Commit Graph

185 Commits (1f8eea53a873030bc19a8d8e57f2e4014160c01c)

Author SHA1 Message Date
Maisem Ali be190e990f ssh/tailssh: restore support for recording locally
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>
2 years ago
Tom DNetto c5bf868940 ssh/tailssh: improve debug logging around revoked sessions
Updates https://github.com/tailscale/corp/issues/10943
Signed-off-by: Tom DNetto <tom@tailscale.com>
2 years ago
Maisem Ali 1b8a0dfe5e ssh/tailssh: also handle recording upload failure during writes
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>
2 years ago
Maisem Ali 7778d708a6 ssh/tailssh: handle dialing multiple recorders and failing open
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>
2 years ago
Andrew Dunham 280255acae
various: add golangci-lint, fix issues (#7905)
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
2 years ago
Maisem Ali d42d570066
ssh/tailssh: handle output matching better in tests (#7799) 2 years ago
Brad Fitzpatrick 2c0bda6e2e ssh/tailssh: make Tailscale SSH work on gokrazy
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali e04acabfde ssh/tailssh: fix race in errors returned when starting recorder
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>
2 years ago
Maisem Ali 5ba57e4661 ssh/tailssh: add tests for recording failure
Updates tailscale/corp#9967

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 09d0b632d4 ssh/tailssh: add session recording test for non-pty sessions
Updates tailscale/corp#9967

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 583e86b7df ssh/tailssh: handle session recording when running in userspace mode
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>
2 years ago
Maisem Ali 8a246487c2 ssh/tailssh: enable recording of non-pty sessions
Updates tailscale/corp#9967

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 8765568373 ssh/tailssh: add docs to CastHeader fields
Updates tailscale/corp#9967

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Will Norris 57a008a1e1 all: pass log IDs as the proper type rather than strings
This change focuses on the backend log ID, which is the mostly commonly
used in the client.  Tests which don't seem to make use of the log ID
just use the zero value.

Signed-off-by: Will Norris <will@tailscale.com>
2 years ago
Andrew Dunham 13377e6458 ssh/tailssh: always assert our final uid/gid
Move the assertions about our post-privilege-drop UID/GID out of the
conditional if statement and always run them; I haven't been able to
find a case where this would fail. Defensively add an envknob to disable
this feature, however, which we can remove after the 1.40 release.

Updates #7616

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Iaec3dba9248131920204bd6c6d34bbc57a148185
2 years ago
Andrew Dunham 9de8287d47 ssh/tailssh: lock OS thread during incubator
This makes it less likely that we trip over bugs like golang/go#1435.

Updates #7616

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ic28c03c3ad8ed5274a795c766b767fa876029f0e
2 years ago
Maisem Ali c350cd1f06 ssh/tailssh: use background context for uploading recordings
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>
2 years ago
Maisem Ali d92047cc30 ssh/tailssh: allow recorders to be configured on the first or final action
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>
2 years ago
Maisem Ali 7a97e64ef0 ssh/tailssh: add more metadata to recording header
Updates tailscale/corp#9967

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 916aa782af ssh/tailssh: stream SSH recordings to configured recorders
Updates tailscale/corp#9967

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Andrew Dunham 39b289578e ssh/tailssh: make uid an int instead of uint64
Follow-up to #7615

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ib4256bff276f6d5cf95838d8e39c87b3643bde37
2 years ago
Andrew Dunham ccace1f7df ssh/tailssh: fix privilege dropping on FreeBSD; add tests
On FreeBSD and Darwin, changing a process's supplementary groups with
setgroups(2) will also change the egid of the process, setting it to the
first entry in the provided list. This is distinct from the behaviour on
other platforms (and possibly a violation of the POSIX standard).

Because of this, on FreeBSD with no TTY, our incubator code would
previously not change the process's gid, because it would read the
newly-changed egid, compare it against the expected egid, and since they
matched, not change the gid. Because we didn't use the 'login' program
on FreeBSD without a TTY, this would propagate to a child process.

This could be observed by running "id -p" in two contexts. The expected
output, and the output returned when running from a SSH shell, is:

    andrew@freebsd:~ $ id -p
    uid         andrew
    groups      andrew

However, when run via "ssh andrew@freebsd id -p", the output would be:

    $ ssh andrew@freebsd id -p
    login       root
    uid         andrew
    rgid        wheel
    groups      andrew

(this could also be observed via "id -g -r" to print just the gid)

We fix this by pulling the details of privilege dropping out into their
own function and prepending the expected gid to the start of the list on
Darwin and FreeBSD.

