From: Chao Yu yuchao0@huawei.com
[ Upstream commit 79bbefb19f1359fb2cbd144d5a054649e7e583be ]
If both compression and fsverity feature is on, generic/572 will report below NULL pointer dereference bug.
BUG: kernel NULL pointer dereference, address: 0000000000000018 RIP: 0010:f2fs_verity_work+0x60/0x90 [f2fs] #PF: supervisor read access in kernel mode Workqueue: fsverity_read_queue f2fs_verity_work [f2fs] RIP: 0010:f2fs_verity_work+0x60/0x90 [f2fs] Call Trace: process_one_work+0x16c/0x3f0 worker_thread+0x4c/0x440 ? rescuer_thread+0x350/0x350 kthread+0xf8/0x130 ? kthread_unpark+0x70/0x70 ret_from_fork+0x35/0x40
There are two issue in f2fs_verity_work(): - it needs to traverse and verify all pages in bio. - if pages in bio belong to non-compressed cluster, accessing decompress IO context stored in page private will cause NULL pointer dereference.
Fix them.
Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/compress.c | 2 ++ fs/f2fs/data.c | 35 ++++++++++++++++++++++++++++++----- 2 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index 1a86e483b0907..eb84c13c1182c 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -476,6 +476,8 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity) out_vunmap_rbuf: vunmap(dic->rbuf); out_free_dic: + if (verity) + refcount_add(dic->nr_cpages - 1, &dic->ref); if (!verity) f2fs_decompress_end_io(dic->rpages, dic->cluster_size, ret, false); diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index b27b721079116..34990866cfe96 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -191,12 +191,37 @@ static void f2fs_verify_pages(struct page **rpages, unsigned int cluster_size)
static void f2fs_verify_bio(struct bio *bio) { - struct page *page = bio_first_page_all(bio); - struct decompress_io_ctx *dic = - (struct decompress_io_ctx *)page_private(page); + struct bio_vec *bv; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bv, bio, iter_all) { + struct page *page = bv->bv_page; + struct decompress_io_ctx *dic; + + dic = (struct decompress_io_ctx *)page_private(page); + + if (dic) { + if (refcount_dec_not_one(&dic->ref)) + continue; + f2fs_verify_pages(dic->rpages, + dic->cluster_size); + f2fs_free_dic(dic); + continue; + } + + if (bio->bi_status || PageError(page)) + goto clear_uptodate;
- f2fs_verify_pages(dic->rpages, dic->cluster_size); - f2fs_free_dic(dic); + if (fsverity_verify_page(page)) { + SetPageUptodate(page); + goto unlock; + } +clear_uptodate: + ClearPageUptodate(page); + ClearPageError(page); +unlock: + unlock_page(page); + } } #endif