ntfs: fix NULL dereference on index allocation open failure

ntfs_index_lookup() returns -ENOENT when ntfs_ia_open() fails to open the
index allocation. This error path leaves icx->ib unset, unlike a missing
key in an otherwise valid index, which returns an insertion context.

ntfs_ie_add() treats -ENOENT as a valid insertion position and dereferences
icx->ib when the lookup is not in the index root. A corrupt $I30 bitmap
attribute can therefore cause a NULL pointer dereference when adding a
directory entry.

Return -EIO for index allocation open failures so insertion aborts through
the existing error path. Keep -ENOENT for genuinely missing keys and
document that other errors leave no valid index entry.

Fixes: 0a8ac0c1fa0b ("ntfs: update directory operations")
Reported-by: 1sh1ro <yangguikun19@qq.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions