From 79bbefb19f1359fb2cbd144d5a054649e7e583be Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Mon, 23 Mar 2020 17:43:04 +0800 Subject: f2fs: fix NULL pointer dereference in f2fs_verity_work() 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 Signed-off-by: Jaegeuk Kim --- fs/f2fs/compress.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/f2fs/compress.c') diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index d66d372d104d..adac6fcb2830 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -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); -- cgit v1.2.3