• Simon Gander's avatar
    hfsplus: fix crash and filesystem corruption when deleting files · 25efb2ff
    Simon Gander authored
    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: default avatarSimon Gander <simon@tuxera.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Reviewed-by: default avatarAnton Altaparmakov <anton@tuxera.com>
    Cc: <stable@vger.kernel.org>
    Link: http://lkml.kernel.org/r/20200327155541.1521-1-simon@tuxera.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    25efb2ff
attributes.c 8.65 KB