Fixes the roaming behavior on Android 5+, a linker issue on Android M,
a few bugs, and adds several new advanced options for VPN profile (MTU,
server port, split tunneling).
Also adds methods and a constructor to parse settings_t from a string
instead of a file.
Fixes#782, #847, #865.
The headers/libraries changed a lot with level 21 so that our app won't
run on devices with Android < 5 when built against it. We currently
don't need any new native APIs so that should be fine.
Android blocks traffic for address families for which no IPs, DNS servers
or routes are installed via VpnService.Builder. Since Android 5+ (API
level 21) it is possible to explicitly allow such traffic to bypass the VPN.
So for proper split tunneling we note whether we saw a VIP and/or DNS
server of a specific family, and if not, allow traffic of that family
to bypass the VPN using the new API (on older systems there is no change
and such traffic will still be blocked). Otherwise, we do what we did so
far, that is, simply install the received routes (traffic selectors), all
other traffic will not be directed to the TUN device and use the underlying
network instead.
If traffic for a family should be blocked we install a default route via
TUN device even if we received more specific traffic selectors from the
server. libipsec will use the actual traffic selectors as IPsec policies
and drop any packets it received that don't match them. We only do this
if we saw any VIPs or DNS servers of a family. Otherwise the traffic for
that family is blocked anyway.
In dual-stack environments the IPv6 connectivity (via autoconfiguration)
might be established before the IPv4 connectivity (via DHCP). It seems
Android triggers the CONNECTIVITY_ACTION broadcast already when the first
family is fully configured. At that time we might not be able to find an
IPv4 source address. And since Android does not trigger the broadcast
again if IPv4 connectivity is established, the connection is broken
afterwards.
So we store the connectivity state and if we are reportedly connected but
still find no source address we trigger a roam event to recheck for an IPv4
address. This will cause regular rechecks if a device enters an IPv6-only
network, but I guess that's rare (otherwise we could limit the number of
rechecks done between connectivity changes).
Before fwmarks were used protected sockets were bound to the outbound
interface via SO_BINDTODEVICE. This does not always seem to work well
together with our connect()/getsockname() trick if the server is covered
by the traffic selectors. Calling protect() again after disconnecting
the socket seems to help, but if there is no connectivity at all we still
get the virtual IP back (maybe protect() does not bind the socket to any
interface then).
When roaming from a mobile network to WiFi on Android 5.x the event
received via ConnectivityManager is triggered before the mobile
connection is fully torn down (i.e. before the interface is disabled and
the routes disappear). So for strongSwan the current path still seems
valid and since no roam event is triggered later the daemon never switches
to WiFi and the connection is broken afterwards.
A possible solution to this is enabling roam events in the kernel-netlink
plugin. That would trigger an event when the device is finally disconnected
from the mobile network. However, this could actually take a some time,
during which traffic continues to be sent via mobile network instead of WiFi.
That's because Android now uses multiple routing tables, routing rules and
fwmarks to direct traffic to the appropriate interface/table, but in our
plugin we don't have the information available that would allow us to make
the switch to a different network/routing table earlier (and we actually
prefer the current path if it is still valid). Additionally, the plugin
produces quite a bit more events than ConnectivityManager (which was one
of the reasons to use the latter in the first place).
This custom kernel-net implementation is now specifically tailored for
Android. Roam events are still triggered via ConnectivityManager but
the source address is determined via connect()/getsockname() on a VPN
excluded UDP socket, which does use the correct routing table as intended
by Android. That way the daemon immediately sees a different source IP
when connectivity changes even if the device is connected to multiple
networks concurrently.
This fixes an issue when using the Android M preview. Bionic's dynamic
linker was changed so that symbols in libraries loaded with RTLD_LOCAL
were not found anymore in dlsym(RTLD_DEFAULT, ...). This is the case
for libraries loaded with System.loadLibrary(), therefore, the plugin
loader in libstrongswan was not able to resolve any symbols defined in
other libraries loaded later. While this seems to have been broken
unintentionally for existing apps (fix at [1]), it will again be a
problem whenever we decide to increase targetSdkVersion beyond 22 (or
until that fix makes it into the system/emulator images).
Unfortunately, the dynamic loader in releases prior to Android 4.3 can't
load libandroidbridge without also loading its dependencies.
[1] https://github.com/android/platform_bionic/commit/1913352c6b
This also adds a new area for advanced settings that is only displayed
if the user requests it (or if advanced settings already have been set).
The min. MTU for IPv6 is 1280, anything lower lets the TUN device
creation fail if an IPv6 address has been assigned. If lower MTUs are
necessary we might be able to catch that later when setting the MTU and
just use at least 1280 if an IPv6 address was assigned, but let's keep
it simple for now.
The destroy() method sets the IKE_SA on the bus to NULL, we reset it to
the current IKE_SA so any events and log messages that follow happen in
the correct context.
A practical example where this is problematic is a DH group mismatch,
which causes the first CREATE_CHILD_SA exchange to fail. Because the SA
was not reset previously, the message() hook for the CREATE_CHILD_SA
response, for instance, was triggered outside the context of an IKE_SA,
that is, the ike_sa parameter was NULL, which is definitely not expected
by several plugins.
Fixes#862.
Changes how acquires are tracked in the trap manager, which fixes
several race conditions. Also fixes races between threads installing
trap policies and the main thread trying to flush the trap policies.
