[PATCH 4.9 157/245] fuse: reject internal errno

From: Greg Kroah-Hartman
Date: Mon Jul 19 2021 - 11:20:46 EST


From: Miklos Szeredi <mszeredi@xxxxxxxxxx>

commit 49221cf86d18bb66fe95d3338cb33bd4b9880ca5 upstream.

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

Reported-by: Anatoly Trosinenko <anatoly.trosinenko@xxxxxxxxx>
Fixes: 334f485df85a ("[PATCH] FUSE - device functions")
Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.14
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/fuse/dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1883,7 +1883,7 @@ static ssize_t fuse_dev_do_write(struct
}

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

spin_lock(&fpq->lock);