Summary: Ref T13624. Depends on D21578. In "sshd" subprocess contexts, use "PhutilErrorLog" to direct errors to both stderr and, if configured, a logfile on disk.
Test Plan:
- Confiugured an error log.
- Forced `ssh-auth` to fatal.
- Saw errors on stderr and in log.
Maniphest Tasks: T13624
Differential Revision: https://secure.phabricator.com/D21579
Summary:
Ref T13436. There's no real security value to doing this comparison, it just wards off evil "security researchers" who get upset if you ever compare two strings with a non-constant-time algorithm.
In practice, SSH public keys are pretty long, pretty public, and have pretty similar lengths. This leads to a relatively large amount of work to do constant-time comparisons on them (we frequently can't abort early after identifying differing string length).
Test Plan: Ran `bin/ssh-auth --sshd-key ...` on `secure` with ~1K keys, saw runtime drop by ~50% (~400ms to ~200ms) with `===`.
Maniphest Tasks: T13436
Differential Revision: https://secure.phabricator.com/D20875
Summary: Depends on D20873. Ref T13436. Allow callers to configure "bin/ssh-auth --sshd-key %k" as an "AuthorizedKeysCommand"; if they do, and we recognize the key, emit just that key in the output.
Test Plan:
- Used `git pull` locally, still worked fine.
- Instrumented things, saw the public key lookup actually work and emit a single key.
- Ran without "--sshd-key", got a full key list as before.
Maniphest Tasks: T13436
Differential Revision: https://secure.phabricator.com/D20874
Summary:
Fixes T12397. Ref T13164. See PHI801.
Several installs have hit various use cases where the path on disk where Phabricator lives changes at runtime. Currently, `bin/ssh-auth` caches a flat file which includes the path to `bin/ssh-exec`, so this may fall out of date if `phabricator/` moves.
These use cases have varying strengths of legitimacy, but "we're migrating to a new set of hosts and the pool is half old machines and half new machines" seems reasonably compelling and not a problem entirely of one's own making.
Test Plan:
- Compared output on `master` to output after change, found them byte-for-byte identical.
- Moved `phabricator/` to `phabricator2/`, ran `bin/ssh-auth`, got updated output.
- Added a new SSH key, saw it appear in the output.
- Grepped for `AUTHFILE_CACHEKEY` (no hits).
- Dropped the cache, verified that the file regenerates cleanly.
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13164, T12397
Differential Revision: https://secure.phabricator.com/D19568
Summary:
Ref T11469. This isn't directly related, but has been on my radar for a while: building SSH keyfiles (particular for installs with a lot of keys, like ours) can be fairly slow.
At least one cluster instance is making multiple clone requests per second. While that should probably be rate limited separately, caching this should mitigate the impact of these requests.
This is pretty straightforward to cache since it's exactly the same every time, and only changes when users modify SSH keys (which is rare).
Test Plan:
- Ran `bin/auth-ssh`, saw authfile generate.
- Ran it again, saw it read from cache.
- Changed an SSH key.
- Ran it again, saw it regenerate.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T11469
Differential Revision: https://secure.phabricator.com/D16744
Summary:
Ref T10917. Currently, when you delete an SSH key, we really truly delete it forever.
This isn't very consistent with other applications, but we built this stuff a long time ago before we were as rigorous about retaining data and making it auditable.
In partiular, destroying data isn't good for auditing after security issues, since it means we can't show you logs of any changes an attacker might have made to your keys.
To prepare to improve this, stop destoying data. This will allow later changes to become transaction-oriented and show normal transaction logs.
The tricky part here is that we have a `UNIQUE KEY` on the public key part of the key.
Instead, I changed this to `UNIQUE (key, isActive)`, where `isActive` is a nullable boolean column. This works because MySQL does not enforce "unique" if part of the key is `NULL`.
So you can't have two rows with `("A", 1)`, but you can have as many rows as you want with `("A", null)`. This lets us keep the "each key may only be active for one user/object" rule without requiring us to delete any data.
Test Plan:
- Ran schema changes.
- Viewed public keys.
- Tried to add a duplicate key, got rejected (already associated with another object).
- Deleted SSH key.
- Verified that the key was no longer actually deleted from the database, just marked inactive (in future changes, I'll update the UI to be more clear about this).
- Uploaded a new copy of the same public key, worked fine (no duplicate key rejection).
- Tried to upload yet another copy, got rejected.
