[PATCH 4.19 026/239] f2fs: fix to do sanity check in is_alive()

[Greg Kroah-Hartman]

From: Chao Yu <chao@xxxxxxxxxx>

commit 77900c45ee5cd5da63bd4d818a41dbdf367e81cd upstream.

In fuzzed image, SSA table may indicate that a data block belongs to
invalid node, which node ID is out-of-range (0, 1, 2 or max_nid), in
order to avoid migrating inconsistent data in such corrupted image,
let's do sanity check anyway before data block migration.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/f2fs/gc.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -589,6 +589,9 @@ static bool is_alive(struct f2fs_sb_info
 		set_sbi_flag(sbi, SBI_NEED_FSCK);
 	}
 
+	if (f2fs_check_nid_range(sbi, dni->ino))
+		return false;
+
 	*nofs = ofs_of_node(node_page);
 	source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
 	f2fs_put_page(node_page, 1);