hSetEncoding of a closed handle segfaults.
https://ghc.haskell.org/trac/ghc/ticket/71618484c0c197 introduced the crash.
In particular, stdin may get closed (by eg, getContents) and then trying
to set its encoding will crash. We didn't need to adjust stdin's
encoding anyway, but only stderr, to work around
https://github.com/yesodweb/persistent/issues/474
Thanks to Mesar Hameed for assistance related to reproducing this bug.
Since the user does not know whether it will run su or sudo, indicate
whether the password prompt will be for root or the user's password,
when possible.
I assume that programs like gksu that can prompt for either depending on
system setup will make clear in their prompt what they're asking for.
weasel explained that apparmor limits on what files tor can read do not
apply to sockets (because they're not files). And apparently the
problems I was seeing with hidden services not being accessible had to
do with onion address propigation and not the location of the socket
file.
remotedaemon looks up the HiddenServicePort in torrc, so if it was
previously configured with the socket in /etc, that will still work.
This commit was sponsored by Denis Dzyubenko on Patreon.
This interacts with it using stdio, which is surprisingly hard.
sendFile does not currently work, due to
https://github.com/warner/magic-wormhole/issues/108
Parsing the output to find the magic code is done as robustly as
possible, and should continue to work unless wormhole radically changes
the format of its codes. Presumably it will never output something that
looks like a wormhole code before the actual wormhole code; that would
also break this. It would be better if there was a way to make
wormhole not mix the code with other output, as requested in
https://github.com/warner/magic-wormhole/issues/104
Only exchange of files/directories is supported. To exchange messages,
https://github.com/warner/magic-wormhole/issues/99 would need to be resolved.
I don't need message exchange however.
The attacker could just send a very lot of data, with no \n and it would
all be buffered in memory until the kernel killed git-annex or perhaps OOM
killed some other more valuable process.
This is a low impact security hole, only affecting communication between
local git-annex and git-annex-shell on the remote system. (With either
able to be the attacker). Only those with the right ssh key can do it. And,
there are probably lots of ways to construct git repositories that make git
use a lot of memory in various ways, which would have similar impact as
this attack.
The fix in P2P/IO.hs would have been higher impact, if it had made it to a
released version, since it would have allowed DOSing the tor hidden
service without needing to authenticate.
(The LockContent and NotifyChanges instances may not be really
exploitable; since the line is read and ignored, it probably gets read
lazily and does not end up staying buffered in memory.)
Display progress meter on send and receive from remote.
Added a new hGetMetered that can read an exact number of bytes (or
less), updating a meter as it goes.
This commit was sponsored by Andreas on Patreon.
On Debian, apparmor prevents tor from reading from most locations. And,
it silently fails if it is prevented from reading the hidden service
socket. I filed #846275 about this; violating the FHS is the least bad of a
bad set of choices until that bug is fixed.
Still a couple bugs:
* Closing the connection to the server leaves git upload-pack /
receive-pack running, which could be used to DOS.
* Sometimes the data is transferred, but it fails at the end, sometimes
with:
git-remote-tor-annex: <socket: 10>: commitBuffer: resource vanished (Broken pipe)
Must be a race condition around shutdown.
Almost working, but there's a bug in the relaying.
Also, made tor hidden service setup pick a random port, to make it harder
to port scan.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
A bit tricky since Proto doesn't support threads. Rather than adding
threading support to it, ended up using a callback that waits for both
data on a Handle, and incoming messages at the same time.
This commit was sponsored by Denis Dzyubenko on Patreon.
For use with tor hidden services, and perhaps other transports later.
Based on Utility.SimpleProtocol, it's a line-based protocol,
interspersed with transfers of bytestrings of a specified size.
Implementation of the local and remote sides of the protocol is done
using a free monad. This lets monadic code be included here, without
tying it to any particular way to get bytes peer-to-peer.
This adds a dependency on the haskell package "free", although that
was probably pulled in transitively from other dependencies already.
This commit was sponsored by Jeff Goeke-Smith on Patreon.
ghc 8 added backtraces on uncaught errors. This is great, but git-annex was
using error in many places for a error message targeted at the user, in
some known problem case. A backtrace only confuses such a message, so omit it.
Notably, commands like git annex drop that failed due to eg, numcopies,
used to use error, so had a backtrace.
This commit was sponsored by Ethan Aubin.
This avoids needing to bind to the right port before something else
does.
The socket is in /var/run/user/$uid/ which ought to be writable by only
that uid. At least it is on linux systems using systemd.
For Windows, may need to revisit this and use ports or something.
The first version of tor to support sockets for hidden services
was 0.2.6.3. That is not in Debian stable, but is available in
backports.
This commit was sponsored by andrea rota.
Tor unfortunately does not come out of the box configured to let hidden
services register themselves on the fly via the ControlPort.
And, changing the config to enable the ControlPort and a particular type
of auth for it may break something already using the ControlPort, or
lessen the security of the system.
So, this leaves only one option to us: Add a hidden service to the
torrc. git-annex enable-tor does so, and picks an unused high port for
tor to listen on for connections to the hidden service.
It's up to the caller to somehow pick a local port to listen on
that won't be used by something else. That may be difficult to do..
This commit was sponsored by Jochen Bartl on Patreon.
