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/*
* Copyright 2017, OnGres.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
* disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
package com.impossibl.postgres.protocol.sasl.scram.message;
import com.impossibl.postgres.protocol.sasl.scram.ScramAttributeValue;
import com.impossibl.postgres.protocol.sasl.scram.ScramAttributes;
import com.impossibl.postgres.protocol.sasl.scram.ScramStringFormatting;
import com.impossibl.postgres.protocol.sasl.scram.exception.ScramParseException;
import com.impossibl.postgres.protocol.sasl.scram.gssapi.Gs2CbindFlag;
import com.impossibl.postgres.protocol.sasl.scram.gssapi.Gs2Header;
import com.impossibl.postgres.protocol.sasl.scram.util.StringWritable;
import com.impossibl.postgres.protocol.sasl.scram.util.StringWritableCsv;
import static com.impossibl.postgres.protocol.sasl.scram.util.Preconditions.checkNotEmpty;
import static com.impossibl.postgres.protocol.sasl.scram.util.Preconditions.checkNotNull;
/**
* Constructs and parses client-first-messages.
* Message contains a {@link Gs2Header}, a username and a nonce. Formal syntax is:
*
* {@code
* client-first-message-bare = [reserved-mext ","] username "," nonce ["," extensions]
* client-first-message = gs2-header client-first-message-bare
* }
*
* Note that extensions are not supported.
*
* @see [RFC5802] Section 7
*/
public class ClientFirstMessage implements StringWritable {
private final Gs2Header gs2Header;
private final String user;
private final String nonce;
/**
* Constructs a client-first-message for the given user, nonce and gs2Header.
* This constructor is intended to be instantiated by a scram client, and not directly.
* The client should be providing the header, and nonce (and probably the user too).
* @param gs2Header The GSS-API header
* @param user The SCRAM user
* @param nonce The nonce for this session
* @throws IllegalArgumentException If any of the arguments is null or empty
*/
public ClientFirstMessage(Gs2Header gs2Header, String user, String nonce) throws IllegalArgumentException {
this.gs2Header = checkNotNull(gs2Header, "gs2Header");
this.user = checkNotNull(user, "user");
this.nonce = checkNotEmpty(nonce, "nonce");
}
private static Gs2Header gs2Header(Gs2CbindFlag gs2CbindFlag, String authzid, String cbindName) {
checkNotNull(gs2CbindFlag, "gs2CbindFlag");
if (Gs2CbindFlag.ENABLED == gs2CbindFlag && null == cbindName) {
throw new IllegalArgumentException("Channel binding name is required if channel binding is specified");
}
return new Gs2Header(gs2CbindFlag, cbindName, authzid);
}
/**
* Constructs a client-first-message for the given parameters.
* Under normal operation, this constructor is intended to be instantiated by a scram client, and not directly.
* However, this constructor is more user- or test-friendly, as the arguments are easier to provide without
* building other indirect object parameters.
* @param gs2CbindFlag The channel-binding flag
* @param authzid The optional authzid
* @param cbindName The optional channel binding name
* @param user The SCRAM user
* @param nonce The nonce for this session
* @throws IllegalArgumentException If the flag, user or nonce are null or empty
*/
public ClientFirstMessage(Gs2CbindFlag gs2CbindFlag, String authzid, String cbindName, String user, String nonce) {
this(gs2Header(gs2CbindFlag, authzid, cbindName), user, nonce);
}
/**
* Constructs a client-first-message for the given parameters, with no channel binding nor authzid.
* Under normal operation, this constructor is intended to be instantiated by a scram client, and not directly.
* However, this constructor is more user- or test-friendly, as the arguments are easier to provide without
* building other indirect object parameters.
* @param user The SCRAM user
* @param nonce The nonce for this session
* @throws IllegalArgumentException If the user or nonce are null or empty
*/
public ClientFirstMessage(String user, String nonce) {
this(gs2Header(Gs2CbindFlag.DISABLED, null, null), user, nonce);
}
public Gs2CbindFlag getChannelBindingFlag() {
return gs2Header.getChannelBindingFlag();
}
public boolean isChannelBinding() {
return gs2Header.getChannelBindingFlag() == Gs2CbindFlag.ENABLED;
}
public String getChannelBindingName() {
return gs2Header.getChannelBindingName();
}
public String getAuthzid() {
return gs2Header.getAuthzid();
}
public Gs2Header getGs2Header() {
return gs2Header;
}
public String getUser() {
return user;
}
public String getNonce() {
return nonce;
}
/**
* Limited version of the {@link StringWritableCsv#toString()} method, that doesn't write the GS2 header.
* This method is useful to construct the auth message used as part of the SCRAM algorithm.
* @param sb A StringBuffer where to write the data to.
* @return The same StringBuffer
*/
public StringBuffer writeToWithoutGs2Header(StringBuffer sb) {
return StringWritableCsv.writeTo(
sb,
new ScramAttributeValue(ScramAttributes.USERNAME, ScramStringFormatting.toSaslName(user)),
new ScramAttributeValue(ScramAttributes.NONCE, nonce)
);
}
@Override
public StringBuffer writeTo(StringBuffer sb) {
StringWritableCsv.writeTo(
sb,
gs2Header,
null // This marks the position of the rest of the elements, required for the ","
);
return writeToWithoutGs2Header(sb);
}
/**
* Construct a {@link ClientFirstMessage} instance from a message (String)
* @param clientFirstMessage The String representing the client-first-message
* @return The instance
* @throws ScramParseException If the message is not a valid client-first-message
* @throws IllegalArgumentException If the message is null or empty
*/
public static ClientFirstMessage parseFrom(String clientFirstMessage)
throws ScramParseException, IllegalArgumentException {
checkNotEmpty(clientFirstMessage, "clientFirstMessage");
Gs2Header gs2Header = Gs2Header.parseFrom(clientFirstMessage); // Takes first two fields
String[] userNonceString;
try {
userNonceString = StringWritableCsv.parseFrom(clientFirstMessage, 2, 2);
}
catch (IllegalArgumentException e) {
throw new ScramParseException("Illegal series of attributes in client-first-message", e);
}
ScramAttributeValue user = ScramAttributeValue.parse(userNonceString[0]);
if (ScramAttributes.USERNAME.getChar() != user.getChar()) {
throw new ScramParseException("user must be the 3rd element of the client-first-message");
}
ScramAttributeValue nonce = ScramAttributeValue.parse(userNonceString[1]);
if (ScramAttributes.NONCE.getChar() != nonce.getChar()) {
throw new ScramParseException("nonce must be the 4th element of the client-first-message");
}
return new ClientFirstMessage(gs2Header, user.getValue(), nonce.getValue());
}
@Override
public String toString() {
return writeTo(new StringBuffer()).toString();
}
}