Add support for importing from Microsoft Authenticator

Adds support for importing TOTP and Microsoft accounts from Microsoft
Authenticator. Microsoft accounts also use TOTP, but with 8 digits instead
of 6.

This implementation suffers from the same bug (#82) as Google Authenticator, but I
haven't thought of a nice way to solve it yet. We should fix that before
including this feature in a release, though.

app/src/main/java/com/beemdevelopment/aegis/importers/DatabaseImporter.java

@@ -32,6 +32,7 @@ public abstract class DatabaseImporter {
         _importers.put("FreeOTP", FreeOtpImporter.class);
         _importers.put("FreeOTP+", FreeOtpPlusImporter.class);
         _importers.put("Google Authenticator", GoogleAuthImporter.class);
+        _importers.put("Microsoft Authenticator", MicrosoftAuthImporter.class);
         _importers.put("Steam", SteamImporter.class);
         _importers.put("WinAuth", WinAuthImporter.class);
 
@@ -40,6 +41,7 @@ public abstract class DatabaseImporter {
         _appImporters.put("FreeOTP", FreeOtpImporter.class);
         _appImporters.put("FreeOTP+", FreeOtpPlusImporter.class);
         _appImporters.put("Google Authenticator", GoogleAuthImporter.class);
+        _appImporters.put("Microsoft Authenticator", MicrosoftAuthImporter.class);
         _appImporters.put("Steam", SteamImporter.class);
     }
 

app/src/main/java/com/beemdevelopment/aegis/importers/MicrosoftAuthImporter.java

@@ -0,0 +1,126 @@
+package com.beemdevelopment.aegis.importers;
+
+import android.content.Context;
+import android.database.Cursor;
+
+import com.beemdevelopment.aegis.encoding.Base32;
+import com.beemdevelopment.aegis.encoding.Base64;
+import com.beemdevelopment.aegis.encoding.EncodingException;
+import com.beemdevelopment.aegis.otp.OtpInfo;
+import com.beemdevelopment.aegis.otp.OtpInfoException;
+import com.beemdevelopment.aegis.otp.TotpInfo;
+import com.beemdevelopment.aegis.vault.VaultEntry;
+
+import java.util.List;
+
+public class MicrosoftAuthImporter extends DatabaseImporter {
+    private static final String _subPath = "databases/PhoneFactor";
+    private static final String _pkgName = "com.azure.authenticator";
+
+    private static final int TYPE_TOTP = 0;
+    private static final int TYPE_MICROSOFT = 1;
+
+    public MicrosoftAuthImporter(Context context) {
+        super(context);
+    }
+
+    @Override
+    protected String getAppPkgName() {
+        return _pkgName;
+    }
+
+    @Override
+    protected String getAppSubPath() {
+        return _subPath;
+    }
+
+    @Override
+    public State read(FileReader reader) throws DatabaseImporterException {
+        SqlImporterHelper helper = new SqlImporterHelper(getContext());
+        List<Entry> entries = helper.read(Entry.class, reader.getStream(), "accounts");
+        return new State(entries);
+    }
+
+    public static class State extends DatabaseImporter.State {
+        private List<Entry> _entries;
+
+        private State(List<Entry> entries) {
+            super(false);
+            _entries = entries;
+        }
+
+        @Override
+        public Result convert() {
+            Result result = new Result();
+
+            for (Entry sqlEntry : _entries) {
+                try {
+                    int type = sqlEntry.getType();
+                    if (type == TYPE_TOTP || type == TYPE_MICROSOFT) {
+                        VaultEntry entry = convertEntry(sqlEntry);
+                        result.addEntry(entry);
+                    }
+                } catch (DatabaseImporterEntryException e) {
+                    result.addError(e);
+                }
+            }
+
+            return result;
+        }
+
+        private static VaultEntry convertEntry(Entry entry) throws DatabaseImporterEntryException {
+            try {
+                byte[] secret;
+                int digits = 6;
+
+                switch (entry.getType()) {
+                    case TYPE_TOTP:
+                        secret = Base32.decode(entry.getSecret());
+                        break;
+                    case TYPE_MICROSOFT:
+                        digits = 8;
+                        secret = Base64.decode(entry.getSecret());
+                        break;
+                    default:
+                        throw new DatabaseImporterEntryException(String.format("Unsupported OTP type: %d", entry.getType()), entry.toString());
+                }
+
+                OtpInfo info = new TotpInfo(secret, "SHA1", digits, 30);
+                return new VaultEntry(info, entry.getUserName(), entry.getIssuer());
+            } catch (EncodingException | OtpInfoException e) {
+                throw new DatabaseImporterEntryException(e, entry.toString());
+            }
+        }
+    }
+
+    private static class Entry extends SqlImporterHelper.Entry {
+        private int _type;
+        private String _secret;
+        private String _issuer;
+        private String _userName;
+
+        public Entry(Cursor cursor) {
+            super(cursor);
+            _type = SqlImporterHelper.getInt(cursor, "account_type");
+            _secret = SqlImporterHelper.getString(cursor, "oath_secret_key");
+            _issuer = SqlImporterHelper.getString(cursor, "name");
+            _userName = SqlImporterHelper.getString(cursor, "username");
+        }
+
+        public int getType() {
+            return _type;
+        }
+
+        public String getSecret() {
+            return _secret;
+        }
+
+        public String getIssuer() {
+            return _issuer;
+        }
+
+        public String getUserName() {
+            return _userName;
+        }
+    }
+}