Finally, we add some tests that run a child process, drop privileges,
and assert that the final UID/GID/additional groups are what we expect.

More information can be found in the following article:
    https://www.usenix.org/system/files/login/articles/325-tsafrir.pdf

Updates #7616
Alternative to #7609

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I0e6513c31b121108b50fe561c89e5816d84a45b9
2 years ago
Maisem Ali 223713d4a1 tailcfg,all: add and use Node.IsTagged()
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali e69682678f ssh/tailssh: use context.WithCancelCause
It was using a custom implmentation of the context.WithCancelCause,
replace usage with stdlib.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 0582829e00 ssh/tailssh: try launching commands with /usr/bin/login on macOS
Updates #4939

Co-authored-by: Adam Eijdenberg <adam@continusec.com>
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 5787989d74 ssh/tailssh: detect user shell correctly on darwin
Updates #6213

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Brad Fitzpatrick b1248442c3 all: update to Go 1.20, use strings.CutPrefix/Suffix instead of our fork
Updates #7123
Updates #5309

Change-Id: I90bcd87a2fb85a91834a0dd4be6e03db08438672
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali 04b57a371e ipn/ipnlocal: drop not required StateKey parameter
This is #cleanup now that #7121 is merged.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 5bba65e978 net/memnet: rename from net/nettest
This is just #cleanup to resolve a TODO

Also add a package doc.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Will Norris 71029cea2d all: update copyright and license headers
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>
2 years ago
Brad Fitzpatrick 1116602d4c ssh/tailssh: add OpenBSD support for Tailscale SSH
And bump go.mod for https://github.com/u-root/u-root/pull/2593

Change-Id: I36ec94c5b2b76d671cb739f1e9a1a43ca1d9d1b1
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick be67b8e75b ssh/tailssh: fix Tailscale SSH to non-root tailscaled
Fix regression from 337c77964b where
tailscaled started calling Setgroups. Prior to that, SSH to a non-root
tailscaled was working.

Instead, ignore any failure calling Setgroups if the groups are
already correct.

Fixes #6888

Change-Id: I561991ddb37eaf2620759c6bcaabd36e0fb2a22d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 8047dfa2dc ssh/tailssh: unify some of the incubator_* GOOS files into incubator.go
In prep for fix for #6888

Change-Id: I79f780c6467a9b7ac03017b27d412d6b0d2f7e6b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 84eaef0bbb ssh/tailssh: don't swallow process exit code in be-child
Thanks to @nshalman and @Soypete for debugging!

Updates #6054

Change-Id: I74550cc31f8a257b37351b8152634c768e1e0a8a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick f837d179b9 ssh/tailssh: fix typo in error message
"look up" is the verb. "lookup" is a noun.

Change-Id: I81c99e12c236488690758fb5c121e7e4e1622a36
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 651e0d8aad ssh/tailssh: add envknob for default PATH
As backup plan, just in case the earlier fix's logic wasn't correct
and we want to experiment in the field or have users have a quicker
fix.

Updates #5285

Change-Id: I7447466374d11f8f609de6dfbc4d9a944770826d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 56f7da0cfd
ssh/tailssh: set default Tailscale SSH $PATH for non-interactive commands
Fixes #5285

Co-authored-by: Andrew Dunham <andrew@tailscale.com>
Change-Id: Ic7e967bf6a53b056cac5f21dd39565d9c31563af
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali 2d653230ef ssh/tailssh: only call CloseWrite when both stdout and stderr are done
Updates #5209

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 4d330bac14 ipn/ipnlocal: add support for multiple user profiles
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Pat Maddox 9bf3ef4167 ssh/tailssh: add Tailscale SSH (server) support on FreeBSD
Change-Id: I607194b6ef99205e777f3df93a74ffe1a2e0344c
Signed-off-by: Pat Maddox <pat@ratiopbc.com>
2 years ago
Brad Fitzpatrick da8def8e13 all: remove old +build tags
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>
2 years ago
Maisem Ali 1440742a1c ssh/tailssh: use root / as cmd.Dir when users HomeDir doesn't exist
Fixes #5224

