This is a note to let you know that I've just added the patch titled
ubi: Fix possible null-ptr-deref in ubi_free_volume()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ubi-fix-possible-null-ptr-deref-in-ubi_free_volume.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 25d336c16d7513ff60da9ec282dd4df07d0b55aa
Author: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Date: Mon Nov 14 18:26:24 2022 +0800
ubi: Fix possible null-ptr-deref in ubi_free_volume()
[ Upstream commit c15859bfd326c10230f09cb48a17f8a35f190342 ]
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: 801c135ce73d ("UBI: Unsorted Block Images")
Suggested-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Reviewed-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index bb3a87cbebf5e..3d0241f8f3ec7 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -480,6 +480,7 @@ 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;
}
}
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 405cc5289d89f..c5dec58846ce8 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -595,6 +595,7 @@ 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;
}
@@ -605,15 +606,14 @@ 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;
}
/**
