI changes:

Increases the NAT-T keepalive interval to 45s. No attempt to send keepalives is made anymore if there is no connectivity.

Fixed the font in the log view on Android 5+.

Native 64-bit build.

Based on version 5.3.2.

Roaming between networks on Android 5 and newer has been fixed.

Adds new advanced profile settings:

Sets the preferred language for remediation instructions to the system language.

EAP-TNC does not require a client certificate anymore.

Fixes a linker issue on Android M.

Fix for CVE-2015-4171.

Based on version 5.2.1 including improved MOBIKE handling and support for IKEv2 fragmentation.

Enables optional PFS (Perfect Forward Secrecy) for IPsec SAs. Proposed are cipher suites with and without DH groups, so it’s up to the VPN server whether PFS is used or not.

Adds basic support for EAP-TLS. Limitations are:

Adds the ability to import CA and server certificates directly into the app. On Android 4.4+ the SAF (Storage Access Framework) is used to allow users to browse for certificate files (if the MIME-type is not set properly the advanced view has to be used to see all files). On older systems the files may be opened from third-party file managers.

The GUI indicates if the connection is being reestablished.

A DNS proxy resolves the VPN server’s hostname while reestablishing (plaintext is blocked otherwise).

Supports ECDSA private keys on recent Android systems (tested on Android 4.4.4)

Based on version 5.1.3 (fixes a security vulnerability).

Links libcrypto (OpenSSL) statically.

Doesn’t limit the number of packets during EAP-TTLS.

Based on version 5.1.1.

Fixed issues with IV generation and padding length calculation for AES-GCM.

Removes the Vstr dependency.

Fixed a regression causing remediation instructions to pile up (EAP-TNC).

Improved recovery after certain connectivity changes.

Added support for EAP-TNC.

Disabled listening on IPv6 because the Linux kernel currently does not support UDP encapsulation of ESP packets for IPv6.

Added support for AES-GCM.

Support for IPv6-in-IPv4 tunnels.

Uses kernel-netlink to handle interface/IP address enumeration.

Added support for multiple authentication, e.g. based on an X.509 certificate followed by EAP (RFC 4739).

Added Polish, Ukrainian, and Russian translations.

Fixed a race condition during reauthentication and a potential freeze while disconnecting.

Added shortcuts to VPN profiles to quickly start specific connections from the launcher.

Added a confirmation dialog if a connection is started but one is already established.

Fixed a few Android 4.2 specific issues.

Added support for MOBIKE e.g. allows switching between different interfaces (e.g. Wifi and 3G/4G).

The app tries to keep the connection established until the user disconnects manually.

Workaround for a private key issue on Android 4.1.

Added loose ID matching: While the client expects the hostname/IP of the VPN server to be contained as subjectAltName in the certificate this allows the responder to use a different IDr than that, as long as it is confirmed by the certificate (the client does not send an IDr anymore).

Fixed a Unicode issue when converting Java to C strings.

Added certificate authentication and fixed reauthentication.