Package org.eclipse.jetty.servlets

Class DoSFilter

  • All Implemented Interfaces:
    javax.servlet.Filter
    Direct Known Subclasses:
    CloseableDoSFilter
    @ManagedObject("limits exposure to abuse from request flooding, whether malicious, or as a result of a misconfigured client")
public class DoSFilter
extends java.lang.Object
implements javax.servlet.Filter
    Denial of Service filter

    This filter is useful for limiting exposure to abuse from request flooding, whether malicious, or as a result of a misconfigured client.

    The filter keeps track of the number of requests from a connection per second. If a limit is exceeded, the request is either rejected, delayed, or throttled.

    When a request is throttled, it is placed in a queue and will only proceed when there is capacity.

    The extractUserId(ServletRequest request) function should be implemented, in order to uniquely identify authenticated users.

    The following init parameters control the behavior of the filter:

    maxRequestsPerSec
    the maximum number of requests from a connection per second. Requests in excess of this are first delayed, then throttled.
    delayMs
    is the delay given to all requests over the rate limit, before they are considered at all. -1 means just reject request, 0 means no delay, otherwise it is the delay.
    maxWaitMs
    how long to blocking wait for the throttle semaphore.
    throttledRequests
    is the number of requests over the rate limit able to be considered at once.
    throttleMs
    how long to async wait for semaphore.
    maxRequestMs
    how long to allow this request to run.
    maxIdleTrackerMs
    how long to keep track of request rates for a connection, before deciding that the user has gone away, and discarding it
    insertHeaders
    if true , insert the DoSFilter headers into the response. Defaults to true.
    remotePort
    if true then rate is tracked by IP+port (effectively connection). Defaults to false.
    ipWhitelist
    a comma-separated list of IP addresses that will not be rate limited
    managedAttr
    if set to true, then this servlet is set as a ServletContext attribute with the filter name as the attribute name. This allows context external mechanism (eg JMX via ContextHandler.MANAGED_ATTRIBUTES) to manage the configuration of the filter.
    tooManyCode
    The status code to send if there are too many requests. By default is 429 (too many requests), but 503 (Unavailable) is another option

    This filter should be configured for DispatcherType.REQUEST and DispatcherType.ASYNC and with <async-supported>true</async-supported>.

    • Field Detail

      • LOG

        private static final Logger LOG

      • IPv4_PATTERN

        private static final java.util.regex.Pattern IPv4_PATTERN

      • IPv6_PATTERN

        private static final java.util.regex.Pattern IPv6_PATTERN

      • CIDR_PATTERN

        private static final java.util.regex.Pattern CIDR_PATTERN

      • __DEFAULT_MAX_REQUESTS_PER_SEC

        private static final int __DEFAULT_MAX_REQUESTS_PER_SEC
        See Also:
        Constant Field Values

      • __DEFAULT_MAX_REQUEST_MS_INIT_PARAM

        private static final long __DEFAULT_MAX_REQUEST_MS_INIT_PARAM
        See Also:
        Constant Field Values

      • __DEFAULT_MAX_IDLE_TRACKER_MS_INIT_PARAM

        private static final long __DEFAULT_MAX_IDLE_TRACKER_MS_INIT_PARAM
        See Also:
        Constant Field Values

      • MANAGED_ATTR_INIT_PARAM

        static final java.lang.String MANAGED_ATTR_INIT_PARAM
        See Also:
        Constant Field Values

      • MAX_REQUESTS_PER_S_INIT_PARAM

        static final java.lang.String MAX_REQUESTS_PER_S_INIT_PARAM
        See Also:
        Constant Field Values

      • THROTTLED_REQUESTS_INIT_PARAM

        static final java.lang.String THROTTLED_REQUESTS_INIT_PARAM
        See Also:
        Constant Field Values

      • THROTTLE_MS_INIT_PARAM

        static final java.lang.String THROTTLE_MS_INIT_PARAM
        See Also:
        Constant Field Values

      • MAX_REQUEST_MS_INIT_PARAM

        static final java.lang.String MAX_REQUEST_MS_INIT_PARAM
        See Also:
        Constant Field Values

      • MAX_IDLE_TRACKER_MS_INIT_PARAM

        static final java.lang.String MAX_IDLE_TRACKER_MS_INIT_PARAM
        See Also:
        Constant Field Values

      • INSERT_HEADERS_INIT_PARAM

        static final java.lang.String INSERT_HEADERS_INIT_PARAM
        See Also:
        Constant Field Values

