AT-AT needs to maintain a key-value CRL cache where each key is the DER
byte-string of the issuer and the value is a dictionary of the CRL file
path and expiration. This way when it checks a client certificate, it
can load the correct CRL by comparing the issuers. This is preferable to
loading all of the CRLs in-memory. However, it still requires that AT-AT
load and parse each CRL when the application boots. Because of the size
of the CRLs and their parsed, in-memory size, this leads to the
application spiking to use nearly 900MB of memory (resting usage is
around 50MB).
This change introduces a small function to ad-hoc parse the CRL and
obtain the information in the CRL we need: the issuer and the
expiration. It does this by reading the CRL byte-by-byte until it
reaches the ASN1 sequence that corresponds to the issuer, and then looks
ahead to find the nextUpdate field (i.e., the expiration date). The
CRLCache class uses this function to build its cache and JSON-serializes
the cache to disk. If another AT-AT application process finds the
serialized version, it will load that copy instead of rebuilding it. It
also entails a change to the function signature for the init method of
CRLCache: now it expects the CRL directory as its second argument,
instead of a list of locations.
The Python script invoked by `script/sync-crls` will rebuild the
location cache each time it's run. This means that when the Kubernetes
CronJob for CRLs runs, it will refresh the cache each time. When a new
application container boots, it will get the refreshed cache.
This also adds a nightly CircleCI job to sync the CRLs and test that the
ad-hoc parsing function returns the same result as a proper parsing
using the Python cryptography library. This provides extra insurance
that the function is returning correct results on real data.
- detect-secrets was previously bumped to 0.13 but the baseline file was
not updated.
- mypy objects to the way the Azure Subscription type was defined. Since
the module is encapsulated for dependency injection, we can either
declare it as a generic or remove the type hint. I did the latter,
since I don't know that we gain anything by the former.
This will allow us to force SSL connections to the database in
production by setting two values:
- PGSSLMODE should be set to "verify-full". This forces the client to
verify the server against a known CA: https://www.postgresql.org/docs/10/libpq-ssl.html
- PGSSLROOTCERT should be set to the path of the public cert for the
relevant CA.
When the database connection is made, these values are passed to the
adapter. For local development, PGSSLMODE is set to "prefer" and
PGSSLROOTCERT is left unset.
Kubernetes config has been added to maintain the root CAs for both Azure
and AWS as k8s ConfigMap objects. These are mounted into the containers
and referenced by PGSSLROOTCERT in the container environment.
The Celery worker cannot render URLs for the app without having a
SERVER_NAME value set. AT-AT's ability to send notifications when an
environment is ready is broken as a result.
This commit sets a null default value for SERVER_NAME in the default
config file. A setting must exist in the INI file in order to be
over-written by an environment variable, which is why we declare it as
null here. There is an additional kwarg, "allow_no_value", that must be
passed to ConfigParser to allow null values.
This also applies the correct domains as SERVER_NAME environment
variables in the Kubernetes ConfigMaps for the AWS and Azure Celery
workers.
