Re: [PATCH v3 14/14] scsi: target: iscsit: free cmds before session free

[Maurizio Lombardi <mlombard@redhat.com>]

po 30. 1. 2023 v 0:45 odesílatel Mike Christie
<michael.christie@oracle.com> napsal:
>
> From: Dmitry Bogdanov <d.bogdanov@yadro.com>
>
> Commands from recovery entries are freed after its session has been
> closed. That leads to use-after-free at command free or NPE with such
> call trace:
>
> Time2Retain timer expired for SID: 1, cleaning up iSCSI session.
> BUG: kernel NULL pointer dereference, address: 0000000000000140
> RIP: 0010:sbitmap_queue_clear+0x3a/0xa0
> Call Trace:
>  target_release_cmd_kref+0xd1/0x1f0 [target_core_mod]
>  transport_generic_free_cmd+0xd1/0x180 [target_core_mod]
>  iscsit_free_cmd+0x53/0xd0 [iscsi_target_mod]
>  iscsit_free_connection_recovery_entries+0x29d/0x320 [iscsi_target_mod]
>  iscsit_close_session+0x13a/0x140 [iscsi_target_mod]
>  iscsit_check_post_dataout+0x440/0x440 [iscsi_target_mod]
>  call_timer_fn+0x24/0x140
>
> Move cleanup of recovery enrties to before session freeing.
>
> Reported-by: Forza <forza@tnonline.net>
> Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
> Signed-off-by: Mike Christie <michael.christie@oracle.com>
> ---
>  drivers/target/iscsi/iscsi_target.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
> index a57527beb340..eac5af87ccd8 100644
> --- a/drivers/target/iscsi/iscsi_target.c
> +++ b/drivers/target/iscsi/iscsi_target.c
> @@ -4547,6 +4547,9 @@ int iscsit_close_session(struct iscsit_session *sess, bool can_sleep)
>         iscsit_stop_time2retain_timer(sess);
>         spin_unlock_bh(&se_tpg->session_lock);
>
> +       if (sess->sess_ops->ErrorRecoveryLevel == 2)
> +               iscsit_free_connection_recovery_entries(sess);
> +
>         /*
>          * transport_deregister_session_configfs() will clear the
>          * struct se_node_acl->nacl_sess pointer now as a iscsi_np process context
> @@ -4570,9 +4573,6 @@ int iscsit_close_session(struct iscsit_session *sess, bool can_sleep)
>
>         transport_deregister_session(sess->se_sess);
>
> -       if (sess->sess_ops->ErrorRecoveryLevel == 2)
> -               iscsit_free_connection_recovery_entries(sess);
> -
>         iscsit_free_all_ooo_cmdsns(sess);
>
>         spin_lock_bh(&se_tpg->session_lock);
> --
> 2.25.1
>

Reviewed-by: Maurizio Lombardi <mlombard@redhat.com>