From fd07f15edcf74de2fb997bd1688872a1e6892de8 Mon Sep 17 00:00:00 2001
From: Ali <>
Date: Wed, 22 Feb 2023 20:58:08 +0400
Subject: [PATCH] Defensive Coding

---
 submodules/Postbox/Sources/Coding.swift | 100 +++++++++++++++++++-----
 1 file changed, 80 insertions(+), 20 deletions(-)

diff --git a/submodules/Postbox/Sources/Coding.swift b/submodules/Postbox/Sources/Coding.swift
index fdbabbf8ef..794aacb0bb 100644
--- a/submodules/Postbox/Sources/Coding.swift
+++ b/submodules/Postbox/Sources/Coding.swift
@@ -727,27 +727,57 @@ public final class PostboxDecoder {
         case .Double:
             offset += 8
         case .String:
-            var length: Int32 = 0
-            memcpy(&length, bytes + offset, 4)
-            offset += 4 + Int(length)
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
+            var valueLength: Int32 = 0
+            memcpy(&valueLength, bytes + offset, 4)
+            offset += 4 + Int(valueLength)
         case .Object:
-            var length: Int32 = 0
-            memcpy(&length, bytes + (offset + 4), 4)
-            offset += 8 + Int(length)
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
+            var valueLength: Int32 = 0
+            memcpy(&valueLength, bytes + (offset + 4), 4)
+            offset += 8 + Int(valueLength)
         case .Int32Array:
-            var length: Int32 = 0
-            memcpy(&length, bytes + offset, 4)
-            offset += 4 + Int(length) * 4
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
+            var valueLength: Int32 = 0
+            memcpy(&valueLength, bytes + offset, 4)
+            offset += 4 + Int(valueLength) * 4
         case .Int64Array:
-            var length: Int32 = 0
-            memcpy(&length, bytes + offset, 4)
-            offset += 4 + Int(length) * 8
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
+            var valueLength: Int32 = 0
+            memcpy(&valueLength, bytes + offset, 4)
+            offset += 4 + Int(valueLength) * 8
         case .ObjectArray:
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
             var subLength: Int32 = 0
             memcpy(&subLength, bytes + offset, 4)
             offset += 4
             var i: Int32 = 0
             while i < subLength {
+                if offset + 4 + 4 > length {
+                    offset = 0
+                    return false
+                }
+                
                 var objectLength: Int32 = 0
                 memcpy(&objectLength, bytes + (offset + 4), 4)
                 offset += 8 + Int(objectLength)
@@ -759,32 +789,62 @@ public final class PostboxDecoder {
             }
             return true
         case .ObjectDictionary:
-            var length: Int32 = 0
-            memcpy(&length, bytes + offset, 4)
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
+            var valueLength: Int32 = 0
+            memcpy(&valueLength, bytes + offset, 4)
             offset += 4
             var i: Int32 = 0
-            while i < length {
+            while i < valueLength {
+                if offset + 4 + 4 > length {
+                    offset = 0
+                    return false
+                }
+                
                 var keyLength: Int32 = 0
                 memcpy(&keyLength, bytes + (offset + 4), 4)
                 offset += 8 + Int(keyLength)
                 
+                if offset + 4 + 4 > length {
+                    offset = 0
+                    return false
+                }
+                
                 var valueLength: Int32 = 0
                 memcpy(&valueLength, bytes + (offset + 4), 4)
                 offset += 8 + Int(valueLength)
                 i += 1
             }
         case .Bytes:
-            var length: Int32 = 0
-            memcpy(&length, bytes + offset, 4)
-            offset += 4 + Int(length)
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
+            var valueLength: Int32 = 0
+            memcpy(&valueLength, bytes + offset, 4)
+            offset += 4 + Int(valueLength)
         case .Nil:
             break
         case .StringArray, .BytesArray:
-            var length: Int32 = 0
-            memcpy(&length, bytes + offset, 4)
+            if offset + 4 > length {
+                offset = 0
+                return false
+            }
+            
+            var valueLength: Int32 = 0
+            memcpy(&valueLength, bytes + offset, 4)
             offset += 4
             var i: Int32 = 0
             while i < length {
+                if offset + 4 > length {
+                    offset = 0
+                    return false
+                }
+                
                 var stringLength: Int32 = 0
                 memcpy(&stringLength, bytes + offset, 4)
                 offset += 4 + Int(stringLength)