From 0a57e0648f9ca51008941f2d99f77c7040f022af Mon Sep 17 00:00:00 2001
From: fmodf <fmodf.ios@gmail.com>
Date: Sun, 8 Sep 2024 16:57:50 +0200
Subject: [PATCH] wip

---
 ConversationsClassic/AppData/AppError.swift   |  1 +
 .../AppData/Client/Client.swift               | 33 +++++++++++++++----
 .../AppData/Services/AESGSMEngine.swift       | 18 ++++++++--
 3 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/ConversationsClassic/AppData/AppError.swift b/ConversationsClassic/AppData/AppError.swift
index 5f5677f..bacb47a 100644
--- a/ConversationsClassic/AppData/AppError.swift
+++ b/ConversationsClassic/AppData/AppError.swift
@@ -8,4 +8,5 @@ enum AppError: Error {
     case invalidContentType
     case invalidLocalName
     case featureNotSupported
+    case securityError
 }
diff --git a/ConversationsClassic/AppData/Client/Client.swift b/ConversationsClassic/AppData/Client/Client.swift
index 418dce6..40a0331 100644
--- a/ConversationsClassic/AppData/Client/Client.swift
+++ b/ConversationsClassic/AppData/Client/Client.swift
@@ -109,20 +109,32 @@ extension Client {
     }
 
     func uploadFile(_ localURL: URL) async throws -> String {
+        // get data from file
         guard let data = try? Data(contentsOf: localURL) else {
             throw AppError.noData
         }
-        let httpModule = connection.module(HttpFileUploadModule.self)
 
+        // encode data with AES_GSM
+        guard let iv = try? AESGSMEngine.generateIV(), let key = try? AESGSMEngine.generateKey() else {
+            throw AppError.securityError
+        }
+        var encodedData = Data()
+        var tag = Data()
+        guard AESGSMEngine.shared.encrypt(iv: iv, key: key, message: data, output: &encodedData, tag: &tag) else {
+            throw AppError.securityError
+        }
+
+        // upload
+        let httpModule = connection.module(HttpFileUploadModule.self)
         let components = try await httpModule.findHttpUploadComponents()
-        guard let component = components.first(where: { $0.maxSize > data.count }) else {
+        guard let component = components.first(where: { $0.maxSize > encodedData.count }) else {
             throw AppError.fileTooBig
         }
 
         let slot = try await httpModule.requestUploadSlot(
             componentJid: component.jid,
             filename: localURL.lastPathComponent,
-            size: data.count,
+            size: encodedData.count,
             contentType: localURL.mimeType
         )
         var request = URLRequest(url: slot.putUri)
@@ -130,13 +142,21 @@ extension Client {
             request.addValue(value, forHTTPHeaderField: key)
         }
         request.httpMethod = "PUT"
-        request.httpBody = data
-        request.addValue(String(data.count), forHTTPHeaderField: "Content-Length")
+        request.httpBody = encodedData
+        request.addValue(String(encodedData.count), forHTTPHeaderField: "Content-Length")
         request.addValue(localURL.mimeType, forHTTPHeaderField: "Content-Type")
         let (_, response) = try await URLSession.shared.data(for: request)
         switch response {
         case let httpResponse as HTTPURLResponse where httpResponse.statusCode == 201:
-            return slot.getUri.absoluteString
+            guard var parts = URLComponents(url: slot.getUri, resolvingAgainstBaseURL: true) else {
+                throw URLError(.badServerResponse)
+            }
+            parts.scheme = "aesgcm"
+            parts.fragment = (iv + key).map { String(format: "%02x", $0) }.joined()
+            guard let shareUrl = parts.url else {
+                throw URLError(.badServerResponse)
+            }
+            return shareUrl.absoluteString
 
         default:
             throw URLError(.badServerResponse)
@@ -169,6 +189,7 @@ private extension Client {
                     switch error {
                     case .noSession:
                         errorMessage = NSLocalizedString("There is no trusted device to send message to", comment: "message encryption failure")
+
                     default:
                         break
                     }
diff --git a/ConversationsClassic/AppData/Services/AESGSMEngine.swift b/ConversationsClassic/AppData/Services/AESGSMEngine.swift
index 114514f..177a389 100644
--- a/ConversationsClassic/AppData/Services/AESGSMEngine.swift
+++ b/ConversationsClassic/AppData/Services/AESGSMEngine.swift
@@ -12,8 +12,8 @@ final class AESGSMEngine: AES_GCM_Engine {
             let symmetricKey = SymmetricKey(data: key)
             let sealedBox = try AES.GCM.seal(message, using: symmetricKey, nonce: AES.GCM.Nonce(data: iv))
 
-            if let output = output {
-                output.pointee = sealedBox.ciphertext
+            if let output = output, let data = sealedBox.combined {
+                output.pointee = data
             }
             if let tag = tag {
                 tag.pointee = sealedBox.tag
@@ -44,4 +44,18 @@ final class AESGSMEngine: AES_GCM_Engine {
             return false
         }
     }
+
+    static func generateIV() throws -> Data {
+        var bytes = [Int8](repeating: 0, count: 12)
+        let status = SecRandomCopyBytes(kSecRandomDefault, bytes.count, &bytes)
+        if status != errSecSuccess {
+            throw AppError.securityError
+        }
+        return Data(bytes: bytes, count: bytes.count)
+    }
+
+    static func generateKey() throws -> Data {
+        let key = SymmetricKey(size: .bits256)
+        return key.withUnsafeBytes { Data($0) }
+    }
 }