Re: [PATCH] ubi: block: fix null-pointer-dereference in ubiblock_create()

[Li Nan]

在 2023/12/8 15:29, Zhihao Cheng 写道:
> 在 2023/12/8 15:13, linan666@xxxxxxxxxxxxxxx 写道:
> > From: Li Nan <linan122@xxxxxxxxxx>
> >
> > If idr_alloc() fails, dev->gd will be put after goto out_cleanup_disk in
> > ubiblock_create(), but dev->gd has not been assigned yet at this time, 
> > and
> > accessing it will trigger a null-pointer-dereference issue. Fix it by put
> > gd directly.
> Function 'put_disk()' checks disk whether is NULL, so I think it's a 
> 'memleak' problem, not a null-ptr-deref problem.
> >

Damn, I overlooked it here. Thanks for your review, I will fix the log
in v2.

> > Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
> > ---
> >   drivers/mtd/ubi/block.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
> > index 309a42aeaa4c..654bd7372cd8 100644
> > --- a/drivers/mtd/ubi/block.c
> > +++ b/drivers/mtd/ubi/block.c
> > @@ -434,7 +434,7 @@ int ubiblock_create(struct ubi_volume_info *vi)
> >       list_del(&dev->list);
> >       idr_remove(&ubiblock_minor_idr, gd->first_minor);
> >   out_cleanup_disk:
> > -    put_disk(dev->gd);
> > +    put_disk(gd);
>
> For memleak solution:
>
> Reviewed-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
>
> >   out_free_tags:
> >       blk_mq_free_tag_set(&dev->tag_set);
> >   out_free_dev:
>
>
> .

--
Thanks,
Nan