Commit b4cb4ecd authored Oct 30, 2018 by Ernesto A. Fernández Committed by Greg Kroah-Hartman Nov 27, 2018

hfs: prevent btree data loss on root split

[ Upstream commit d057c036672f33d43a5f7344acbb08cf3a8a0c09 ]

This bug is triggered whenever hfs_brec_update_parent() needs to split
the root node.  The height of the btree is not increased, which leaves
the new node orphaned and its records lost.  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/9750b1415685c4adca10766895f6d5ef12babdb0.1535682463.git.ernesto.mnd.fernandez@gmail.com


Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
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>

parent 235fbd9c

fs/hfs/brec.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -424,6 +424,10 @@ skip:
		if (new_node) {
		__be32 cnid;

		if (!new_node->parent) {
		hfs_btree_inc_height(tree);
		new_node->parent = tree->root;
		}
		fd->bnode = hfs_bnode_find(tree, new_node->parent);
		/* create index key and entry */
		hfs_bnode_read_key(new_node, fd->search_key, 14);