- Generated a new keypair.
- Tried to upload a duplicate to an Almanac device, got rejected.
- Generated a new pair for a device.
- Trusted a device key.
- Untrusted a device key.
- "Deleted" a device key.
- Tried to trust a deleted device key, got "inactive" message.
- Ran `bin/ssh-auth`, got good output with unique keys.
- Ran `cat ~/.ssh/id_rsa.pub | ./bin/ssh-auth-key`, got good output with one key.
- Used `auth.querypublickeys` Conduit method to query keys, got good active keys.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T10917
Differential Revision: https://secure.phabricator.com/D15943
Summary: Fixes T7034. Like HTTP, proxy requests to the correct host if a repository has an Almanac service host.
Test Plan: Ran VCS requests through the proxy.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T7034
Differential Revision: https://secure.phabricator.com/D11543
Summary: Ref T7034. This is a second special case, like commit hooks, where we need some help from Phabricator to make instance identity knowable.
Test Plan: Connected to an instance and ran SSH commands.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T7034
Differential Revision: https://secure.phabricator.com/D11539
Summary:
Ref T5833. This fixes a few weird things with this table:
- A bunch of columns were nullable for no reason.
- We stored an MD5 hash of the key (unusual) but never used it and callers were responsible for manually populating it.
- We didn't perform known-key-text lookups by using an index.
Test Plan:
- Ran migrations.
- Faked duplicate keys, saw them clean up correctly.
- Added new keys.
- Generated new keys.
- Used `bin/auth-ssh` and `bin/auth-ssh-key`.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T5833
Differential Revision: https://secure.phabricator.com/D10805
Summary:
Ref T5833. Currently, SSH keys are associated only with users, and are a bit un-modern. I want to let Almanac Devices have SSH keys so devices in a cluster can identify to one another.
For example, with hosted installs, initialization will go something like this:
- A request comes in for `company.phacility.com`.
- A SiteSource (from D10787) makes a Conduit call to Almanac on the master install to check if `company` is a valid install and pull config if it is.
- This call can be signed with an SSH key which identifies a trusted Almanac Device.
In the cluster case, a web host can make an authenticated call to a repository host with similar key signing.
To move toward this, put a proper Query class on top of SSH key access (this diff). In following diffs, I'll:
- Rename `userPHID` to `objectPHID`.
- Move this to the `auth` database.
- Provide UI for device/key association.
An alternative approach would be to build some kind of special token layer in Conduit, but I think that would be a lot harder to manage in the hosting case. This gives us a more direct attack on trusting requests from machines and recognizing machines as first (well, sort of second-class) actors without needing things like fake user accounts.
Test Plan:
- Added and removed SSH keys.
- Added and removed SSH keys from a bot account.
- Tried to edit an unonwned SSH key (denied).
- Ran `bin/ssh-auth`, got sensible output.
- Ran `bin/ssh-auth-key`, got sensible output.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T5833
Differential Revision: https://secure.phabricator.com/D10790
Summary: Ran `arc lint --apply-patches --everything` over rP, mainly to change double quotes to single quotes where appropriate. These changes also validate that the `ArcanistXHPASTLinter::LINT_DOUBLE_QUOTE` rule is working as expected.
Test Plan: Eyeballed it.
Reviewers: #blessed_reviewers, epriestley
Reviewed By: #blessed_reviewers, epriestley
Subscribers: epriestley, Korvin, hach-que
Differential Revision: https://secure.phabricator.com/D9431
Summary: If no ssh keys are in phabricator, bin/ssh-auth errors with undefined `$lines`. This fixes that case and explicitly tells the user no rows were found.
Test Plan: Ran bin/ssh-auth before and after change with no ssh keys in the system. Error goes away after change.
Reviewers: #blessed_reviewers, epriestley
Reviewed By: epriestley
CC: epriestley, aran, Korvin
Differential Revision: https://secure.phabricator.com/D7675
Summary:
Fixes T2229. This sets the stage for a patch similar to D7417, but for SSH. In particular, SSH 6.2 introduced an `AuthorizedKeysCommand` directive, which lets us do this in a mostly-reasonable way without needing users to patch sshd (if they have a recent enough version, at least).
The way the `AuthorizedKeysCommand` works is that it gets run and produces an `authorized_keys`-style file fragment. This isn't ideal, because we have to dump every key into the result, but should be fine for most installs. The earlier patch against `sshd` passes the public key itself, which allows the script to just look up the key. We might use this eventually, since it can scale much better, so I haven't removed it.
