[PATCH] libiscsi: Fix use-after-free race during iscsi_session_teardown

From: Khazhismel Kumykov
Date: Wed Jul 12 2017 - 19:07:58 EST


Session attributes exposed through sysfs were freed before the device
was destroyed, resulting in a potential use-after-free. Free these
attributes after removing the device.

Signed-off-by: Khazhismel Kumykov <khazhy@xxxxxxxxxx>
---
drivers/scsi/libiscsi.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 42381adf0769..f9199bebaec7 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -2851,9 +2851,6 @@ EXPORT_SYMBOL_GPL(iscsi_session_setup);
/**
* iscsi_session_teardown - destroy session, host, and cls_session
* @cls_session: iscsi session
- *
- * The driver must have called iscsi_remove_session before
- * calling this.
*/
void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
{
@@ -2863,6 +2860,8 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)

iscsi_pool_free(&session->cmdpool);

+ iscsi_remove_session(session);
+
kfree(session->password);
kfree(session->password_in);
kfree(session->username);
@@ -2877,7 +2876,8 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
kfree(session->portal_type);
kfree(session->discovery_parent_type);

- iscsi_destroy_session(cls_session);
+ iscsi_free_session(cls_session);
+
iscsi_host_dec_session_cnt(shost);
module_put(owner);
}
--
2.13.2.932.g7449e964c-goog

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