At a high level, it switches us to a distroless base container image, but that also includes several related bits:
- Add a writable /tmp but make the rest of our filesystems read-only at runtime.
- Condense our main server binaries into a single pinniped-server binary. This saves a bunch of space in
the image due to duplicated library code. The correct behavior is dispatched based on `os.Args[0]`, and
the `pinniped-server` binary is symlinked to `pinniped-concierge` and `pinniped-supervisor`.
- Strip debug symbols from our binaries. These aren't really useful in a distroless image anyway and all the
normal stuff you'd expect to work, such as stack traces, still does.
- Add a separate `pinniped-concierge-kube-cert-agent` binary with "sleep" and "print" functionality instead of
using builtin /bin/sleep and /bin/cat for the kube-cert-agent. This is split from the main server binary
because the loading/init time of the main server binary was too large for the tiny resource footprint we
established in our kube-cert-agent PodSpec. Using a separate binary eliminates this issue and the extra
binary adds only around 1.5MiB of image size.
- Switch the kube-cert-agent code to use a JSON `{"tls.crt": "<b64 cert>", "tls.key": "<b64 key>"}` format.
This is more robust to unexpected input formatting than the old code, which simply concatenated the files
with some extra newlines and split on whitespace.
- Update integration tests that made now-invalid assumptions about the `pinniped-server` image.
Signed-off-by: Matt Moyer <moyerm@vmware.com>
This change updates the impersonator to always authorize every
request instead of relying on the Kuberentes API server to perform
the check on the impersonated request. This protects us from
scenarios where we fail to correctly impersonate the user due to
some bug in our proxy logic. We still rely completely on the API
server to perform admission checks on the impersonated requests.
Signed-off-by: Monis Khan <mok@vmware.com>
This change updates the impersonation proxy code to run as a
distinct service account that only has permission to impersonate
identities. Thus any future vulnerability that causes the
impersonation headers to be dropped will fail closed instead of
escalating to the concierge's default service account which has
significantly more permissions.
Signed-off-by: Monis Khan <mok@vmware.com>
WithImpersonation already deletes impersonation headers and has done
so since the early days:
https://github.com/kubernetes/kubernetes/pull/36769
ensureNoImpersonationHeaders will still reject any request that has
impersonation headers set so we will always fail closed.
Signed-off-by: Monis Khan <mok@vmware.com>
When anonymous authentication is disabled, the impersonation proxy
will no longer authenticate anonymous requests other than calls to
the token credential request API (this API is used to retrieve
credentials and thus must be accessed anonymously).
Signed-off-by: Benjamin A. Petersen <ben@benjaminapetersen.me>
Signed-off-by: Monis Khan <mok@vmware.com>
This change updates the impersonator logic to pass through requests
that authenticated via a bearer token that asserts a UID. This
allows us to support service account tokens (as well as any other
form of token based authentication).
Signed-off-by: Monis Khan <mok@vmware.com>
This change updates the impersonator logic to use the delegated
authorizer for all non-rest verbs such as impersonate. This allows
it to correctly perform authorization checks for incoming requests
that set impersonation headers while not performing unnecessary
checks that are already handled by KAS.
The audit layer is enabled to track the original user who made the
request. This information is then included in a reserved extra
field original-user-info.impersonation-proxy.concierge.pinniped.dev
as a JSON blob.
Signed-off-by: Monis Khan <mok@vmware.com>
Instead of using the LongRunningFunc to determine if we can safely
use http2, follow the same logic as the aggregation proxy and only
use http2 when the request is not an upgrade.
Signed-off-by: Monis Khan <mok@vmware.com>
When the frontend connection to our proxy is closed, the proxy falls through to
a panic(), which means the HTTP handler goroutine is killed, so we were not
seeing this log statement.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
We were previously issuing both client certs and server certs with
both extended key usages included. Split the Issue*() methods into
separate methods for issuing server certs versus client certs so
they can have different extended key usages tailored for each use
case.
Also took the opportunity to clean up the parameters of the Issue*()
methods and New() methods to more closely match how we prefer to call
them. We were always only passing the common name part of the
pkix.Name to New(), so now the New() method just takes the common name
as a string. When making a server cert, we don't need to set the
deprecated common name field, so remove that param. When making a client
cert, we're always making it in the format expected by the Kube API
server, so just accept the username and group as parameters directly.
The impersonator_test.go unit test now starts the impersonation
server and makes real HTTP requests against it using client-go.
It is backed by a fake Kube API server.
The CA IssuePEM() method was missing the argument to allow a slice
of IP addresses to be passed in.
To make an impersonation request, first make a TokenCredentialRequest
to get a certificate. That cert will either be issued by the Kube
API server's CA or by a new CA specific to the impersonator. Either
way, you can then make a request to the impersonator and present
that client cert for auth and the impersonator will accept it and
make the impesonation call on your behalf.
The impersonator http handler now borrows some Kube library code
to handle request processing. This will allow us to more closely
mimic the behavior of a real API server, e.g. the client cert
auth will work exactly like the real API server.
Signed-off-by: Monis Khan <mok@vmware.com>
Also:
- Changed base64 encoding of impersonator bearer tokens to use
`base64.StdEncoding` to make it easier for users to manually
create a token using the unix `base64` command
- Test the headers which are and are not passed through to the Kube API
by the impersonator more carefully in the unit tests
- More WIP on concierge_impersonation_proxy_test.go
Signed-off-by: Margo Crawford <margaretc@vmware.com>
This change adds a new virtual aggregated API that can be used by
any user to echo back who they are currently authenticated as. This
has general utility to end users and can be used in tests to
validate if authentication was successful.
Signed-off-by: Monis Khan <mok@vmware.com>
If someone has already set impersonation headers in their request, then
we should fail loudly so the client knows that its existing impersonation
headers will not work.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
