Introduce limits to prevent unauthorized users from exhausting all
ephemeral ports on agents:
* `{https,rpc}_handshake_timeout`
* `{http,rpc}_max_conns_per_client`
The handshake timeout closes connections that have not completed the TLS
handshake by the deadline (5s by default). For RPC connections this
timeout also separately applies to first byte being read so RPC
connections with TLS enabled have `rpc_handshake_time * 2` as their
deadline.
The connection limit per client prevents a single remote TCP peer from
exhausting all ephemeral ports. The default is 100, but can be lowered
to a minimum of 26. Since streaming RPC connections create a new TCP
connection (until MultiplexV2 is used), 20 connections are reserved for
Raft and non-streaming RPCs to prevent connection exhaustion due to
streaming RPCs.
All limits are configurable and may be disabled by setting them to `0`.
This also includes a fix that closes connections that attempt to create
TLS RPC connections recursively. While only users with valid mTLS
certificates could perform such an operation, it was added as a
safeguard to prevent programming errors before they could cause resource
exhaustion.
Passes in agent enable_debug config to nomad server and client configs.
This allows for rpc endpoints to have more granular control if they
should be enabled or not in combination with ACLs.
enable debug on client test
Adds new package that can be used by client and server RPC endpoints to
facilitate monitoring based off of a logger
clean up old code
small comment about write
rm old comment about minsize
rename to Monitor
Removes connection logic from monitor command
Keep connection logic in endpoints, use a channel to send results from
monitoring
use new multisink logger and interfaces
small test for dropped messages
update go-hclogger and update sink/intercept logger interfaces
* Allow server TLS configuration to be reloaded via SIGHUP
* dynamic tls reloading for nomad agents
* code cleanup and refactoring
* ensure keyloader is initialized, add comments
* allow downgrading from TLS
* initalize keyloader if necessary
* integration test for tls reload
* fix up test to assert success on reloaded TLS configuration
* failure in loading a new TLS config should remain at current
Reload only the config if agent is already using TLS
* reload agent configuration before specific server/client
lock keyloader before loading/caching a new certificate
* introduce a get-or-set method for keyloader
* fixups from code review
* fix up linting errors
* fixups from code review
* add lock for config updates; improve copy of tls config
* GetCertificate only reloads certificates dynamically for the server
* config updates/copies should be on agent
* improve http integration test
* simplify agent reloading storing a local copy of config
* reuse the same keyloader when reloading
* Test that server and client get reloaded but keep keyloader
* Keyloader exposes GetClientCertificate as well for outgoing connections
* Fix spelling
* correct changelog style
Fixes#2525
We used to be checking a RequireTLS field that was never set. Instead we
can just check the TLSConfig.EnableRPC field and require TLS if it's
enabled.
Added a few unfortunately slow integration tests to assert the intended
behavior of misconfigured RPC TLS.
Also disable a lot of noisy test logging when -v isn't specified.
