In order to avoid DLL preloading attacks, we should be careful about where we
load DLLs from. These packages load graphics DLLs, which may be provided by the
OS, by a graphics vendor, or even by individual applications. As such, we can't
restrict loading them to just system32-provided paths. Instead, we invoke
LoadLibraryEx [0] with the LOAD_LIBRARY_SEARCH_DEFAULT_DIRS path, which will search
system32, application-defined paths, and the path of the primary application
executable. This mode ignores the system %PATH% variable, which dramatically
reduces the attack surface of malicious or unintended DLLs.
Applications may add custom paths to the search list by calling the standard
windows AddDllDirectory function [1] prior to attempting to initialize GL.
Thanks to Mohsen Mirzakhani and Utkarsh Satya Prakash for bringing this to
our attention.
[0] https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa
[1] https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-adddlldirectory
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
According to #565 X11 GPU drivers don't deal well with recreation of
EGL surfaces.
Thanks to Walter Schneider for debugging this issue and coming up with
the original patch.
Fixes: https://todo.sr.ht/~eliasnaur/gio/565
Co-authored-by: Walter Werner SCHNEIDER <contact@schnwalter.eu>
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Without eglTerminate, using EGL will crash or report spurious errors after
creating and destroying enough contexts. The test program in #528
takes 5-10 window cycles before errors show up for me.
Fixes: https://todo.sr.ht/~eliasnaur/gio/528
Signed-off-by: Elias Naur <mail@eliasnaur.com>
OpenGL stores the current context in thread-local memory, but commit
4f5baa9a51 removed a runtime.LockOSThread from app.Window that ensured
the goroutine that drives the context stays on the operating thread that
has the context current. This change restores the thread lock.
As a bonus, this change makes the OpenGL contexts responsible for locking
the thread at MakeCurrent, thereby removing LockOSThread calls from GPU
backend-agnostic code.
Fixes: https://todo.sr.ht/~eliasnaur/gio/334
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Both the OpenGL and the Direct3D API are stateful and gpu.GPU renders to
the render target current when Frame is called.
Modern GPU API such as Metal don't have a concept of a current render
target, and the target even changes each frame.
Add RenderTarget and add an explicit target argument to GPU.Frame as
well as the underlying driver.Device.BeginFrame.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
glFinish depends on package gl which is about to require a function
pointer loader. eglWaitClient is in the EGL API and always available.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
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