From 2f5ddf12a9058cef80f17a1fc3635fc2b3f46c18 Mon Sep 17 00:00:00 2001
From: Pierre Bourdon <delroth@gmail.com>
Date: Sun, 6 Aug 2017 22:18:20 +0200
Subject: [PATCH] WFS: Normalize paths before opening.

---
 Source/Core/Core/IOS/WFS/WFSSRV.cpp | 24 +++++++++++++++++++++---
 Source/Core/Core/IOS/WFS/WFSSRV.h   |  2 +-
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/Source/Core/Core/IOS/WFS/WFSSRV.cpp b/Source/Core/Core/IOS/WFS/WFSSRV.cpp
index 1f82768ad4..6ff55a8e66 100644
--- a/Source/Core/Core/IOS/WFS/WFSSRV.cpp
+++ b/Source/Core/Core/IOS/WFS/WFSSRV.cpp
@@ -135,7 +135,7 @@ IPCCommandResult WFSSRV::IOCtl(const IOCtlRequest& request)
     u16 path_len = Memory::Read_U16(request.buffer_in + 0x20);
     std::string path = Memory::GetString(request.buffer_in + 0x22, path_len);
 
-    path = ExpandPath(path);
+    path = NormalizePath(path);
 
     u16 fd = GetNewFileDescriptor();
     FileDescriptor* fd_obj = &m_fds[fd];
@@ -204,7 +204,7 @@ IPCCommandResult WFSSRV::IOCtl(const IOCtlRequest& request)
   return GetDefaultReply(return_error_code);
 }
 
-std::string WFSSRV::ExpandPath(const std::string& path) const
+std::string WFSSRV::NormalizePath(const std::string& path) const
 {
   std::string expanded;
   if (!path.empty() && path[0] == '~')
@@ -219,7 +219,25 @@ std::string WFSSRV::ExpandPath(const std::string& path) const
   {
     expanded = path;
   }
-  return expanded;
+
+  std::vector<std::string> components = SplitString(expanded, '/');
+  std::vector<std::string> normalized_components;
+  for (const auto& component : components)
+  {
+    if (component.empty() || component == ".")
+    {
+      continue;
+    }
+    else if (component == ".." && !normalized_components.empty())
+    {
+      normalized_components.pop_back();
+    }
+    else
+    {
+      normalized_components.push_back(component);
+    }
+  }
+  return "/" + JoinStrings(normalized_components, "/");
 }
 
 WFSSRV::FileDescriptor* WFSSRV::FindFileDescriptor(u16 fd)
diff --git a/Source/Core/Core/IOS/WFS/WFSSRV.h b/Source/Core/Core/IOS/WFS/WFSSRV.h
index 86302a80bb..889bfc25fd 100644
--- a/Source/Core/Core/IOS/WFS/WFSSRV.h
+++ b/Source/Core/Core/IOS/WFS/WFSSRV.h
@@ -39,7 +39,7 @@ private:
   std::string m_home_directory;
   std::string m_current_directory;
 
-  std::string ExpandPath(const std::string& path) const;
+  std::string NormalizePath(const std::string& path) const;
 
   enum
   {