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OpenCloudOS-Kernel
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ubi: Fix possible null-ptr-deref in ubi_free_volume() 

It willl cause null-ptr-deref in the following case:

uif_init()
  ubi_add_volume()
    cdev_add() -> if it fails, call kill_volumes()
    device_register()

kill_volumes() -> if ubi_add_volume() fails call this function
  ubi_free_volume()
    cdev_del()
    device_unregister() -> trying to delete a not added device,
			   it causes null-ptr-deref

So in ubi_free_volume(), it delete devices whether they are added
or not, it will causes null-ptr-deref.

Handle the error case whlie calling ubi_add_volume() to fix this
problem. If add volume fails, set the corresponding vol to null,
so it can not be accessed in kill_volumes() and release the
resource in ubi_add_volume() error path.

Fixes: 801c135ce7 ("UBI: Unsorted Block Images")
Suggested-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Yang Yingliang 2022-11-14 18:26:24 +08:00 committed by Richard Weinberger
parent 7af73882dd
commit c15859bfd3
2 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/mtd/ubi/build.c
View File

@ -470,6 +470,7 @@ static int uif_init(struct ubi_device *ubi)
err = ubi_add_volume(ubi, ubi->volumes[i]);
if (err) {
ubi_err(ubi, "cannot add volume %d", i);
ubi->volumes[i] = NULL;
goto out_volumes;
}
}

12
drivers/mtd/ubi/vmt.c
View File

@ -582,6 +582,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
if (err) {
ubi_err(ubi, "cannot add character device for volume %d, error %d",
vol_id, err);
vol_release(&vol->dev);
return err;
}
@ -592,15 +593,14 @@ int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
vol->dev.groups = volume_dev_groups;
dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
err = device_register(&vol->dev);
if (err)
goto out_cdev;
if (err) {
cdev_del(&vol->cdev);
put_device(&vol->dev);
return err;
}
self_check_volumes(ubi);
return err;
out_cdev:
cdev_del(&vol->cdev);
return err;
}
/**