      • TRACK_SESSIONS_INIT_PARAM

        @Deprecated
static final java.lang.String TRACK_SESSIONS_INIT_PARAM
        Deprecated.
        See Also:
        Constant Field Values

      • REMOTE_PORT_INIT_PARAM

        static final java.lang.String REMOTE_PORT_INIT_PARAM
        See Also:
        Constant Field Values

      • IP_WHITELIST_INIT_PARAM

        static final java.lang.String IP_WHITELIST_INIT_PARAM
        See Also:
        Constant Field Values

      • _suspended

        private final java.lang.String _suspended

      • _resumed

        private final java.lang.String _resumed

      • _rateTrackers

        private final java.util.concurrent.ConcurrentHashMap<java.lang.String,​DoSFilter.RateTracker> _rateTrackers

      • _whitelist

        private final java.util.List<java.lang.String> _whitelist

      • _tooManyCode

        private int _tooManyCode

      • _delayMs

        private volatile long _delayMs

      • _throttleMs

        private volatile long _throttleMs

      • _maxWaitMs

        private volatile long _maxWaitMs

      • _maxRequestMs

        private volatile long _maxRequestMs

      • _maxIdleTrackerMs

        private volatile long _maxIdleTrackerMs

      • _insertHeaders

        private volatile boolean _insertHeaders

      • _remotePort

        private volatile boolean _remotePort

      • _enabled

        private volatile boolean _enabled

      • _name

        private volatile java.lang.String _name

      • _passes

        private java.util.concurrent.Semaphore _passes

      • _throttledRequests

        private volatile int _throttledRequests

      • _maxRequestsPerSec

        private volatile int _maxRequestsPerSec

      • _queue

        private final java.util.Queue<javax.servlet.AsyncContext> _queue

      • _asyncListener

        private final javax.servlet.AsyncListener _asyncListener

      • _context

        private javax.servlet.ServletContext _context

    • Constructor Detail

      • DoSFilter

        public DoSFilter()

    • Method Detail

      • init

        public void init​(javax.servlet.FilterConfig filterConfig)
          throws javax.servlet.ServletException
        Specified by:
        init in interface javax.servlet.Filter
        Throws:
        javax.servlet.ServletException

      • startScheduler

        protected Scheduler startScheduler()
                            throws javax.servlet.ServletException
        Throws:
        javax.servlet.ServletException

      • doFilter

        public void doFilter​(javax.servlet.ServletRequest request,
                     javax.servlet.ServletResponse response,
                     javax.servlet.FilterChain filterChain)
              throws java.io.IOException,
                     javax.servlet.ServletException
        Specified by:
        doFilter in interface javax.servlet.Filter
        Throws:
        java.io.IOException
        javax.servlet.ServletException

      • doFilter

        protected void doFilter​(javax.servlet.http.HttpServletRequest request,
                        javax.servlet.http.HttpServletResponse response,
                        javax.servlet.FilterChain filterChain)
                 throws java.io.IOException,
                        javax.servlet.ServletException
        Throws:
        java.io.IOException
        javax.servlet.ServletException

      • throttleRequest

        private void throttleRequest​(javax.servlet.http.HttpServletRequest request,
                             javax.servlet.http.HttpServletResponse response,
                             javax.servlet.FilterChain filterChain,
                             DoSFilter.RateTracker tracker)
                      throws java.io.IOException,
                             javax.servlet.ServletException
        Throws:
        java.io.IOException
        javax.servlet.ServletException

      • doFilterChain

        protected void doFilterChain​(javax.servlet.FilterChain chain,
                             javax.servlet.http.HttpServletRequest request,
                             javax.servlet.http.HttpServletResponse response)
                      throws java.io.IOException,
                             javax.servlet.ServletException
        Throws:
        java.io.IOException
        javax.servlet.ServletException

      • onRequestTimeout

        protected void onRequestTimeout​(javax.servlet.http.HttpServletRequest request,
                                javax.servlet.http.HttpServletResponse response,
                                java.lang.Thread handlingThread)
        Invoked when the request handling exceeds getMaxRequestMs().

        By default, an HTTP 503 response is returned and the handling thread is interrupted.

