diff options
Diffstat (limited to 'app/src/main/java/dev/msfjarvis/aps/util/totp')
3 files changed, 171 insertions, 0 deletions
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/totp/Otp.kt b/app/src/main/java/dev/msfjarvis/aps/util/totp/Otp.kt new file mode 100644 index 00000000..551b2e5d --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/totp/Otp.kt @@ -0,0 +1,73 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ + +package dev.msfjarvis.aps.util.totp + +import com.github.michaelbull.result.Err +import com.github.michaelbull.result.runCatching +import java.nio.ByteBuffer +import java.util.Locale +import javax.crypto.Mac +import javax.crypto.spec.SecretKeySpec +import kotlin.experimental.and +import org.apache.commons.codec.binary.Base32 + +object Otp { + + private val BASE_32 = Base32() + private val STEAM_ALPHABET = "23456789BCDFGHJKMNPQRTVWXY".toCharArray() + + init { + check(STEAM_ALPHABET.size == 26) + } + + fun calculateCode(secret: String, counter: Long, algorithm: String, digits: String) = runCatching { + val algo = "Hmac${algorithm.toUpperCase(Locale.ROOT)}" + val decodedSecret = BASE_32.decode(secret) + val secretKey = SecretKeySpec(decodedSecret, algo) + val digest = Mac.getInstance(algo).run { + init(secretKey) + doFinal(ByteBuffer.allocate(8).putLong(counter).array()) + } + // Least significant 4 bits are used as an offset into the digest. + val offset = (digest.last() and 0xf).toInt() + // Extract 32 bits at the offset and clear the most significant bit. + val code = digest.copyOfRange(offset, offset + 4) + code[0] = (0x7f and code[0].toInt()).toByte() + val codeInt = ByteBuffer.wrap(code).int + check(codeInt > 0) + if (digits == "s") { + // Steam + var remainingCodeInt = codeInt + buildString { + repeat(5) { + append(STEAM_ALPHABET[remainingCodeInt % 26]) + remainingCodeInt /= 26 + } + } + } else { + // Base 10, 6 to 10 digits + val numDigits = digits.toIntOrNull() + when { + numDigits == null -> { + return Err(IllegalArgumentException("Digits specifier has to be either 's' or numeric")) + } + numDigits < 6 -> { + return Err(IllegalArgumentException("TOTP codes have to be at least 6 digits long")) + } + numDigits > 10 -> { + return Err(IllegalArgumentException("TOTP codes can be at most 10 digits long")) + } + else -> { + // 2^31 = 2_147_483_648, so we can extract at most 10 digits with the first one + // always being 0, 1, or 2. Pad with leading zeroes. + val codeStringBase10 = codeInt.toString(10).padStart(10, '0') + check(codeStringBase10.length == 10) + codeStringBase10.takeLast(numDigits) + } + } + } + } +} diff --git a/app/src/main/java/dev/msfjarvis/aps/util/totp/TotpFinder.kt b/app/src/main/java/dev/msfjarvis/aps/util/totp/TotpFinder.kt new file mode 100644 index 00000000..fb43980c --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/totp/TotpFinder.kt @@ -0,0 +1,32 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ + +package dev.msfjarvis.aps.util.totp + +/** + * Defines a class that can extract relevant parts of a TOTP URL for use by the app. + */ +interface TotpFinder { + + /** + * Get the TOTP secret from the given extra content. + */ + fun findSecret(content: String): String? + + /** + * Get the number of digits required in the final OTP. + */ + fun findDigits(content: String): String + + /** + * Get the TOTP timeout period. + */ + fun findPeriod(content: String): Long + + /** + * Get the algorithm for the TOTP secret. + */ + fun findAlgorithm(content: String): String +} diff --git a/app/src/main/java/dev/msfjarvis/aps/util/totp/UriTotpFinder.kt b/app/src/main/java/dev/msfjarvis/aps/util/totp/UriTotpFinder.kt new file mode 100644 index 00000000..21910a3a --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/totp/UriTotpFinder.kt @@ -0,0 +1,66 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ + +package dev.msfjarvis.aps.util.totp + +import android.net.Uri + +/** + * [Uri] backed TOTP URL parser. + */ +class UriTotpFinder : TotpFinder { + + override fun findSecret(content: String): String? { + content.split("\n".toRegex()).forEach { line -> + if (line.startsWith(TOTP_FIELDS[0])) { + return Uri.parse(line).getQueryParameter("secret") + } + if (line.startsWith(TOTP_FIELDS[1], ignoreCase = true)) { + return line.split(": *".toRegex(), 2).toTypedArray()[1] + } + } + return null + } + + override fun findDigits(content: String): String { + content.split("\n".toRegex()).forEach { line -> + if (line.startsWith(TOTP_FIELDS[0]) && + Uri.parse(line).getQueryParameter("digits") != null) { + return Uri.parse(line).getQueryParameter("digits")!! + } + } + return "6" + } + + override fun findPeriod(content: String): Long { + content.split("\n".toRegex()).forEach { line -> + if (line.startsWith(TOTP_FIELDS[0]) && + Uri.parse(line).getQueryParameter("period") != null) { + val period = Uri.parse(line).getQueryParameter("period")!!.toLongOrNull() + if (period != null && period > 0) + return period + } + } + return 30 + } + + override fun findAlgorithm(content: String): String { + content.split("\n".toRegex()).forEach { line -> + if (line.startsWith(TOTP_FIELDS[0]) && + Uri.parse(line).getQueryParameter("algorithm") != null) { + return Uri.parse(line).getQueryParameter("algorithm")!! + } + } + return "sha1" + } + + companion object { + + val TOTP_FIELDS = arrayOf( + "otpauth://totp", + "totp:" + ) + } +} |