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Kernel: Utilize AK::Userspace<T> in the ioctl interface

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It's easy to forget the responsibility of validating and safely copying
kernel parameters in code that is far away from syscalls. ioctl's are
one such example, and bugs there are just as dangerous as at the root
syscall level.

To avoid this case, utilize the AK::Userspace<T> template in the ioctl
kernel interface so that implementors have no choice but to properly
validate and copy ioctl pointer arguments.
This commit is contained in:
Brian Gianforcaro 2021-07-26 02:47:00 -07:00 • committed by Ali Mohammad Pur
parent 0bb3d83a48
commit 9a04f53a0f
16 changed files with 99 additions and 93 deletions
Download patch file Download diff file Expand all files Collapse all files

34
Kernel/Graphics/VirtIOGPU/FrameBufferDevice.cpp
View file

@ -140,19 +140,19 @@ void FrameBufferDevice::set_buffer(int buffer_index)
buffer.dirty_rect = {};
}
int FrameBufferDevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
int FrameBufferDevice::ioctl(FileDescription&, unsigned request, Userspace<void*> arg)
{
REQUIRE_PROMISE(video);
switch (request) {
case FB_IOCTL_GET_SIZE_IN_BYTES: {
auto* out = (size_t*)arg;
auto out = static_ptr_cast<size_t*>(arg);
size_t value = m_buffer_size * 2;
if (!copy_to_user(out, &value))
return -EFAULT;
return 0;
}
case FB_IOCTL_SET_RESOLUTION: {
auto* user_resolution = (FBResolution*)arg;
auto user_resolution = static_ptr_cast<FBResolution*>(arg);
FBResolution resolution;
if (!copy_from_user(&resolution, user_resolution))
return -EFAULT;
@ -164,8 +164,8 @@ int FrameBufferDevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
return 0;
}
case FB_IOCTL_GET_RESOLUTION: {
auto* user_resolution = (FBResolution*)arg;
FBResolution resolution;
auto user_resolution = static_ptr_cast<FBResolution*>(arg);
FBResolution resolution {};
resolution.pitch = pitch();
resolution.width = width();
resolution.height = height();
@ -174,7 +174,7 @@ int FrameBufferDevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
return 0;
}
case FB_IOCTL_SET_BUFFER: {
auto buffer_index = (int)arg;
auto buffer_index = static_cast<int>(arg.ptr());
if (!is_valid_buffer_index(buffer_index))
return -EINVAL;
if (m_last_set_buffer_index.exchange(buffer_index) != buffer_index && m_are_writes_active)
@ -182,19 +182,20 @@ int FrameBufferDevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
return 0;
}
case FB_IOCTL_FLUSH_BUFFERS: {
FBFlushRects user_flush_rects;
if (!copy_from_user(&user_flush_rects, (FBFlushRects*)arg))
auto user_flush_rects = static_ptr_cast<FBFlushRects*>(arg);
FBFlushRects flush_rects;
if (!copy_from_user(&flush_rects, user_flush_rects))
return -EFAULT;
if (!is_valid_buffer_index(user_flush_rects.buffer_index))
if (!is_valid_buffer_index(flush_rects.buffer_index))
return -EINVAL;
if (Checked<unsigned>::multiplication_would_overflow(user_flush_rects.count, sizeof(FBRect)))
if (Checked<unsigned>::multiplication_would_overflow(flush_rects.count, sizeof(FBRect)))
return -EFAULT;
if (m_are_writes_active && user_flush_rects.count > 0) {
auto& buffer = buffer_from_index(user_flush_rects.buffer_index);
if (m_are_writes_active && flush_rects.count > 0) {
auto& buffer = buffer_from_index(flush_rects.buffer_index);
MutexLocker locker(m_gpu.operation_lock());
for (unsigned i = 0; i < user_flush_rects.count; i++) {
for (unsigned i = 0; i < flush_rects.count; i++) {
FBRect user_dirty_rect;
if (!copy_from_user(&user_dirty_rect, &user_flush_rects.rects[i]))
if (!copy_from_user(&user_dirty_rect, &flush_rects.rects[i]))
return -EFAULT;
Protocol::Rect dirty_rect {
.x = user_dirty_rect.x,
@ -224,13 +225,14 @@ int FrameBufferDevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
return 0;
}
case FB_IOCTL_GET_BUFFER_OFFSET: {
auto user_buffer_offset = static_ptr_cast<FBBufferOffset*>(arg);
FBBufferOffset buffer_offset;
if (!copy_from_user(&buffer_offset, (FBBufferOffset*)arg))
if (!copy_from_user(&buffer_offset, user_buffer_offset))
return -EFAULT;
if (!is_valid_buffer_index(buffer_offset.buffer_index))
return -EINVAL;
buffer_offset.offset = (size_t)buffer_offset.buffer_index * m_buffer_size;
if (!copy_to_user((FBBufferOffset*)arg, &buffer_offset))
if (!copy_to_user(user_buffer_offset, &buffer_offset))
return -EFAULT;
return 0;
}