valkey/TLS.md
Oran Agra 4faddf18ca Build TLS as a loadable module
* Support BUILD_TLS=module to be loaded as a module via config file or
  command line. e.g. redis-server --loadmodule redis-tls.so
* Updates to redismodule.h to allow it to be used side by side with
  server.h by defining REDISMODULE_CORE_MODULE
* Changes to server.h, redismodule.h and module.c to avoid repeated
  type declarations (gcc 4.8 doesn't like these)
* Add a mechanism for non-ABI neutral modules (ones who include
  server.h) to refuse loading if they detect not being built together with
  redis (release.c)
* Fix wrong signature of RedisModuleDefragFunc, this could break
  compilation of a module, but not the ABI
* Move initialization of listeners in server.c to be after loading
  the modules
* Config TLS after initialization of listeners
* Init cluster after initialization of listeners
* Add TLS module to CI
* Fix a test suite race conditions:
  Now that the listeners are initialized later, it's not sufficient to
  wait for the PID message in the log, we need to wait for the "Server
  Initialized" message.
* Fix issues with moduleconfigs test as a result from start_server
  waiting for "Server Initialized"
* Fix issues with modules/infra test as a result of an additional module
  present

Notes about Sentinel:
Sentinel can't really rely on the tls module, since it uses hiredis to
initiate connections and depends on OpenSSL (won't be able to use any
other connection modules for that), so it was decided that when TLS is
built as a module, sentinel does not support TLS at all.
This means that it keeps using redis_tls_ctx and redis_tls_client_ctx directly.

Example code of config in redis-tls.so(may be use in the future):
RedisModuleString *tls_cfg = NULL;

void tlsInfo(RedisModuleInfoCtx *ctx, int for_crash_report) {
    UNUSED(for_crash_report);
    RedisModule_InfoAddSection(ctx, "");
    RedisModule_InfoAddFieldLongLong(ctx, "var", 42);
}

int tlsCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
{
    if (argc != 2) return RedisModule_WrongArity(ctx);
    return RedisModule_ReplyWithString(ctx, argv[1]);
}

RedisModuleString *getStringConfigCommand(const char *name, void *privdata) {
    REDISMODULE_NOT_USED(name);
    REDISMODULE_NOT_USED(privdata);
    return tls_cfg;
}

int setStringConfigCommand(const char *name, RedisModuleString *new, void *privdata, RedisModuleString **err) {
    REDISMODULE_NOT_USED(name);
    REDISMODULE_NOT_USED(err);
    REDISMODULE_NOT_USED(privdata);
    if (tls_cfg) RedisModule_FreeString(NULL, tls_cfg);
    RedisModule_RetainString(NULL, new);
    tls_cfg = new;
    return REDISMODULE_OK;
}

int RedisModule_OnLoad(void *ctx, RedisModuleString **argv, int argc)
{
    ....
    if (RedisModule_CreateCommand(ctx,"tls",tlsCommand,"",0,0,0) == REDISMODULE_ERR)
        return REDISMODULE_ERR;

    if (RedisModule_RegisterStringConfig(ctx, "cfg", "", REDISMODULE_CONFIG_DEFAULT, getStringConfigCommand, setStringConfigCommand, NULL, NULL) == REDISMODULE_ERR)
        return REDISMODULE_ERR;

    if (RedisModule_LoadConfigs(ctx) == REDISMODULE_ERR) {
        if (tls_cfg) {
            RedisModule_FreeString(ctx, tls_cfg);
            tls_cfg = NULL;
        }
        return REDISMODULE_ERR;
    }
    ...
}

Co-authored-by: zhenwei pi <pizhenwei@bytedance.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
2022-08-23 12:37:56 +03:00

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Markdown

TLS Support
===========
Getting Started
---------------
### Building
To build with TLS support you'll need OpenSSL development libraries (e.g.
libssl-dev on Debian/Ubuntu).
To build TLS support as Redis built-in:
Run `make BUILD_TLS=yes`.
Or to build TLS as Redis module:
Run `make BUILD_TLS=module`.
Note that sentinel mode does not support TLS module.
### Tests
To run Redis test suite with TLS, you'll need TLS support for TCL (i.e.
`tcl-tls` package on Debian/Ubuntu).
1. Run `./utils/gen-test-certs.sh` to generate a root CA and a server
certificate.
2. Run `./runtest --tls` or `./runtest-cluster --tls` to run Redis and Redis
Cluster tests in TLS mode.
3. Run `./runtest --tls-module` or `./runtest-cluster --tls-module` to
run Redis and Redis cluster tests in TLS mode with Redis module.
### Running manually
To manually run a Redis server with TLS mode (assuming `gen-test-certs.sh` was
invoked so sample certificates/keys are available):
For TLS built-in mode:
./src/redis-server --tls-port 6379 --port 0 \
--tls-cert-file ./tests/tls/redis.crt \
--tls-key-file ./tests/tls/redis.key \
--tls-ca-cert-file ./tests/tls/ca.crt
For TLS module mode:
./src/redis-server --tls-port 6379 --port 0 \
--tls-cert-file ./tests/tls/redis.crt \
--tls-key-file ./tests/tls/redis.key \
--tls-ca-cert-file ./tests/tls/ca.crt \
--loadmodule src/redis-tls.so
To connect to this Redis server with `redis-cli`:
./src/redis-cli --tls \
--cert ./tests/tls/redis.crt \
--key ./tests/tls/redis.key \
--cacert ./tests/tls/ca.crt
This will disable TCP and enable TLS on port 6379. It's also possible to have
both TCP and TLS available, but you'll need to assign different ports.
To make a Replica connect to the master using TLS, use `--tls-replication yes`,
and to make Redis Cluster use TLS across nodes use `--tls-cluster yes`.
Connections
-----------
All socket operations now go through a connection abstraction layer that hides
I/O and read/write event handling from the caller.
**Multi-threading I/O is not currently supported for TLS**, as a TLS connection
needs to do its own manipulation of AE events which is not thread safe. The
solution is probably to manage independent AE loops for I/O threads and longer
term association of connections with threads. This may potentially improve
overall performance as well.
Sync IO for TLS is currently implemented in a hackish way, i.e. making the
socket blocking and configuring socket-level timeout. This means the timeout
value may not be so accurate, and there would be a lot of syscall overhead.
However I believe that getting rid of syncio completely in favor of pure async
work is probably a better move than trying to fix that. For replication it would
probably not be so hard. For cluster keys migration it might be more difficult,
but there are probably other good reasons to improve that part anyway.
To-Do List
----------
- [ ] redis-benchmark support. The current implementation is a mix of using
hiredis for parsing and basic networking (establishing connections), but
directly manipulating sockets for most actions. This will need to be cleaned
up for proper TLS support. The best approach is probably to migrate to hiredis
async mode.
- [ ] redis-cli `--slave` and `--rdb` support.
Multi-port
----------
Consider the implications of allowing TLS to be configured on a separate port,
making Redis listening on multiple ports:
1. Startup banner port notification
2. Proctitle
3. How slaves announce themselves
4. Cluster bus port calculation