[PATCH 3.16 003/328] EDAC, i7core: Fix memleaks and use-after-free on probe and remove

[Ben Hutchings]

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit 6c974d4dfafe5e9ee754f2a6fba0eb1864f1649e upstream.

Make sure to free and deregister the addrmatch and chancounts devices
allocated during probe in all error paths. Also fix use-after-free in a
probe error path and in the remove success path where the devices were
being put before before deregistration.

Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
Fixes: 356f0a30860d ("i7core_edac: change the mem allocation scheme to make Documentation/kobject.txt happy")
Link: http://lkml.kernel.org/r/20180612124335.6420-2-johan@xxxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/edac/i7core_edac.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -1190,15 +1190,14 @@ static int i7core_create_sysfs_devices(s
 
 	rc = device_add(pvt->addrmatch_dev);
 	if (rc < 0)
-		return rc;
+		goto err_put_addrmatch;
 
 	if (!pvt->is_registered) {
 		pvt->chancounts_dev = kzalloc(sizeof(*pvt->chancounts_dev),
 					      GFP_KERNEL);
 		if (!pvt->chancounts_dev) {
-			put_device(pvt->addrmatch_dev);
-			device_del(pvt->addrmatch_dev);
-			return -ENOMEM;
+			rc = -ENOMEM;
+			goto err_del_addrmatch;
 		}
 
 		pvt->chancounts_dev->type = &all_channel_counts_type;
@@ -1212,9 +1211,18 @@ static int i7core_create_sysfs_devices(s
 
 		rc = device_add(pvt->chancounts_dev);
 		if (rc < 0)
-			return rc;
+			goto err_put_chancounts;
 	}
 	return 0;
+
+err_put_chancounts:
+	put_device(pvt->chancounts_dev);
+err_del_addrmatch:
+	device_del(pvt->addrmatch_dev);
+err_put_addrmatch:
+	put_device(pvt->addrmatch_dev);
+
+	return rc;
 }
 
 static void i7core_delete_sysfs_devices(struct mem_ctl_info *mci)
@@ -1229,11 +1237,11 @@ static void i7core_delete_sysfs_devices(
 	device_remove_file(&mci->dev, &dev_attr_inject_enable);
 
 	if (!pvt->is_registered) {
-		put_device(pvt->chancounts_dev);
 		device_del(pvt->chancounts_dev);
+		put_device(pvt->chancounts_dev);
 	}
-	put_device(pvt->addrmatch_dev);
 	device_del(pvt->addrmatch_dev);
+	put_device(pvt->addrmatch_dev);
 }
 
 /****************************************************************************