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: <sta...@vger.kernel.org> # 4.19+
Signed-off-by: Gao Xiang <gaoxian...@huawei.com>
---
 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]);
+               }
                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;
-- 
2.17.1

_______________________________________________
devel mailing list
de...@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel

Reply via email to