Similar changes were added to the shunt manager which previously
used no locking at all.
Fixes#1014.
When flush() is called there might be threads in install() waiting for
trap policies to get installed (without holding the lock). We have to
wait until they updated the entries with the respective CHILD_SAs before
destroying the list.
We also have to prevent further trap policy installations (and wait until
threads in install() are really finished), otherwise we might end up
destroying CHILD_SA objects after the kernel interface implementations
have already been unloaded (avoiding this is the whole point of calling
flush() before unloading the plugins).
This fixes potential race conditions in case complete() or flush() is
executed before or concurrently with a thread that handles an acquire.
It will also simplify tracking multiple acquires created for the same
trap policy in the future.
Also fixes the behavior in some error situations.
This basically reverts f4e822c1b4 ("trap-manager: don't check-in
nonexisting IKE_SA if acquire fails"). As checkout_by_config() could
return an already existing and established IKE_SA we have to properly
destroy it, for instance, in case other threads are waiting to check
it out. checkin_and_destroy() should handle the case of a new SA
properly (it produces a log message on level 1, though).
In some situations it might be valid for a host that configures
right=%any to reestablish or reauthenticate an IKE_SA. Using %any would
immediately abort the initiation causing the new SA to fail (which
might already have the existing CHILD_SAs assigned).
Fixes#1027.
If static local addresses are configured we should use their address family
as a hint when resolving the remote address.
We don't do this if %any is configured as this might break existing
configurations (%any4 and %any6 are however used as hint).
Threads might still be allocating SPIs (e.g. triggered by an acquire or
an inbound message) while the main thread calls flush(). If there is a
context switch right after such a thread successfully checked this->rng
in get_spi() and the main thread destroys the RNG instance right then,
that worker thread will cause a segmentation fault when it continues and
attempts to call get_bytes().
Fixes#1014.
As it turns out, getpwnam_r, getgrnam_r, and friends will return
ERANGE if _any_ user or group on the system is larger than will fit
into the scratch buffer you pass to them.
This reworks the resolve_uid and resolve_gid methods plus
init_supplementary_groups to use a variable-size buffer that is grown
until the results fit.
Based on a patch by Evan Broder.
Closesstrongswan/strongswan#12.
This fixes a DoS and potential remote code execution vulnerability that was
caused because the original payload type that was returned previously was
used to cast such payload objects to payloads of the indicated type (e.g.
when logging notify payloads with a payload type for the wrong IKE version).
Fixes CVE-2015-3991.
Only one of `--user-install` and `--install-dir` may be set and if
`--user-install` is the default on a system installation will fail
unless we disable it explicitly.
Fixes#914.
Installing them might not work well when building distro packages (e.g.
with DESTDIR installs). It might be easier to install them later with a
script in the distro package.
When building from source on the local system it could still be useful to
install the packages directly, which can be enabled with separate configure
options.
The main problem with DESTDIR installations of the Python Egg is that
easy_install creates or modifies a file called easy-install.pth in the
installation directory. So it's not actually possible to simply copy
the results in DESTDIR over to the actual system as that file would have
to be merged with any existing one.
Fixes#914.
We also don't require setup.py to exist during cleanup, as e.g. with
make distcheck the source directory is not writable when the build directory
is cleaned, so setup.py can't be created (to just get removed again anyway
if VICI and the Python Eggs haven't been enabled previously).
Instead of just implicitly destroying the old SA we properly delete it to
notify the other peer (if the other peer keeps the SA up after the
reauthentication and sends DPDs it might consider us dead even though the
new SA is up, that seems to be the case with racoon). We delay the DELETE
a bit to give the other peer time to get the new SA fully established.
Since DELETE messages are not retransmitted it is still possible that
the other peer misses that we deleted the SA.
The interface is currently not very nice, but if we ever were able to
safely checkout multiple SAs concurrently we could add something similar
to ike_rekey() and call that when we detect a reauthentication.
There are several situations that the previous code didn't handle that
well, for example, interim updates during rekeying (until the rekeyed SA
was deleted the numbers were too high, then suddenly dropped afterwards),
or rekeying for IKEv1 in general because rekeyed IPsec SAs stay installed
until they expire (so if they were still around when the IKE_SA was
terminated, the reported numbers in the Stop message were too high).
If intermediate updates are not used the cache entries for rekeyed
CHILD_SA will accumulate, we can't clean them up as we don't get
child_updown() events for them.
If we sent retransmits for a message and didn't receive a response it might
still arrive later. Such a message will be queued on the socket. The next
read will then return not the expected response but the one for the earlier
request. For this message the verification will fail and the message gets
discarded. But with the earlier code the actual response was never received.
Instead, a subsequent request resulted in the same failure and so on.
Fixes#838.
The only purpose of starter is to control the IKE daemon, so we
terminate it if the daemon executable is not found (e.g. because
DAEMON_NAME is incorrect).
This removes the charonstart setting (it was not actually configurable
anymore).
Since the removal of pluto this is quite superfluous. The flag itself
might be useful to avoid starting charon if the executable does not
exist for some reason (e.g. if DAEMON_NAME is incorrect).
Returning FAILED in the constructor is wrong, but returning NULL doesn't work
either as it's currently assumed tasks always can be created.
Therefore, delay this check until we actually try to allocate a nonce.
Tobias Brunner