usb: gadget: f_fs: Fix ioctl error handling

[ Upstream commit 8e4c1d0618 ]

When ffs_epfile_ioctl handles FUNCTIONFS_DMABUF_* ioctls, it's currently
falling through when copy_from_user fails.

However, this fallthrough isn't being checked properly, so the handler
continues executing further than it should. It then tries the secondary
dispatch where it ultimately gives up and returns -ENOTTY.

The end result is invalid ioctl invocations will yield a -ENOTTY rather
than an -EFAULT.

It's a common pattern elsewhere in the kernel code to directly return
-EFAULT when copy_from_user fails. So we update ffs_epfile_ioctl to do
the same and fix this issue.

Signed-off-by: Sam Day <me@samcday.com>
Link: https://patch.msgid.link/20260108-ffs-dmabuf-ioctl-fix-v1-1-e51633891a81@samcday.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sam Day 2026-01-08 08:30:20 +10:00 • committed by Sasha Levin
commit 7a8ac86f51