From: Yang Yingliang yangyingliang@huawei.com
[ 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@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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mtd/ubi/build.c | 1 + drivers/mtd/ubi/vmt.c | 12 ++++++------ 2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c index 53aa4de6b963f..3499ff2649d54 100644 --- a/drivers/mtd/ubi/build.c +++ b/drivers/mtd/ubi/build.c @@ -468,6 +468,7 @@ 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 2e5bd473e5e25..d79323e8ea29d 100644 --- a/drivers/mtd/ubi/vmt.c +++ b/drivers/mtd/ubi/vmt.c @@ -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; }
/**