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xen/scsiback: Fix a TMR related use-after-free 

scsiback_release_cmd() must not dereference se_cmd->se_tmr_req
because that memory is freed by target_free_cmd_mem() before
scsiback_release_cmd() is called. Fix this use-after-free by
inlining struct scsiback_tmr into struct vscsibk_pend.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: David Disseldorp <ddiss@suse.de>
Cc: xen-devel@lists.xenproject.org
Cc: <stable@vger.kernel.org> # 3.18+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Bart Van Assche 2017-05-23 16:48:36 -07:00 committed by Nicholas Bellinger
parent 13fdd4458e
commit 9f4ab18ac5
1 changed files with 9 additions and 24 deletions
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33
drivers/xen/xen-scsiback.c
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@ -134,9 +134,7 @@ struct vscsibk_pend {
struct page *pages[VSCSI_MAX_GRANTS];
struct se_cmd se_cmd;
};
struct scsiback_tmr {
atomic_t tmr_complete;
wait_queue_head_t tmr_wait;
};
@ -599,26 +597,20 @@ static void scsiback_device_action(struct vscsibk_pend *pending_req,
struct scsiback_tpg *tpg = pending_req->v2p->tpg;
struct scsiback_nexus *nexus = tpg->tpg_nexus;
struct se_cmd *se_cmd = &pending_req->se_cmd;
struct scsiback_tmr *tmr;
u64 unpacked_lun = pending_req->v2p->lun;
int rc, err = FAILED;
tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
if (!tmr) {
target_put_sess_cmd(se_cmd);
goto err;
}
init_waitqueue_head(&tmr->tmr_wait);
init_waitqueue_head(&pending_req->tmr_wait);
rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
&pending_req->sense_buffer[0],
unpacked_lun, tmr, act, GFP_KERNEL,
unpacked_lun, NULL, act, GFP_KERNEL,
tag, TARGET_SCF_ACK_KREF);
if (rc)
goto err;
wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
wait_event(pending_req->tmr_wait,
atomic_read(&pending_req->tmr_complete));
err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
SUCCESS : FAILED;
@ -626,9 +618,8 @@ static void scsiback_device_action(struct vscsibk_pend *pending_req,
scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
transport_generic_free_cmd(&pending_req->se_cmd, 1);
return;
err:
if (tmr)
kfree(tmr);
scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
}
@ -1389,12 +1380,6 @@ static int scsiback_check_stop_free(struct se_cmd *se_cmd)
static void scsiback_release_cmd(struct se_cmd *se_cmd)
{
struct se_session *se_sess = se_cmd->se_sess;
struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
if (se_tmr && se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) {
struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
kfree(tmr);
}
percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
}
@ -1455,11 +1440,11 @@ static int scsiback_queue_status(struct se_cmd *se_cmd)
static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
{
struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
struct vscsibk_pend *pending_req = container_of(se_cmd,
struct vscsibk_pend, se_cmd);
atomic_set(&tmr->tmr_complete, 1);
wake_up(&tmr->tmr_wait);
atomic_set(&pending_req->tmr_complete, 1);
wake_up(&pending_req->tmr_wait);
}
static void scsiback_aborted_task(struct se_cmd *se_cmd)