Asks user for permission before installing apps with private entitlements

AltStore/Extensions/NSError+LocalizedFailure.swift

@@ -25,3 +25,18 @@ extension NSError
         return error
     }
 }
+
+protocol ALTLocalizedError: LocalizedError, CustomNSError
+{
+    var errorFailure: String? { get }
+}
+
+extension ALTLocalizedError
+{
+    var errorUserInfo: [String : Any] {
+        let userInfo = [NSLocalizedDescriptionKey: self.errorDescription,
+                        NSLocalizedFailureReasonErrorKey: self.failureReason,
+                        NSLocalizedFailureErrorKey: self.errorFailure].compactMapValues { $0 }
+        return userInfo
+    }
+}

AltStore/Managing Apps/AppManager.swift

@@ -396,6 +396,11 @@ private extension AppManager
             self.set(progress, for: operation)
         }
         
+        if let viewController = presentingViewController
+        {
+            group.context.presentingViewController = viewController
+        }
+        
         /* Authenticate (if necessary) */
         var authenticationOperation: AuthenticationOperation?
         if group.context.session == nil
@@ -503,6 +508,16 @@ private extension AppManager
         }
         progress.addChild(downloadOperation.progress, withPendingUnitCount: 25)
         
+        /* Verify App */
+        let verifyOperation = VerifyAppOperation(context: context)
+        verifyOperation.resultHandler = { (result) in
+            switch result
+            {
+            case .failure(let error): context.error = error
+            case .success: break
+            }
+        }
+        verifyOperation.addDependency(downloadOperation)
         
         /* Refresh Anisette Data */
         let refreshAnisetteDataOperation = FetchAnisetteDataOperation(context: group.context)
@@ -513,7 +528,7 @@ private extension AppManager
             case .success(let anisetteData): group.context.session?.anisetteData = anisetteData
             }
         }
-        refreshAnisetteDataOperation.addDependency(downloadOperation)
+        refreshAnisetteDataOperation.addDependency(verifyOperation)
         
         
         /* Fetch Provisioning Profiles */
@@ -579,7 +594,7 @@ private extension AppManager
         progress.addChild(installOperation.progress, withPendingUnitCount: 30)
         installOperation.addDependency(sendAppOperation)
         
-        let operations = [downloadOperation, refreshAnisetteDataOperation, fetchProvisioningProfilesOperation, resignAppOperation, sendAppOperation, installOperation]
+        let operations = [downloadOperation, verifyOperation, refreshAnisetteDataOperation, fetchProvisioningProfilesOperation, resignAppOperation, sendAppOperation, installOperation]
         group.add(operations)
         self.run(operations, context: group.context)
         

AltStore/Operations/OperationContexts.swift

@@ -17,6 +17,8 @@ class OperationContext
     var server: Server?
     var error: Error?
     
+    var presentingViewController: UIViewController?
+    
     let operations: NSHashTable<Foundation.Operation>
     
     init(server: Server? = nil, error: Error? = nil, operations: [Foundation.Operation] = [])

AltStore/Operations/VerifyAppOperation.swift

@@ -0,0 +1,131 @@
+//
+//  VerifyAppOperation.swift
+//  AltStore
+//
+//  Created by Riley Testut on 5/2/20.
+//  Copyright © 2020 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+import AltSign
+import AltKit
+
+import Roxas
+
+enum VerificationError: ALTLocalizedError
+{
+    case privateEntitlements(ALTApplication, [String: Any])
+    
+    var app: ALTApplication {
+        switch self {
+        case .privateEntitlements(let app, _): return app
+        }
+    }
+    
+    var errorFailure: String? {
+        return String(format: NSLocalizedString("“%@” could not be installed.", comment: ""), app.name)
+    }
+    
+    var failureReason: String? {
+        switch self
+        {
+        case .privateEntitlements(let app, _):
+            return String(format: NSLocalizedString("“%@” requires private permissions.", comment: ""), app.name)
+        }
+    }
+}
+
+@objc(VerifyAppOperation)
+class VerifyAppOperation: ResultOperation<Void>
+{
+    let context: AppOperationContext
+    var verificationHandler: ((VerificationError) -> Bool)?
+    
+    init(context: AppOperationContext)
+    {
+        self.context = context
+        
+        super.init()
+    }
+    
+    override func main()
+    {
+        super.main()
+        
+        do
+        {
+            if let error = self.context.error
+            {
+                throw error
+            }
+            
+            guard let app = self.context.app else { throw OperationError.invalidParameters }
+                        
+            if let commentStart = app.entitlementsString.range(of: "<!---><!-->"), let commentEnd = app.entitlementsString.range(of: "<!-- -->")
+            {
+                // Psychic Paper private entitlements.
+                
+                let entitlementsStart = app.entitlementsString.index(after: commentStart.upperBound)
+                let rawEntitlements = String(app.entitlementsString[entitlementsStart ..< commentEnd.lowerBound])
+                
+                let plistTemplate = """
+                    <?xml version="1.0" encoding="UTF-8"?>
+                    <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+                    <plist version="1.0">
+                        <dict>
+                        %@
+                        </dict>
+                    </plist>
+                    """
+                let entitlementsPlist = String(format: plistTemplate, rawEntitlements)
+                let entitlements = try PropertyListSerialization.propertyList(from: entitlementsPlist.data(using: .utf8)!, options: [], format: nil) as! [String: Any]
+                
+                let error = VerificationError.privateEntitlements(app, entitlements)
+                self.process(error) { (result) in
+                    self.finish(result.mapError { $0 as Error })
+                }
+                
+                return
+            }
+            
+            self.finish(.success(()))
+        }
+        catch
+        {
+            self.finish(.failure(error))
+        }
+    }
+}
+
+private extension VerifyAppOperation
+{
+    func process(_ error: VerificationError, completion: @escaping (Result<Void, VerificationError>) -> Void)
+    {
+        guard let presentingViewController = self.context.presentingViewController else { return completion(.failure(error)) }
+        
+        DispatchQueue.main.async {
+            switch error
+            {
+            case .privateEntitlements(_, let entitlements):
+                let permissions = entitlements.keys.sorted().joined(separator: "\n")
+                let message = String(format: NSLocalizedString("""
+                    You must allow access to these private permissions before continuing:
+
+                    %@
+
+                    Private permissions allow apps to do more than normally allowed by iOS, including potentially accessing sensitive private data. Make sure to only install apps from sources you trust.
+                    """, comment: ""), permissions)
+                
+                let alertController = UIAlertController(title: error.failureReason ?? error.localizedDescription, message: message, preferredStyle: .alert)
+                alertController.addAction(UIAlertAction(title: NSLocalizedString("Allow Access", comment: ""), style: .destructive) { (action) in
+                    completion(.success(()))
+                })
+                alertController.addAction(UIAlertAction(title: NSLocalizedString("Deny Access", comment: ""), style: .default, handler: { (action) in
+                    completion(.failure(error))
+                }))
+                presentingViewController.present(alertController, animated: true, completion: nil)
+            }
+        }
+    }
+}