From a9946a99f24e17644b2b7796ec8be10c8913f38b Mon Sep 17 00:00:00 2001
From: Sergey Bugaev <bugaevc@serenityos.org>
Date: Thu, 28 May 2020 17:32:20 +0300
Subject: [PATCH] Kernel: Pass a FileDescription to File::chmod() and
 File::chown()

We're going to make use of it in the next commit. But the idea is we want to
know how this File (more specifically, InodeFile) was opened in order to decide
how chown()/chmod() should behave, in particular whether it should be allowed or
not. Note that many other File operations, such as read(), write(), and ioctl(),
already require the caller to pass a FileDescription.
---
 Kernel/FileSystem/File.h              | 4 ++--
 Kernel/FileSystem/FileDescription.cpp | 4 ++--
 Kernel/FileSystem/InodeFile.cpp       | 6 ++++--
 Kernel/FileSystem/InodeFile.h         | 4 ++--
 Kernel/Net/LocalSocket.cpp            | 4 ++--
 Kernel/Net/LocalSocket.h              | 4 ++--
 6 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/Kernel/FileSystem/File.h b/Kernel/FileSystem/File.h
index 0ba1fb239fe..02fc6143268 100644
--- a/Kernel/FileSystem/File.h
+++ b/Kernel/FileSystem/File.h
@@ -82,8 +82,8 @@ public:
     virtual String absolute_path(const FileDescription&) const = 0;
 
     virtual KResult truncate(u64) { return KResult(-EINVAL); }
-    virtual KResult chown(uid_t, gid_t) { return KResult(-EBADF); }
-    virtual KResult chmod(mode_t) { return KResult(-EBADF); }
+    virtual KResult chown(FileDescription&, uid_t, gid_t) { return KResult(-EBADF); }
+    virtual KResult chmod(FileDescription&, mode_t) { return KResult(-EBADF); }
 
     virtual const char* class_name() const = 0;
 
diff --git a/Kernel/FileSystem/FileDescription.cpp b/Kernel/FileSystem/FileDescription.cpp
index 6b7e4a507a8..984eadfd50b 100644
--- a/Kernel/FileSystem/FileDescription.cpp
+++ b/Kernel/FileSystem/FileDescription.cpp
@@ -330,13 +330,13 @@ void FileDescription::set_file_flags(u32 flags)
 KResult FileDescription::chmod(mode_t mode)
 {
     LOCKER(m_lock);
-    return m_file->chmod(mode);
+    return m_file->chmod(*this, mode);
 }
 
 KResult FileDescription::chown(uid_t uid, gid_t gid)
 {
     LOCKER(m_lock);
-    return m_file->chown(uid, gid);
+    return m_file->chown(*this, uid, gid);
 }
 
 }
diff --git a/Kernel/FileSystem/InodeFile.cpp b/Kernel/FileSystem/InodeFile.cpp
index a5f8550c3dd..3e244345060 100644
--- a/Kernel/FileSystem/InodeFile.cpp
+++ b/Kernel/FileSystem/InodeFile.cpp
@@ -97,13 +97,15 @@ KResult InodeFile::truncate(u64 size)
     return KSuccess;
 }
 
-KResult InodeFile::chown(uid_t uid, gid_t gid)
+KResult InodeFile::chown(FileDescription& description, uid_t uid, gid_t gid)
 {
+    ASSERT(description.inode() == m_inode);
     return VFS::the().chown(*m_inode, uid, gid);
 }
 
-KResult InodeFile::chmod(mode_t mode)
+KResult InodeFile::chmod(FileDescription& description, mode_t mode)
 {
+    ASSERT(description.inode() == m_inode);
     return VFS::the().chmod(*m_inode, mode);
 }
 
diff --git a/Kernel/FileSystem/InodeFile.h b/Kernel/FileSystem/InodeFile.h
index 14e8f335ed1..46ddc9e86e9 100644
--- a/Kernel/FileSystem/InodeFile.h
+++ b/Kernel/FileSystem/InodeFile.h
@@ -54,8 +54,8 @@ public:
     virtual String absolute_path(const FileDescription&) const override;
 
     virtual KResult truncate(u64) override;
-    virtual KResult chown(uid_t, gid_t) override;
-    virtual KResult chmod(mode_t) override;
+    virtual KResult chown(FileDescription&, uid_t, gid_t) override;
+    virtual KResult chmod(FileDescription&, mode_t) override;
 
     virtual const char* class_name() const override { return "InodeFile"; }
 
diff --git a/Kernel/Net/LocalSocket.cpp b/Kernel/Net/LocalSocket.cpp
index da4f330794d..0b074813cea 100644
--- a/Kernel/Net/LocalSocket.cpp
+++ b/Kernel/Net/LocalSocket.cpp
@@ -375,7 +375,7 @@ KResult LocalSocket::getsockopt(FileDescription& description, int level, int opt
     }
 }
 
-KResult LocalSocket::chmod(mode_t mode)
+KResult LocalSocket::chmod(FileDescription&, mode_t mode)
 {
     if (m_file)
         return m_file->chmod(mode);
@@ -384,7 +384,7 @@ KResult LocalSocket::chmod(mode_t mode)
     return KSuccess;
 }
 
-KResult LocalSocket::chown(uid_t uid, gid_t gid)
+KResult LocalSocket::chown(FileDescription&, uid_t uid, gid_t gid)
 {
     if (m_file)
         return m_file->chown(uid, gid);
diff --git a/Kernel/Net/LocalSocket.h b/Kernel/Net/LocalSocket.h
index 6a64ededa88..8435480d535 100644
--- a/Kernel/Net/LocalSocket.h
+++ b/Kernel/Net/LocalSocket.h
@@ -60,8 +60,8 @@ public:
     virtual ssize_t sendto(FileDescription&, const void*, size_t, int, const sockaddr*, socklen_t) override;
     virtual ssize_t recvfrom(FileDescription&, void*, size_t, int flags, sockaddr*, socklen_t*) override;
     virtual KResult getsockopt(FileDescription&, int level, int option, void*, socklen_t*) override;
-    virtual KResult chown(uid_t, gid_t) override;
-    virtual KResult chmod(mode_t) override;
+    virtual KResult chown(FileDescription&, uid_t, gid_t) override;
+    virtual KResult chmod(FileDescription&, mode_t) override;
 
 private:
     explicit LocalSocket(int type);