/*
  Name:         EncryptWithHMAC.java
  Licensing:    LGPL

  API:          Sun (http://java.sun.com) JCE 1.2.2 API (cleanroom implementation by Bouncy Castle)
  Provider:     Bouncy Castle (http://www.bouncycastle.org)

  Disclaimer:

  COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY OF ANY KIND,
  EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES THAT THE COVERED CODE
  IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE OR NON-INFRINGING. THE ENTIRE
  RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED CODE IS WITH YOU. SHOULD ANY COVERED CODE
  PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR)
  ASSUME THE COST OF ANY NECESSARY SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY
  CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED
  HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
*/

package net.sourceforge.jcetaglib.taglib.crypto;

import net.sourceforge.jcetaglib.lib.CertTools;
import net.sourceforge.jcetaglib.lib.Clean;
import net.sourceforge.jcetaglib.lib.Hybrid;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.BodyTagSupport;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.cert.X509Certificate;

/**
 * JSP tag used for encrypting data with a HMAC code
 *
 * @jsp.tag
 * name="encryptwithhmac"
 * display-name="EncryptWithHMAC"
 * body-content="JSP"
 * example="
 *		<jce:encryptwithhmac

 * 			var=\"foralice\"

 *			value=\"<%= new StringBuffer(\"Encrypt this string\") %>\"

 *			scope=\"page\"

 *			recpemfile=\"C:/keystores/alice.cert\"/>"
 *
 * description="JSP tag used for encrypting data with a HMAC code"
 *
 * @author Gert Van Ham
 * @author hamgert@users.sourceforge.net
 * @author http://jcetaglib.sourceforge.net
 * @version $Id: EncryptWithHMAC.java,v 1.5 2004/04/15 07:28:35 hamgert Exp $
 */
public class EncryptWithHMAC extends BodyTagSupport {
    private static final String PAGE = "page";
    private static final String REQUEST = "request";
    private static final String SESSION = "session";
    private static final String APPLICATION = "application";

    private StringBuffer value; // tag attribute
    private String var;     // tag attribute
    private int scope = PageContext.PAGE_SCOPE;      // tag attribute

    private String file;                // tag attribute
    private String newfile;                // tag attribute

    private String algorithm = "AES";          // tag attribute
    private String seed;          							// tag attribute
    private int strength = 256;             // tag attribute
    private String mode = "CBC";               // tag attribute
    private String padding = "PKCS7Padding";   // tag attribute

    /* Attributes for receiver's certificate */

    // receiver's certificate as string
    private String recpemstring;             // tag attribute

    // ... OR as PEM file
    private String recpemfile;              // tag attribute

    private StringBuffer input;    // what we'll store in scope:var
    private StringBuffer output;   // return text

    public static int getScope(String scope) {
        int ret = PageContext.PAGE_SCOPE; // default

        if (REQUEST.equalsIgnoreCase(scope))
            ret = PageContext.REQUEST_SCOPE;
        else if (SESSION.equalsIgnoreCase(scope))
            ret = PageContext.SESSION_SCOPE;
        else if (APPLICATION.equalsIgnoreCase(scope))
            ret = PageContext.APPLICATION_SCOPE;
        else if (PAGE.equalsIgnoreCase(scope))
            ret = PageContext.PAGE_SCOPE;

        return ret;
    } //getScope()

    public int doEndTag() throws JspException {
        X509Certificate reccert = null;

        // determine the value by...
        if (value != null) {
            // ... reading our attribute
            input = value;
        } else {
            // ... retrieving and trimming our body
            if (bodyContent == null || bodyContent.getString() == null) {
                input = new StringBuffer("");
            } else {
                input = new StringBuffer(bodyContent.getString().trim());
            }
        }

        // loading the receiver's public key
        try {
            if (recpemfile == null || recpemfile == "") {
                // use PEM string
                InputStream pemstream = new ByteArrayInputStream(recpemstring.getBytes());
                reccert = CertTools.getCertfromPEM(pemstream);
            } else {
                // use PEM store
                reccert = CertTools.getCertfromPEM(recpemfile);
            }
        } catch (Exception e) {
            throw new JspException("JCE Exception - PEM could not be loaded: " + e.getMessage(), e);
        }

