From a47d4cb5a7e004f5dca4e2eb26167406b4eac16b Mon Sep 17 00:00:00 2001
From: Hannes Oud <hannes.oud.dev@gmail.com>
Date: Fri, 6 Nov 2020 13:02:09 +0100
Subject: [PATCH] Restore UnofficialReceipt parsing after transitioning to
 ASN1Decoder

---
 .../AppReceiptValidator.swift                 | 36 +++++++++++++++++--
 .../UnofficialReceipt.swift                   |  9 ++---
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/AppReceiptValidator/AppReceiptValidator/AppReceiptValidator.swift b/AppReceiptValidator/AppReceiptValidator/AppReceiptValidator.swift
index c9982f4..009fa75 100644
--- a/AppReceiptValidator/AppReceiptValidator/AppReceiptValidator.swift
+++ b/AppReceiptValidator/AppReceiptValidator/AppReceiptValidator.swift
@@ -201,7 +201,37 @@ private extension AppReceiptValidator {
         receipt.originalAppVersion = contents.originalApplicationVersion
         receipt.expirationDate = contents.receiptExpirationDate
 
-        return (receipt: receipt, unofficialReceipt: .init(entries: []))
+        return (receipt: receipt, unofficialReceipt: (parseUnofficialParts ? self.parseUnofficialReceipt(pkcs7: pkcs7) : .init(entries: [])))
+    }
+
+    func parseUnofficialReceipt(pkcs7: ASN1Decoder.PKCS7) -> UnofficialReceipt {
+        guard let receiptBlock = pkcs7.mainBlock.findOid(.pkcs7data)?.parent?.sub?.last?.sub(0)?.sub(0),
+              let items = receiptBlock.sub else { return .init(entries: []) }
+
+        let entries: [UnofficialReceipt.Entry] = items.compactMap { item in
+            guard let fieldType = (item.sub(0)?.value as? Data)?.toIntValue(),
+                  KnownReceiptAttribute(rawValue: fieldType) == nil else { return nil }
+
+            let fieldValueString = item.sub(2)?.asString
+            if let meaning = KnownUnofficialReceiptAttribute(rawValue: fieldType) {
+                switch meaning.parsingType {
+                case .string:
+                    if let string = fieldValueString {
+                        return UnofficialReceipt.Entry(attributeNumber: fieldType, meaning: meaning, value: .string(string))
+                    }
+                case .data:
+                    if let data = item.sub(2)?.rawValue {
+                        return UnofficialReceipt.Entry(attributeNumber: fieldType, meaning: meaning, value: .bytes(data))
+                    }
+                }
+            }
+
+            if let string = fieldValueString {
+                return UnofficialReceipt.Entry(attributeNumber: fieldType, meaning: nil, value: .string(string))
+            }
+            return UnofficialReceipt.Entry(attributeNumber: fieldType, meaning: nil, value: item.sub(2)?.rawValue.map { .bytes($0) })
+        }
+        return UnofficialReceipt(entries: entries)
     }
 }
 
@@ -210,7 +240,7 @@ private extension AppReceiptValidator {
 private extension AppReceiptValidator {
 
     /// See Receipt.swift for details and a link to Apple reference
-    enum KnownReceiptAttribute: Int32 {
+    enum KnownReceiptAttribute: UInt64 {
         case bundleIdentifier = 2
         case appVersion = 3
         case opaqueValue = 4
@@ -222,7 +252,7 @@ private extension AppReceiptValidator {
     }
 
     /// See Receipt.swift for details and a link to Apple reference
-    enum KnownInAppPurchaseAttribute: Int32 {
+    enum KnownInAppPurchaseAttribute: UInt64 {
         case quantity = 1701
         case productIdentifier = 1702
         case transactionIdentifier = 1703
diff --git a/AppReceiptValidator/AppReceiptValidator/UnofficialReceipt.swift b/AppReceiptValidator/AppReceiptValidator/UnofficialReceipt.swift
index e30f10b..f5e5f87 100644
--- a/AppReceiptValidator/AppReceiptValidator/UnofficialReceipt.swift
+++ b/AppReceiptValidator/AppReceiptValidator/UnofficialReceipt.swift
@@ -22,7 +22,7 @@ public struct UnofficialReceipt {
             case bytes(Data)
         }
 
-        public internal(set) var attributeNumber: Int32
+        public internal(set) var attributeNumber: UInt64
         public internal(set) var meaning: KnownUnofficialReceiptAttribute?
         public internal(set) var value: Value?
     }
@@ -42,7 +42,7 @@ public struct UnofficialReceipt {
     }
 }
 
-public enum KnownUnofficialReceiptAttribute: Int32 {
+public enum KnownUnofficialReceiptAttribute: UInt64 {
 
     case provisioningType = 0 // String, probably Provisioning-Type, Encountered Values: "Production", "ProductionSandbox", "ProductionVPP"
     case date1 = 8 // some date, same as receiptCreationDate possibly
@@ -54,15 +54,12 @@ public enum KnownUnofficialReceiptAttribute: Int32 {
 
     enum ParsingType {
         case string
-        case date
         case data
     }
 
     var parsingType: ParsingType {
         switch self {
-        case .date1, .date2, .date3:
-            return .date
-        case .provisioningType, .ageRating, .clientName:
+        case .provisioningType, .ageRating, .clientName, .date1, .date2, .date3:
             return .string
         }
     }