SocketPermission JDK 1.6)

Description

publicfinal class SocketPermission

This class represents access to a network via sockets.

This class represents access to a network via sockets. A SocketPermission consists of a host specification and a set of "actions" specifying ways to connect to that host. The host is specified as

    host = (hostname | IPv4address | iPv6reference) [:portrange]
    portrange = portnumber | -portnumber | portnumber-[portnumber]

The host is expressed as a DNS name, as a numerical IP address, or as "localhost" (for the local machine). The wildcard "*" may be included once in a DNS name host specification. If it is included, it must be in the leftmost position, as in "*.sun.com".

The format of the IPv6reference should follow that specified in RFC 2732: Format for Literal IPv6 Addresses in URLs:

    ipv6reference = "[" IPv6address "]"

For example, you can construct a SocketPermission instance as the following:

    String hostAddress = inetaddress.getHostAddress();
    if (inetaddress instanceof Inet6Address) {
        sp = new SocketPermission("[" + hostAddress + "]:" + port, action);
    } else {
        sp = new SocketPermission(hostAddress + ":" + port, action);
    }

    String host = url.getHost();
    sp = new SocketPermission(host + ":" + port, action);

The full uncompressed form of an IPv6 literal address is also valid.

The port or portrange is optional. A port specification of the form "N-", where N is a port number, signifies all ports numbered N and above, while a specification of the form "-N" indicates all ports numbered N and below.

The possible ways to connect to the host are

 accept
 connect
 listen
 resolve

The "listen" action is only meaningful when used with "localhost". The "resolve" action is implied when any of the other actions are present. The action "resolve" refers to host/ip name service lookups.

As an example of the creation and meaning of SocketPermissions, note that if the following permission:

   p1 = new SocketPermission("puffin.eng.sun.com:7777", "connect,accept");

is granted to some code, it allows that code to connect to port 7777 on puffin.eng.sun.com, and to accept connections on that port.

Similarly, if the following permission:

   p1 = new SocketPermission("puffin.eng.sun.com:7777", "connect,accept");
   p2 = new SocketPermission("localhost:1024-", "accept,connect,listen");

is granted to some code, it allows that code to accept connections on, connect to, or listen on any port between 1024 and 65535 on the local host.

Note: Granting code permission to accept or make connections to remote hosts may be dangerous because malevolent code can then more easily transfer and share confidential data among parties who may not otherwise have access to the data.

See also: Permissions SocketPermission

Constructors

pack-private SocketPermission (String host, int mask)

public SocketPermission (String host, String action)

Creates a new SocketPermission object with the specified actions.

Creates a new SocketPermission object with the specified actions. The host is expressed as a DNS name, or as a numerical IP address. Optionally, a port or a portrange may be supplied (separated from the DNS name or IP address by a colon).

To specify the local machine, use "localhost" as the host. Also note: An empty host String ("") is equivalent to "localhost".

The actions parameter contains a comma-separated list of the actions granted for the specified host (and port(s)). Possible actions are "connect", "listen", "accept", "resolve", or any combination of those. "resolve" is automatically added when any of the other three are specified.

Examples of SocketPermission instantiation are the following:

    nr = new SocketPermission("www.catalog.com", "connect");
    nr = new SocketPermission("www.sun.com:80", "connect");
    nr = new SocketPermission("*.sun.com", "connect");
    nr = new SocketPermission("*.edu", "resolve");
    nr = new SocketPermission("204.160.241.0", "connect");
    nr = new SocketPermission("localhost:1024-65535", "listen");
    nr = new SocketPermission("204.160.241.0:1024-65535", "connect");

Parameters:
- host - the hostname or IPaddress of the computer, optionally including a colon followed by a port or port range.
- action - the action string.

Methods

Hide/Show inherited methods

public void checkGuard (Object object) throws SecurityException [Inherited From Permission]

Implements the guard interface for a permission.

Implements the guard interface for a permission. The
SecurityManager.checkPermission method is called,
passing this permission object as the permission to check.
Returns silently if access is granted. Otherwise, throws
a SecurityException.
Parameters:
- object - the object being guarded (currently ignored).
Throws:
- SecurityException - if a security manager exists and its checkPermission method doesn't allow access.
See Also: Guard, GuardedObject, SecurityManager.checkPermission(java.security.Permission),

public boolean equals (Object obj) [Specified in Permission]

Checks two SocketPermission objects for equality.

public String getActions () [Specified in Permission]

Returns the canonical string representation of the actions.

pack-private void getCanonName () throws UnknownHostException

attempt to get the fully qualified domain name

pack-private void getIP () throws UnknownHostException

get IP addresses.

pack-private int getMask ()

Return the current action mask.

publicfinal String getName () [Inherited From Permission]

Returns the name of this Permission.

Returns the name of this Permission.
For example, in the case of a java.io.FilePermission,
the name will be a pathname.
Returns: the name of this Permission.

public int hashCode () [Specified in Permission]

Returns the hash code value for this object.

public boolean implies (Permission p) [Specified in Permission]

Checks if this socket permission object "implies" the specified permission.

More specifically, this method first ensures that all of the following are true (and returns false if any of them are not):

p is an instanceof SocketPermission,
p's actions are a proper subset of this object's actions, and
p's port range is included in this port range. Note: port range is ignored when p only contains the action, 'resolve'.

Then implies checks each of the following, in order, and for each returns true if the stated condition is true:

If this object was initialized with a single IP address and one of p's IP addresses is equal to this object's IP address.
If this object is a wildcard domain (such as *.sun.com), and p's canonical name (the name without any preceding *) ends with this object's canonical host name. For example, *.sun.com implies *.eng.sun.com..
If this object was not initialized with a single IP address, and one of this object's IP addresses equals one of p's IP addresses.
If this canonical name equals p's canonical name.

If none of the above are true, implies returns false.
Returns: true if the specified permission is implied by this object, false if not.
Parameters:
- p - the permission to check against.

pack-private boolean impliesIgnoreMask (SocketPermission that)

Checks if the incoming Permission's action are a proper subset of the this object's actions.

public PermissionCollection newPermissionCollection () [Overrides Permission]

Returns a new PermissionCollection object for storing SocketPermission objects.

public String toString () [Inherited From Permission]

Returns a string describing this Permission.