From 5b616a05de88d4be0136156a26fae9da855939f6 Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@canonical.com>
Date: Wed, 30 Mar 2016 08:46:31 +0800
Subject: [PATCH] block: partition: initialize percpuref before sending out
KOBJ_ADD
commit b30a337ca27c4f40439e4bfb290cba5f88d73bb7 upstream.
The initialization of partition's percpu_ref should have been done before
sending out KOBJ_ADD uevent, which may cause userspace to read partition
table. So the uninitialized percpu_ref may be accessed in data path.
This patch fixes this issue reported by Naveen.
Reported-by: Naveen Kaje <nkaje@codeaurora.org>
Tested-by: Naveen Kaje <nkaje@codeaurora.org>
Fixes: 6c71013ecb7e2(block: partition: convert percpu ref)
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
block/partition-generic.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/block/partition-generic.c b/block/partition-generic.c
index 746935a5973c..a241e3900bc9 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -349,15 +349,20 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
goto out_del;
}
+ err = hd_ref_init(p);
+ if (err) {
+ if (flags & ADDPART_FLAG_WHOLEDISK)
+ goto out_remove_file;
+ goto out_del;
+ }
+
/* everything is up and running, commence */
rcu_assign_pointer(ptbl->part[partno], p);
/* suppress uevent if the disk suppresses it */
if (!dev_get_uevent_suppress(ddev))
kobject_uevent(&pdev->kobj, KOBJ_ADD);
-
- if (!hd_ref_init(p))
- return p;
+ return p;
out_free_info:
free_part_info(p);
@@ -366,6 +371,8 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
out_free:
kfree(p);
return ERR_PTR(err);
+out_remove_file:
+ device_remove_file(pdev, &dev_attr_whole_disk);
out_del:
kobject_put(p->holder_dir);
device_del(pdev);
--
2.30.9