The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 49221cf86d18bb66fe95d3338cb33bd4b9880ca5 Mon Sep 17 00:00:00 2001

From: Miklos Szeredi mszeredi@redhat.com Date: Tue, 22 Jun 2021 09:15:35 +0200 Subject: [PATCH] fuse: reject internal errno

Don't allow userspace to report errors that could be kernel-internal.

Reported-by: Anatoly Trosinenko anatoly.trosinenko@gmail.com Fixes: 334f485df85a ("[PATCH] FUSE - device functions") Cc: stable@vger.kernel.org # v2.6.14 Signed-off-by: Miklos Szeredi mszeredi@redhat.com

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 6e63bcba2a40..b8d58aa08206 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1867,7 +1867,7 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud, }

err = -EINVAL; - if (oh.error <= -1000 || oh.error > 0) + if (oh.error <= -512 || oh.error > 0) goto copy_finish;

spin_lock(&fpq->lock);