From c7858622ec7b1dfb6ad8b8006814faab7a3ed3c6 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 26 Jan 2021 15:25:18 +0100
Subject: [PATCH] Kernel: Update process promise states on execve() and fork()

We now move the execpromises state into the regular promises, and clear
the execpromises state.

Also make sure to duplicate the promise state on fork.

This fixes an issue where "su" would launch a shell which immediately
crashed due to not having pledged "stdio".
---
 Kernel/Process.h           | 1 +
 Kernel/Syscalls/execve.cpp | 4 ++++
 Kernel/Syscalls/fork.cpp   | 2 ++
 Kernel/Syscalls/pledge.cpp | 4 +++-
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Kernel/Process.h b/Kernel/Process.h
index 3acafcccbb6..c761bbabf04 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -637,6 +637,7 @@ private:
 
     bool m_has_promises { false };
     u32 m_promises { 0 };
+    bool m_has_execpromises { false };
     u32 m_execpromises { 0 };
 
     VeilState m_veil_state { VeilState::None };
diff --git a/Kernel/Syscalls/execve.cpp b/Kernel/Syscalls/execve.cpp
index 13485826630..b6ebe30e66d 100644
--- a/Kernel/Syscalls/execve.cpp
+++ b/Kernel/Syscalls/execve.cpp
@@ -544,6 +544,10 @@ int Process::do_exec(NonnullRefPtr<FileDescription> main_program_description, Ve
     m_environment = environment;
 
     m_promises = m_execpromises;
+    m_has_promises = m_has_execpromises;
+
+    m_execpromises = 0;
+    m_has_execpromises = false;
 
     m_veil_state = VeilState::None;
     m_unveiled_paths.clear();
diff --git a/Kernel/Syscalls/fork.cpp b/Kernel/Syscalls/fork.cpp
index edf359c3a54..db600ee562c 100644
--- a/Kernel/Syscalls/fork.cpp
+++ b/Kernel/Syscalls/fork.cpp
@@ -43,6 +43,8 @@ pid_t Process::sys$fork(RegisterState& regs)
     child->m_root_directory_relative_to_global_root = m_root_directory_relative_to_global_root;
     child->m_promises = m_promises;
     child->m_execpromises = m_execpromises;
+    child->m_has_promises = m_has_promises;
+    child->m_has_execpromises = m_has_execpromises;
     child->m_veil_state = m_veil_state;
     child->m_unveiled_paths = m_unveiled_paths.deep_copy();
     child->m_fds = m_fds;
diff --git a/Kernel/Syscalls/pledge.cpp b/Kernel/Syscalls/pledge.cpp
index d101295ee7f..0613ab575ea 100644
--- a/Kernel/Syscalls/pledge.cpp
+++ b/Kernel/Syscalls/pledge.cpp
@@ -84,7 +84,9 @@ int Process::sys$pledge(Userspace<const Syscall::SC_pledge_params*> user_params)
             return -EPERM;
     }
 
-    m_has_promises = true;
+    m_has_promises = m_has_promises || !promises.is_null();
+    m_has_execpromises = m_has_execpromises || !execpromises.is_null();
+
     m_promises = new_promises;
     m_execpromises = new_execpromises;