        Parameters:
        request - the current request
        response - the current response
        handlingThread - the handling thread

      • closeConnection

        @Deprecated
protected void closeConnection​(javax.servlet.http.HttpServletRequest request,
                               javax.servlet.http.HttpServletResponse response,
                               java.lang.Thread thread)
        Deprecated.
        use onRequestTimeout(HttpServletRequest, HttpServletResponse, Thread) instead
        Parameters:
        request - the current request
        response - the current response
        thread - the handling thread

      • getMaxPriority

        @Deprecated
protected DoSFilter.RateType getMaxPriority()
        Deprecated.
        Priority no longer supported
        Returns:
        null

      • getRateTracker

        DoSFilter.RateTracker getRateTracker​(javax.servlet.ServletRequest request)
        Return a request rate tracker associated with this connection; keeps track of this connection's request rate. If this is not the first request from this connection, return the existing object with the stored stats. If it is the first request, then create a new request tracker.

        Assumes that each connection has an identifying characteristic, and goes through them in order, taking the first that matches: user id (logged in), client IP address. Unidentifiable connections are lumped into one.

        Parameters:
        request - the current request
        Returns:
        the request rate tracker for the current connection

      • removeFromRateTracker

        public void removeFromRateTracker​(java.lang.String id)

      • checkWhitelist

        protected boolean checkWhitelist​(java.lang.String candidate)

      • checkWhitelist

        @Deprecated
protected boolean checkWhitelist​(java.util.List<java.lang.String> whitelist,
                                 java.lang.String candidate)
        Deprecated.

      • subnetMatch

        protected boolean subnetMatch​(java.lang.String subnetAddress,
                              java.lang.String address)

      • addressToBytes

        private byte[] addressToBytes​(java.lang.String address)

      • prefixToBytes

        private byte[] prefixToBytes​(int prefix,
                             int length)

      • destroy

        public void destroy()
        Specified by:
        destroy in interface javax.servlet.Filter

      • stopScheduler

        protected void stopScheduler()

      • extractUserId

        @Deprecated
protected java.lang.String extractUserId​(javax.servlet.ServletRequest request)
        Deprecated.
        User ID no longer supported
        Parameters:
        request - ignored
        Returns:
        null

      • getMaxRequestsPerSec

        @ManagedAttribute("maximum number of requests allowed from a connection per second")
public int getMaxRequestsPerSec()
        Get maximum number of requests from a connection per second. Requests in excess of this are first delayed, then throttled.
        Returns:
        maximum number of requests

      • setMaxRequestsPerSec

        public void setMaxRequestsPerSec​(int value)
        Get maximum number of requests from a connection per second. Requests in excess of this are first delayed, then throttled.
        Parameters:
        value - maximum number of requests

      • getDelayMs

        @ManagedAttribute("delay applied to all requests over the rate limit (in ms)")
public long getDelayMs()
        Get delay (in milliseconds) that is applied to all requests over the rate limit, before they are considered at all.
        Returns:
        the delay in milliseconds

      • setDelayMs

        public void setDelayMs​(long value)
        Set delay (in milliseconds) that is applied to all requests over the rate limit, before they are considered at all.
        Parameters:
        value - delay (in milliseconds), 0 - no delay, -1 - reject request

      • getMaxWaitMs

        @ManagedAttribute("maximum time the filter will block waiting throttled connections, (0 for no delay, -1 to reject requests)")
public long getMaxWaitMs()
        Get maximum amount of time (in milliseconds) the filter will blocking wait for the throttle semaphore.
        Returns:
        maximum wait time

      • setMaxWaitMs

        public void setMaxWaitMs​(long value)
        Set maximum amount of time (in milliseconds) the filter will blocking wait for the throttle semaphore.
        Parameters:
        value - maximum wait time

      • getThrottledRequests

        @ManagedAttribute("number of requests over rate limit")
public int getThrottledRequests()
        Get number of requests over the rate limit able to be considered at once.
        Returns:
        number of requests

      • setThrottledRequests

        public void setThrottledRequests​(int value)
        Set number of requests over the rate limit able to be considered at once.
        Parameters:
        value - number of requests

      • getThrottleMs

        @ManagedAttribute("amount of time to async wait for semaphore")
public long getThrottleMs()
        Get amount of time (in milliseconds) to async wait for semaphore.
        Returns:
        wait time

      • setThrottleMs

        public void setThrottleMs​(long value)
        Set amount of time (in milliseconds) to async wait for semaphore.
        Parameters:
        value - wait time

      • getMaxRequestMs

        @ManagedAttribute("maximum time to allow requests to process (in ms)")
public long getMaxRequestMs()
        Get maximum amount of time (in milliseconds) to allow the request to process.
        Returns:
        maximum processing time

