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);
>
next prev parent 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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