        // encrypt with MAC
        try {
            if (file != null) {
                if (seed == null) {
                    Hybrid.encryptFileWithHMAC(file
                            , newfile
                            , reccert.getPublicKey()
                            , algorithm
                            , null
                            , strength
                            , mode
                            , padding);
                } else {
                    Hybrid.encryptFileWithHMAC(file
                            , newfile
                            , reccert.getPublicKey()
                            , algorithm
                            , seed.getBytes()
                            , strength
                            , mode
                            , padding);
                }
            } else {
                if (seed == null) {
                    output = Hybrid.encryptWithHMAC(input
                            , reccert.getPublicKey()
                            , algorithm
                            , null
                            , strength
                            , mode
                            , padding);
                } else {
                    output = Hybrid.encryptWithHMAC(input
                            , reccert.getPublicKey()
                            , algorithm
                            , seed.getBytes()
                            , strength
                            , mode
                            , padding);
                }
            }
        } catch (Exception e) {
            throw new JspException("JCE Exception: " + e.getMessage(), e);
        }

        // decide what to do with the result
        if (var != null) {
            if (output != null) {
                pageContext.setAttribute(var, output, scope);
            }
        } else {
            if (file == null || file == "") {
                if (bodyContent != null) {
                    bodyContent.clearBody();
                }

                try {
                    JspWriter w = pageContext.getOut();
                    w.print(output);
                } catch (IOException ex) {
                    throw new JspException(ex.getMessage(), ex);
                }
            }
        }

        return EVAL_PAGE;
    }

    public void release() {
        // Cleanup all sensitive information
        Clean.blank(value);
        Clean.blank(input);
        Clean.blank(output);

        super.release();
    } //release()

    /**
     * @jsp.attribute
     *     description="Optional attribute, the string to encrypt or decrypt. The body of the tag will be taken if omitted"
     *     type="java.lang.StringBuffer"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setValue(StringBuffer value) {
        this.value = value;
    }

    public StringBuffer getValue() {
        return value;
    }

    /**
     * @jsp.attribute
     *     description="Optional attribute, variable to store the encrypted string. The string will be printed if omitted"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="false"
     */
    public void setVar(String var) {
        this.var = var;
    }

    public String getVar() {
        return var;
    }

    /**
     * @jsp.attribute
     *     description="Scope of the 'var' attribute. Can be 'page', 'session', 'request' or 'application'. Default is 'page'"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="false"
     */
    public void setScope(String scope) {
        this.scope = getScope(scope);
    }

    /**
     * @jsp.attribute
     *     description="The key algorithm. Default is 'AES'"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setAlgorithm(String algorithm) {
        this.algorithm = algorithm;
    }

    /**
     * @jsp.attribute
     *     description="Optional seed for SecureRandom "
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setSeed(String seed) {
        this.seed = seed;
    }

    /**
     * @jsp.attribute
     *     description="The key size in bits (integer value). Values depends on the used algorithm (see next paragraph). Default is 256 (for AES)"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setStrength(int strength) {
        this.strength = strength;
    }

    /**
     * @jsp.attribute
     *     description="Encryption mode. Default is 'CBC'"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setMode(String mode) {
        this.mode = mode;
    }

    /**
     * @jsp.attribute
     *     description="Padding scheme. Default is 'PKCS7Padding'"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setPadding(String padding) {
        this.padding = padding;
    }

    /**
     * @jsp.attribute
     *     description="The receiver's certificate stored in a PEM file"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setRecpemfile(String recpemfile) {
        this.recpemfile = recpemfile;
    }

    /**
     * @jsp.attribute
     *     description="The receiver's certificate as a PEM formatted string"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setRecpemstring(String recpemstring) {
        this.recpemstring = recpemstring;
    }

    /**
     * @jsp.attribute
     *     description="Encrypts a file instead of a string"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setFile(String file) {
        this.file = file;
    }

    /**
     * @jsp.attribute
     *     description="File(name) to store the encrypted data"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setNewfile(String newfile) {
        this.newfile = newfile;
    }
}