Generally, auth is split into two scripts now which mostly do the same thing:
- `ssh-auth` is the AuthorizedKeysCommand auth, which takes nothing and dumps the whole keyfile.
- `ssh-auth-key` is the slightly cleaner and more scalable (but patch-dependent) version, which takes the public key and dumps only matching options.
I also reworked the argument parsing to be a bit more sane.
Test Plan:
This is somewhat-intentionally a bit obtuse since I don't really want anyone using it yet, but basically:
- Copy `phabricator-ssh-hook.sh` to somewhere like `/usr/libexec/openssh/`, chown it `root` and chmod it `500`.
- This script should probably also do a username check in the future.
- Create a copy of `sshd_config` and fix the paths/etc. Point the KeyScript at your copy of the hook.
- Start a copy of sshd (6.2 or newer) with `-f <your config file>` and maybe `-d -d -d` to foreground and debug.
- Run `ssh -p 2222 localhost` or similar.
Specifically, I did this setup and then ran a bunch of commands like:
- `ssh host` (denied, no command)
- `ssh host ls` (denied, not supported)
- `echo '{}' | ssh host conduit conduit.ping` (works)
Reviewers: btrahan
Reviewed By: btrahan
CC: hach-que, aran
Maniphest Tasks: T2229, T2230
Differential Revision: https://secure.phabricator.com/D7419
Summary:
- Original command is in SSH_ORIGINAL_COMMAND, not normal argv.
- Use PhutilShellLexer to parse it.
- Fix a protocol encoding issue with ConduitSSHWorkflow. I think I'm going to make this protocol accept multiple commands anyway because SSH pipes are crazy expensive to build (even locally, they're ~300ms).
Test Plan: With other changes, successfully executed "arc list --conduit-uri=ssh://localhost:2222".
Reviewers: btrahan, vrana
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T550
Differential Revision: https://secure.phabricator.com/D4232
Summary:
- Build "sshd-auth" (for authentication) and "sshd-exec" (for command execution) binaries. These are callable by "sshd-vcs", located [[https://github.com/epriestley/sshd-vcs | in my account on GitHub]]. They are based on precursors [[https://github.com/epriestley/sshd-vcs-glue | here on GitHub]] which I deployed for TenXer about a year ago, so I have some confidence they at least basically work.
- The problem this solves is that normally every user would need an account on a machine to connect to it, and/or their public keys would all need to be listed in `~/.authorized_keys`. This is a big pain in most installs. Software like Gitosis/Gitolite solve this problem by giving you an easy way to add public keys to `~/.authorized_keys`, but this is pretty gross.
- Roughly, instead of looking in `~/.authorized_keys` when a user connects, the patched sshd instead runs `echo <public key> | sshd-auth`. The `sshd-auth` script looks up the public key and authorizes the matching user, if they exist. It also forces sshd to run `sshd-exec` instead of a normal shell.
- `sshd-exec` receives the authenticated user and any command which was passed to ssh (like `git receive-pack`) and can route them appropriately.
- Overall, this permits a single account to be set up on a server which all Phabricator users can connect to without any extra work, and which can safely execute commands and apply appropriate permissions, and disable users when they are disabled in Phabricator and all that stuff.
- Build out "sshd-exec" to do more thorough checks and setup, and delegate command execution to Workflows (they now exist, and did not when I originally built this stuff).
- Convert @btrahan's conduit API script into a workflow and slightly simplify it (ConduitCall did not exist at the time it was written).
The next steps here on the Repository side are to implement Workflows for Git, SVN and HG wire protocols. These will mostly just proxy the protocols, but also need to enforce permissions. So the approach will basically be:
- Implement workflows for stuff like `git receive-pack`.
- These workflows will implement enough of the underlying protocol to determine what resource the user is trying to access, and whether they want to read or write it.
- They'll then do a permissons check, and kick the user out if they don't have permission to do whatever they are trying to do.
- If the user does have permission, we just proxy the rest of the transaction.
Next steps on the Conduit side are more simple:
- Make ConduitClient understand "ssh://" URLs.
Test Plan: Ran `sshd-exec --phabricator-ssh-user epriestley conduit differential.query`, etc. This will get a more comprehensive test once I set up sshd-vcs.
Reviewers: btrahan, vrana
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T603, T550
Differential Revision: https://secure.phabricator.com/D4229
