| Message ID | 20210910010220.24073-3-dinghui@sangfor.com.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | fix several bugs about libiscsi | expand |
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); >
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 <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); >> >
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);
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 <dinghui@sangfor.com.cn> --- drivers/scsi/libiscsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)