ErrDenied was added in [our fork of
x/crypto/ssh](acc6f8fe8d)
to short-circuit auth attempts once one fails.
In the case of our callbacks, this error is returned when SSH policy
check determines that a connection should not be allowed. Both
`NoClientAuthCallback` and `PublicKeyHandler` check the policy and will
fail anyway. The `fakePasswordHandler` returns true only if
`NoClientAuthCallback` succeeds the policy check, so it checks it
indirectly too.
The difference here is that a client might attempt all 2-3 auth methods
instead of just `none` but will fail to authenticate regardless.
Updates #8593
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
Run `staticcheck` with `U1000` to find unused code. This cleans up about
a half of it. I'll do the other half separately to keep PRs manageable.
Updates #cleanup
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
This takes advantage of existing functionality in ipn/ipnlocal to adjust
the local clock based on periodic time signals from the control server.
This way, when checking things like SSHRule expirations, calculations are
protected incorrectly set local clocks.
Fixestailscale/corp#15796
Signed-off-by: Percy Wegmann <percy@tailscale.com>
We were incrementing the sftp metric on regular sessions
too, not just sftp.
Updates #cleanup
Change-Id: I63027a39cffb3e03397c6e4829b1620c10fa3130
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
There are two race conditions in output handling.
The first race condition is due to a misuse of exec.Cmd.StdoutPipe.
The documentation explicitly forbids concurrent use of StdoutPipe
with exec.Cmd.Wait (see golang/go#60908) because Wait will
close both sides of the pipe once the process ends without
any guarantees that all data has been read from the pipe.
To fix this, we allocate the os.Pipes ourselves and
manage cleanup ourselves when the process has ended.
The second race condition is because sshSession.run waits
upon exec.Cmd to finish and then immediately proceeds to call ss.Exit,
which will close all output streams going to the SSH client.
This may interrupt any asynchronous io.Copy still copying data.
To fix this, we close the write-side of the os.Pipes after
the process has finished (and before calling ss.Exit) and
synchronously wait for the io.Copy routines to finish.
Fixes#7601
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
Co-authored-by: Maisem Ali <maisem@tailscale.com>
This basically allows running services on the SSH client and reaching
them from the SSH server during the session.
Updates #6575
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This change introduces a SSHSessionRecordingFailed event type
that is used when a session recording fails to start or fails during a
session, and the on failure indicates that it should fail open.
Updates tailscale/corp#9967
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
We were only closing on side of the pty/tty pair.
Close the other side too.
Thanks to @fritterhoff for reporting and debugging the issue!
Fixes#8119
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This change adds a ConnectionID field to both SSHEventNotifyRequest and
CastHeader that identifies the ID of a connection to the SSH server.
Updates tailscale/corp#9967
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This change sends an SSHEventNotificationRequest over noise when a
SSH session is set to fail closed and the session is unable to start
because a recorder is not available or a session is terminated because
connection to the recorder is ended. Each of these scenarios have their
own event type.
Updates tailscale/corp#9967
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
We removed it earlier in 916aa782af, but we still want to support it for some time longer.
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Previously we would error out when the recording server disappeared after the in memory
buffer filled up for the io.Copy. This makes it so that we handle failing open correctly
in that path.
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This adds support to try dialing out to multiple recorders each
with a 5s timeout and an overall 30s timeout. It also starts respecting
the actions `OnRecordingFailure` field if set, if it is not set
it fails open.
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This adds an initial and intentionally minimal configuration for
golang-ci, fixes the issues reported, and adds a GitHub Action to check
new pull requests against this linter configuration.
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I8f38fbc315836a19a094d0d3e986758b9313f163
There were two code paths that could fail depending on how fast
the recorder responses. This fixes that by returning the correct
error from both paths.
Fixes#7707
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Previously it would dial out using the http.DefaultClient, however that doesn't work
when tailscaled is running in userspace mode (e.g. when testing).
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Otherwise we see errors like
```
ssh-session(sess-20230322T005655-5562985593): recording: error sending recording to <addr>:80: Post "http://<addr>:80/record": context canceled
```
The ss.ctx is closed when the session closes, but we don't want to break the upload at that time. Instead we want to wait for the session to
close the writer when it finishes, which it is already doing.
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Currently we only send down recorders in first action, allow the final action
to replace them but not to drop them.
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This updates all source files to use a new standard header for copyright
and license declaration. Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.
This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.
Updates #6865
Signed-off-by: Will Norris <will@tailscale.com>
"look up" is the verb. "lookup" is a noun.
Change-Id: I81c99e12c236488690758fb5c121e7e4e1622a36
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
The //go:build syntax was introduced in Go 1.17:
https://go.dev/doc/go1.17#build-lines
gofmt has kept the +build and go:build lines in sync since
then, but enough time has passed. Time to remove them.
Done with:
perl -i -npe 's,^// \+build.*\n,,' $(git grep -l -F '+build')
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
If the username includes a suffix of +password, then we accept
password auth and just let them in like it were no auth.
This exists purely for SSH clients that get confused by seeing success
to their initial auth type "none".
Co-authored-by: Maisem Ali <maisem@tailscale.com>
Change-Id: I616d4c64d042449fb164f615012f3bae246e91ec
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This was preventing tailscaled from shutting down properly if there were
active sessions in certain states (e.g. waiting in check mode).
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This was assumed to be the fix for mosh not working, however turns out
all we really needed was the duplicate fd also introduced in the same
commit (af412e8874).
Fixes#5103
Signed-off-by: Maisem Ali <maisem@tailscale.com>
The io/ioutil package has been deprecated as of Go 1.16 [1]. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.
Reference: https://golang.org/doc/go1.16#ioutil
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