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Brad Fitzpatrick e24de8a617 ssh/tailssh: add password-forcing workaround for buggy SSH clients
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>
2 years ago
Emmanuel T Odeke 680f8d9793 all: fix more resource leaks found by staticmajor
Updates #5706

Signed-off-by: Emmanuel T Odeke <emmanuel@orijtech.com>
2 years ago
Maisem Ali f172fc42f7 ssh/tailssh: close sshContext on context cancellation
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>
2 years ago
Maisem Ali 4de1601ef4 ssh/tailssh: add support for sending multiple banners
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali ecf6cdd830 ssh/tailssh: add TestSSHAuthFlow
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali f16b77de5d ssh/tailssh: do the full auth flow during ssh auth
Fixes #5091

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali b84ec521bf ssh/tailssh: do not send EOT on session disconnection
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>
2 years ago
Brad Fitzpatrick b1bd96f114 go.mod, ssh/tailssh: fix ImplictAuthMethod typo
Fixes #5745

Change-Id: Ie8bc88bd465a9cb35b0ae7782d61ce96480473ee
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Josh Soref d4811f11a0 all: fix spelling mistakes
Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>
2 years ago
Eng Zer Jun f0347e841f refactor: move from io/ioutil to io and os packages
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>
2 years ago
Brad Fitzpatrick 74674b110d envknob: support changing envknobs post-init
Updates #5114

Change-Id: Ia423fc7486e1b3f3180a26308278be0086fae49b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 4950fe60bd syncs, all: move to using Go's new atomic types instead of ours
Fixes #5185

Change-Id: I850dd532559af78c3895e2924f8237ccc328449d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 8725b14056 all: migrate more code code to net/netip directly
Instead of going through the tailscale.com/net/netaddr transitional
wrappers.

Updates #5162

Change-Id: I3dafd1c2effa1a6caa9b7151ecf6edd1a3fda3dd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali 02a765743e ssh/tailssh: fix deadlock in expandDelegateURL
Also rename it to expandDelegateURLLocked, previously it was trying
to acquire the mutex while holding the mutex.

Fixes #5235

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Brad Fitzpatrick a12aad6b47 all: convert more code to use net/netip directly
perl -i -npe 's,netaddr.IPPrefixFrom,netip.PrefixFrom,' $(git grep -l -F netaddr.)
    perl -i -npe 's,netaddr.IPPortFrom,netip.AddrPortFrom,' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPrefix,netip.Prefix,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPort,netip.AddrPort,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IP\b,netip.Addr,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPv6Raw\b,netip.AddrFrom16,g' $(git grep -l -F netaddr. )
    goimports -w .

Then delete some stuff from the net/netaddr shim package which is no
longer neeed.

Updates #5162

Change-Id: Ia7a86893fe21c7e3ee1ec823e8aba288d4566cd8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 6a396731eb all: use various net/netip parse funcs directly
Mechanical change with perl+goimports.

Changed {Must,}Parse{IP,IPPrefix,IPPort} to their netip variants, then
goimports -d .

Finally, removed the net/netaddr wrappers, to prevent future use.

Updates #5162

Change-Id: I59c0e38b5fbca5a935d701645789cddf3d7863ad
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 7eaf5e509f net/netaddr: start migrating to net/netip via new netaddr adapter package
Updates #5162

Change-Id: Id7bdec303b25471f69d542f8ce43805328d56c12
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali 3e06b9ea7a ssh/tailssh: add "ssh" to conn logs
Fixes #5089

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 480fd6c797 ssh/tailssh: handle not-authenticated-yet connections in matchRule
Also make more fields in conn.info thread safe, there was previously a
data race here.

Fixes #5110

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali af412e8874 ssh/tailssh: better handling of signals and exits
We were not handling errors occurred while copying data between the subprocess and the connection.
This makes it so that we pass the appropriate signals when to the process and the connection.

This also fixes mosh.

Updates #4919

Co-authored-by: James Tucker <raggi@tailscale.com>
Co-authored-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Brad Fitzpatrick 3b1f99ded1 ssh/tailssh: fix Tailscale SSH to Linux Arch machines
See https://github.com/tailscale/tailscale/issues/4924#issuecomment-1168201823

Arch uses a different login binary that makes the -h flag set the PAM
service to "remote". So if they don't have that configured, don't pass -h.

