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| author | Lizhi Xu <lizhi.xu@windriver.com> | 2025-04-14 10:11:23 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-04-15 19:15:14 +0300 |
| commit | bc2c46426f2d95e58c82f394531afdd034c8706c (patch) | |
| tree | 5eaf7db4f520c11bbf11873a85a4db77e55d88bf | |
| parent | 1ae5e4c0626d6954114d9725990ac9c498f3b1ab (diff) | |
| download | linux-bc2c46426f2d95e58c82f394531afdd034c8706c.tar.xz | |
software node: Prevent link creation failure from causing kobj reference count imbalance
syzbot reported a uaf in software_node_notify_remove. [1]
When any of the two sysfs_create_link() in software_node_notify() fails,
the swnode->kobj reference count will not increase normally, which will
cause swnode to be released incorrectly due to the imbalance of kobj reference
count when executing software_node_notify_remove().
Increase the reference count of kobj before creating the link to avoid uaf.
[1]
BUG: KASAN: slab-use-after-free in software_node_notify_remove+0x1bc/0x1c0 drivers/base/swnode.c:1108
Read of size 1 at addr ffff888033c08908 by task syz-executor105/5844
Freed by task 5844:
software_node_notify_remove+0x159/0x1c0 drivers/base/swnode.c:1106
device_platform_notify_remove drivers/base/core.c:2387 [inline]
Fixes: 9eb59204d519 ("iommufd/selftest: Add set_dev_pasid in mock iommu")
Reported-by: syzbot+2ff22910687ee0dfd48e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2ff22910687ee0dfd48e
Tested-by: syzbot+2ff22910687ee0dfd48e@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250414071123.1228331-1-lizhi.xu@windriver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/base/swnode.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c index b1726a3515f6..5c78fa6ae772 100644 --- a/drivers/base/swnode.c +++ b/drivers/base/swnode.c @@ -1080,6 +1080,7 @@ void software_node_notify(struct device *dev) if (!swnode) return; + kobject_get(&swnode->kobj); ret = sysfs_create_link(&dev->kobj, &swnode->kobj, "software_node"); if (ret) return; @@ -1089,8 +1090,6 @@ void software_node_notify(struct device *dev) sysfs_remove_link(&dev->kobj, "software_node"); return; } - - kobject_get(&swnode->kobj); } void software_node_notify_remove(struct device *dev) |