[PATCH AUTOSEL 5.10 09/24] scsi: target: iscsit: Free cmds before session free

Sasha Levin
2023-05-04T20:02:25Z

From: Dmitry Bogdanov <d.bogdanov@yadro.com>

[ Upstream commit d8990b5a4d065f38f35d69bcd627ec5a7f8330ca ]

Commands from recovery entries are freed after 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>
Link: https://lore.kernel.org/r/20230319015620.96006-7-michael.christie@oracle.com
Reviewed-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 a237f1cf9bd60..7ad290577320e 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -4383,6 +4383,9 @@ int iscsit_close_session(struct iscsi_session *sess)
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
@@ -4410,9 +4413,6 @@ int iscsit_close_session(struct iscsi_session *sess)

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);
--
2.39.2