[PATCH] hfsplus: fix null-ptr-deref in hfs_find_init()

[Yang Yingliang]

It may lead a null-ptr-deref in hfs_find_init() by
mounting a crafted hfs filesystem. So We need check
tree in hfs_find_init().

Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
---
 fs/hfsplus/bfind.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c
index ca2ba8c..85bef3e 100644
--- a/fs/hfsplus/bfind.c
+++ b/fs/hfsplus/bfind.c
@@ -16,6 +16,9 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
 {
 	void *ptr;
 
+	if (!tree)
+		return -EINVAL;
+
 	fd->tree = tree;
 	fd->bnode = NULL;
 	ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
-- 
1.8.3