/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cassandra.service;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.atomic.AtomicLong;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.auth.*;
import org.apache.cassandra.config.Config;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.config.Schema;
import org.apache.cassandra.cql3.QueryHandler;
import org.apache.cassandra.cql3.QueryProcessor;
import org.apache.cassandra.cql3.functions.Function;
import org.apache.cassandra.db.SystemKeyspace;
import org.apache.cassandra.exceptions.AuthenticationException;
import org.apache.cassandra.exceptions.InvalidRequestException;
import org.apache.cassandra.exceptions.UnauthorizedException;
import org.apache.cassandra.schema.SchemaKeyspace;
import org.apache.cassandra.thrift.ThriftValidation;
import org.apache.cassandra.tracing.TraceKeyspace;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.JVMStabilityInspector;
import org.apache.cassandra.utils.CassandraVersion;
/**
* State related to a client connection.
*/
public class ClientState
{
private static final Logger logger = LoggerFactory.getLogger(ClientState.class);
public static final CassandraVersion DEFAULT_CQL_VERSION = org.apache.cassandra.cql3.QueryProcessor.CQL_VERSION;
private static final Set<IResource> READABLE_SYSTEM_RESOURCES = new HashSet<>();
private static final Set<IResource> PROTECTED_AUTH_RESOURCES = new HashSet<>();
private static final Set<String> ALTERABLE_SYSTEM_KEYSPACES = new HashSet<>();
private static final Set<IResource> DROPPABLE_SYSTEM_TABLES = new HashSet<>();
static
{
// We want these system cfs to be always readable to authenticated users since many tools rely on them
// (nodetool, cqlsh, bulkloader, etc.)
for (String cf : Arrays.asList(SystemKeyspace.LOCAL, SystemKeyspace.PEERS))
READABLE_SYSTEM_RESOURCES.add(DataResource.table(SystemKeyspace.NAME, cf));
SchemaKeyspace.ALL.forEach(table -> READABLE_SYSTEM_RESOURCES.add(DataResource.table(SchemaKeyspace.NAME, table)));
if (!Config.isClientMode())
{
PROTECTED_AUTH_RESOURCES.addAll(DatabaseDescriptor.getAuthenticator().protectedResources());
PROTECTED_AUTH_RESOURCES.addAll(DatabaseDescriptor.getAuthorizer().protectedResources());
PROTECTED_AUTH_RESOURCES.addAll(DatabaseDescriptor.getRoleManager().protectedResources());
}
// allow users with sufficient privileges to alter KS level options on AUTH_KS and
// TRACING_KS, and also to drop legacy tables (users, credentials, permissions) from
// AUTH_KS
ALTERABLE_SYSTEM_KEYSPACES.add(AuthKeyspace.NAME);
ALTERABLE_SYSTEM_KEYSPACES.add(TraceKeyspace.NAME);
DROPPABLE_SYSTEM_TABLES.add(DataResource.table(AuthKeyspace.NAME, PasswordAuthenticator.LEGACY_CREDENTIALS_TABLE));
DROPPABLE_SYSTEM_TABLES.add(DataResource.table(AuthKeyspace.NAME, CassandraRoleManager.LEGACY_USERS_TABLE));
DROPPABLE_SYSTEM_TABLES.add(DataResource.table(AuthKeyspace.NAME, CassandraAuthorizer.USER_PERMISSIONS));
}
// Current user for the session
private volatile AuthenticatedUser user;
private volatile String keyspace;
private static final QueryHandler cqlQueryHandler;
static
{
QueryHandler handler = QueryProcessor.instance;
String customHandlerClass = System.getProperty("cassandra.custom_query_handler_class");
if (customHandlerClass != null)
{
try
{
handler = FBUtilities.construct(customHandlerClass, "QueryHandler");
logger.info("Using {} as query handler for native protocol queries (as requested with -Dcassandra.custom_query_handler_class)", customHandlerClass);
}
catch (Exception e)
{
JVMStabilityInspector.inspectThrowable(e);
logger.info("Cannot use class {} as query handler ({}), ignoring by defaulting on normal query handling", customHandlerClass, e.getMessage());
}
}
cqlQueryHandler = handler;
}
// isInternal is used to mark ClientState as used by some internal component
// that should have an ability to modify system keyspace.
