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From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Nuno Sa <nuno.sa@analog.com>
Subject: [PATCH v2 3/8] iio: core: Switch to krealloc_array()
Date:   Fri, 21 Jul 2023 20:00:17 +0300
Message-Id: <20230721170022.3461-4-andriy.shevchenko@linux.intel.com>
In-Reply-To: <20230721170022.3461-1-andriy.shevchenko@linux.intel.com>
References: <20230721170022.3461-1-andriy.shevchenko@linux.intel.com>
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Let the krealloc_array() copy the original data and
check for a multiplication overflow.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
---
 drivers/iio/industrialio-core.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 4e45740331ee..6e28c2a3d223 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1465,7 +1465,7 @@ int iio_device_register_sysfs_group(struct iio_dev *indio_dev,
 	const struct attribute_group **new, **old = iio_dev_opaque->groups;
 	unsigned int cnt = iio_dev_opaque->groupcounter;
 
-	new = krealloc(old, sizeof(*new) * (cnt + 2), GFP_KERNEL);
+	new = krealloc_array(old, cnt + 2, sizeof(*new), GFP_KERNEL);
 	if (!new)
 		return -ENOMEM;
 
@@ -1483,13 +1483,13 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
 {
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
+	struct attribute **attrs, **attr, *clk = NULL;
 	struct iio_dev_attr *p;
-	struct attribute **attr, *clk = NULL;
 
 	/* First count elements in any existing group */
-	if (indio_dev->info->attrs) {
-		attr = indio_dev->info->attrs->attrs;
-		while (*attr++ != NULL)
+	attrs = indio_dev->info->attrs ? indio_dev->info->attrs->attrs : NULL;
+	if (attrs) {
+		for (attr = attrs; *attr; attr++)
 			attrcount_orig++;
 	}
 	attrcount = attrcount_orig;
@@ -1521,20 +1521,14 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
 	if (clk)
 		attrcount++;
 
+	/* Copy across original attributes, and point to original binary attributes */
 	iio_dev_opaque->chan_attr_group.attrs =
-		kcalloc(attrcount + 1,
-			sizeof(iio_dev_opaque->chan_attr_group.attrs[0]),
-			GFP_KERNEL);
+		krealloc_array(attrs, attrcount + 1, sizeof(*attrs), GFP_KERNEL);
 	if (iio_dev_opaque->chan_attr_group.attrs == NULL) {
 		ret = -ENOMEM;
 		goto error_clear_attrs;
 	}
-	/* Copy across original attributes, and point to original binary attributes */
 	if (indio_dev->info->attrs) {
-		memcpy(iio_dev_opaque->chan_attr_group.attrs,
-		       indio_dev->info->attrs->attrs,
-		       sizeof(iio_dev_opaque->chan_attr_group.attrs[0])
-		       *attrcount_orig);
 		iio_dev_opaque->chan_attr_group.is_visible =
 			indio_dev->info->attrs->is_visible;
 		iio_dev_opaque->chan_attr_group.bin_attrs =
-- 
2.40.0.1.gaa8946217a0b