Thanks to @eddiezane for debugging!

Updates #4924

Change-Id: I8d33e0afb2dfb99517bcea2f9d5d0c6247519b3c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali 40503ef07a ssh/tailssh: fix logging typo
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali c434e47f2d ssh/tailssh: always use current time for policy evaluation
Whenever the SSH policy changes we revaluate all open connections to
make sure they still have access. This check was using the wrong
timestamp and would match against expired policies, however this really
isn't a problem today as we don't have policy that would be impacted by
this check. Fixing it for future use.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali a7d2024e35 ssh/tailssh: allow multiple sessions on the same conn
Fixes #4920
Fixes tailscale/corp#5633
Updates #4479

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Adam Eijdenberg 9294a14a37 ssh/tailssh: limit setgroups to 16 on macOS
Fixes #4938

Signed-off-by: Adam Eijdenberg <adam@continusec.com>
2 years ago
Adam Eijdenberg 7f807fef6c ssh/tailssh: fix /usr/bin/login args on macOS
Fixes #4931

Signed-off-by: Adam Eijdenberg <adam@continusec.com>
2 years ago
Brad Fitzpatrick e428bba7a3 ssh/tailssh: add metrics
Updates #3802

Change-Id: Ic9a4b8c51cff6dfe148a1c78bc0e5074195b7f80
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Maisem Ali 928530a112 ipn/ipnlocal: shutdown sshServer on tailscale down
Also lazify SSHServer initialization to allow restarting the server on a
subsequent `tailscale up`

Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Maisem Ali 575aacb1e2 ssh/tailssh: terminate sessions on stdout copy failures
Currently, killing a SCP copy with a Ctrl+C leaves the session hanging
even though the stdout copy goroutine fails with an io.EOF. Taking a
step back, when we are unable to send any more data back to the client
we should just terminate the session as the client will stop getting any
response from the server anyways.

Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Maisem Ali 7cd8c3e839 ssh/tailssh: terminate sessions when tailscaled shutsdown
Ideally we would re-establish these sessions when tailscaled comes back
up, however we do not do that yet so this is better than leaking the
sessions.

Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Maisem Ali 760740905e ssh/tailssh: only use `login` with TTY sessions
Otherwise, the shell exits immediately causing applications like mosh
and VSCode to fail.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Maisem Ali 5cd56fe8d5 ssh/tailssh: exec into `login` when launching a shell
This has the added benefit of displaying the MOTD and reducing our
dependency on the DBus interface.

Fixes #4627
Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Maisem Ali a253057fc3 ssh/tailssh: refactor incubator flags
Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Brad Fitzpatrick c1445155ef ssh/tailssh: handle Control-C during hold-and-delegate prompt
Fixes #4549

Change-Id: Iafc61af5e08cd03564d39cf667e940b2417714cc
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Maisem Ali 3012a2e1ca ssh/tailssh,ipn/ipnlocal: terminate any active sessions on `up --ssh=false`
Currently the ssh session isn't terminated cleanly, instead the packets
are just are no longer routed to the in-proc SSH server. This makes it
so that clients get a disconnection when the `RunSSH` pref changes to
`false`.

Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Brad Fitzpatrick 910ae68e0b util/mak: move tailssh's mapSet into a new package for reuse elsewhere
Change-Id: Idfe95db82275fd2be6ca88f245830731a0d5aecf
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
James Tucker c2eff20008 ssh/tailssh: avoid user ssh configuration in tests
Signed-off-by: James Tucker <james@tailscale.com>
3 years ago
David Anderson a364bf2b62 ssh/tailssh: various typo fixes, clarifications.
Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Brad Fitzpatrick c994eba763 ssh/tailssh: simplify matchRule with Reject rules
Updates #3802

Change-Id: I59fe111eef5ac8abbcbcec922e293712a65a4830
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Maisem Ali 31094d557b ssh/tailssh: chmod the auth socket to be only user accessible
Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Maisem Ali 337c77964b ssh/tailssh: set groups and gid in the incubated process
Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Brad Fitzpatrick 8ac4d52b59 ssh/tailssh: filter accepted environment variables
Noted by @danderson

Updates #3802

Change-Id: Iac70717ed57f11726209ac1ea93ddc6696605f94
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 89832c1a95 tailcfg: fix typo in SessionDuration field name
Noted by @danderson.

