hfs: prevent crash on exit from failed search

[ Upstream commit dc2572791d3a41bab94400af2b6bca9d71ccd303 ]

hfs_find_exit() expects fd->bnode to be NULL after a search has failed.
hfs_brec_insert() may instead set it to an error-valued pointer.  Fix
this to prevent a crash.

Link: http://lkml.kernel.org/r/53d9749a029c41b4016c495fc5838c9dba3afc52.1530294815.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c
index 6fc766d..2a6f3c6 100644 (file)
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -74,9 +74,10 @@ int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
        if (!fd->bnode) {
                if (!tree->root)
                        hfs_btree_inc_height(tree);
-               fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
-               if (IS_ERR(fd->bnode))
-                       return PTR_ERR(fd->bnode);
+               node = hfs_bnode_find(tree, tree->leaf_head);
+               if (IS_ERR(node))
+                       return PTR_ERR(node);
+               fd->bnode = node;
                fd->record = -1;
        }
        new_node = NULL;