      • setMaxRequestMs

        public void setMaxRequestMs​(long value)
        Set maximum amount of time (in milliseconds) to allow the request to process.
        Parameters:
        value - maximum processing time

      • getMaxIdleTrackerMs

        @ManagedAttribute("maximum time to track of request rates for connection before discarding")
public long getMaxIdleTrackerMs()
        Get maximum amount of time (in milliseconds) to keep track of request rates for a connection, before deciding that the user has gone away, and discarding it.
        Returns:
        maximum tracking time

      • setMaxIdleTrackerMs

        public void setMaxIdleTrackerMs​(long value)
        Set maximum amount of time (in milliseconds) to keep track of request rates for a connection, before deciding that the user has gone away, and discarding it.
        Parameters:
        value - maximum tracking time

      • getName

        public java.lang.String getName()
        The unique name of the filter when there is more than one DosFilter instance.
        Returns:
        the name

      • setName

        public void setName​(java.lang.String name)
        Parameters:
        name - the name to set

      • isInsertHeaders

        @ManagedAttribute("inser DoSFilter headers in response")
public boolean isInsertHeaders()
        Check flag to insert the DoSFilter headers into the response.
        Returns:
        value of the flag

      • setInsertHeaders

        public void setInsertHeaders​(boolean value)
        Set flag to insert the DoSFilter headers into the response.
        Parameters:
        value - value of the flag

      • isTrackSessions

        @Deprecated
public boolean isTrackSessions()
        Deprecated.
        Session tracking is no longer supported
        Get flag to have usage rate tracked by session if a session exists.
        Returns:
        value of the flag

      • setTrackSessions

        @Deprecated
public void setTrackSessions​(boolean value)
        Deprecated.
        Session tracking is no longer supported
        Set flag to have usage rate tracked by session if a session exists.
        Parameters:
        value - value of the flag

      • isRemotePort

        @ManagedAttribute("usage rate is tracked by IP+port is session tracking not used")
public boolean isRemotePort()
        Get flag to have usage rate tracked by IP+port (effectively connection)
        Returns:
        value of the flag

      • setRemotePort

        public void setRemotePort​(boolean value)
        Set flag to have usage rate tracked by IP+port (effectively connection)
        Parameters:
        value - value of the flag

      • isEnabled

        @ManagedAttribute("whether this filter is enabled")
public boolean isEnabled()
        Returns:
        whether this filter is enabled

      • setEnabled

        public void setEnabled​(boolean enabled)
        Parameters:
        enabled - whether this filter is enabled

      • getTooManyCode

        public int getTooManyCode()
        Status code for Rejected for too many requests.
        Returns:
        the configured status code (default: 429 - Too Many Requests)

      • setTooManyCode

        public void setTooManyCode​(int tooManyCode)

      • getWhitelist

        @ManagedAttribute("list of IPs that will not be rate limited")
public java.lang.String getWhitelist()
        Get a list of IP addresses that will not be rate limited.
        Returns:
        comma-separated whitelist

      • setWhitelist

        public void setWhitelist​(java.lang.String commaSeparatedList)
        Set a list of IP addresses that will not be rate limited.
        Parameters:
        commaSeparatedList - comma-separated whitelist

      • clearWhitelist

        @ManagedOperation("clears the list of IP addresses that will not be rate limited")
public void clearWhitelist()
        Clears the list of whitelisted IP addresses

      • addWhitelistAddress

        @ManagedOperation("adds an IP address that will not be rate limited")
public boolean addWhitelistAddress​(@Name("address")
                                   java.lang.String address)
        Adds the given IP address, either in the form of a dotted decimal notation A.B.C.D or in the CIDR notation A.B.C.D/M, to the list of whitelisted IP addresses.
        Parameters:
        address - the address to add
        Returns:
        whether the address was added to the list
        See Also:
        removeWhitelistAddress(String)

      • addWhitelistAddress

        private boolean addWhitelistAddress​(java.util.List<java.lang.String> list,
                                    java.lang.String address)

      • removeWhitelistAddress

        @ManagedOperation("removes an IP address that will not be rate limited")
public boolean removeWhitelistAddress​(@Name("address")
                                      java.lang.String address)
        Removes the given address from the list of whitelisted IP addresses.
        Parameters:
        address - the address to remove
        Returns:
        whether the address was removed from the list
        See Also:
        addWhitelistAddress(String)

      • createRemotePortId

        private java.lang.String createRemotePortId​(javax.servlet.ServletRequest request)