From: Yang Yingliang <yangyingliang@huawei.com> stable inclusion from stable-v4.19.276 commit 45b2c5ca4d2edae70f19fdb086bd927840c4c309 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/12950 CVE: CVE-2023-54087 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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> Signed-off-by: Wang Zhaolong <wangzhaolong@huaweicloud.com> --- 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 df888c34499e..3e7e5b51eafd 100644 --- a/drivers/mtd/ubi/build.c +++ b/drivers/mtd/ubi/build.c @@ -478,10 +478,11 @@ static int uif_init(struct ubi_device *ubi) for (i = 0; i < ubi->vtbl_slots; i++) if (ubi->volumes[i]) { 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; } } return 0; diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c index 405cc5289d89..c5dec58846ce 100644 --- a/drivers/mtd/ubi/vmt.c +++ b/drivers/mtd/ubi/vmt.c @@ -593,29 +593,29 @@ int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol) dev = MKDEV(MAJOR(ubi->cdev.dev), vol->vol_id + 1); err = cdev_add(&vol->cdev, dev, 1); if (err) { ubi_err(ubi, "cannot add character device for volume %d, error %d", vol_id, err); + vol_release(&vol->dev); return err; } vol->dev.release = vol_release; vol->dev.parent = &ubi->dev; vol->dev.devt = dev; vol->dev.class = &ubi_class; 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; } /** * ubi_free_volume - free volume. * @ubi: UBI device description object -- 2.34.3