public final boolean isInternal;
// The remote address of the client - null for internal clients.
private final InetSocketAddress remoteAddress;
// The biggest timestamp that was returned by getTimestamp/assigned to a query. This is global to ensure that the
// timestamp assigned are strictly monotonic on a node, which is likely what user expect intuitively (more likely,
// most new user will intuitively expect timestamp to be strictly monotonic cluster-wise, but while that last part
// is unrealistic expectation, doing it node-wise is easy).
private static final AtomicLong lastTimestampMicros = new AtomicLong(0);
/**
* Construct a new, empty ClientState for internal calls.
*/
private ClientState()
{
this.isInternal = true;
this.remoteAddress = null;
}
protected ClientState(InetSocketAddress remoteAddress)
{
this.isInternal = false;
this.remoteAddress = remoteAddress;
if (!DatabaseDescriptor.getAuthenticator().requireAuthentication())
this.user = AuthenticatedUser.ANONYMOUS_USER;
}
/**
* @return a ClientState object for internal C* calls (not limited by any kind of auth).
*/
public static ClientState forInternalCalls()
{
return new ClientState();
}
/**
* @return a ClientState object for external clients (thrift/native protocol users).
*/
public static ClientState forExternalCalls(SocketAddress remoteAddress)
{
return new ClientState((InetSocketAddress)remoteAddress);
}
/**
* This clock guarantees that updates for the same ClientState will be ordered
* in the sequence seen, even if multiple updates happen in the same millisecond.
*/
public long getTimestamp()
{
while (true)
{
long current = System.currentTimeMillis() * 1000;
long last = lastTimestampMicros.get();
long tstamp = last >= current ? last + 1 : current;
if (lastTimestampMicros.compareAndSet(last, tstamp))
return tstamp;
}
}
/**
* Returns a timestamp suitable for paxos given the timestamp of the last known commit (or in progress update).
* <p>
* Paxos ensures that the timestamp it uses for commits respects the serial order of those commits. It does so
* by having each replica reject any proposal whose timestamp is not strictly greater than the last proposal it
* accepted. So in practice, which timestamp we use for a given proposal doesn't affect correctness but it does
* affect the chance of making progress (if we pick a timestamp lower than what has been proposed before, our
* new proposal will just get rejected).
* <p>
* As during the prepared phase replica send us the last propose they accepted, a first option would be to take
* the maximum of those last accepted proposal timestamp plus 1 (and use a default value, say 0, if it's the
* first known proposal for the partition). This would most work (giving commits the timestamp 0, 1, 2, ...
* in the order they are commited) up to 2 important caveats:
* 1) it would give a very poor experience when Paxos and non-Paxos updates are mixed in the same partition,
* since paxos operations wouldn't be using microseconds timestamps. And while you shouldn't theoretically
* mix the 2 kind of operations, this would still be pretty unintuitive. And what if you started writing
* normal updates and realize later you should switch to Paxos to enforce a property you want?
* 2) this wouldn't actually be safe due to the expiration set on the Paxos state table.
* <p>
* So instead, we initially chose to use the current time in microseconds as for normal update. Which works in
* general but mean that clock skew creates unavailability periods for Paxos updates (either a node has his clock
* in the past and he may no be able to get commit accepted until its clock catch up, or a node has his clock in
* the future and then once one of its commit his accepted, other nodes ones won't be until they catch up). This
* is ok for small clock skew (few ms) but can be pretty bad for large one.
