"TelegramAPIUrlsKeeper" now have two new things: properties "webAppDataSecretKey" and fun "checkWebAppLink"

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## 0.38.16
 
+* `Core`:
+    * `TelegramAPIUrlsKeeper` now have two new things: properties `webAppDataSecretKey` and fun `checkWebAppLink`
+
 ## 0.38.15
 
 * `Common`:

tgbotapi.core/src/commonMain/kotlin/dev/inmo/tgbotapi/utils/Crypto.kt

@@ -0,0 +1,7 @@
+package dev.inmo.tgbotapi.utils
+
+import dev.inmo.micro_utils.crypto.SourceString
+
+internal expect fun SourceString.hmacSha256(key: String): String
+
+internal expect fun SourceString.hex(): String

tgbotapi.core/src/commonMain/kotlin/dev/inmo/tgbotapi/utils/TelegramAPIUrlsKeeper.kt

@@ -18,6 +18,10 @@ class TelegramAPIUrlsKeeper(
     token: String,
     hostUrl: String = telegramBotAPIDefaultUrl
 ) {
+    val webAppDataSecretKey by lazy {
+        token.hmacSha256("WebAppData")
+    }
+
     val commonAPIUrl: String
     val fileBaseUrl: String
 
@@ -28,4 +32,10 @@ class TelegramAPIUrlsKeeper(
     }
 
     fun createFileLinkUrl(filePath: String) = "${fileBaseUrl}/$filePath"
+
+    /**
+     * @param rawData Data from [dev.inmo.tgbotapi.webapps.WebApp.initData]
+     * @param hash Data from [dev.inmo.tgbotapi.webapps.WebApp.initDataUnsafe] from the field [dev.inmo.tgbotapi.webapps.WebAppInitData.hash]
+     */
+    fun checkWebAppLink(rawData: String, hash: String) = rawData.hmacSha256(webAppDataSecretKey).hex() == hash
 }

tgbotapi.core/src/jsMain/kotlin/dev/inmo/tgbotapi/utils/CryptoActual.kt

@@ -0,0 +1,8 @@
+package dev.inmo.tgbotapi.utils
+
+import dev.inmo.micro_utils.crypto.CryptoJS
+import dev.inmo.micro_utils.crypto.SourceString
+
+actual fun SourceString.hmacSha256(key: String) = CryptoJS.asDynamic().HmacSHA256(this, key).unsafeCast<String>()
+
+actual fun SourceString.hex() = CryptoJS.asDynamic().format.Hex(this).unsafeCast<String>()

tgbotapi.core/src/jvmMain/kotlin/dev/inmo/tgbotapi/utils/CryptoActual.kt

@@ -0,0 +1,29 @@
+package dev.inmo.tgbotapi.utils
+
+import dev.inmo.micro_utils.crypto.SourceBytes
+import dev.inmo.micro_utils.crypto.SourceString
+import javax.crypto.Mac
+import javax.crypto.spec.SecretKeySpec
+
+val HEX_ARRAY = "0123456789ABCDEF".toCharArray()
+
+private fun SourceBytes.hex(): String {
+    val hexChars = CharArray(size * 2)
+    for (j in indices) {
+        val v: Int = this[j].toInt() and 0xFF
+        hexChars[j * 2] = HEX_ARRAY[v ushr 4]
+        hexChars[j * 2 + 1] = HEX_ARRAY[v and 0x0F]
+    }
+    return String(hexChars)
+}
+
+actual fun SourceString.hmacSha256(key: String): String {
+    val mac = Mac.getInstance("HmacSHA256")
+
+    val secretKey = SecretKeySpec(key.toByteArray(), "HmacSHA256")
+    mac.init(secretKey)
+
+    return mac.doFinal(toByteArray()).hex()
+}
+
+actual fun SourceString.hex(): String = toByteArray().hex()

tgbotapi.webapps/build.gradle

@@ -27,6 +27,13 @@ repositories {
 }
 
 kotlin {
+    jvm {
+        compilations.main {
+            kotlinOptions {
+                jvmTarget = "1.8"
+            }
+        }
+    }
     js(IR) {
         browser()
         nodejs()

tgbotapi.webapps/src/commonMain/kotlin/dev/inmo/tgbotapi/webapps/CheckWebAppData.kt

@@ -0,0 +1,9 @@
+package dev.inmo.tgbotapi.webapps
+
+import dev.inmo.tgbotapi.utils.*
+
+/**
+ * @param rawData Data from [dev.inmo.tgbotapi.webapps.WebApp.initData]
+ * @param hash Data from [dev.inmo.tgbotapi.webapps.WebApp.initDataUnsafe] from the field [dev.inmo.tgbotapi.webapps.WebAppInitData.hash]
+ */
+fun TelegramAPIUrlsKeeper.checkWebAppLink(rawData: String, hash: String) = rawData.hmacSha256(webAppDataSecretKey).hex() == hash

tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt

@@ -1,6 +1,7 @@
 package dev.inmo.tgbotapi.webapps
 
 import dev.inmo.micro_utils.crypto.CryptoJS
+import dev.inmo.tgbotapi.utils.TelegramAPIUrlsKeeper
 
 external class WebApp {
     val initData: String
@@ -76,6 +77,7 @@ fun WebApp.onMainButtonClicked(eventHandler: EventHandler) = onEvent(EventType.M
  */
 fun WebApp.onViewportChanged(eventHandler: ViewportChangedEventHandler) = onEvent(EventType.ViewportChanged, eventHandler)
 
-fun WebApp.isInitDataSafe(botToken: String) = CryptoJS.hex(
+fun WebApp.isInitDataSafe(botToken: String) = TelegramAPIUrlsKeeper(botToken).checkWebAppLink(
-    CryptoJS.HmacSHA256(botToken, "WebAppData")
+    initData,
-) == initDataUnsafe.hash
+    initDataUnsafe.hash
+)