Bluetooth: mgmt: fix pending command UAF in EIR updates

Bluetooth: mgmt: fix pending command UAF in EIR updates

MGMT_OP_SET_LOCAL_NAME is handled asynchronously on powered controllers
and can run set_name_sync().  When the controller is BR/EDR capable,
set_name_sync() updates the local name and then rebuilds EIR data through
eir_create().  The EIR builder walks hdev->uuids, but the UUID list can
be changed and entries can be freed by MGMT_OP_ADD_UUID and
MGMT_OP_REMOVE_UUID.

pending_eir_or_class() is meant to serialize management commands that
can change EIR or the class of device, but it did not include
MGMT_OP_SET_LOCAL_NAME.  In addition, it walked hdev->mgmt_pending
without hdev->mgmt_pending_lock even though pending commands are added
and removed under that mutex.  A racing command completion can therefore
remove and free a pending command while pending_eir_or_class() is still
inspecting it, leading to a use-after-free in the pending-command list or
allowing a local name update to rebuild EIR while UUID entries are being
removed.

Take hdev->mgmt_pending_lock while scanning hdev->mgmt_pending and treat
MGMT_OP_SET_LOCAL_NAME as an EIR/class-affecting pending command on the
powered asynchronous path.  Check for a conflicting pending command before
copying the new short name so a rejected SET_LOCAL_NAME request does not
modify hdev->short_name.

Fixes: 6fe26f694c82 ("Bluetooth: MGMT: Protect mgmt_pending list with its own lock")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: Codex:gpt-5.4
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Signed-off-by: Ren Wei <enjou1224z@gmail.com>
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>