Re-evaluate authenticated connections on policy updates and at session
and forwarding gates. Close connections whose grants are revoked or
narrowed, including forwarding permissions, user identity, duration,
AcceptEnv, and effective recording requirements. Recheck rule-derived
AcceptEnv and recording configuration for delegated connections too.
Compare recorder lists with duplicate counts preserved so duplicate
entries cannot hide a change of recording destination.
Treat recording-failure changes in either direction as material,
including fail-open to fail-closed transitions. An inconclusive user
lookup retains the previous identity but does not skip other policy
checks, including for `"*": "="` mappings. An absent account or a changed
username, UID, or primary GID revokes the connection.
Preserve explicit getent failures when the os/user fallback cannot find
the account, instead of treating every lookup failure as account deletion.
Numeric UID mappings use LookupId in the fallback, not Lookup by name.
Known limitation: NSS can report a directory-only account as not found
(getent exit status 2) during an sssd/LDAP outage. If the fallback also
reports the account missing, this is indistinguishable from deletion and
still revokes the connection. This availability tradeoff remains accepted
for now; explicit command failures, timeouts, and malformed output do not
by themselves establish that an account was deleted.
Reject forwarding requests using the latched Allow bit before doing a
policy recheck. Forwarding gates still re-evaluate policy, but use the
latched account identity rather than spawning getent for every forwarded
connection (including each SSH -D request). Account identity is rechecked
at authentication completion, policy updates, rule expiry, and session
gates.
Re-arm rule-expiry timers under the policy recheck lock and prevent
re-arming after teardown. Add connection-level login grace, extending
it during delegation and stopping it only on SSH authentication
success, not on unsigned key queries or partial authentication.
Close the raw transport and cancel delegated authentication on teardown.
Add regression tests for these transitions, wait for the auth-completion
recheck before test policy flips, and release stalled recorder handlers
even on test failure.
Updates tailscale/corp#50380
Signed-off-by: James Tucker <james@tailscale.com>
An NSS uid like "00" passed the string != "0" check but parses to 0 in
the incubator, so a session could bypass non-root checks and run as
root. Compare the uid numerically instead; non-numeric uids keep the
previous behavior.
Updates tailscale/corp#50380
Signed-off-by: James Tucker <james@tailscale.com>
Before invoking 'id -Gz <user>', apply the same input validation as the
getent path (checkGetentInput), so a crafted username like '-u' can't be
interpreted as an option by the id command.
parseGetentUser now rejects multi-line (multiple or corrupted records)
output and validates the username and shell fields (no leading dashes,
control characters, or invalid UTF-8), the fields that are used to look
up and run a session. Also add the missing leading-dash regression test
for the 'id' call path.
The passwd format has no escaping — gecos sub-fields are comma-separated
— so an eighth colon-separated field means a stray colon in some field,
shifting every field after it: home parses as a gecos fragment and the
shell as the real home directory. Short records keep the existing
treatment (padded, with the default-shell fallback); over-long records
now fail closed like the other corrupt-output cases.
Updates tailscale/corp#50380
Signed-off-by: James Tucker <james@tailscale.com>
Users on FreeBSD run into a similar problem as has been reported for
Linux #11682 and fixed in #11682: because the tailscaled binaries
that we distribute are static and don't link cgo tailscaled fails to
fetch group IDs that are returned via NSS when spawning an ssh child
process.
This change extends the fallback on the 'id' command that was put in
place as part of #11682 to FreeBSD. More precisely, we try to fetch
the group IDs with the 'id' command first, and only if that fails do
we fall back on the logic in the os/user package.
Updates #14025
Signed-off-by: Gesa Stupperich <gesa@tailscale.com>
This file was never truly necessary and has never actually been used in
the history of Tailscale's open source releases.
A Brief History of AUTHORS files
---
The AUTHORS file was a pattern developed at Google, originally for
Chromium, then adopted by Go and a bunch of other projects. The problem
was that Chromium originally had a copyright line only recognizing
Google as the copyright holder. Because Google (and most open source
projects) do not require copyright assignemnt for contributions, each
contributor maintains their copyright. Some large corporate contributors
then tried to add their own name to the copyright line in the LICENSE
file or in file headers. This quickly becomes unwieldy, and puts a
tremendous burden on anyone building on top of Chromium, since the
license requires that they keep all copyright lines intact.
The compromise was to create an AUTHORS file that would list all of the
copyright holders. The LICENSE file and source file headers would then
include that list by reference, listing the copyright holder as "The
Chromium Authors".
This also become cumbersome to simply keep the file up to date with a
high rate of new contributors. Plus it's not always obvious who the
copyright holder is. Sometimes it is the individual making the
contribution, but many times it may be their employer. There is no way
for the proejct maintainer to know.
Eventually, Google changed their policy to no longer recommend trying to
keep the AUTHORS file up to date proactively, and instead to only add to
it when requested: https://opensource.google/docs/releasing/authors.
They are also clear that:
> Adding contributors to the AUTHORS file is entirely within the
> project's discretion and has no implications for copyright ownership.
It was primarily added to appease a small number of large contributors
that insisted that they be recognized as copyright holders (which was
entirely their right to do). But it's not truly necessary, and not even
the most accurate way of identifying contributors and/or copyright
holders.
In practice, we've never added anyone to our AUTHORS file. It only lists
Tailscale, so it's not really serving any purpose. It also causes
confusion because Tailscalars put the "Tailscale Inc & AUTHORS" header
in other open source repos which don't actually have an AUTHORS file, so
it's ambiguous what that means.
Instead, we just acknowledge that the contributors to Tailscale (whoever
they are) are copyright holders for their individual contributions. We
also have the benefit of using the DCO (developercertificate.org) which
provides some additional certification of their right to make the
contribution.
The source file changes were purely mechanical with:
git ls-files | xargs sed -i -e 's/\(Tailscale Inc &\) AUTHORS/\1 contributors/g'
Updates #cleanup
Change-Id: Ia101a4a3005adb9118051b3416f5a64a4a45987d
Signed-off-by: Will Norris <will@tailscale.com>
All wasi* are GOARCH wasm, so check that instead.
Updates #12732
Change-Id: Id3cc346295c1641bcf80a6c5eb1ad65488509656
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Remove the restriction that getent is skipped on non-Linux unixes.
Improve validation of the parsed output from getent, in case unknown
systems return unusable information.
Fixes#12730.
Signed-off-by: Ross Williams <ross@ross-williams.net>
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
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>
James Tucker