Refactor TOTP implementation and expand SteamGuard hacks (#1460)

* UriTotpFinder: commonize query parameter handling

* gitignore: add more IDEA files

* TotpFinder: add `findIssuer`

* PasswordEntry: don't eagerly fetch TOTP related fields

* format-common: expand SteamGuard workaround

* CHANGELOG: add SteamGuard workaround

2 files changed, 13 insertions, 4 deletions

diff --git a/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/Otp.kt b/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/Otp.kt
index 65284441..f1f71e00 100644
--- a/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/Otp.kt
+++ b/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/Otp.kt
@@ -23,8 +23,13 @@ internal object Otp {
     check(STEAM_ALPHABET.size == 26)
   }
 
-  fun calculateCode(secret: String, counter: Long, algorithm: String, digits: String) =
-      runCatching {
+  fun calculateCode(
+    secret: String,
+    counter: Long,
+    algorithm: String,
+    digits: String,
+    issuer: String?,
+  ) = runCatching {
     val algo = "Hmac${algorithm.uppercase(Locale.ROOT)}"
     val decodedSecret = BASE_32.decode(secret)
     val secretKey = SecretKeySpec(decodedSecret, algo)
@@ -40,8 +45,9 @@ internal object Otp {
     code[0] = (0x7f and code[0].toInt()).toByte()
     val codeInt = ByteBuffer.wrap(code).int
     check(codeInt > 0)
-    if (digits == "s") {
-      // Steam
+    // SteamGuard is a horrible OTP implementation that generates non-standard 5 digit OTPs as well
+    // as uses a custom character set.
+    if (digits == "s" || issuer == "Steam") {
       var remainingCodeInt = codeInt
       buildString {
         repeat(5) {
diff --git a/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/TotpFinder.kt b/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/TotpFinder.kt
index 64f22065..1cb7de97 100644
--- a/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/TotpFinder.kt
+++ b/format-common/src/main/kotlin/dev/msfjarvis/aps/util/totp/TotpFinder.kt
@@ -20,6 +20,9 @@ public interface TotpFinder {
   /** Get the algorithm for the TOTP secret. */
   public fun findAlgorithm(content: String): String
 
+  /** Get the issuer for the TOTP secret, if any. */
+  public fun findIssuer(content: String): String?
+
   public companion object {
     public val TOTP_FIELDS: Array<String> = arrayOf("otpauth://totp", "totp:")
   }