[PATCH v2 0/2] ASoC: mediatek: fix use-after-free in driver remove path

[PATCH v2 0/2] ASoC: mediatek: fix use-after-free in driver remove path

[Trevor Wu]

These patches concern modifications made in mt8186[1]. The clock
unregistration mechanism used in mt8188 and mt8195 is similar with
mt8186, resulting in the same problem existing within the driver.
Therefore, the solution has also been applied to these two platforms.

[1] https://lore.kernel.org/all/20230511092437.1.I31cceffc8c45bb1af16eb613e197b3df92cdc19e@changeid/

Changes since v1:
  - remove unnecessary cast

Trevor Wu (2):
  ASoC: mediatek: mt8188: fix use-after-free in driver remove path
  ASoC: mediatek: mt8195: fix use-after-free in driver remove path

 sound/soc/mediatek/mt8188/mt8188-afe-clk.c    |  7 ---
 sound/soc/mediatek/mt8188/mt8188-afe-clk.h    |  1 -
 sound/soc/mediatek/mt8188/mt8188-afe-pcm.c    |  4 --
 sound/soc/mediatek/mt8188/mt8188-audsys-clk.c | 47 ++++++++++---------
 sound/soc/mediatek/mt8188/mt8188-audsys-clk.h |  1 -
 sound/soc/mediatek/mt8195/mt8195-afe-clk.c    |  5 --
 sound/soc/mediatek/mt8195/mt8195-afe-clk.h    |  1 -
 sound/soc/mediatek/mt8195/mt8195-afe-pcm.c    |  4 --
 sound/soc/mediatek/mt8195/mt8195-audsys-clk.c | 47 ++++++++++---------
 sound/soc/mediatek/mt8195/mt8195-audsys-clk.h |  1 -
 10 files changed, 48 insertions(+), 70 deletions(-)

-- 
2.18.0

[PATCH v2 1/2] ASoC: mediatek: mt8188: fix use-after-free in driver remove path

[Trevor Wu]

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>
---
 sound/soc/mediatek/mt8188/mt8188-afe-clk.c    |  7 ---
 sound/soc/mediatek/mt8188/mt8188-afe-clk.h    |  1 -
 sound/soc/mediatek/mt8188/mt8188-afe-pcm.c    |  4 --
 sound/soc/mediatek/mt8188/mt8188-audsys-clk.c | 47 ++++++++++---------
 sound/soc/mediatek/mt8188/mt8188-audsys-clk.h |  1 -
 5 files changed, 24 insertions(+), 36 deletions(-)

diff --git a/sound/soc/mediatek/mt8188/mt8188-afe-clk.c b/sound/soc/mediatek/mt8188/mt8188-afe-clk.c
index 4c24d0b9e90d..e69c1bb2cb23 100644
--- a/sound/soc/mediatek/mt8188/mt8188-afe-clk.c
+++ b/sound/soc/mediatek/mt8188/mt8188-afe-clk.c
@@ -436,13 +436,6 @@ int mt8188_afe_init_clock(struct mtk_base_afe *afe)
 	return 0;
 }
 
-void mt8188_afe_deinit_clock(void *priv)
-{
-	struct mtk_base_afe *afe = priv;
-
-	mt8188_audsys_clk_unregister(afe);
-}
-
 int mt8188_afe_enable_clk(struct mtk_base_afe *afe, struct clk *clk)
 {
 	int ret;
diff --git a/sound/soc/mediatek/mt8188/mt8188-afe-clk.h b/sound/soc/mediatek/mt8188/mt8188-afe-clk.h
index 904505d10841..ec53c171c170 100644
--- a/sound/soc/mediatek/mt8188/mt8188-afe-clk.h
+++ b/sound/soc/mediatek/mt8188/mt8188-afe-clk.h
@@ -111,7 +111,6 @@ int mt8188_afe_get_default_mclk_source_by_rate(int rate);
 int mt8188_get_apll_by_rate(struct mtk_base_afe *afe, int rate);
 int mt8188_get_apll_by_name(struct mtk_base_afe *afe, const char *name);
 int mt8188_afe_init_clock(struct mtk_base_afe *afe);
-void mt8188_afe_deinit_clock(void *priv);
 int mt8188_afe_enable_clk(struct mtk_base_afe *afe, struct clk *clk);
 void mt8188_afe_disable_clk(struct mtk_base_afe *afe, struct clk *clk);
 int mt8188_afe_set_clk_rate(struct mtk_base_afe *afe, struct clk *clk,
diff --git a/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c b/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c
index c3fd32764da0..6a24b339444b 100644
--- a/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c
+++ b/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c
@@ -3256,10 +3256,6 @@ static int mt8188_afe_pcm_dev_probe(struct platform_device *pdev)
 	if (ret)
 		return dev_err_probe(dev, ret, "init clock error");
 
-	ret = devm_add_action_or_reset(dev, mt8188_afe_deinit_clock, (void *)afe);
-	if (ret)
-		return ret;
-
 	spin_lock_init(&afe_priv->afe_ctrl_lock);
 
 	mutex_init(&afe->irq_alloc_lock);
diff --git a/sound/soc/mediatek/mt8188/mt8188-audsys-clk.c b/sound/soc/mediatek/mt8188/mt8188-audsys-clk.c
index be1c53bf4729..c796ad8b62ee 100644
--- a/sound/soc/mediatek/mt8188/mt8188-audsys-clk.c
+++ b/sound/soc/mediatek/mt8188/mt8188-audsys-clk.c
@@ -138,6 +138,29 @@ static const struct afe_gate aud_clks[CLK_AUD_NR_CLK] = {
 	GATE_AUD6(CLK_AUD_GASRC11, "aud_gasrc11", "top_asm_h", 11),
 };
 
