In case a malicious initiator sends some random data immediately after a login PDU; the iscsi_target_sk_data_ready() callback will schedule the login_work and, at the same time, the negotiation may end without clearing the LOGIN_FLAGS_INITIAL_PDU flag (because no additional PDU exchanges are required to complete the login). The login has been completed but the login_work function will find the LOGIN_FLAGS_INITIAL_PDU flag set and will never stop from rescheduling itself; at this point, if the initiator drops the connection, the iscsit_conn structure will be freed, login_work will dereference a released socket structure and the kernel crashes. BUG: kernel NULL pointer dereference, address: 0000000000000230 PF: supervisor write access in kernel mode PF: error_code(0x0002) - not-present page Workqueue: events iscsi_target_do_login_rx [iscsi_target_mod] RIP: 0010:_raw_read_lock_bh+0x15/0x30 Call trace: iscsi_target_do_login_rx+0x75/0x3f0 [iscsi_target_mod] process_one_work+0x1e8/0x3c0 Fix this bug by forcing login_work to stop after the login has been completed and the socket callbacks have been restored. Signed-off-by: Maurizio Lombardi <mlombard@xxxxxxxxxx> --- drivers/target/iscsi/iscsi_target_nego.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index f2919319ad38..e58bdffe2931 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -1058,6 +1058,7 @@ static int iscsi_target_do_login(struct iscsit_conn *conn, struct iscsi_login *l login->tsih = conn->sess->tsih; login->login_complete = 1; iscsi_target_restore_sock_callbacks(conn); + cancel_delayed_work_sync(&conn->login_work); if (iscsi_target_do_tx_login_io(conn, login) < 0) return -1; -- 2.31.1
