Some clients don't request 'none' authentication. Instead, they immediately supply
a password or public key. This change allows them to do so, but ignores the supplied
credentials and authenticates using Tailscale instead.
Updates #14922
Signed-off-by: Percy Wegmann <percy@tailscale.com>
This fork golang.org/x/crypto/ssh (at upstream x/crypto git rev e47973b1c1)
into tailscale.com/tempfork/sshtest/ssh so we can hack up the client in weird
ways to simulate other SSH clients seen in the wild.
Two changes were made to the files when they were copied from x/crypto:
* internal/poly1305 imports were replaced by the non-internal version;
no code changes otherwise. It didn't need the internal one.
* all decode-with-passphrase funcs were deleted, to avoid
using the internal package x/crypto/ssh/internal/bcrypt_pbkdf
Then the tests passed.
Updates #14969
Change-Id: Ibf1abebfe608c75fef4da0255314f65e54ce5077
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Shells on OpenBSD don't support the -l option. This means that when
handling SSH in-process, we can't give the user a login shell, but this
change at least allows connecting at all.
Updates #13338
Signed-off-by: Percy Wegmann <percy@tailscale.com>
Shells on FreeBSD don't support the -l option. This means that when
handling SSH in-process, we can't give the user a login shell, but this
change at least allows connecting at all.
Updates #13338
Signed-off-by: Percy Wegmann <percy@tailscale.com>
The upstream crypto package now supports sending banners at any time during
authentication, so the Tailscale fork of crypto/ssh is no longer necessary.
github.com/tailscale/golang-x-crypto is still needed for some custom ACME
autocert functionality.
tempfork/gliderlabs is still necessary because of a few other customizations,
mostly related to TTY handling.
Originally implemented in 46fd4e58a27495263336b86ee961ee28d8c332b7,
which was reverted in b60f6b849af1fae1cf343be98f7fb1714c9ea165 to
keep the change out of v1.80.
Updates #8593
Signed-off-by: Percy Wegmann <percy@tailscale.com>
This reverts commit 46fd4e58a27495263336b86ee961ee28d8c332b7.
We don't want to include this in 1.80 yet, but can add it back post 1.80.
Updates #8593
Signed-off-by: Percy Wegmann <percy@tailscale.com>
The upstream crypto package now supports sending banners at any time during
authentication, so the Tailscale fork of crypto/ssh is no longer necessary.
github.com/tailscale/golang-x-crypto is still needed for some custom ACME
autocert functionality.
tempfork/gliderlabs is still necessary because of a few other customizations,
mostly related to TTY handling.
Updates #8593
Signed-off-by: Percy Wegmann <percy@tailscale.com>
These erroneously blocked a recent PR, which I fixed by simply
re-running CI. But we might as well fix them anyway.
These are mostly `printf` to `print` and a couple of `!=` to `!Equal()`
Updates #cleanup
Signed-off-by: Will Norris <will@tailscale.com>
When we first made Tailscale SSH, we assumed people would want public
key support soon after. Turns out that hasn't been the case; people
love the Tailscale identity authentication and check mode.
In light of CVE-2024-45337, just remove all our public key code to not
distract people, and to make the code smaller. We can always get it
back from git if needed.
Updates tailscale/corp#25131
Updates golang/go#70779
Co-authored-by: Percy Wegmann <percy@tailscale.com>
Change-Id: I87a6e79c2215158766a81942227a18b247333c22
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
The v2 endpoint supports HTTP/2 bidirectional streaming and acks for
received bytes. This is used to detect when a recorder disappears to
more quickly terminate the session.
Updates https://github.com/tailscale/corp/issues/24023
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
This adds a new generic result type (motivated by golang/go#70084) to
try it out, and uses it in the new lineutil package (replacing the old
lineread package), changing that package to return iterators:
sometimes over []byte (when the input is all in memory), but sometimes
iterators over results of []byte, if errors might happen at runtime.
Updates #12912
Updates golang/go#70084
Change-Id: Iacdc1070e661b5fb163907b1e8b07ac7d51d3f83
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This allows passing through any environment variables that we set ourselves, for example DBUS_SESSION_BUS_ADDRESS.
Updates #11175
Co-authored-by: Mario Minardi <mario@tailscale.com>
Signed-off-by: Percy Wegmann <percy@tailscale.com>
Add logic to set environment variables that match the SSH rule's
`acceptEnv` settings in the SSH session's environment.
Updates https://github.com/tailscale/corp/issues/22775
Signed-off-by: Mario Minardi <mario@tailscale.com>
Add logic for parsing and matching against our planned format for
AcceptEnv values. Namely, this supports direct matches against string
values and matching where * and ? are treated as wildcard characters
which match against an arbitrary number of characters and a single
character respectively.
Actually using this logic in non-test code will come in subsequent
changes.
Updates https://github.com/tailscale/corp/issues/22775
Signed-off-by: Mario Minardi <mario@tailscale.com>
this commit changes usermetrics to be non-global, this is a building
block for correct metrics if a go process runs multiple tsnets or
in tests.
Updates #13420
Updates tailscale/corp#22075
Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
And update a few callers as examples of motivation. (there are a
couple others, but these are the ones where it's prettier)
Updates #cleanup
Change-Id: Ic8c5cb7af0a59c6e790a599136b591ebe16d38eb
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
In prep for updating to new staticcheck required for Go 1.23.
