Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <86e1ee74-72b7-fc89-08ee-562980f2a4e9@collabora.com>
Date:   Thu, 1 Jun 2023 12:02:32 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.11.2
Subject: Re: [PATCH v2 1/2] ASoC: mediatek: mt8188: fix use-after-free in
 driver remove path
Content-Language: en-US
To:     Trevor Wu <trevor.wu@mediatek.com>, broonie@kernel.org,
        lgirdwood@gmail.com, tiwai@suse.com, perex@perex.cz,
        matthias.bgg@gmail.com
Cc:     dianders@chromium.org, alsa-devel@alsa-project.org,
        linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20230601033318.10408-1-trevor.wu@mediatek.com>
 <20230601033318.10408-2-trevor.wu@mediatek.com>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20230601033318.10408-2-trevor.wu@mediatek.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

Il 01/06/23 05:33, Trevor Wu ha scritto:
> During mt8188_afe_init_clock(), mt8188_audsys_clk_register() was called
> followed by several other devm functions. The caller of
> mt8188_afe_init_clock() utilized devm_add_action_or_reset() to call
> mt8188_afe_deinit_clock(). However, the order was incorrect, causing a
> use-after-free issue during remove time.
> 
> At probe time, the order of calls was:
> 1. mt8188_audsys_clk_register
> 2. afe_priv->clk = devm_kcalloc
> 3. afe_priv->clk[i] = devm_clk_get
> 
> At remove time, the order of calls was:
> 1. mt8188_audsys_clk_unregister
> 3. free afe_priv->clk[i]
> 2. free afe_priv->clk
> 
> To resolve the problem, it's necessary to move devm_add_action_or_reset()
> to the appropriate position so that the remove order can be 3->2->1.
> 
> Fixes: f6b026479b13 ("ASoC: mediatek: mt8188: support audio clock control")
> Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>