Rather than hoping that the AF_SYSTEM fd is of type utun, and then
calling "2" on it to get the name -- which could be defined as something
else for a different AF_SYSTEM socket type -- instead simply query the
AF_SYSTEM control socket ID with getpeername. This has one catch, which
is that the ID is dynamically allocated, so we resolve it using the
qualified name. Normally we'd make a new AF_SYSTEM socket for this, but
since that's not allowed in the sandbox, we reuse the AF_SYSTEM socket
that we're checking. At this point in the flow, we know that it's a
proper AF_SYSTEM one, based on the first sockaddr member; we just don't
know that it's a utun variety.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This is a bit of a kludge, until I find something better. We simply
iterate through all FDs, and call getsockopt on each one until we find
the utun FD. This works, and completes rather quickly (fd is usually 6
or 7). Rather than maintain the old path for older kernels, just use
this for all versions, to get more coverage. Other techniques involve
undocumented APIs; this one has the advantage of using nothing
undocumented.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The general Network Extension framework is incredibly buggy, and a
timeout when setting the network settings does not necessarily imply
that the whole operation failed. Simply log the condition and move on.
This restores the app's old behavior.
Reported-by: Filipe Mendonça <cfilipem@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Jason A. Donenfeld
Andrej Mihajlov