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From: Mike Christie <michael.christie@oracle.com>
To: Ding Hui <dinghui@sangfor.com.cn>,
	lduncan@suse.com, cleech@redhat.com, jejb@linux.ibm.com,
	martin.petersen@oracle.com, open-iscsi@googlegroups.com,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] scsi: libiscsi: fix invalid pointer dereference in iscsi_eh_session_reset
Date: Fri, 10 Sep 2021 11:38:51 -0500	[thread overview]
Message-ID: <302af74d-5b72-5b2f-050a-33f0978e321f@oracle.com> (raw)
In-Reply-To: <20210910010220.24073-3-dinghui@sangfor.com.cn>

On 9/9/21 8:02 PM, Ding Hui wrote:
> like commit 5db6dd14b313 ("scsi: libiscsi: Fix NULL pointer dereference in
> iscsi_eh_session_reset"), access conn->persistent_address here is not safe
> too.
> 
> The persistent_address is independent of conn refcount, so maybe
> already freed by iscsi_conn_teardown(), also we put the refcount of conn
> above, the conn pointer may be invalid.

This shouldn't happen like you describe above, because when we wake up
we will see the session->state is ISCSI_STATE_TERMINATE. We will then
not reference the conn in that code below.

However, it looks like we could hit an issue where if a user was resetting
the persistent_address or targetname via iscsi_set_param -> iscsi_switch_str_param
then we could be accessing freed memory. I think we need the frwd_lock when swapping
the strings in iscsi_switch_str_param.


> 
> Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
> ---
>  drivers/scsi/libiscsi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
> index 712a45368385..69b3b2148328 100644
> --- a/drivers/scsi/libiscsi.c
> +++ b/drivers/scsi/libiscsi.c
> @@ -2531,8 +2531,8 @@ int iscsi_eh_session_reset(struct scsi_cmnd *sc)
>  	spin_lock_bh(&session->frwd_lock);
>  	if (session->state == ISCSI_STATE_LOGGED_IN) {
>  		ISCSI_DBG_EH(session,
> -			     "session reset succeeded for %s,%s\n",
> -			     session->targetname, conn->persistent_address);
> +			     "session reset succeeded for %s\n",
> +			     session->targetname);
>  	} else
>  		goto failed;
>  	spin_unlock_bh(&session->frwd_lock);
> 


  reply	other threads:[~2021-09-10 16:39 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-10  1:02 [RESEND] [PATCH 0/3] fix several bugs about libiscsi Ding Hui
2021-09-10  1:02 ` [PATCH 1/3] scsi: libiscsi: move init ehwait to iscsi_session_setup() Ding Hui
2021-09-10 16:25   ` Mike Christie
2021-09-11  9:37     ` Ding Hui
2021-09-10  1:02 ` [PATCH 2/3] scsi: libiscsi: fix invalid pointer dereference in iscsi_eh_session_reset Ding Hui
2021-09-10 16:38   ` Mike Christie [this message]
2021-09-11  9:52     ` Ding Hui
2021-09-10  1:02 ` [PATCH 3/3] scsi: libiscsi: get ref to conn in iscsi_eh_device/target_reset() Ding Hui
2021-09-10 16:46   ` Mike Christie
  -- strict thread matches above, loose matches on Subject: below --
2021-09-09 15:47 [PATCH 1/3] scsi: libiscsi: move init ehwait to iscsi_session_setup() Ding Hui
2021-09-09 15:47 ` [PATCH 2/3] scsi: libiscsi: fix invalid pointer dereference in iscsi_eh_session_reset Ding Hui

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