From: Simon Gander simon@tuxera.com
[ Upstream commit 25efb2ffdf991177e740b2f63e92b4ec7d310a92 ]
When removing files containing extended attributes, the hfsplus driver may remove the wrong entries from the attributes b-tree, causing major filesystem damage and in some cases even kernel crashes.
To remove a file, all its extended attributes have to be removed as well. The driver does this by looking up all keys in the attributes b-tree with the cnid of the file. Each of these entries then gets deleted using the key used for searching, which doesn't contain the attribute's name when it should. Since the key doesn't contain the name, the deletion routine will not find the correct entry and instead remove the one in front of it. If parent nodes have to be modified, these become corrupt as well. This causes invalid links and unsorted entries that not even macOS's fsck_hfs is able to fix.
To fix this, modify the search key before an entry is deleted from the attributes b-tree by copying the found entry's key into the search key, therefore ensuring that the correct entry gets removed from the tree.
Signed-off-by: Simon Gander simon@tuxera.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Reviewed-by: Anton Altaparmakov anton@tuxera.com Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20200327155541.1521-1-simon@tuxera.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/hfsplus/attributes.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/hfsplus/attributes.c b/fs/hfsplus/attributes.c index e6d554476db41..eeebe80c6be4a 100644 --- a/fs/hfsplus/attributes.c +++ b/fs/hfsplus/attributes.c @@ -292,6 +292,10 @@ static int __hfsplus_delete_attr(struct inode *inode, u32 cnid, return -ENOENT; }
+ /* Avoid btree corruption */ + hfs_bnode_read(fd->bnode, fd->search_key, + fd->keyoffset, fd->keylength); + err = hfs_brec_remove(fd); if (err) return err;