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| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-07-22 00:24:09 -0700 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-07-24 14:19:43 -0700 |
| commit | 417c20a9bdd1e876384127cf096d8ae8b559066c (patch) | |
| tree | dc8c04ab25bf7d0d987f3fdb228fd361ed8e2364 /drivers/target | |
| parent | 7359df25a53386dd33c223672bbd12cb49d0ce4f (diff) | |
| download | linux-417c20a9bdd1e876384127cf096d8ae8b559066c.tar.bz2 | |
iscsi-target: Fix use-after-free during TPG session shutdown
This patch fixes a use-after-free bug in iscsit_release_sessions_for_tpg()
where se_portal_group->session_lock was incorrectly released/re-acquired
while walking the active se_portal_group->tpg_sess_list.
The can result in a NULL pointer dereference when iscsit_close_session()
shutdown happens in the normal path asynchronously to this code, causing
a bogus dereference of an already freed list entry to occur.
To address this bug, walk the session list checking for the same state
as before, but move entries to a local list to avoid dropping the lock
while walking the active list.
As before, signal using iscsi_session->session_restatement=1 for those
list entries to be released locally by iscsit_free_session() code.
Reported-by: Sunilkumar Nadumuttlu <sjn@datera.io>
Cc: Sunilkumar Nadumuttlu <sjn@datera.io>
Cc: <stable@vger.kernel.org> # v3.1+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
| -rw-r--r-- | drivers/target/iscsi/iscsi_target.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 4e68b62193ed..afab32376126 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -4765,6 +4765,7 @@ int iscsit_release_sessions_for_tpg(struct iscsi_portal_group *tpg, int force) struct iscsi_session *sess; struct se_portal_group *se_tpg = &tpg->tpg_se_tpg; struct se_session *se_sess, *se_sess_tmp; + LIST_HEAD(free_list); int session_count = 0; spin_lock_bh(&se_tpg->session_lock); @@ -4786,14 +4787,17 @@ int iscsit_release_sessions_for_tpg(struct iscsi_portal_group *tpg, int force) } atomic_set(&sess->session_reinstatement, 1); spin_unlock(&sess->conn_lock); - spin_unlock_bh(&se_tpg->session_lock); - iscsit_free_session(sess); - spin_lock_bh(&se_tpg->session_lock); + list_move_tail(&se_sess->sess_list, &free_list); + } + spin_unlock_bh(&se_tpg->session_lock); + list_for_each_entry_safe(se_sess, se_sess_tmp, &free_list, sess_list) { + sess = (struct iscsi_session *)se_sess->fabric_sess_ptr; + + iscsit_free_session(sess); session_count++; } - spin_unlock_bh(&se_tpg->session_lock); pr_debug("Released %d iSCSI Session(s) from Target Portal" " Group: %hu\n", session_count, tpg->tpgt); |