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authorErnesto A. Fernández <ernesto.mnd.fernandez@gmail.com>2018-10-30 15:06:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-31 08:54:13 -0700
commitd057c036672f33d43a5f7344acbb08cf3a8a0c09 (patch)
tree8bffb2a92f5aee8f9cce013f5476992c8a528ffb
parent19a9d0f1acf75e8be8cfba19c1a34e941846fa2b (diff)
downloadlinux-d057c036672f33d43a5f7344acbb08cf3a8a0c09.tar.bz2
hfs: prevent btree data loss on root split
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>
-rw-r--r--fs/hfs/brec.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c
index 9a8772465a90..da25c49203cc 100644
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -425,6 +425,10 @@ 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);