From 5aa36b089f09346787e44f9850924faae1fda363 Mon Sep 17 00:00:00 2001
From: hsm <hsm@lamia.panaceas.james.local>
Date: Sun, 29 May 2016 03:12:09 +0100
Subject: ssh authentication support

---
 .../keychain/pgp/PgpSignEncryptOperation.java      | 79 ++++++++++++++++++++--
 1 file changed, 72 insertions(+), 7 deletions(-)

(limited to 'OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java')

diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java
index 7a1d99927..a855dcac8 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java
@@ -24,6 +24,7 @@ import android.net.Uri;
 import android.os.Parcelable;
 import android.support.annotation.NonNull;
 
+import org.bouncycastle.bcpg.HashAlgorithmTags;
 import org.bouncycastle.bcpg.ArmoredOutputStream;
 import org.bouncycastle.bcpg.BCPGOutputStream;
 import org.bouncycastle.bcpg.CompressionAlgorithmTags;
@@ -58,6 +59,10 @@ import org.sufficientlysecure.keychain.util.Log;
 import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.ProgressScaler;
 
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+import java.nio.ByteBuffer;
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.BufferedReader;
@@ -165,6 +170,7 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
         return executeInternal(input, cryptoInput, inputData, outputStream);
     }
 
+
     /**
      * Signs and/or encrypts data based on parameters of class
      */
@@ -238,7 +244,10 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
                 }
 
                 // Make sure we are allowed to sign here!
-                if (!signingKey.canSign()) {
+                if ((!signingKey.canSign() && !data.isSshAuth()) ||
+                        (!signingKey.canAuthenticate() && data.isSshAuth())) {
+                    Log.w(Constants.TAG, "canSign " + signingKey.canSign() + " canAuthenticate "
+                        + signingKey.canAuthenticate() + " isSshAuth  "+ data.isSshAuth());
                     log.add(LogType.MSG_PSE_ERROR_KEY_SIGN, indent);
                     return new PgpSignEncryptResult(PgpSignEncryptResult.RESULT_ERROR, log);
                 }
@@ -298,7 +307,11 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
             // Use requested hash algo
             int requestedAlgorithm = data.getSignatureHashAlgorithm();
             if (requestedAlgorithm == PgpSecurityConstants.OpenKeychainHashAlgorithmTags.USE_DEFAULT) {
-                data.setSignatureHashAlgorithm(PgpSecurityConstants.DEFAULT_HASH_ALGORITHM);
+                if (data.isSshAuth()) {
+                    data.setSignatureHashAlgorithm(HashAlgorithmTags.SHA1);
+                } else {
+                    data.setSignatureHashAlgorithm(PgpSecurityConstants.DEFAULT_HASH_ALGORITHM);
+                }
             }
         }
         updateProgress(R.string.progress_preparing_streams, 2, 100);
@@ -386,6 +399,7 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
         ByteArrayOutputStream detachedByteOut = null;
         ArmoredOutputStream detachedArmorOut = null;
         BCPGOutputStream detachedBcpgOut = null;
+        MessageDigest raw_digest = null;
 
         long opTime, startTime = System.currentTimeMillis();
 
@@ -491,6 +505,28 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
             } else if (enableSignature && data.isDetachedSignature()) {
                 /* detached signature */
 
+                // JMM - GROSS HACK
+                //
+                // The PGP stack doesn't do signatures of arbitary data: it wants
+                // to use its own structure for the message, so we have
+                // to be creative. We let the pgp stack do its stuff, but when
+                // it calls out to the NFC stack, we catch it and swap the
+                // message digest for own own.
+                //
+                // this means we have to check cyrptoInput for the correct
+                // hash ourselves on the 2nd trip through when the
+                // client resents the request.
+                //
+
+                if (data.isSshAuth()) {
+                    try {
+                        raw_digest = MessageDigest.getInstance("SHA-1");
+                    } catch (NoSuchAlgorithmException e) {
+                        log.add(LogType.MSG_PSE_ERROR_IO, indent);
+                        return new PgpSignEncryptResult(PgpSignEncryptResult.RESULT_ERROR, log);
+                    }
+                }
+
                 updateProgress(R.string.progress_signing, 8, 100);
                 log.add(LogType.MSG_PSE_SIGNING_DETACHED, indent);
 
@@ -515,6 +551,9 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
                 while ((length = in.read(buffer)) > 0) {
                     // no output stream is written, no changed to original data!
 
+                    if (raw_digest != null)
+                        raw_digest.update(buffer, 0, length);
+
                     signatureGenerator.update(buffer, 0, length);
 
                     alreadyWritten += length;
@@ -582,11 +621,37 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
                         signatureGenerator.generate().encode(pOut);
                     }
                 } catch (NfcSyncPGPContentSignerBuilder.NfcInteractionNeeded e) {
-                    // this secret key diverts to a OpenPGP card, throw exception with hash that will be signed
-                    log.add(LogType.MSG_PSE_PENDING_NFC, indent);
-                    return new PgpSignEncryptResult(log, RequiredInputParcel.createSecurityTokenSignOperation(
-                            signingKey.getRing().getMasterKeyId(), signingKey.getKeyId(),
-                            e.hashToSign, e.hashAlgo, cryptoInput.getSignatureTime()), cryptoInput);
+
+                    // JMM - 2nd part of gross hack
+                    // first swap the message digest for the raw one
+                    // before this hits the NFC stack
+
+                    if (raw_digest != null)
+                        e.hashToSign = raw_digest.digest();
+
+                    // Test to see if we already have the answer for the hash
+                    // as the test in encode() above was checking the wrong
+                    // hash.
+
+                    byte [] answer = cryptoInput.getCryptoData().get(ByteBuffer.wrap(e.hashToSign));
+
+                    if (raw_digest == null || answer == null)  {
+                        // We haven't done the hash yet, so kick it off to the NFC stack
+
+                        // this secret key diverts to a OpenPGP card, throw exception with hash that will be signed
+
+                        log.add(LogType.MSG_PSE_PENDING_NFC, indent);
+                        return new PgpSignEncryptResult(log, RequiredInputParcel.createSecurityTokenSignOperation(
+                                signingKey.getRing().getMasterKeyId(), signingKey.getKeyId(),
+                                e.hashToSign, e.hashAlgo, cryptoInput.getSignatureTime()), cryptoInput);
+                    } else if (raw_digest != null) {
+                        // We've aready done the work, replace the output stream
+                        // from the PGP signature with just the signature as we want just
+                        // a raw signature
+
+                        detachedByteOut = new ByteArrayOutputStream();
+                        detachedByteOut.write(answer, 0, answer.length);
+                    }
                 }
             }
 
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