From 08e0e2eb417d7c9a50b4309b4cdcef70b8554537 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Thu, 11 Mar 2021 13:23:23 +0100
Subject: [PATCH] Kernel: Move process umask into protected data :^)

---
 Kernel/Process.h          | 3 +--
 Kernel/Syscalls/fork.cpp  | 5 ++---
 Kernel/Syscalls/umask.cpp | 1 +
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/Kernel/Process.h b/Kernel/Process.h
index 41128a00163..6ff695547b7 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -117,6 +117,7 @@ protected:
     u32 m_promises { 0 };
     bool m_has_execpromises { false };
     u32 m_execpromises { 0 };
+    mode_t m_umask { 022 };
 };
 
 class ProcessBase : public ProtectedProcessBase {
@@ -595,8 +596,6 @@ private:
 
     RefPtr<TTY> m_tty;
 
-    mode_t m_umask { 022 };
-
     WeakPtr<Region> m_master_tls_region;
     size_t m_master_tls_size { 0 };
     size_t m_master_tls_alignment { 0 };
diff --git a/Kernel/Syscalls/fork.cpp b/Kernel/Syscalls/fork.cpp
index c1b1088157a..4016206d182 100644
--- a/Kernel/Syscalls/fork.cpp
+++ b/Kernel/Syscalls/fork.cpp
@@ -44,19 +44,18 @@ KResultOr<pid_t> Process::sys$fork(RegisterState& regs)
     child->m_veil_state = m_veil_state;
     child->m_unveiled_paths = m_unveiled_paths.deep_copy();
     child->m_fds = m_fds;
-    child->m_umask = m_umask;
     child->m_signal_trampoline = m_signal_trampoline;
     child->m_pg = m_pg;
 
     {
-        child->unprotect_data();
+        ProtectedDataMutationScope scope { *child };
         child->m_promises = m_promises;
         child->m_execpromises = m_execpromises;
         child->m_has_promises = m_has_promises;
         child->m_has_execpromises = m_has_execpromises;
         child->m_sid = m_sid;
         child->m_extra_gids = m_extra_gids;
-        child->protect_data();
+        child->m_umask = m_umask;
     }
 
     dbgln_if(FORK_DEBUG, "fork: child={}", child);
diff --git a/Kernel/Syscalls/umask.cpp b/Kernel/Syscalls/umask.cpp
index c2f05921365..fa26a8a2ed4 100644
--- a/Kernel/Syscalls/umask.cpp
+++ b/Kernel/Syscalls/umask.cpp
@@ -32,6 +32,7 @@ KResultOr<mode_t> Process::sys$umask(mode_t mask)
 {
     REQUIRE_PROMISE(stdio);
     auto old_mask = m_umask;
+    ProtectedDataMutationScope scope { *this };
     m_umask = mask & 0777;
     return old_mask;
 }