Updates #3802

Change-Id: Ide15f3f28e30f6abb5c94d7dcd218bd9482752a0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Maisem Ali 695f8a1d7e ssh/tailssh: add support for sftp
Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Brad Fitzpatrick 5b4154342e ssh/tailssh: fix double SSH-2.0- prefix in greeting banner
gliderlabs/ssh was already adding the "SSH-2.0-" prefix.

Updates #3802

Change-Id: I19a1cd9308371a2898e7883cf26e94c9b54bab29
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Maisem Ali 2b8b887d55 ssh/tailssh: send banner messages during auth, move more to conn
(VSCode Live Share between Brad & Maisem!)

Updates #3802

Change-Id: Id8edca4481b0811debfdf56d4ccb1a46f71dd6d3
Co-Authored-By: Brad Fitzpatrick <bradfitz@tailscale.com>
Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Brad Fitzpatrick f74ee80abe ssh/tailssh: support expansions in public key fetch URL too
Updates #3802

Change-Id: I5aa98bdab14fd1c1c00ba63b93f8d7e670f72437
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Maisem Ali 14d077fc3a ssh/tailssh: terminate ssh auth early if no policy can match
Also bump github.com/tailscale/golang-x-crypto/ssh

Updates #3802

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Brad Fitzpatrick 8b81254992 ipn/ipnlocal: reject tailscale up --ssh if disabled on tailnet
Updates #3802

Change-Id: I3f1e839391fe9b28270f506f4bb8d8e3d36716f5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Maisem Ali 91a187bf87 ssh/tailssh: make checkStillValid also consider username changes
Currently if the policy changes and the session is logged in with local
user "u1" and the new policy says they can only login with "u2" now, the
user doesn't get kicked out because they had requested
`rando@<ssh-host>` and the defaulting had made that go to `u1`.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Brad Fitzpatrick 93221b4535 ssh/tailssh: cache public keys fetched from URLs
Updates #3802

Change-Id: I96715bae02bce6ea19f16b1736d1bbcd7bcf3534
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick ade7bd8745 ssh/tailssh: close sessions on policy change if no longer allowed
Updates #3802

Change-Id: I98503c2505b77ac9d0cc792614fcdb691761a70c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 8ee044ea4a ssh/tailssh: make the SSH server a singleton, register with LocalBackend
Remove the weird netstack -> tailssh dependency and instead have tailssh
register itself with ipnlocal when linked.

This makes tailssh.server a singleton, so we can have a global map of
all sessions.

Updates #3802

Change-Id: Iad5caec3a26a33011796878ab66b8e7b49339f29
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick da14e024a8 tailcfg, ssh/tailssh: optionally support SSH public keys in wire policy
And clean up logging.

Updates #3802

Change-Id: I756dc2d579a16757537142283d791f1d0319f4f0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 3d180c0376 go.mod, ssh/tailssh, tempfork/gliderlabs: bump x/crypto/ssh fork for NoClientAuthCallback
Prep for evaluating SSHPolicy earlier to decide whether certs are
required, which requires knowing the target SSH user.

Updates #3802

Change-Id: I2753ec8069e7f19c9121300d0fb0813c1c627c36
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 5a44f9f5b5 tempfork: temporarily fork gliderlabs/ssh and x/crypto/ssh
While we rearrange/upstream things.

gliderlabs/ssh is forked into tempfork from our prior fork
at be8b7add40

x/crypto/ssh OTOH is forked at
https://github.com/tailscale/golang-x-crypto because it was gnarlier
to vendor with various internal packages, etc.
Its git history shows where it starts (2c7772ba30643b7a2026cbea938420dce7c6384d).

Updates #3802

Change-Id: I546e5cdf831cfc030a6c42557c0ad2c58766c65f
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 0861923c21 ssh/tailssh, tailcfg: add more HoldAndDelegate expansions, document
Updates #3802

Change-Id: I447f06b49e2a917bffe36881d0634c9195085512
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 091ea4a4a5 ssh/tailssh: support placeholders in SSHAction.HoldAndDelegate URL
Updates #3802

Change-Id: I60f9827409d14fd4f4824d102ba11db49bf0d365
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago