From 649abc01bcacd67abebdbc23c89a3a9b9917fc8f Mon Sep 17 00:00:00 2001
From: Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
Date: Sun, 21 Feb 2021 19:18:55 +0100
Subject: [PATCH] Kernel: Implement 'copy_time_from_user' functions to sanitize
 arguments

---
 Kernel/StdLib.cpp | 26 ++++++++++++++++++++++++++
 Kernel/StdLib.h   |  6 ++++++
 2 files changed, 32 insertions(+)

diff --git a/Kernel/StdLib.cpp b/Kernel/StdLib.cpp
index 00a7010453..48e7208409 100644
--- a/Kernel/StdLib.cpp
+++ b/Kernel/StdLib.cpp
@@ -63,6 +63,32 @@ String copy_string_from_user(Userspace<const char*> user_str, size_t user_str_si
     return copy_string_from_user(user_str.unsafe_userspace_ptr(), user_str_size);
 }
 
+[[nodiscard]] Optional<Time> copy_time_from_user(const timespec* ts_user)
+{
+    timespec ts;
+    if (!copy_from_user(&ts, ts_user, sizeof(timespec))) {
+        return {};
+    }
+    return Time::from_timespec(ts);
+}
+[[nodiscard]] Optional<Time> copy_time_from_user(const timeval* tv_user)
+{
+    timeval tv;
+    if (!copy_from_user(&tv, tv_user, sizeof(timeval))) {
+        return {};
+    }
+    return Time::from_timeval(tv);
+}
+
+template<>
+[[nodiscard]] Optional<Time> copy_time_from_user<const timeval>(Userspace<const timeval*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
+template<>
+[[nodiscard]] Optional<Time> copy_time_from_user<timeval>(Userspace<timeval*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
+template<>
+[[nodiscard]] Optional<Time> copy_time_from_user<const timespec>(Userspace<const timespec*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
+template<>
+[[nodiscard]] Optional<Time> copy_time_from_user<timespec>(Userspace<timespec*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
+
 Optional<u32> user_atomic_fetch_add_relaxed(volatile u32* var, u32 val)
 {
     if (FlatPtr(var) & 3)
diff --git a/Kernel/StdLib.h b/Kernel/StdLib.h
index 5fc7396f86..129cb1d470 100644
--- a/Kernel/StdLib.h
+++ b/Kernel/StdLib.h
@@ -28,7 +28,9 @@
 
 #include <AK/Checked.h>
 #include <AK/Forward.h>
+#include <AK/Time.h>
 #include <AK/Userspace.h>
+#include <Kernel/UnixTypes.h>
 
 namespace Syscall {
 struct StringArgument;
@@ -36,6 +38,10 @@ struct StringArgument;
 
 [[nodiscard]] String copy_string_from_user(const char*, size_t);
 [[nodiscard]] String copy_string_from_user(Userspace<const char*>, size_t);
+[[nodiscard]] Optional<Time> copy_time_from_user(const timespec*);
+[[nodiscard]] Optional<Time> copy_time_from_user(const timeval*);
+template<typename T>
+[[nodiscard]] Optional<Time> copy_time_from_user(Userspace<T*> src);
 
 [[nodiscard]] Optional<u32> user_atomic_fetch_add_relaxed(volatile u32* var, u32 val);
 [[nodiscard]] Optional<u32> user_atomic_exchange_relaxed(volatile u32* var, u32 val);