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References: <20230112071842.819123-1-korantwork@gmail.com>
In-Reply-To: <20230112071842.819123-1-korantwork@gmail.com>
From:   Xinghui Li <korantwork@gmail.com>
Date:   Fri, 3 Feb 2023 17:49:09 +0800
Message-ID: <CAEm4hYX3Db4NW+zkuwPep5CF3=ojXxKHPrEB+erOeA+o8d+4FQ@mail.gmail.com>
Subject: Re: [PATCH] drm/nouveau/mmu: Fix an UAF issue in NVKM
To:     bskeggs@redhat.com, kherbst@redhat.com, airlied@gmail.com,
        daniel@ffwll.ch
Cc:     linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        nouveau@lists.freedesktop.org, Xinghui Li <korantli@tencent.com>,
        loydlv <loydlv@tencent.com>
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hi all
friendly ping...

<korantwork@gmail.com> =E4=BA=8E2023=E5=B9=B41=E6=9C=8812=E6=97=A5=E5=91=A8=
=E5=9B=9B 15:18=E5=86=99=E9=81=93=EF=BC=9A
>
> From: Xinghui Li <korantli@tencent.com>
>
> In nvkm_mem_new_host, the mem is be alloced. And mem->memory is
> assigned to pmemory. During this process, the mem will be free if
> the error occurs. But the *pmemory still points to the &mem->memory
> which has been relased.Laterly, the nvkm_memory_unref will put the
> memory which points to the pmemory again.So, we set the *pmemory to
> NULL to avoid UAF issue.
>
> Reported-by: loydlv <loydlv@tencent.com>
> Signed-off-by: Xinghui Li <korantli@tencent.com>
> ---
>  drivers/gpu/drm/nouveau/nvkm/subdev/mmu/mem.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/mem.c b/drivers/gpu/=
drm/nouveau/nvkm/subdev/mmu/mem.c
> index 92e363dbbc5a..ab30eb1fc0a3 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/mem.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/mem.c
> @@ -185,6 +185,7 @@ nvkm_mem_new_host(struct nvkm_mmu *mmu, int type, u8 =
page, u64 size,
>         } else
>         if ( (ret =3D nvif_unvers(ret, &argv, &argc, args->vn))) {
>                 kfree(mem);
> +               *pmemory =3D NULL;
>                 return ret;
>         }
>
> --
> 2.31.1
>