4.9-stable review patch. If anyone has any objections, please let me know.
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[ 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... 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 --- fs/hfs/brec.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c index 2a6f3c67cb3f..2e713673df42 100644 --- a/fs/hfs/brec.c +++ b/fs/hfs/brec.c @@ -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);