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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Anatoly Trosinenko <anatoly.trosinenko@gmail.com>,
        Miklos Szeredi <mszeredi@redhat.com>
Subject: [PATCH 4.9 157/245] fuse: reject internal errno
Date:   Mon, 19 Jul 2021 16:51:39 +0200
Message-Id: <20210719144945.481765333@linuxfoundation.org>
In-Reply-To: <20210719144940.288257948@linuxfoundation.org>
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From: Miklos Szeredi <mszeredi@redhat.com>

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>

---
 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);