Unverified Commit dc93f0dc authored by Trevor Wu's avatar Trevor Wu Committed by Mark Brown
Browse files

ASoC: mediatek: mt8195: fix use-after-free in driver remove path 



During mt8195_afe_init_clock(), mt8195_audsys_clk_register() was called
followed by several other devm functions. At mt8195_afe_deinit_clock()
located at mt8195_afe_pcm_dev_remove(), mt8195_audsys_clk_unregister()
was called.

However, there was an issue with the order in which these functions were
called. Specifically, the remove callback of platform_driver was called
before devres released the resource, resulting in a use-after-free issue
during remove time.

At probe time, the order of calls was:
1. mt8195_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. mt8195_audsys_clk_unregister
3. free afe_priv->clk[i]
2. free afe_priv->clk

To resolve the problem, we can utilize devm_add_action_or_reset() in
mt8195_audsys_clk_register() so that the remove order can be changed to
3->2->1.

Fixes: 6746cc85 ("ASoC: mediatek: mt8195: add platform driver")
Signed-off-by: default avatarTrevor Wu <trevor.wu@mediatek.com>
Reviewed-by: default avatarDouglas Anderson <dianders@chromium.org>
Reviewed-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230601033318.10408-3-trevor.wu@mediatek.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent fd67a7a1

sound/soc/mediatek/mt8195/mt8195-afe-clk.c

+0 −5
Original line number Diff line number Diff line
@@ -410,11 +410,6 @@ int mt8195_afe_init_clock(struct mtk_base_afe *afe) 
	return 0;

}



void mt8195_afe_deinit_clock(struct mtk_base_afe *afe)

{

	mt8195_audsys_clk_unregister(afe);

}



int mt8195_afe_enable_clk(struct mtk_base_afe *afe, struct clk *clk)

{

	int ret;

sound/soc/mediatek/mt8195/mt8195-afe-clk.h

+0 −1
Original line number Diff line number Diff line
@@ -101,7 +101,6 @@ int mt8195_afe_get_mclk_source_clk_id(int sel); 
int mt8195_afe_get_mclk_source_rate(struct mtk_base_afe *afe, int apll);

int mt8195_afe_get_default_mclk_source_by_rate(int rate);

int mt8195_afe_init_clock(struct mtk_base_afe *afe);

void mt8195_afe_deinit_clock(struct mtk_base_afe *afe);

int mt8195_afe_enable_clk(struct mtk_base_afe *afe, struct clk *clk);

void mt8195_afe_disable_clk(struct mtk_base_afe *afe, struct clk *clk);

int mt8195_afe_prepare_clk(struct mtk_base_afe *afe, struct clk *clk);

sound/soc/mediatek/mt8195/mt8195-afe-pcm.c

+0 −4
Original line number Diff line number Diff line
@@ -3255,15 +3255,11 @@ static int mt8195_afe_pcm_dev_probe(struct platform_device *pdev) 


static void mt8195_afe_pcm_dev_remove(struct platform_device *pdev)

{

	struct mtk_base_afe *afe = platform_get_drvdata(pdev);



	snd_soc_unregister_component(&pdev->dev);



	pm_runtime_disable(&pdev->dev);

	if (!pm_runtime_status_suspended(&pdev->dev))

		mt8195_afe_runtime_suspend(&pdev->dev);



	mt8195_afe_deinit_clock(afe);

}



static const struct of_device_id mt8195_afe_pcm_dt_match[] = {

sound/soc/mediatek/mt8195/mt8195-audsys-clk.c

+24 −23
Original line number Diff line number Diff line
@@ -148,6 +148,29 @@ static const struct afe_gate aud_clks[CLK_AUD_NR_CLK] = { 
	GATE_AUD6(CLK_AUD_GASRC19, "aud_gasrc19", "top_asm_h", 19),

};



static void mt8195_audsys_clk_unregister(void *data)

{

	struct mtk_base_afe *afe = data;

	struct mt8195_afe_private *afe_priv = afe->platform_priv;

	struct clk *clk;

	struct clk_lookup *cl;

	int i;



	if (!afe_priv)

		return;



	for (i = 0; i < CLK_AUD_NR_CLK; i++) {

		cl = afe_priv->lookup[i];

		if (!cl)

			continue;



		clk = cl->clk;

		clk_unregister_gate(clk);



		clkdev_drop(cl);

	}

}



int mt8195_audsys_clk_register(struct mtk_base_afe *afe)

{

	struct mt8195_afe_private *afe_priv = afe->platform_priv;
@@ -188,27 +211,5 @@ int mt8195_audsys_clk_register(struct mtk_base_afe *afe) 
		afe_priv->lookup[i] = cl;

	}



	return 0;

}



void mt8195_audsys_clk_unregister(struct mtk_base_afe *afe)

{

	struct mt8195_afe_private *afe_priv = afe->platform_priv;

	struct clk *clk;

	struct clk_lookup *cl;

	int i;



	if (!afe_priv)

		return;



	for (i = 0; i < CLK_AUD_NR_CLK; i++) {

		cl = afe_priv->lookup[i];

		if (!cl)

			continue;



		clk = cl->clk;

		clk_unregister_gate(clk);



		clkdev_drop(cl);

	}

	return devm_add_action_or_reset(afe->dev, mt8195_audsys_clk_unregister, afe);

}

sound/soc/mediatek/mt8195/mt8195-audsys-clk.h

+0 −1
Original line number Diff line number Diff line
@@ -10,6 +10,5 @@ 
#define _MT8195_AUDSYS_CLK_H_



int mt8195_audsys_clk_register(struct mtk_base_afe *afe);

void mt8195_audsys_clk_unregister(struct mtk_base_afe *afe);



#endif