linux/include/target
Nicholas Bellinger 057085e522 target: Fix race for SCF_COMPARE_AND_WRITE_POST checking
This patch addresses a race + use after free where the first
stage of COMPARE_AND_WRITE in compare_and_write_callback()
is rescheduled after the backend sends the secondary WRITE,
resulting in second stage compare_and_write_post() callback
completing in target_complete_ok_work() before the first
can return.

Because current code depends on checking se_cmd->se_cmd_flags
after return from se_cmd->transport_complete_callback(),
this results in first stage having SCF_COMPARE_AND_WRITE_POST
set, which incorrectly falls through into second stage CAW
processing code, eventually triggering a NULL pointer
dereference due to use after free.

To address this bug, pass in a new *post_ret parameter into
se_cmd->transport_complete_callback(), and depend upon this
value instead of ->se_cmd_flags to determine when to return
or fall through into ->queue_status() code for CAW.

Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-11-28 19:33:15 -08:00
..
iscsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-09-11 19:00:42 -07:00
target_core_backend.h target: Return descriptor format sense data in case the LU spans 64bit sectors 2015-07-23 22:54:21 -07:00
target_core_base.h target: Fix race for SCF_COMPARE_AND_WRITE_POST checking 2015-11-28 19:33:15 -08:00
target_core_fabric.h target/qla2xxx: Honor max_data_sg_nents I/O transfer limit 2015-09-11 00:31:39 -07:00