* <p>
* Hence our current solution: we mix both approaches. That is, we compare the timestamp of the last known
* accepted proposal and the local time. If the local time is greater, we use it, thus keeping paxos timestamps
* locked to the current time in general (making mixing Paxos and non-Paxos more friendly, and behaving correctly
* when the paxos state expire (as long as your maximum clock skew is lower than the Paxos state expiration
* time)). Otherwise (the local time is lower than the last proposal, meaning that this last proposal was done
* with a clock in the future compared to the local one), we use the last proposal timestamp plus 1, ensuring
* progress.
*
* @param minTimestampToUse the max timestamp of the last proposal accepted by replica having responded
* to the prepare phase of the paxos round this is for. In practice, that's the minimum timestamp this method
* may return.
* @return a timestamp suitable for a Paxos proposal (using the reasoning described above). Note that
* contrarily to the {@link #getTimestamp()} method, the return value is not guaranteed to be unique (nor
* monotonic) across calls since it can return it's argument (so if the same argument is passed multiple times,
* it may be returned multiple times). Note that we still ensure Paxos "ballot" are unique (for different
* proposal) by (securely) randomizing the non-timestamp part of the UUID.
*/
public long getTimestampForPaxos(long minTimestampToUse)
{
while (true)
{
long current = Math.max(System.currentTimeMillis() * 1000, minTimestampToUse);
long last = lastTimestampMicros.get();
long tstamp = last >= current ? last + 1 : current;
// Note that if we ended up picking minTimestampMicrosToUse (it was "in the future"), we don't
// want to change the local clock, otherwise a single node in the future could corrupt the clock
// of all nodes and for all inserts (since non-paxos inserts also use lastTimestampMicros).
// See CASSANDRA-11991
if (tstamp == minTimestampToUse || lastTimestampMicros.compareAndSet(last, tstamp))
return tstamp;
}
}
public static QueryHandler getCQLQueryHandler()
{
return cqlQueryHandler;
}
public InetSocketAddress getRemoteAddress()
{
return remoteAddress;
}
public String getRawKeyspace()
{
return keyspace;
}
public String getKeyspace() throws InvalidRequestException
{
if (keyspace == null)
throw new InvalidRequestException("No keyspace has been specified. USE a keyspace, or explicitly specify keyspace.tablename");
return keyspace;
}
public void setKeyspace(String ks) throws InvalidRequestException
{
// Skip keyspace validation for non-authenticated users. Apparently, some client libraries
// call set_keyspace() before calling login(), and we have to handle that.
if (user != null && Schema.instance.getKSMetaData(ks) == null)
throw new InvalidRequestException("Keyspace '" + ks + "' does not exist");
keyspace = ks;
}
/**
* Attempts to login the given user.
*/
public void login(AuthenticatedUser user) throws AuthenticationException
{
// Login privilege is not inherited via granted roles, so just
// verify that the role with the credentials that were actually
// supplied has it
if (user.isAnonymous() || DatabaseDescriptor.getRoleManager().canLogin(user.getPrimaryRole()))
this.user = user;
else
throw new AuthenticationException(String.format("%s is not permitted to log in", user.getName()));
}
public void hasAllKeyspacesAccess(Permission perm) throws UnauthorizedException
{
if (isInternal)
return;
validateLogin();
ensureHasPermission(perm, DataResource.root());
}
public void hasKeyspaceAccess(String keyspace, Permission perm) throws UnauthorizedException, InvalidRequestException
{
hasAccess(keyspace, perm, DataResource.keyspace(keyspace));
}
public void hasColumnFamilyAccess(String keyspace, String columnFamily, Permission perm)
throws UnauthorizedException, InvalidRequestException
{
ThriftValidation.validateColumnFamily(keyspace, columnFamily);
