This reverts commit 1fd82d32e0. It causes
connection storms to snowball into a node crash via this mechanism:
1. large node suffers mild connection storm
2. password hash requests queue up on alien hash thread
3. incoming hash requests queue faster than the alien thread can retire them.
4. auth latency grows without bounds
5. this encourages the clients to create new connections
6. problem grows
Reverting the patch restores the hash stall, but at least prevents node
crashes.
Fixes#26461 (2025.1)
Closesscylladb/scylladb#26462
Analysis of customer stalls revealed that the function `detail::hash_with_salt` (invoked by `passwords::check`) often blocks the reactor. Internally, this function uses the external `crypt_r` function to compute password hashes, which is CPU-intensive.
This PR addresses the issue in two ways:
1) `sha-512` is now the only password hashing scheme for new passwords (it was already the common-case).
2) `passwords::check` is moved to a dedicated alien thread.
Regarding point 1: before this change, the following hashing schemes were supported by `identify_best_supported_scheme()`: bcrypt_y, bcrypt_a, SHA-512, SHA-256, and MD5. The reason for this was that the `crypt_r` function used for password hashing comes from an external library (currently `libxcrypt`), and the supported hashing algorithms vary depending on the library in use. However:
- The bcrypt schemes never worked properly because their prefixes lack the required round count (e.g. `$2y$` instead of `$2y$05$`). Moreover, bcrypt is slower than SHA-512, so it not good idea to fix or use it.
- SHA-256 and SHA-512 both belong to the SHA-2 family. Libraries that support one almost always support the other, so it’s very unlikely to find SHA-256 without SHA-512.
- MD5 is no longer considered secure for password hashing.
Regarding point 2: the `passwords::check` call now runs on a shared alien thread created at database startup. An `std::mutex` synchronizes that thread with the shards. In theory this could introduce a frequent lock contention, but in practice each shard handles only a few hundred new connections per second—even during storms. There is already `_conns_cpu_concurrency_semaphore` in `generic_server` limits the number of concurrent connection handlers.
Fixes https://github.com/scylladb/scylladb/issues/24524
Backport not needed, as it is a new feature.
Closesscylladb/scylladb#24924
* github.com:scylladb/scylladb:
main: utils: add thread names to alien workers
auth: move passwords::check call to alien thread
test: wait for 3 clients with given username in test_service_level_api
auth: refactor password checking in password_authenticator
auth: make SHA-512 the only password hashing scheme for new passwords
auth: whitespace change in identify_best_supported_scheme()
auth: require scheme as parameter for `generate_salt`
auth: check password hashing scheme support on authenticator start
(cherry picked from commit c762425ea7)
since we only need the full definition of boost::regex in the .cc
file, where we
- define the constructor and destructor
- and actually use the regex.
there is no need to include boost/regex.hpp in the header, in order
to keep the preprocessed header smaller. let's use a header only
contains forward declarations in header, and include the full
definition in the .cc file.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
It doesn't need it apart from a forward declaration.
Files that lost necessary includes are adjusted, and some users
of auth_version_t are redirected to the definition outside system_keyspace.
The main theme of this commit is executing drop
keyspace/table/aggregate/function statements in a single
transaction together with auth auto-revoke logic.
This is the logic which cleans related permissions after
resource is deleted.
It contains serveral parts which couldn't easily be split
into separate commits mainly because mutation collector related
paths can't be mixed together. It would require holding multiple
guards which we don't support. Another reason is that with mutation
collector the changes are announced in a single place, at the end
of statement execution, if we'd announce something in the middle
then it'd lead to raft concurrent modification infinite loop as it'd
invalidate our guard taken at the begining of statement execution.
So this commit contains:
- moving auto-revoke code to statement execution from migration_listener
* only for auth-v2 flow, to not break the old one
* it's now executed during statement execution and not merging schemas,
which means it produces mutations once as it should and not on each
node separately
* on_before callback family wasn't used because I consider it much
less readable code. Long term we want to remove
auth_migration_listener.
- adding mutation collector to revoke_all
* auto-revoke uses this function so it had to be changed,
auth::revoke_all free function wrapper was added as cql3
layer should not use underlying_authorizer() directly.
- adding mutation collector to drop_role
* because it depends on revoke_all and we can't mix old and new flows
* we need to switch all functions auth::drop_role call uses
* gradual use of previously introduced modify_membership, otherwise
we would need to switch even more code in this commit
This is done to achieve single transaction semantics.
grant_permissions_to_creator is logically part of create role
but its change will be included in following commits
as it spans multiple usages.
Additinally we disabled rollback during create role as
it won't work and is not needed with single transaction logic.
In a follow-up patch abort_source will be used
inside those methods. Current pattern is that abort_source
is passed everywhere as non const so it needs to be
executed in non const context.
Closesscylladb/scylladb#17312
Fixes#10099
Adds the com.scylladb.auth.CertificateAuthenticator type. If set as authenticator,
will extract roles from TLS authentication certificate (not wire cert - those are
server side) subject, based on configurable regex.
Example:
scylla.yaml:
authenticator: com.scylladb.auth.CertificateAuthenticator
auth_superuser_name: <name>
auth_certificate_role_queries:
- source: SUBJECT
query: CN=([^,\s]+)
client_encryption_options:
enabled: True
certificate: <server cert>
keyfile: <server key>
truststore: <shared trust>
require_client_auth: True
In a client, then use a certificate signed with the <shared trust>
store as auth cert, with the common name <name>. I.e. for cqlsh
set "usercert" and "userkey" to these certificate files.
No user/password needs to be sent, but role will be picked up
from auth certificate. If none is present, the transport will
reject the connection. If the certificate subject does not
contain a recongnized role name (from config or set in tables)
the authenticator mechanism will reject it.
Otherwise, connection becomes the role described.
