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Commit f014824e authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
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[S390] cio: fix use after free in s390 debug feature 



When using s390dbf with "%s" in sprintf format strings the string itself
is not copied to the dbf buffer.
Since in this case only pointers are stored in the s390dbf, we should
not use dev_name - which is bound to the lifetime of the device.
Reading this entry from s390dbf after the device was released will cause
an use after free error.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 3f09bb89

drivers/s390/cio/device.c

+9 −5
Original line number Diff line number Diff line
@@ -2038,7 +2038,9 @@ static void __ccw_device_pm_restore(struct ccw_device *cdev) 
	spin_unlock_irq(sch->lock);

	if (ret) {

		CIO_MSG_EVENT(0, "Couldn't start recognition for device "

			      "%s (ret=%d)\n", dev_name(&cdev->dev), ret);

			      "0.%x.%04x (ret=%d)\n",

			      cdev->private->dev_id.ssid,

			      cdev->private->dev_id.devno, ret);

		spin_lock_irq(sch->lock);

		cdev->private->state = DEV_STATE_DISCONNECTED;

		spin_unlock_irq(sch->lock);
@@ -2101,8 +2103,9 @@ static int ccw_device_pm_restore(struct device *dev) 
	}

	/* check if the device id has changed */

	if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {

		CIO_MSG_EVENT(0, "resume: sch %s: failed (devno changed from "

			      "%04x to %04x)\n", dev_name(&sch->dev),

		CIO_MSG_EVENT(0, "resume: sch 0.%x.%04x: failed (devno "

			      "changed from %04x to %04x)\n",

			      sch->schid.ssid, sch->schid.sch_no,

			      cdev->private->dev_id.devno,

			      sch->schib.pmcw.dev);

		goto out_unreg_unlock;
@@ -2135,8 +2138,9 @@ static int ccw_device_pm_restore(struct device *dev) 
	if (cm_enabled) {

		ret = ccw_set_cmf(cdev, 1);

		if (ret) {

			CIO_MSG_EVENT(2, "resume: cdev %s: cmf failed "

				      "(rc=%d)\n", dev_name(&cdev->dev), ret);

			CIO_MSG_EVENT(2, "resume: cdev 0.%x.%04x: cmf failed "

				      "(rc=%d)\n", cdev->private->dev_id.ssid,

				      cdev->private->dev_id.devno, ret);

			ret = 0;

		}

	}