Updates #12912
Change-Id: If77892a023b79c6fa798f936fc80428fd4ce0673
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Instead of changing the working directory before launching the incubator process,
this now just changes the working directory after dropping privileges, at which
point we're more likely to be able to enter the user's home directory since we're
running as the user.
For paths that use the 'login' or 'su -l' commands, those already take care of changing
the working directory to the user's home directory.
Fixes#13120
Signed-off-by: Percy Wegmann <percy@tailscale.com>
This involved the following:
1. Pass the su command path as first of args in call to unix.Exec to make sure that busybox sees the correct program name.
Busybox is a single executable userspace that implements various core userspace commands in a single binary. You'll
see it used via symlinking, so that for example /bin/su symlinks to /bin/busybox. Busybox knows that you're trying
to execute /bin/su because argv[0] is '/bin/su'. When we called unix.Exec, we weren't including the program name for
argv[0], which caused busybox to fail with 'applet not found', meaning that it didn't know which command it was
supposed to run.
2. Tell su to whitelist the SSH_AUTH_SOCK environment variable in order to support ssh agent forwarding.
3. Run integration tests on alpine, which uses busybox.
4. Increment CurrentCapabilityVersion to allow turning on SSH V2 behavior from control.
Fixes#12849
Signed-off-by: Percy Wegmann <percy@tailscale.com>
cmd/k8s-operator,k8s-operator/sessionrecording,sessionrecording,ssh/tailssh: refactor session recording functionality
Refactor SSH session recording functionality (mostly the bits related to
Kubernetes API server proxy 'kubectl exec' session recording):
- move the session recording bits used by both Tailscale SSH
and the Kubernetes API server proxy into a shared sessionrecording package,
to avoid having the operator to import ssh/tailssh
- move the Kubernetes API server proxy session recording functionality
into a k8s-operator/sessionrecording package, add some abstractions
in preparation for adding support for a second streaming protocol (WebSockets)
Updates tailscale/corp#19821
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
cmd/k8s-operator,ssh/tailssh,tsnet: optionally record kubectl exec sessions
The Kubernetes operator's API server proxy, when it receives a request
for 'kubectl exec' session now reads 'RecorderAddrs', 'EnforceRecorder'
fields from tailcfg.KubernetesCapRule.
If 'RecorderAddrs' is set to one or more addresses (of a tsrecorder instance(s)),
it attempts to connect to those and sends the session contents
to the recorder before forwarding the request to the kube API
server. If connection cannot be established or fails midway,
it is only allowed if 'EnforceRecorder' is not true (fail open).
Updates tailscale/corp#19821
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
Co-authored-by: Maisem Ali <maisem@tailscale.com>
This allows the SSH_AUTH_SOCK environment variable to work inside of
su and agent forwarding to succeed.
Fixes#12467
Signed-off-by: Percy Wegmann <percy@tailscale.com>
Previously, we were registering TCP and UDP connections in the same map,
which could result in erroneously removing a mapping if one of the two
connections completes while the other one is still active.
Add a "proto string" argument to these functions to avoid this.
Additionally, take the "proto" argument in LocalAPI, and plumb that
through from the CLI and add a new LocalClient method.
Updates tailscale/corp#20600
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I35d5efaefdfbf4721e315b8ca123f0c8af9125fb
Checking in the incubator as this used to do fails because
the getenforce command is not on the PATH.
Updates #12442
Signed-off-by: Percy Wegmann <percy@tailscale.com>
This allows pam authentication to run for ssh sessions, triggering
automation like pam_mkhomedir.
Updates #11854
Signed-off-by: Percy Wegmann <percy@tailscale.com>
In prep for it being required in more places.
Updates #11874
Change-Id: Ib743205fc2a6c6ff3d2c4ed3a2b28cac79156539
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Since the tailscaled binaries that we distribute are static and don't
link cgo, we previously wouldn't fetch group IDs that are returned via
NSS. Try shelling out to the 'id' command, similar to how we call
'getent', to detect such cases.
Updates #11682
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I9bdc938bd76c71bc130d44a97cc2233064d64799
Since we already track active SSH connections, it's not hard to
proactively reject updates until those finish. We attempt to do the same
on the control side, but the detection latency for new connections is in
the minutes, which is not fast enough for common short sessions.
Handle a `force=true` query parameter to override this behavior, so that
control can still trigger an update on a server where some long-running
abandoned SSH session is open.
Updates https://github.com/tailscale/corp/issues/18556
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
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>
This package is a wrapper for os/user that handles non-cgo builds,
gokrazy and user shells.
Updates tailscale/corp#15405
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
This PR removes calls to ioutil library and replaces them
with their new locations in the io and os packages.
Fixes#9034
Updates #5210
Signed-off-by: Marwan Sulaiman <marwan@tailscale.com>
If the connection provided to sftp.NewServer is closed,
Serve returns the io.EOF error verbatim from io.Reader.Read.
This is an odd error since this is an expected situation,
so we manually ignore io.EOF.
This is somewhat buggy since the sftp package itself
incorrectly reports io.EOF in cases where it should actually
be reporting io.ErrUnexpectedEOF.
See https://github.com/pkg/sftp/pull/554 which patches Serve to
return nil on clean closes and fixes buggy uses of io.ReadFull.
Fixes#8592
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
