f2fs: fix NULL pointer dereference in f2fs_verity_work() (79bbefb1) · Commits · 戴 / test

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>

fs/f2fs/compress.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -477,6 +477,8 @@ out_vunmap_cbuf:
		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);

fs/f2fs/data.c

+30 −5

Original line number	Diff line number	Diff line
		@@ -187,12 +187,37 @@ 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;

		f2fs_verify_pages(dic->rpages, dic->cluster_size);
		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;

		if (fsverity_verify_page(page)) {
		SetPageUptodate(page);
		goto unlock;
		}
		clear_uptodate:
		ClearPageUptodate(page);
		ClearPageError(page);
		unlock:
		unlock_page(page);
		}
		}
		#endif

Admin message