ladybird/Kernel/Syscalls/profiling.cpp
Andreas Kling cbcf891040 Kernel: Move select Process members into protected memory
Process member variable like m_euid are very valuable targets for
kernel exploits and until now they have been writable at all times.

This patch moves m_euid along with a whole bunch of other members
into a new Process::ProtectedData struct. This struct is remapped
as read-only memory whenever we don't need to write to it.

This means that a kernel write primitive is no longer enough to
overwrite a process's effective UID, you must first unprotect the
protected data where the UID is stored. :^)
2021-03-10 22:30:02 +01:00

90 lines
3 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/CoreDump.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/PerformanceEventBuffer.h>
#include <Kernel/Process.h>
namespace Kernel {
PerformanceEventBuffer* g_global_perf_events;
bool g_profiling_all_threads;
KResultOr<int> Process::sys$profiling_enable(pid_t pid)
{
REQUIRE_NO_PROMISES;
if (pid == -1) {
if (!is_superuser())
return EPERM;
ScopedCritical critical;
if (g_global_perf_events)
g_global_perf_events->clear();
else
g_global_perf_events = PerformanceEventBuffer::try_create_with_size(32 * MiB).leak_ptr();
g_profiling_all_threads = true;
return 0;
}
ScopedSpinLock lock(g_processes_lock);
auto process = Process::from_pid(pid);
if (!process)
return ESRCH;
if (process->is_dead())
return ESRCH;
if (!is_superuser() && process->uid() != euid())
return EPERM;
if (!process->create_perf_events_buffer_if_needed())
return ENOMEM;
process->set_profiling(true);
return 0;
}
KResultOr<int> Process::sys$profiling_disable(pid_t pid)
{
if (pid == -1) {
if (!is_superuser())
return EPERM;
ScopedCritical critical;
g_profiling_all_threads = false;
return 0;
}
ScopedSpinLock lock(g_processes_lock);
auto process = Process::from_pid(pid);
if (!process)
return ESRCH;
if (!is_superuser() && process->uid() != euid())
return EPERM;
if (!process->is_profiling())
return EINVAL;
process->set_profiling(false);
return 0;
}
}