In the initial release of Redis 6.2 setting a user to only allow pubsub access to
a specific channel, and doing ACL SAVE, resulted in an assertion when
ACL LOAD was used. This was later changed by #8723 (not yet released),
but still not properly resolved (now it errors instead of crash).
The problem is that the server that generates an ACL file, doesn't know what
would be the setting of the acl-pubsub-default config in the server that will load it.
so ACL SAVE needs to always start with resetchannels directive.
This should still be compatible with old acl files (from redis 6.0), and ones from earlier
versions of 6.2 that didn't mess with channels.
Co-authored-by: Harkrishn Patro <harkrisp@amazon.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
Background:
Redis 6.2 added ACL control for pubsub channels (#7993), which were supposed
to be permissive by default to retain compatibility with redis 6.0 ACL.
But due to a bug, only newly created users got this `acl-pubsub-default` applied,
while overwritten (updated) users got reset to `resetchannels` (denied).
Since the "default" user exists before loading the config file,
any ACL change to it, results in an update / overwrite.
So when a "default" user is loaded from config file or include ACL
file with no channels related rules, the user will not have any
permissions to any channels. But other users will have default
permissions to any channels.
When upgraded from 6.0 with config rewrite, this will lead to
"default" user channels permissions lost.
When users are loaded from include file, then call "acl load", users
will also lost channels permissions.
Similarly, the `reset` ACL rule, would have reset the user to be denied
access to any channels, ignoring `acl-pubsub-default` and breaking
compatibility with redis 6.0.
The implication of this fix is that it regains compatibility with redis 6.0,
but breaks compatibility with redis 6.2.0 and 2.0.1. e.g. after the upgrade,
the default user will regain access to pubsub channels.
Other changes:
Additionally this commit rename server.acl_pubusub_default to
server.acl_pubsub_default and fix typo in acl tests.
Add publish channel permissions check in processCommand.
processCommand didn't check publish channel permissions, so we can
queue a publish command in a transaction. But when exec the transaction,
it will fail with -NOPERM.
We also union keys/commands/channels permissions check togegher in
ACLCheckAllPerm. Remove pubsubCheckACLPermissionsOrReply in
publishCommand/subscribeCommand/psubscribeCommand. Always
check permissions in processCommand/execCommand/
luaRedisGenericCommand.
This validation was only done for sub-commands and not for commands.
These would have been valid (not produce any error)
ACL SETUSER bob +@all +client
ACL SETUSER bob +client +client
so no reason for this one to fail:
ACL SETUSER bob +client +client|id
One example why this is needed is that pfdebug wasn't part of the @hyperloglog
group and now it is. so something like:
acl setuser user1 +@hyperloglog +pfdebug|test
would have succeeded in early 6.0.x, and fail in 6.2 RC3
Co-authored-by: Harkrishn Patro <harkrisp@amazon.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
Fixes#7923.
This PR appropriates the special `&` symbol (because `@` and `*` are taken),
followed by a literal value or pattern for describing the Pub/Sub patterns that
an ACL user can interact with. It is similar to the existing key patterns
mechanism in function (additive) and implementation (copy-pasta). It also adds
the allchannels and resetchannels ACL keywords, naturally.
The default user is given allchannels permissions, whereas new users get
whatever is defined by the acl-pubsub-default configuration directive. For
backward compatibility in 6.2, the default of this directive is allchannels but
this is likely to be changed to resetchannels in the next major version for
stronger default security settings.
Unless allchannels is set for the user, channel access permissions are checked
as follows :
* Calls to both PUBLISH and SUBSCRIBE will fail unless a pattern matching the
argumentative channel name(s) exists for the user.
* Calls to PSUBSCRIBE will fail unless the pattern(s) provided as an argument
literally exist(s) in the user's list.
Such failures are logged to the ACL log.
Runtime changes to channel permissions for a user with existing subscribing
clients cause said clients to disconnect unless the new permissions permit the
connections to continue. Note, however, that PSUBSCRIBErs' patterns are matched
literally, so given the change bar:* -> b*, pattern subscribers to bar:* will be
disconnected.
Notes/questions:
* UNSUBSCRIBE, PUNSUBSCRIBE and PUBSUB remain unprotected due to lack of reasons
for touching them.
Before this commit, we would have continued to add replies to the reply buffer even if client
output buffer limit is reached, so the used memory would keep increasing over the configured limit.
What's more, we shouldn’t write any reply to the client if it is set 'CLIENT_CLOSE_ASAP' flag
because that doesn't conform to its definition and we will close all clients flagged with
'CLIENT_CLOSE_ASAP' in ‘beforeSleep’.
Because of code execution order, before this, we may firstly write to part of the replies to
the socket before disconnecting it, but in fact, we may can’t send the full replies to clients
since OS socket buffer is limited. But this unexpected behavior makes some commands work well,
for instance ACL DELUSER, if the client deletes the current user, we need to send reply to client
and close the connection, but before, we close the client firstly and write the reply to reply
buffer. secondly, we shouldn't do this despite the fact it works well in most cases.
We add a flag 'CLIENT_CLOSE_AFTER_COMMAND' to mark clients, this flag means we will close the
client after executing commands and send all entire replies, so that we can write replies to
reply buffer during executing commands, send replies to clients, and close them later.
We also fix some implicit problems. If client output buffer limit is enforced in 'multi/exec',
all commands will be executed completely in redis and clients will not read any reply instead of
partial replies. Even more, if the client executes 'ACL deluser' the using user in 'multi/exec',
it will not read the replies after 'ACL deluser' just like before executing 'client kill' itself
in 'multi/exec'.
We added some tests for output buffer limit breach during multi-exec and using a pipeline of
many small commands rather than one with big response.
Co-authored-by: Oran Agra <oran@redislabs.com>