+static void mt8188_audsys_clk_unregister(void *data)
+{
+	struct mtk_base_afe *afe = data;
+	struct mt8188_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 mt8188_audsys_clk_register(struct mtk_base_afe *afe)
 {
 	struct mt8188_afe_private *afe_priv = afe->platform_priv;
@@ -179,27 +202,5 @@ int mt8188_audsys_clk_register(struct mtk_base_afe *afe)
 		afe_priv->lookup[i] = cl;
 	}
 
-	return 0;
-}
-
-void mt8188_audsys_clk_unregister(struct mtk_base_afe *afe)
-{
-	struct mt8188_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, mt8188_audsys_clk_unregister, afe);
 }
diff --git a/sound/soc/mediatek/mt8188/mt8188-audsys-clk.h b/sound/soc/mediatek/mt8188/mt8188-audsys-clk.h
index 6c5f463ad7e4..45b0948c4a06 100644
--- a/sound/soc/mediatek/mt8188/mt8188-audsys-clk.h
+++ b/sound/soc/mediatek/mt8188/mt8188-audsys-clk.h
@@ -10,6 +10,5 @@
 #define _MT8188_AUDSYS_CLK_H_
 
 int mt8188_audsys_clk_register(struct mtk_base_afe *afe);
-void mt8188_audsys_clk_unregister(struct mtk_base_afe *afe);
 
 #endif
-- 
2.18.0

Re: [PATCH v2 1/2] ASoC: mediatek: mt8188: fix use-after-free in driver remove path

[AngeloGioacchino Del Regno]

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>

Re: [PATCH v2 1/2] ASoC: mediatek: mt8188: fix use-after-free in driver remove path

[Alexandre Mergnat]

On 01/06/2023 05:33, Trevor Wu wrote:
> 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.

Sounds good

Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>

-- 
Regards,
Alexandre

[PATCH v2 2/2] ASoC: mediatek: mt8195: fix use-after-free in driver remove path

[Trevor Wu]

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: 6746cc858259 ("ASoC: mediatek: mt8195: add platform driver")
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---
 sound/soc/mediatek/mt8195/mt8195-afe-clk.c    |  5 --
 sound/soc/mediatek/mt8195/mt8195-afe-clk.h    |  1 -
 sound/soc/mediatek/mt8195/mt8195-afe-pcm.c    |  4 --
 sound/soc/mediatek/mt8195/mt8195-audsys-clk.c | 47 ++++++++++---------
 sound/soc/mediatek/mt8195/mt8195-audsys-clk.h |  1 -
 5 files changed, 24 insertions(+), 34 deletions(-)

diff --git a/sound/soc/mediatek/mt8195/mt8195-afe-clk.c b/sound/soc/mediatek/mt8195/mt8195-afe-clk.c
index 9ca2cb8c8a9c..f35318ae0739 100644
--- a/sound/soc/mediatek/mt8195/mt8195-afe-clk.c
+++ b/sound/soc/mediatek/mt8195/mt8195-afe-clk.c
@@ -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;
diff --git a/sound/soc/mediatek/mt8195/mt8195-afe-clk.h b/sound/soc/mediatek/mt8195/mt8195-afe-clk.h
index 40663e31becd..a08c0ee6c860 100644
--- a/sound/soc/mediatek/mt8195/mt8195-afe-clk.h
+++ b/sound/soc/mediatek/mt8195/mt8195-afe-clk.h
@@ -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);
diff --git a/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c b/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c
index d22cf1664d8a..a0f2012211fb 100644
--- a/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c
+++ b/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c
@@ -3224,15 +3224,11 @@ 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[] = {
diff --git a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c
index e0670e0dbd5b..38594bc3f2f7 100644
--- a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c
+++ b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c
@@ -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);
 }
diff --git a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h
index 239d31016ba7..69db2dd1c9e0 100644
--- a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h
+++ b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h
@@ -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
-- 
2.18.0

Re: [PATCH v2 2/2] ASoC: mediatek: mt8195: fix use-after-free in driver remove path

[AngeloGioacchino Del Regno]

Il 01/06/23 05:33, Trevor Wu ha scritto:
> 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: 6746cc858259 ("ASoC: mediatek: mt8195: add platform driver")
> 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>

Re: [PATCH v2 2/2] ASoC: mediatek: mt8195: fix use-after-free in driver remove path

[Alexandre Mergnat]

On 01/06/2023 05:33, Trevor Wu wrote:
> 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.

Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>

-- 
Regards,
Alexandre

Re: [PATCH v2 0/2] ASoC: mediatek: fix use-after-free in driver remove path

[Mark Brown]

On Thu, 01 Jun 2023 11:33:16 +0800, Trevor Wu wrote:
> These patches concern modifications made in mt8186[1]. The clock
> unregistration mechanism used in mt8188 and mt8195 is similar with
> mt8186, resulting in the same problem existing within the driver.
> Therefore, the solution has also been applied to these two platforms.
> 
> [1] https://lore.kernel.org/all/20230511092437.1.I31cceffc8c45bb1af16eb613e197b3df92cdc19e@changeid/
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/2] ASoC: mediatek: mt8188: fix use-after-free in driver remove path
      commit: fd67a7a1a22ce47fcbc094c4b6e164c34c652cbe
[2/2] ASoC: mediatek: mt8195: fix use-after-free in driver remove path
      commit: dc93f0dcb436dfd24a06c5b3c0f4c5cd9296e8e5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark