From b3096276bba15e213d15caeb680e7d3bafa18b54 Mon Sep 17 00:00:00 2001
From: Brian Gianforcaro <bgianf@serenityos.org>
Date: Thu, 29 Apr 2021 01:41:30 -0700
Subject: [PATCH] Kernel: Harden sys$poll Vector usage against OOM.

---
 Kernel/Syscalls/select.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Kernel/Syscalls/select.cpp b/Kernel/Syscalls/select.cpp
index 175a07e650eb5b..e39c4b670787b4 100644
--- a/Kernel/Syscalls/select.cpp
+++ b/Kernel/Syscalls/select.cpp
@@ -154,7 +154,8 @@ KResultOr<int> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> user_
         nfds_checked *= params.nfds;
         if (nfds_checked.has_overflow())
             return EFAULT;
-        fds_copy.resize(params.nfds);
+        if (!fds_copy.try_resize(params.nfds))
+            return ENOMEM;
         if (!copy_from_user(fds_copy.data(), &params.fds[0], nfds_checked.value()))
             return EFAULT;
     }
@@ -174,7 +175,8 @@ KResultOr<int> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> user_
             block_flags |= BlockFlags::Write;
         if (pfd.events & POLLPRI)
             block_flags |= BlockFlags::ReadPriority;
-        fds_info.append({ description.release_nonnull(), block_flags });
+        if (!fds_info.try_append({ description.release_nonnull(), block_flags }))
+            return ENOMEM;
     }
 
     auto current_thread = Thread::current();