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Date:   Sat, 20 May 2023 11:21:08 +0200
From:   Christian Brauner <brauner@kernel.org>
To:     David Howells <dhowells@redhat.com>
Cc:     Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        Jeff Layton <jlayton@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Hillf Danton <hdanton@sina.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Christoph Hellwig <hch@lst.de>,
        Steve French <stfrench@microsoft.com>,
        John Hubbard <jhubbard@nvidia.com>
Subject: Re: [PATCH v21 02/30] splice: Make filemap_splice_read() check
 s_maxbytes
Message-ID: <20230520-abzweigen-jurymitglied-600e651d784b@brauner>
References: <20230520000049.2226926-1-dhowells@redhat.com>
 <20230520000049.2226926-3-dhowells@redhat.com>
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On Sat, May 20, 2023 at 01:00:21AM +0100, David Howells wrote:
> Make filemap_splice_read() check s_maxbytes analogously to filemap_read().
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Christoph Hellwig <hch@lst.de>
> cc: Steve French <stfrench@microsoft.com>
> cc: Jens Axboe <axboe@kernel.dk>
> cc: Al Viro <viro@zeniv.linux.org.uk>
> cc: David Hildenbrand <david@redhat.com>
> cc: John Hubbard <jhubbard@nvidia.com>
> cc: linux-mm@kvack.org
> cc: linux-block@vger.kernel.org
> cc: linux-fsdevel@vger.kernel.org
> ---
>  mm/filemap.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index a2006936a6ae..0fcb0b80c2e2 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2887,6 +2887,9 @@ ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
>  	bool writably_mapped;
>  	int i, error = 0;
>  
> +	if (unlikely(*ppos >= in->f_mapping->host->i_sb->s_maxbytes))

Pointer deref galore
Reviewed-by: Christian Brauner <brauner@kernel.org>