fuse: fix matching of FUSE_DEV_IOC_CLONE command
authorAlessio Balsini <balsini@android.com>
Fri, 19 Mar 2021 15:05:14 +0000 (15:05 +0000)
committerMiklos Szeredi <mszeredi@redhat.com>
Wed, 14 Apr 2021 08:40:57 +0000 (10:40 +0200)
commit6076f5f341e612152879bfda99f0b76c1953bf0b
tree8b390af9ddf99cabc2a55ca566fe0c35fec5db20
parentaa6ff555f0e62bc1c85a2d181c1fae95d47c00ce
fuse: fix matching of FUSE_DEV_IOC_CLONE command

With commit f8425c939663 ("fuse: 32-bit user space ioctl compat for fuse
device") the matching constraints for the FUSE_DEV_IOC_CLONE ioctl command
are relaxed, limited to the testing of command type and number.  As Arnd
noticed, this is wrong as it wouldn't ensure the correctness of the data
size or direction for the received FUSE device ioctl.

Fix by bringing back the comparison of the ioctl received by the FUSE
device to the originally generated FUSE_DEV_IOC_CLONE.

Fixes: f8425c939663 ("fuse: 32-bit user space ioctl compat for fuse device")
Reported-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fs/fuse/dev.c