Security fix: Disallow hostname starting with a dash, which would get
passed to ssh and be treated an option. This could be used by an attacker
who provides a crafted ssh url (for eg a git remote) to execute arbitrary
code via ssh -oProxyCommand.
No CVE has yet been assigned for this hole.
The same class of security hole recently affected git itself,
CVE-2017-1000117.
Method: Identified all places where ssh is run, by git grep '"ssh"'
Converted them all to use a SshHost, if they did not already, for
specifying the hostname.
SshHost was made a data type with a smart constructor, which rejects
hostnames starting with '-'.
Note that git-annex already contains extensive use of Utility.SafeCommand,
which fixes a similar class of problem where a filename starting with a
dash gets passed to a program which treats it as an option.
This commit was sponsored by Jochen Bartl on Patreon.
This works, but needs more testing and work on cases like encrypted repos,
enabling existing repositories, etc.
This commit was sponsored by Shaun Westmacott.
This was a reversion caused by the relative path changes in 5.20150113.
Other uses of addAuthorizedKeys seem to be ok. If the user enters a
directory like ~/annex, it writes GIT_ANNEX_SHELL_DIRECTORY=annex, and
git-annex-shell assumes that's relative to HOME.
This has not been tested at all. It compiles!
The only known missing things are support for encryption, and for get/set
of special remote configuration, and of key state. (The latter needs
separate work to add a new per-key log file to store that state.)
Only thing I don't much like is that initremote needs to be passed both
type=external and externaltype=foo. It would be better to have just
type=foo
Most of this is quite straightforward code, that largely wrote itself given
the types. The only tricky parts were:
* Need to lock the remote when using it to eg make a request, because
in theory git-annex could have multiple threads that each try to use
a remote at the same time. I don't think that git-annex ever does
that currently, but better safe than sorry.
* Rather than starting up every external special remote program when
git-annex starts, they are started only on demand, when first used.
This will avoid slowdown, especially when running fast git-annex query
commands. Once started, they keep running until git-annex stops, currently,
which may not be ideal, but it's hard to know a better time to stop them.
* Bit of a chicken and egg problem with caching the cost of the remote,
because setting annex-cost in the git config needs the remote to already
be set up. Managed to finesse that.
This commit was sponsored by Lukas Anzinger.
Improved probing the remote server, so it gathers a list of the
capabilities it has. From that list, we can determine which types
of remotes are supported, and display an appropriate UI.
The new buttons for making gcrypt repos don't work yet, but the old buttons
for unencrypted git repo and encrypted rsync repo have been adapted to the
new data types and are working.
This commit was sponsored by David Schmitt.
webapp: Adds newly created repositories to one of these groups:
clients, drives, servers
This is heuristic, but it's a pretty good heuristic, and can always be
configured.
