This is a note to let you know that I've just added the patch titled

staging: erofs: detect potential multiref due to corrupted images

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-next branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release during the merge window.

If you have any questions about this process, please let me know.

From e12a0ce2fa69798194f3a8628baf6edfbd5c548f Mon Sep 17 00:00:00 2001

From: Gao Xiang gaoxiang25@huawei.com Date: Wed, 21 Aug 2019 22:01:52 +0800 Subject: staging: erofs: detect potential multiref due to corrupted images

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@vger.kernel.org # 4.19+ Signed-off-by: Gao Xiang gaoxiang25@huawei.com Reviewed-by: Chao Yu yuchao0@huawei.com Link: https://lore.kernel.org/r/20190821140152.229648-1-gaoxiang25@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/erofs/zdata.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/erofs/zdata.c b/drivers/staging/erofs/zdata.c index 4d6faaab04f5..60d7c20db87d 100644 --- a/drivers/staging/erofs/zdata.c +++ b/drivers/staging/erofs/zdata.c @@ -798,6 +798,7 @@ static int z_erofs_decompress_pcluster(struct super_block *sb, for (i = 0; i < nr_pages; ++i) pages[i] = NULL;

+ err = 0; z_erofs_pagevec_ctor_init(&ctor, Z_EROFS_NR_INLINE_PAGEVECS, cl->pagevec, 0);

@@ -819,8 +820,17 @@ 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]); + err = -EFSCORRUPTED; + } pages[pagenr] = page; } z_erofs_pagevec_ctor_exit(&ctor, true); @@ -828,7 +838,6 @@ static int z_erofs_decompress_pcluster(struct super_block *sb, overlapped = false; compressed_pages = pcl->compressed_pages;

- err = 0; for (i = 0; i < clusterpages; ++i) { unsigned int pagenr;

@@ -852,7 +861,12 @@ 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]); + err = -EFSCORRUPTED; + } pages[pagenr] = page;

overlapped = true;