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.
Signed-off-by: Ding Hui <[email protected]>
---
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);
--
2.17.1
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 <[email protected]>
> ---
> 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);
>
On 2021/9/11 12:38 上午, Mike Christie wrote:
> 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.
>
Thanks for your detailed explanation, I'll drop 2/3 and 3/3 in v2 patch.
I expect that the persistent_address issue be fixed in your future patchset.
Sorry for my ignorance.
>
>>
>> Signed-off-by: Ding Hui <[email protected]>
>> ---
>> 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);
>>
>
--
Thanks,
-dinghui