From: Alessio Balsini balsini@android.com
[ Upstream commit 6076f5f341e612152879bfda99f0b76c1953bf0b ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/fuse/dev.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index c0fee830a34e..a5ceccc5ef00 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -2233,11 +2233,8 @@ static long fuse_dev_ioctl(struct file *file, unsigned int cmd, int oldfd; struct fuse_dev *fud = NULL;
- if (_IOC_TYPE(cmd) != FUSE_DEV_IOC_MAGIC) - return -ENOTTY; - - switch (_IOC_NR(cmd)) { - case _IOC_NR(FUSE_DEV_IOC_CLONE): + switch (cmd) { + case FUSE_DEV_IOC_CLONE: res = -EFAULT; if (!get_user(oldfd, (__u32 __user *)arg)) { struct file *old = fget(oldfd);