Before this change, `saslauthd_authenticator` prevented dropping
roles. The current documentation instructs users to `Ensure Scylla has
the same users and roles as listed in the LDAP directory`. Therefore,
ScyllaDB should allow dropping roles so administrators can remove
obsolete roles from both LDAP and ScyllaDB.
The code change is minimal — dropping a role is a no-op, similar to the
existing no-op implementations for successful `create` and `alter`
operations.
`saslauthd_authenticator_test` is updated to verify that dropping
a role doesn't throw anymore.
Fixes: scylladb/scylladb#25571Closesscylladb/scylladb#25574
Analysis of customer stalls showed that the `detail::hash_with_salt`
function, called from `passwords::check`, often blocks the reactor.
This function internally uses the `crypt_r` function from an external
library to compute password hashes, which is a CPU-intensive operation.
To prevent such reactor stalls, this commit moves the
`passwords::check` call to a dedicated alien thread. This thread is
created at system startup and is shared by all shards.
Within the alien thread, an `std::mutex` synchronizes access between
the thread and the shards. While this could theoretically cause
frequent lock contentions, in practice, even during connection storms,
the number of new connections per second per shard is limited
(typically hundreds per second). Additionally, the
`_conns_cpu_concurrency_semaphore` in `generic_server` ensures that not
too many connections are processed at once.
Fixesscylladb/scylladb#24524
This PR extends authentication with 2 mechanisms:
- a new role_manager subclass, which allows managing users via
LDAP server,
- a new authenticator, which delegates plaintext authentication
to a running saslauthd daemon.
The features have been ported from the enterprise repository
with their test.py tests and the documentation as part of
changing license to source available.
Fixes: scylladb/scylla-enterprise#5000Fixes: scylladb/scylla-enterprise#5001Closesscylladb/scylladb#22030
