From 3e9a68fcc6c16be69abfa27d5fd3a2cbfc620bb0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Parm=C3=A9nides=20GV?= Date: Wed, 3 Apr 2013 19:34:40 +0200 Subject: Fixed bug #2146 => A calculation is now fine. Next step: fix M1 calculation, since right now (using tests) response() method is not doing OK. Added new SRPSession modifying response() method from JBoss SRP implementation. Added hosts-for-android-emulator. Use with the following commands to be able to test on api.lvh.me: adb shell mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system adb push ~/workspace/leap_android/hosts-for-android-emulator /system/etc/hosts --- src/se/leap/leapclient/LeapSRPSession.java | 193 +++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 src/se/leap/leapclient/LeapSRPSession.java (limited to 'src/se/leap/leapclient/LeapSRPSession.java') diff --git a/src/se/leap/leapclient/LeapSRPSession.java b/src/se/leap/leapclient/LeapSRPSession.java new file mode 100644 index 00000000..1d1f0c9d --- /dev/null +++ b/src/se/leap/leapclient/LeapSRPSession.java @@ -0,0 +1,193 @@ +package se.leap.leapclient; + +import java.math.BigInteger; +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; +import java.util.Arrays; + +import org.jboss.security.Util; +import org.jboss.security.srp.SRPClientSession; +import org.jboss.security.srp.SRPParameters; +import org.jboss.security.srp.SRPPermission; + +public class LeapSRPSession { + + private SRPParameters params; + private BigInteger N; + private BigInteger g; + private BigInteger x; + private BigInteger v; + private byte[] s; + private BigInteger a; + private BigInteger A; + private byte[] K; + /** The M1 = H(H(N) xor H(g) | H(U) | s | A | B | K) hash */ + private MessageDigest clientHash; + /** The M2 = H(A | M | K) hash */ + private MessageDigest serverHash; + + private static int A_LEN; + + /** Creates a new SRP server session object from the username, password + verifier, + @param username, the user ID + @param password, the user clear text password + @param params, the SRP parameters for the session + */ + public LeapSRPSession(String username, char[] password, SRPParameters params) + { + this(username, password, params, null); + } + + /** Creates a new SRP server session object from the username, password + verifier, + @param username, the user ID + @param password, the user clear text password + @param params, the SRP parameters for the session + @param abytes, the random exponent used in the A public key. This must be + 8 bytes in length. + */ + public LeapSRPSession(String username, char[] password, SRPParameters params, + byte[] abytes) + { + try + { + // Initialize the secure random number and message digests + Util.init(); + } + catch(NoSuchAlgorithmException e) + { + } + this.params = params; + this.g = new BigInteger(1, params.g); + this.N = new BigInteger(1, params.N); + if( abytes != null ) + { + A_LEN = 8*abytes.length; + /* TODO Why did they put this condition? + if( 8*abytes.length != A_LEN ) + throw new IllegalArgumentException("The abytes param must be " + +(A_LEN/8)+" in length, abytes.length="+abytes.length); + */ + this.a = new BigInteger(abytes); + } + + // Calculate x = H(s | H(U | ':' | password)) + byte[] xb = Util.calculatePasswordHash(username, password, params.s); + this.x = new BigInteger(1, xb); + this.v = g.modPow(x, N); // g^x % N + + serverHash = Util.newDigest(); + clientHash = Util.newDigest(); + // H(N) + byte[] hn = Util.newDigest().digest(params.N); + // H(g) + byte[] hg = Util.newDigest().digest(params.g); + // clientHash = H(N) xor H(g) + byte[] hxg = Util.xor(hn, hg, 20); + clientHash.update(hxg); + // clientHash = H(N) xor H(g) | H(U) + clientHash.update(Util.newDigest().digest(username.getBytes())); + // clientHash = H(N) xor H(g) | H(U) | s + clientHash.update(params.s); + K = null; + } + + /** + * @returns The exponential residue (parameter A) to be sent to the server. + */ + public byte[] exponential() + { + byte[] Abytes = null; + if(A == null) + { + /* If the random component of A has not been specified use a random + number */ + if( a == null ) + { + BigInteger one = BigInteger.ONE; + do + { + a = new BigInteger(A_LEN, Util.getPRNG()); + } while(a.compareTo(one) <= 0); + } + A = g.modPow(a, N); + Abytes = Util.trim(A.toByteArray()); + // clientHash = H(N) xor H(g) | H(U) | A + clientHash.update(Abytes); + // serverHash = A + serverHash.update(Abytes); + } + return Abytes; + } + + public byte[] response(byte[] Bbytes) throws NoSuchAlgorithmException { + // clientHash = H(N) xor H(g) | H(U) | s | A | B + clientHash.update(Bbytes); + + /* + var B = new BigInteger(ephemeral, 16); + var Bstr = ephemeral; + // u = H(A,B) + var u = new BigInteger(SHA256(hex2a(Astr + Bstr)), 16); + // x = H(s, H(I:p)) + var x = this.calcX(salt); + //S = (B - kg^x) ^ (a + ux) + var kgx = k.multiply(g.modPow(x, N)); + var aux = a.add(u.multiply(x)); + S = B.subtract(kgx).modPow(aux, N); + K = SHA256(hex2a(S.toString(16))); + */ + byte[] hA = Util.newDigest().digest(A.toByteArray()); + MessageDigest u_digest = Util.newDigest(); + u_digest.update(A.toByteArray()); + u_digest.update(Bbytes); + clientHash.update(u_digest.digest()); + byte[] ub = new BigInteger(clientHash.digest()).toByteArray(); + // Calculate S = (B - g^x) ^ (a + u * x) % N + BigInteger B = new BigInteger(1, Bbytes); + if( B.compareTo(v) < 0 ) + B = B.add(N); + BigInteger u = new BigInteger(1, ub); + BigInteger B_v = B.subtract(v); + BigInteger a_ux = a.add(u.multiply(x)); + BigInteger S = B_v.modPow(a_ux, N); + // K = SessionHash(S) + MessageDigest sessionDigest = MessageDigest.getInstance(params.hashAlgorithm); + K = sessionDigest.digest(S.toByteArray()); + // clientHash = H(N) xor H(g) | H(U) | A | B | K + clientHash.update(K); + byte[] M1 = clientHash.digest(); + return M1; + } + + + /** + * @param M2 The server's response to the client's challenge + * @returns True if and only if the server's response was correct. + */ + public boolean verify(byte[] M2) + { + // M2 = H(A | M1 | K) + byte[] myM2 = serverHash.digest(); + boolean valid = Arrays.equals(M2, myM2); + return valid; + } + + /** Returns the negotiated session K, K = SHA_Interleave(S) + @return the private session K byte[] + @throws SecurityException - if the current thread does not have an + getSessionKey SRPPermission. + */ + public byte[] getSessionKey() throws SecurityException + { + SecurityManager sm = System.getSecurityManager(); + if( sm != null ) + { + SRPPermission p = new SRPPermission("getSessionKey"); + sm.checkPermission(p); + } + return K; + } + +} -- cgit v1.2.3