From: Miklos Szeredi <mszeredi@redhat.com>
Date: Tue, 22 Jun 2021 07:15:35 +0000 (+0200)
Subject: fuse: reject internal errno
X-Git-Tag: v4.4.276~67
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c9ad6621c7cc9221fa4b00874bd951fe7fc92106;p=thirdparty%2Fkernel%2Fstable.git

fuse: reject internal errno

commit 49221cf86d18bb66fe95d3338cb33bd4b9880ca5 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index d74675364f7b3..38a12b0e395fd 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1931,7 +1931,7 @@ 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 err_finish;
 
 	spin_lock(&fpq->lock);