Add support for otpauth:// and otpauth-migration:// QR scan during login

2026-06-05 01:15:59 +05:00
parent 6a910facaf
commit 33eb33e18c
4 changed files with 177 additions and 14 deletions
@@ -0,0 +1,116 @@
+package sh.sar.basedbank.util
+
+import android.net.Uri
+import android.util.Base64
+
+data class OtpEntry(val name: String, val issuer: String, val secret: String)
+
+object OtpauthParser {
+
+    fun parse(raw: String): List<OtpEntry> = when {
+        raw.startsWith("otpauth-migration://") -> parseMigration(raw)
+        raw.startsWith("otpauth://") -> parseStandard(raw)?.let { listOf(it) } ?: emptyList()
+        else -> emptyList()
+    }
+
+    private fun parseStandard(raw: String): OtpEntry? {
+        val uri = Uri.parse(raw)
+        val secret = uri.getQueryParameter("secret") ?: return null
+        val issuer = uri.getQueryParameter("issuer") ?: ""
+        val label = uri.path?.trimStart('/') ?: ""
+        val name = if (':' in label) label.substringAfter(':').trim() else label
+        return OtpEntry(name, issuer, secret.uppercase())
+    }
+
+    private fun parseMigration(raw: String): List<OtpEntry> {
+        val data = Uri.parse(raw).getQueryParameter("data") ?: return emptyList()
+        val bytes = try { Base64.decode(data, Base64.DEFAULT) } catch (_: Exception) { return emptyList() }
+        val reader = ProtobufReader(bytes)
+        val entries = mutableListOf<OtpEntry>()
+        while (reader.hasMore()) {
+            val tag = reader.readVarint().toInt()
+            val fieldNum = tag ushr 3
+            val wireType = tag and 0x7
+            if (fieldNum == 1 && wireType == 2) {
+                parseOtpParameters(reader.readBytes())?.let { entries.add(it) }
+            } else {
+                reader.skip(wireType)
+            }
+        }
+        return entries
+    }
+
+    private fun parseOtpParameters(bytes: ByteArray): OtpEntry? {
+        val reader = ProtobufReader(bytes)
+        var secret: ByteArray? = null
+        var name = ""
+        var issuer = ""
+        var type = 2 // default to TOTP
+        while (reader.hasMore()) {
+            val tag = reader.readVarint().toInt()
+            val fieldNum = tag ushr 3
+            val wireType = tag and 0x7
+            when (fieldNum) {
+                1 -> secret = reader.readBytes()
+                2 -> name = String(reader.readBytes(), Charsets.UTF_8)
+                3 -> issuer = String(reader.readBytes(), Charsets.UTF_8)
+                6 -> type = reader.readVarint().toInt()
+                else -> reader.skip(wireType)
+            }
+        }
+        if (type == 1) return null // skip HOTP
+        val secretBase32 = base32Encode(secret ?: return null)
+        return OtpEntry(name, issuer, secretBase32)
+    }
+
+    private fun base32Encode(bytes: ByteArray): String {
+        val alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
+        val sb = StringBuilder()
+        var buffer = 0
+        var bitsLeft = 0
+        for (b in bytes) {
+            buffer = (buffer shl 8) or (b.toInt() and 0xFF)
+            bitsLeft += 8
+            while (bitsLeft >= 5) {
+                bitsLeft -= 5
+                sb.append(alphabet[(buffer ushr bitsLeft) and 0x1F])
+            }
+        }
+        if (bitsLeft > 0) sb.append(alphabet[(buffer shl (5 - bitsLeft)) and 0x1F])
+        return sb.toString()
+    }
+
+    private class ProtobufReader(private val bytes: ByteArray) {
+        private var pos = 0
+
+        fun hasMore() = pos < bytes.size
+
+        fun readVarint(): Long {
+            var result = 0L
+            var shift = 0
+            while (pos < bytes.size) {
+                val b = bytes[pos++].toInt() and 0xFF
+                result = result or ((b and 0x7F).toLong() shl shift)
+                if (b and 0x80 == 0) break
+                shift += 7
+            }
+            return result
+        }
+
+        fun readBytes(): ByteArray {
+            val len = readVarint().toInt()
+            val data = bytes.copyOfRange(pos, pos + len)
+            pos += len
+            return data
+        }
+
+        fun skip(wireType: Int) {
+            when (wireType) {
+                0 -> readVarint()
+                1 -> pos += 8
+                2 -> readBytes()
+                5 -> pos += 4
+            }
+        }
+    }
+}