ALSA: hda: cs35l56: Fix system name string leaks

cs35l56_hda_read_acpi() gets an allocated ACPI _SUB string from
acpi_get_subsystem_id(). On success, that string is used to create the
firmware system name.

Several error paths after the _SUB lookup can return without releasing
the allocated string. This includes speaker ID lookup errors other than
-ENOENT, and errors after a firmware system name has been allocated.

Use scoped cleanup for the temporary _SUB string and make
cs35l56->system_name device-managed. This releases the temporary _SUB
string on every error path and lets devres release the firmware system
name on probe failure and device removal.

Fixes: 6f03b446cbae ("ALSA: hda: cs35l56: Add support for speaker id")
Fixes: 40b1c2f9b299 ("ALSA: hda/cs35l56: Workaround bad dev-index on Lenovo Yoga Book 9i GenX")
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Reviewed-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260522-alsa-cs35l56-system-name-leak-v4-1-a6154dd09cd9@gmail.com

1 files changed, 9 insertions, 8 deletions

diff --git a/sound/hda/codecs/side-codecs/cs35l56_hda.c b/sound/hda/codecs/side-codecs/cs35l56_hda.c
index cdbc576569ef..a0ea08eb96a9 100644
--- a/sound/hda/codecs/side-codecs/cs35l56_hda.c
+++ b/sound/hda/codecs/side-codecs/cs35l56_hda.c
@@ -1025,7 +1025,7 @@ static int cs35l56_hda_read_acpi(struct cs35l56_hda *cs35l56, int hid, int id)
 	u32 values[HDA_MAX_COMPONENTS];
 	char hid_string[8];
 	struct acpi_device *adev;
-	const char *property, *sub;
+	const char *property;
 	int i, ret;
 
 	/*
@@ -1047,7 +1047,8 @@ static int cs35l56_hda_read_acpi(struct cs35l56_hda *cs35l56, int hid, int id)
 	/* Initialize things that could be overwritten by a fixup */
 	cs35l56->index = -1;
 
-	sub = acpi_get_subsystem_id(ACPI_HANDLE(cs35l56->base.dev));
+	const char *sub __free(kfree) = acpi_get_subsystem_id(ACPI_HANDLE(cs35l56->base.dev));
+
 	ret = cs35l56_hda_apply_platform_fixups(cs35l56, sub, &id);
 	if (ret)
 		return ret;
@@ -1095,15 +1096,16 @@ static int cs35l56_hda_read_acpi(struct cs35l56_hda *cs35l56, int hid, int id)
 		ret = cirrus_scodec_get_speaker_id(cs35l56->base.dev, cs35l56->index,
 						   cs35l56->num_amps, -1);
 		if (ret == -ENOENT) {
-			cs35l56->system_name = sub;
+			cs35l56->system_name = devm_kstrdup(cs35l56->base.dev, sub, GFP_KERNEL);
 		} else if (ret >= 0) {
-			cs35l56->system_name = kasprintf(GFP_KERNEL, "%s-spkid%d", sub, ret);
-			kfree(sub);
-			if (!cs35l56->system_name)
-				return -ENOMEM;
+			cs35l56->system_name = devm_kasprintf(cs35l56->base.dev, GFP_KERNEL,
+							      "%s-spkid%d", sub, ret);
 		} else {
 			return ret;
 		}
+
+		if (!cs35l56->system_name)
+			return -ENOMEM;
 	}
 
 	cs35l56->base.reset_gpio = devm_gpiod_get_index_optional(cs35l56->base.dev,
@@ -1254,7 +1256,6 @@ void cs35l56_hda_remove(struct device *dev)
 
 	cs_dsp_remove(&cs35l56->cs_dsp);
 
-	kfree(cs35l56->system_name);
 	pm_runtime_put_noidle(cs35l56->base.dev);
 
 	gpiod_set_value_cansleep(cs35l56->base.reset_gpio, 0);