From 1c21a48055a67ceb693e9c2587824a8de60a217c Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Fri, 27 Oct 2017 22:19:26 -0800 Subject: target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK This patch fixes bug where early se_cmd exceptions that occur before backend execution can result in use-after-free if/when a subsequent ABORT_TASK occurs for the same tag. Since an early se_cmd exception will have had se_cmd added to se_session->sess_cmd_list via target_get_sess_cmd(), it will not have CMD_T_COMPLETE set by the usual target_complete_cmd() backend completion path. This causes a subsequent ABORT_TASK + __target_check_io_state() to signal ABORT_TASK should proceed. As core_tmr_abort_task() executes, it will bring the outstanding se_cmd->cmd_kref count down to zero releasing se_cmd, after se_cmd has already been queued with error status into fabric driver response path code. To address this bug, introduce a CMD_T_PRE_EXECUTE bit that is set at target_get_sess_cmd() time, and cleared immediately before backend driver dispatch in target_execute_cmd() once CMD_T_ACTIVE is set. Then, check CMD_T_PRE_EXECUTE within __target_check_io_state() to determine when an early exception has occured, and avoid aborting this se_cmd since it will have already been queued into fabric driver response path code. Reported-by: Donald White Cc: Donald White Cc: Mike Christie Cc: Hannes Reinecke Cc: stable@vger.kernel.org # 3.14+ Signed-off-by: Nicholas Bellinger --- include/target/target_core_base.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/target') diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index d3139a95ea77..ccf501b8359c 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -490,6 +490,7 @@ struct se_cmd { #define CMD_T_STOP (1 << 5) #define CMD_T_TAS (1 << 10) #define CMD_T_FABRIC_STOP (1 << 11) +#define CMD_T_PRE_EXECUTE (1 << 12) spinlock_t t_state_lock; struct kref cmd_kref; struct completion t_transport_stop_comp; -- cgit v1.2.3