On 2019-8-19 18:34, Gao Xiang wrote:
> As reported by erofs-utils fuzzer, currently, multiref
> (ondisk deduplication) hasn't been supported for now,
> we should forbid it properly.
>
> Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.19+
> Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx>
> ---
> drivers/staging/erofs/zdata.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/erofs/zdata.c b/drivers/staging/erofs/zdata.c
> index aae2f2b8353f..5b6fef5181af 100644
> --- a/drivers/staging/erofs/zdata.c
> +++ b/drivers/staging/erofs/zdata.c
> @@ -816,8 +816,16 @@ static int z_erofs_decompress_pcluster(struct super_block *sb,
> pagenr = z_erofs_onlinepage_index(page);
>
> DBG_BUGON(pagenr >= nr_pages);
> - DBG_BUGON(pages[pagenr]);
>
> + /*
> + * currently EROFS doesn't support multiref(dedup),
> + * so here erroring out one multiref page.
> + */
> + if (unlikely(pages[pagenr])) {
> + DBG_BUGON(1);
> + SetPageError(pages[pagenr]);
> + z_erofs_onlinepage_endio(pages[pagenr]);
Should set err meanwhile?
> + }
> pages[pagenr] = page;
> }
> z_erofs_pagevec_ctor_exit(&ctor, true);
> @@ -849,7 +857,11 @@ static int z_erofs_decompress_pcluster(struct super_block *sb,
> pagenr = z_erofs_onlinepage_index(page);
>
> DBG_BUGON(pagenr >= nr_pages);
> - DBG_BUGON(pages[pagenr]);
> + if (unlikely(pages[pagenr])) {
> + DBG_BUGON(1);
> + SetPageError(pages[pagenr]);
> + z_erofs_onlinepage_endio(pages[pagenr]);
> + }
> pages[pagenr] = page;
>
> overlapped = true;
>
