Commit 8e4c1d06 authored by Sam Day's avatar Sam Day Committed by Greg Kroah-Hartman
Browse files

usb: gadget: f_fs: Fix ioctl error handling 



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: default avatarSam Day <me@samcday.com>
Link: https://patch.msgid.link/20260108-ffs-dmabuf-ioctl-fix-v1-1-e51633891a81@samcday.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent da0faa25

drivers/usb/gadget/function/f_fs.c

+6 −12
Original line number Diff line number Diff line
@@ -1748,10 +1748,8 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, 
	{

		int fd;



		if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {

			ret = -EFAULT;

			break;

		}

		if (copy_from_user(&fd, (void __user *)value, sizeof(fd)))

			return -EFAULT;



		return ffs_dmabuf_attach(file, fd);

	}
@@ -1759,10 +1757,8 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, 
	{

		int fd;



		if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {

			ret = -EFAULT;

			break;

		}

		if (copy_from_user(&fd, (void __user *)value, sizeof(fd)))

			return -EFAULT;



		return ffs_dmabuf_detach(file, fd);

	}
@@ -1770,10 +1766,8 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, 
	{

		struct usb_ffs_dmabuf_transfer_req req;



		if (copy_from_user(&req, (void __user *)value, sizeof(req))) {

			ret = -EFAULT;

			break;

		}

		if (copy_from_user(&req, (void __user *)value, sizeof(req)))

			return -EFAULT;



		return ffs_dmabuf_transfer(file, &req);

	}