From 0b58fd5aef7b2b88913cc5645d7b7cbee3db93d0 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 16 Aug 2022 20:16:17 +0200
Subject: [PATCH] Kernel: Remove unnecessary TOCTOU bug in sys$pipe()

We don't need to explicitly check for EMFILE conditions before doing
anything in sys$pipe(). The fd allocation code will take care of it
for us anyway.
---
 Kernel/Syscalls/pipe.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/Kernel/Syscalls/pipe.cpp b/Kernel/Syscalls/pipe.cpp
index 50f497555a..10c8c01f84 100644
--- a/Kernel/Syscalls/pipe.cpp
+++ b/Kernel/Syscalls/pipe.cpp
@@ -13,9 +13,7 @@ ErrorOr<FlatPtr> Process::sys$pipe(int pipefd[2], int flags)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     TRY(require_promise(Pledge::stdio));
-    auto open_count = fds().with_shared([](auto& fds) { return fds.open_count(); });
-    if (open_count + 2 > OpenFileDescriptions::max_open())
-        return EMFILE;
+
     // Reject flags other than O_CLOEXEC, O_NONBLOCK
     if ((flags & (O_CLOEXEC | O_NONBLOCK)) != flags)
         return EINVAL;