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From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To:     alsa-devel@alsa-project.org
Cc:     tiwai@suse.de, broonie@kernel.org, linux-kernel@vger.kernel.org,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        Cheng-Yi Chiang <cychiang@chromium.org>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Guenter Roeck <groeck@chromium.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Benson Leung <bleung@chromium.org>
Subject: [PATCH 04/23] ASoC: cros_ec_codec: remove null pointer dereference warning
Date:   Fri, 12 Mar 2021 12:22:27 -0600
Message-Id: <20210312182246.5153-5-pierre-louis.bossart@linux.intel.com>
In-Reply-To: <20210312182246.5153-1-pierre-louis.bossart@linux.intel.com>
References: <20210312182246.5153-1-pierre-louis.bossart@linux.intel.com>
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Cppcheck complains of a possible issue:

sound/soc/codecs/cros_ec_codec.c:98:10: warning: Possible null pointer
dereference: in [nullPointer]
  memcpy(in, msg->data, insize);
         ^
sound/soc/codecs/cros_ec_codec.c:162:34: note: Calling function
'send_ec_host_command', 5th argument 'NULL' value is 0
       (uint8_t *)&p, sizeof(p), NULL, 0);
                                 ^
sound/soc/codecs/cros_ec_codec.c:98:10: note: Null pointer dereference
  memcpy(in, msg->data, insize);
         ^

In practice the access to the pointer is protected by another
argument, but this is likely to fool other static analysis tools. Add
a test to avoid doing the memcpy if the pointer is NULL or the size is
zero.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 sound/soc/codecs/cros_ec_codec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/cros_ec_codec.c b/sound/soc/codecs/cros_ec_codec.c
index c4772f82485a..a201d652aca2 100644
--- a/sound/soc/codecs/cros_ec_codec.c
+++ b/sound/soc/codecs/cros_ec_codec.c
@@ -94,7 +94,7 @@ static int send_ec_host_command(struct cros_ec_device *ec_dev, uint32_t cmd,
 	if (ret < 0)
 		goto error;
 
-	if (insize)
+	if (in && insize)
 		memcpy(in, msg->data, insize);
 
 	ret = 0;
-- 
2.25.1