git-annex/doc/git-annex-p2phttp.mdwn
Joey Hess de138c642b
p2phttp: Allow unauthenticated users to lock content by default
* p2phttp: Allow unauthenticated users to lock content by default.
* p2phttp: Added --unauth-nolocking option to prevent unauthenticated
  users from locking content.

The rationalle for this is that locking is not really a write operation, so
makes sense to allow in a repository that only allows read-only access. Not
supporting locking in that situation will prevent the user from dropping
content from a special remote they control in cases where the other copy of
the content is on the p2phttp server.

Also, when p2phttp is configured to also allow authenticated access,
lockcontent was resulting in a password prompt for users who had no way to
authenticate. And there is no good way to distinguish between the two types
of users client side.

--unauth-nolocking anticipates that this might be abused, and seems better
than disabling unauthenticated access entirely if a server is being
attacked. It may be that rate limiting locking by IP address or similar
would be an effective measure in such a situation. Or just limiting the
number of locks by anonymous users that can be live at any one time. Since
the impact of such an DOS attempt is limited to preventing dropping content
from the server, it seems not a very appealing target anyway.
2024-10-21 10:02:12 -04:00

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# NAME
git-annex-p2phttp - HTTP server for the git-annex API
# SYNOPSIS
git-annex p2phttp
# DESCRIPTION
This is a HTTP server for the git-annex API.
It is the git-annex equivilant of git-http-backend(1), for serving
a repository over HTTP with write access for authenticated users.
This does not serve the git repository over HTTP, only the git-annex
API.
Typically a remote will have `remote.name.url` set to a http url
as usual, and `remote.name.annexUrl` set to an annex+http url such as
"annex+http://example.com/git-annex/". The annex+http url is
served by this server, and uses port 9417 by default.
As well as serving the git-annex HTTP API, this server provides a
convenient way to download the content of any key, by using the path
"/git-annex/$uuid/$key". For example:
$ curl http://example.com:9417/git-annex/f11773f0-11e1-45b2-9805-06db16768efe/key/SHA256E-s6--5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03
hello
# OPTIONS
* `--jobs=N` `-JN`
This or annex.jobs must be set to configure the number of worker
threads that serve connections to the webserver.
Since the webserver itself also uses one of these threads,
this needs to be set to 2 or more.
A good choice is often one worker per CPU core: `--jobs=cpus`
* `--proxyconnections=N`
When this command is run in a repository that is configured to act as a
proxy for some of its remotes, this is the maximum number of idle
connections to keep open to proxied remotes.
The default is 1.
* `--clusterjobs=N`
When this command is run in a repository that is a gateway for a cluster,
this is the number of concurrent jobs to use to access nodes of the
cluster, per connection to the webserver.
The default is 1.
A good choice for this will be a balance between the number of nodes
in the cluster and the value of `--jobs`.
For example, if the cluster has 4 nodes, and `--jobs=4`, using
`--clusterjobs=4` will make all nodes in the cluster be accessed
concurrently, which is often optimal. But around 20 cores can be needed
when the webserver is busy.
* `--port=N`
Port to listen on. The default is port 9417, which is the default
port used for an annex+http or annex+https url.
It is not recommended to run this command as root in order to
use a low port like port 80. It will not drop permissions when run as
root.
* `--bind=address`
What address to bind to. The default is to bind to all addresses.
* `--certfile=filename`
TLS certificate file to use. Combining this with `--privatekeyfile`
makes the server use HTTPS.
* `--privatekeyfile=filename`
TLS private key file to use. Combining this with `--certfile`
makes the server use HTTPS.
* `--chainfile=filename`
TLS chain file to use. This option can be repeated any number of times.
* `--authenv`
Allows users to be authenticated with a username and password.
For security, this only allows authentication when the user connects over
HTTPS.
To configure the passwords, set environment variables
like `GIT_ANNEX_P2PHTTP_PASSWORD_alice=foo123`
The permissions of users can also be configured by setting
environment variables like
`GIT_ANNEX_P2PHTTP_PERMISSIONS_alice=readonly`. The value
can be either "readonly" or "appendonly". When this is not set,
the default is to give the user full read+write+remove access.
* `--authenv-http`
Like `--authenv`, but allows authentication when the user connects
over HTTP. This is not secure, since HTTP basic authentication is not
encrypted.
* `--unauth-readonly`
Allows unauthenticated users to read the repository, but not make
modifications to it.
This can be combined with `--authenv` or `--authenv-http` to allow
anonymous readonly access, and authenticated write access.
* `--unauth-appendonly`
Allows unauthenticated users to read the repository, and store data in
it, but not remove data from it.
This can be combined with `--authenv` or `--authenv-http` to allow
anonymous appendonly access, and authenticated remove access.
* `--unauth-nolocking`
By default, when `--unauth-readonly` or `--unauth-appendonly` is used,
unauthenticated users are allowed to lock content in the repository.
This option prevents that.
Locking content prevents it from being dropped from the repository
so it may be that an unauthenticated user abuses that, and this option
can be used in such a situation.
Note that enabling this option will prevent unauthenticated users from
dropping content from their other remotes in some cases.
* `--wideopen`
Gives unauthenticated users full read+write+remove access to the
repository.
Please think carefully before enabling this option.
# SEE ALSO
[[git-annex]](1)
git-http-backend(1)
[[git-annex-shell]](1)
[[git-annex-updateproxy]](1)
[[git-annex-initcluster]](1)
[[git-annex-updatecluster]](1)
<https://git-annex.branchable.com/design/p2p_protocol_over_http/>
# AUTHOR
Joey Hess <id@joeyh.name>
<http://git-annex.branchable.com/>
Warning: Automatically converted into a man page by mdwn2man. Edit with care