hasAccess(keyspace, perm, DataResource.table(keyspace, columnFamily));
}
private void hasAccess(String keyspace, Permission perm, DataResource resource)
throws UnauthorizedException, InvalidRequestException
{
validateKeyspace(keyspace);
if (isInternal)
return;
validateLogin();
preventSystemKSSchemaModification(keyspace, resource, perm);
if ((perm == Permission.SELECT) && READABLE_SYSTEM_RESOURCES.contains(resource))
return;
if (PROTECTED_AUTH_RESOURCES.contains(resource))
if ((perm == Permission.CREATE) || (perm == Permission.ALTER) || (perm == Permission.DROP))
throw new UnauthorizedException(String.format("%s schema is protected", resource));
ensureHasPermission(perm, resource);
}
public void ensureHasPermission(Permission perm, IResource resource) throws UnauthorizedException
{
if (DatabaseDescriptor.getAuthorizer() instanceof AllowAllAuthorizer)
return;
// Access to built in functions is unrestricted
if(resource instanceof FunctionResource && resource.hasParent())
if (((FunctionResource)resource).getKeyspace().equals(SystemKeyspace.NAME))
return;
checkPermissionOnResourceChain(perm, resource);
}
// Convenience method called from checkAccess method of CQLStatement
// Also avoids needlessly creating lots of FunctionResource objects
public void ensureHasPermission(Permission permission, Function function)
{
// Save creating a FunctionResource is we don't need to
if (DatabaseDescriptor.getAuthorizer() instanceof AllowAllAuthorizer)
return;
// built in functions are always available to all
if (function.isNative())
return;
checkPermissionOnResourceChain(permission, FunctionResource.function(function.name().keyspace,
function.name().name,
function.argTypes()));
}
private void checkPermissionOnResourceChain(Permission perm, IResource resource)
{
for (IResource r : Resources.chain(resource))
if (authorize(r).contains(perm))
return;
throw new UnauthorizedException(String.format("User %s has no %s permission on %s or any of its parents",
user.getName(),
perm,
resource));
}
private void preventSystemKSSchemaModification(String keyspace, DataResource resource, Permission perm) throws UnauthorizedException
{
// we only care about schema modification.
if (!((perm == Permission.ALTER) || (perm == Permission.DROP) || (perm == Permission.CREATE)))
return;
// prevent system keyspace modification
if (Schema.isSystemKeyspace(keyspace))
throw new UnauthorizedException(keyspace + " keyspace is not user-modifiable.");
// allow users with sufficient privileges to alter KS level options on AUTH_KS and
// TRACING_KS, and also to drop legacy tables (users, credentials, permissions) from
// AUTH_KS
if (ALTERABLE_SYSTEM_KEYSPACES.contains(resource.getKeyspace().toLowerCase())
&& ((perm == Permission.ALTER && !resource.isKeyspaceLevel())
|| (perm == Permission.DROP && !DROPPABLE_SYSTEM_TABLES.contains(resource))))
{
throw new UnauthorizedException(String.format("Cannot %s %s", perm, resource));
}
}
public void validateLogin() throws UnauthorizedException
{
if (user == null)
throw new UnauthorizedException("You have not logged in");
}
public void ensureNotAnonymous() throws UnauthorizedException
{
validateLogin();
if (user.isAnonymous())
throw new UnauthorizedException("You have to be logged in and not anonymous to perform this request");
}
public void ensureIsSuper(String message) throws UnauthorizedException
{
if (DatabaseDescriptor.getAuthenticator().requireAuthentication() && (user == null || !user.isSuper()))
throw new UnauthorizedException(message);
}
private static void validateKeyspace(String keyspace) throws InvalidRequestException
{
if (keyspace == null)
throw new InvalidRequestException("You have not set a keyspace for this session");
}
public AuthenticatedUser getUser()
{
return user;
}
public static CassandraVersion[] getCQLSupportedVersion()
{
return new CassandraVersion[]{ QueryProcessor.CQL_VERSION };
}
private Set<Permission> authorize(IResource resource)
{
return user.getPermissions(resource);
}
}