[PATCH v2] dma-buf: acquire name lock before read/write dma_buf.name

[guangming.cao at mediatek.com]

From: Guangming Cao <Guangming.Cao at mediatek.com>

On Fri, 2021-10-08 at 12:24 +0200, Christian König wrote:
> Am 08.10.21 um 09:54 schrieb guangming.cao at mediatek.com:
> > From: Guangming Cao <Guangming.Cao at mediatek.com>
> > 
> > Because dma-buf.name can be freed in func: "dma_buf_set_name",
> > so, we need to acquire lock first before we read/write dma_buf.name
> > to prevent Use After Free(UAF) issue.
> > 
> > Signed-off-by: Guangming Cao <Guangming.Cao at mediatek.com>
> 
> Reviewed-by: Christian König <christian.koenig at amd.com>
> 
> Going to push that upstream if nobody else objects.
> 
> Thanks,
> Christian.

Just a gentle ping for this patch, please kindly let me know how is it going.

> 
> > ---
> >   drivers/dma-buf/dma-buf.c | 3 +++
> >   1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> > index 511fe0d217a0..a7f6fd13a635 100644
> > --- a/drivers/dma-buf/dma-buf.c
> > +++ b/drivers/dma-buf/dma-buf.c
> > @@ -1372,6 +1372,8 @@ static int dma_buf_debug_show(struct seq_file
> > *s, void *unused)
> >   		if (ret)
> >   			goto error_unlock;
> >   
> > +
> > +		spin_lock(&buf_obj->name_lock);
> >   		seq_printf(s,
> > "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
> >   				buf_obj->size,
> >   				buf_obj->file->f_flags, buf_obj->file-
> > >f_mode,
> > @@ -1379,6 +1381,7 @@ static int dma_buf_debug_show(struct seq_file
> > *s, void *unused)
> >   				buf_obj->exp_name,
> >   				file_inode(buf_obj->file)->i_ino,
> >   				buf_obj->name ?: "");
> > +		spin_unlock(&buf_obj->name_lock);
> >   
> >   		robj = buf_obj->resv;
> >   		fence = dma_resv_excl_fence(robj);
> 
> 
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