(WIP) Change password when key is stripped #1692

Approach:
Find the first unstripped secret key and use it for passphrase verification
All unstripped keys will have their passphrase changed to new passphrase, if possible.

Current Progress:
Changing the passphrase of keys works fine.
Refactoring to combine "modifySecretKeyring" and newly added method, "modifyKeyRingPassword"
may be possible if given the go-ahead.

1 files changed, 66 insertions, 6 deletions

diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
index ce9c30894..abfdf0966 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
@@ -72,6 +72,8 @@ import org.sufficientlysecure.keychain.operations.results.OperationResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.OperationLog;
 import org.sufficientlysecure.keychain.operations.results.PgpEditKeyResult;
+import org.sufficientlysecure.keychain.service.ChangeUnlockParcel;
+import org.sufficientlysecure.keychain.service.PassphraseChangeParcel;
 import org.sufficientlysecure.keychain.service.SaveKeyringParcel;
 import org.sufficientlysecure.keychain.service.SaveKeyringParcel.Algorithm;
 import org.sufficientlysecure.keychain.service.SaveKeyringParcel.Curve;
@@ -345,6 +347,64 @@ public class PgpKeyOperation {
 
     }
 
+
+    public PgpEditKeyResult modifyKeyRingPassword(CanonicalizedSecretKeyRing wsKR,
+                                                  CryptoInputParcel cryptoInput,
+                                                  PassphraseChangeParcel passphraseParcel) {
+
+        OperationLog log = new OperationLog();
+        int indent = 0;
+
+        if (passphraseParcel.mMasterKeyId == null || passphraseParcel.mMasterKeyId != wsKR.getMasterKeyId()) {
+            log.add(LogType.MSG_MF_ERROR_KEYID, indent);
+            return new PgpEditKeyResult(PgpEditKeyResult.RESULT_ERROR, log, null);
+        }
+
+        log.add(LogType.MSG_MF, indent,
+                KeyFormattingUtils.convertKeyIdToHex(wsKR.getMasterKeyId()));
+        indent += 1;
+        progress(R.string.progress_building_key, 0);
+
+        // We work on bouncycastle object level here
+        PGPSecretKeyRing sKR = wsKR.getRing();
+        PGPSecretKey masterSecretKey = sKR.getSecretKey();
+        PGPPublicKey masterPublicKey = masterSecretKey.getPublicKey();
+        // Make sure the fingerprint matches
+        if (passphraseParcel.mFingerprint == null || !Arrays.equals(passphraseParcel.mFingerprint,
+                masterSecretKey.getPublicKey().getFingerprint())) {
+            log.add(LogType.MSG_MF_ERROR_FINGERPRINT, indent);
+            return new PgpEditKeyResult(PgpEditKeyResult.RESULT_ERROR, log, null);
+        }
+
+        if (!cryptoInput.hasPassphrase()) {
+            log.add(LogType.MSG_MF_REQUIRE_PASSPHRASE, indent);
+
+            return new PgpEditKeyResult(log, RequiredInputParcel.createRequiredSignPassphrase(
+                    masterSecretKey.getKeyID(), passphraseParcel.mValidSubkeyId,
+                    cryptoInput.getSignatureTime()), cryptoInput);
+        } else {
+            progress(R.string.progress_modify_passphrase, 70);
+            log.add(LogType.MSG_MF_PASSPHRASE, indent);
+            indent += 1;
+
+            try {
+                sKR = applyNewPassphrase(sKR, masterPublicKey, cryptoInput.getPassphrase(),
+                                        passphraseParcel.mNewUnlock.mNewPassphrase, log, indent);
+                if (sKR == null) {
+                    // The error has been logged above, just return a bad state
+                    return new PgpEditKeyResult(PgpEditKeyResult.RESULT_ERROR, log, null);
+                }
+            } catch (PGPException e) {
+                throw new UnsupportedOperationException("Failed to build encryptor/decryptor!");
+            }
+
+            indent -= 1;
+            progress(R.string.progress_done, 100);
+            log.add(LogType.MSG_MF_SUCCESS, indent);
+            return new PgpEditKeyResult(OperationResult.RESULT_OK, log, new UncachedKeyRing(sKR));
+        }
+    }
+
     /** This method introduces a list of modifications specified by a SaveKeyringParcel to a
      * WrappedSecretKeyRing.
      *
@@ -1223,6 +1283,7 @@ public class PgpKeyOperation {
                 PgpSecurityConstants.SECRET_KEY_ENCRYPTOR_SYMMETRIC_ALGO, encryptorHashCalc,
                 PgpSecurityConstants.SECRET_KEY_ENCRYPTOR_S2K_COUNT)
                 .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(newPassphrase.getCharArray());
+        int keysModified = 0;
 
         for (PGPSecretKey sKey : new IterableIterator<>(sKR.getSecretKeys())) {
             log.add(LogType.MSG_MF_PASSPHRASE_KEY, indent,
@@ -1236,12 +1297,6 @@ public class PgpKeyOperation {
                 ok = true;
             } catch (PGPException e) {
 
-                // if this is the master key, error!
-                if (sKey.getKeyID() == masterPublicKey.getKeyID()) {
-                    log.add(LogType.MSG_MF_ERROR_PASSPHRASE_MASTER, indent+1);
-                    return null;
-                }
-
                 // being in here means decrypt failed, likely due to a bad passphrase try
                 // again with an empty passphrase, maybe we can salvage this
                 try {
@@ -1264,7 +1319,12 @@ public class PgpKeyOperation {
             }
 
             sKR = PGPSecretKeyRing.insertSecretKey(sKR, sKey);
+            keysModified++;
+        }
 
+        if(keysModified == 0) {
+            log.add(LogType.MSG_MF_ERROR_PASSPHRASES_UNCHANGED, indent+1);
+            return null;
         }
 
         return sKR;