In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks
When parsing endpoint descriptors, ffs_data_got_descs() generates the
eps_addrmap which contains the endpoint direction. However, epfile->in
was previously only populated in ffs_func_eps_enable() which executes
upon USB host connection. As a result, early userspace ioctls like
FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see
epfile->in as 0, leading to incorrect DMA directions.
By moving the initialization to ffs_epfiles_create(), epfile->in is
accurate before userspace opens the endpoint files.