[PATCH AUTOSEL 4.14 096/150] hfs: fix BUG on bnode parent update

Sasha Levin
2019-11-16T15:49:56Z

From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit ef75bcc5763d130451a99825f247d301088b790b ]

hfs_brec_update_parent() may hit BUG_ON() if the first record of both a
leaf node and its parent are changed, and if this forces the parent to
be split. It is not possible for this to happen on a valid hfs
filesystem because the index nodes have fixed length keys.

For reasons I ignore, the hfs module does have support for a number of
hfsplus features. A corrupt btree header may report variable length
keys and trigger this BUG, so it's better to fix it.

Link: http://lkml.kernel.org/r/cf9b02d57f806217a2b1bf5db8c3e39730d8f603.1535682463.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
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 <sashal@kernel.org>
---
fs/hfs/brec.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c
index da25c49203cc5..896396554bcc1 100644
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -445,6 +445,7 @@ static int hfs_brec_update_parent(struct hfs_find_data *fd)
/* restore search_key */
hfs_bnode_read_key(node, fd->search_key, 14);
}
+ new_node = NULL;
}

if (!rec && node->parent)
--
2.20.1