[PATCH 5.15 115/230] ASoC: rt5682: fix an incorrect NULL check on list iterator

From: Greg Kroah-Hartman
Date: Mon Jul 11 2022 - 05:51:14 EST

From: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>

[ Upstream commit c8618d65007ba68d7891130642d73e89372101e8 ]

The bug is here:
if (!dai) {

The list iterator value 'dai' will *always* be set and non-NULL
by for_each_component_dais(), so it is incorrect to assume that
the iterator value will be NULL if the list is empty or no element
is found (In fact, it will be a bogus pointer to an invalid struct
object containing the HEAD). Otherwise it will bypass the check
'if (!dai) {' (never call dev_err() and never return -ENODEV;)
and lead to invalid memory access lately when calling
'rt5682_set_bclk1_ratio(dai, factor);'.

To fix the bug, just return rt5682_set_bclk1_ratio(dai, factor);
when found the 'dai', otherwise dev_err() and return -ENODEV;

Cc: stable@xxxxxxxxxxxxxxx
Fixes: ebbfabc16d23d ("ASoC: rt5682: Add CCF usage for providing I2S clks")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220327081002.12684-1-xiam0nd.tong@xxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
sound/soc/codecs/rt5682.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/sound/soc/codecs/rt5682.c b/sound/soc/codecs/rt5682.c
index 80d199843b8c..8a9e1a4fa03e 100644
--- a/sound/soc/codecs/rt5682.c
+++ b/sound/soc/codecs/rt5682.c
@@ -2822,14 +2822,11 @@ static int rt5682_bclk_set_rate(struct clk_hw *hw, unsigned long rate,

for_each_component_dais(component, dai)
if (dai->id == RT5682_AIF1)
- break;
- if (!dai) {
- dev_err(rt5682->i2c_dev, "dai %d not found in component\n",
- RT5682_AIF1);
- return -ENODEV;
- }
+ return rt5682_set_bclk1_ratio(dai, factor);

- return rt5682_set_bclk1_ratio(dai, factor);
+ dev_err(rt5682->i2c_dev, "dai %d not found in component\n",
+ RT5682_AIF1);
+ return -ENODEV;

static const struct clk_ops rt5682_dai_clk_ops[RT5682_DAI_NUM_CLKS] = {