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From:   Vaibhav Agarwal <vaibhav.sr@gmail.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Alex Elder <elder@kernel.org>, Johan Hovold <johan@kernel.org>,
        Mark Greer <mgreer@animalcreek.com>
Cc:     greybus-dev@lists.linaro.org, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org,
        Vaibhav Agarwal <vaibhav.sr@gmail.com>,
        Colin Ian King <colin.king@canonical.com>
Subject: [PATCH v3] staging: greybus: audio: fix uninitialized value issue
Date:   Fri, 14 Aug 2020 18:03:15 +0530
Message-Id: <bc4f29eb502ccf93cd2ffd98db0e319fa7d0f247.1597408126.git.vaibhav.sr@gmail.com>
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The current implementation for gbcodec_mixer_dapm_ctl_put() uses
uninitialized gbvalue for comparison with updated value. This was found
using static analysis with coverity.

Uninitialized scalar variable (UNINIT)
11. uninit_use: Using uninitialized value
gbvalue.value.integer_value[0].
460        if (gbvalue.value.integer_value[0] != val) {

This patch fixes the issue with fetching the gbvalue before using it for
    comparision.

Fixes: 6339d2322c47 ("greybus: audio: Add topology parser for GB codec")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
---
Changelog:
v2: Fix the missing check for return value after get_control.
v3: Use single exit path to avoid missing autosuspend sequence.
---
 drivers/staging/greybus/audio_topology.c | 29 ++++++++++++------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/staging/greybus/audio_topology.c b/drivers/staging/greybus/audio_topology.c
index 2f9fdbdcd547..83b38ae8908c 100644
--- a/drivers/staging/greybus/audio_topology.c
+++ b/drivers/staging/greybus/audio_topology.c
@@ -456,6 +456,15 @@ static int gbcodec_mixer_dapm_ctl_put(struct snd_kcontrol *kcontrol,
 	val = ucontrol->value.integer.value[0] & mask;
 	connect = !!val;

+	ret = gb_pm_runtime_get_sync(bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_audio_gb_get_control(module->mgmt_connection, data->ctl_id,
+				      GB_AUDIO_INVALID_INDEX, &gbvalue);
+	if (ret)
+		goto exit;
+
 	/* update ucontrol */
 	if (gbvalue.value.integer_value[0] != val) {
 		for (wi = 0; wi < wlist->num_widgets; wi++) {
@@ -466,25 +475,17 @@ static int gbcodec_mixer_dapm_ctl_put(struct snd_kcontrol *kcontrol,
 		gbvalue.value.integer_value[0] =
 			cpu_to_le32(ucontrol->value.integer.value[0]);

-		ret = gb_pm_runtime_get_sync(bundle);
-		if (ret)
-			return ret;
-
 		ret = gb_audio_gb_set_control(module->mgmt_connection,
 					      data->ctl_id,
 					      GB_AUDIO_INVALID_INDEX, &gbvalue);
-
-		gb_pm_runtime_put_autosuspend(bundle);
-
-		if (ret) {
-			dev_err_ratelimited(codec_dev,
-					    "%d:Error in %s for %s\n", ret,
-					    __func__, kcontrol->id.name);
-			return ret;
-		}
 	}

-	return 0;
+exit:
+	gb_pm_runtime_put_autosuspend(bundle);
+	if (ret)
+		dev_err_ratelimited(codec_dev, "%d:Error in %s for %s\n", ret,
+				    __func__, kcontrol->id.name);
+	return ret;
 }

 #define SOC_DAPM_MIXER_GB(xname, kcount, data) \

base-commit: fc80c51fd4b23ec007e88d4c688f2cac1b8648e7
--
2.27.0