linux-kernel - [PATCH v2] i2c: dev: Fix memory leak when underlying adapter does not support I2C

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Message-ID: <20241108001542.255155-1-ipylypiv@google.com>
Date: Fri,  8 Nov 2024 00:15:42 +0000
From: Igor Pylypiv <ipylypiv@...gle.com>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>, Jean Delvare <jdelvare@...e.de>, 
	Andi Shyti <andi.shyti@...nel.org>
Cc: linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Igor Pylypiv <ipylypiv@...gle.com>
Subject: [PATCH v2] i2c: dev: Fix memory leak when underlying adapter does not
 support I2C

Early return in i2cdev_ioctl_rdwr() failed to free the memory allocated
by the caller. Move freeing the memory to the function where it has been
allocated to prevent similar leaks in the future.

Fixes: 97ca843f6ad3 ("i2c: dev: Check for I2C_FUNC_I2C before calling i2c_transfer")
Signed-off-by: Igor Pylypiv <ipylypiv@...gle.com>
---
 drivers/i2c/i2c-dev.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 61f7c4003d2f..7717db1f4c23 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -251,10 +251,8 @@ static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
 		return -EOPNOTSUPP;
 
 	data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
-	if (data_ptrs == NULL) {
-		kfree(msgs);
+	if (data_ptrs == NULL)
 		return -ENOMEM;
-	}
 
 	res = 0;
 	for (i = 0; i < nmsgs; i++) {
@@ -302,7 +300,6 @@ static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
 		for (j = 0; j < i; ++j)
 			kfree(msgs[j].buf);
 		kfree(data_ptrs);
-		kfree(msgs);
 		return res;
 	}
 
@@ -316,7 +313,6 @@ static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
 		kfree(msgs[i].buf);
 	}
 	kfree(data_ptrs);
-	kfree(msgs);
 	return res;
 }
 
@@ -446,6 +442,7 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case I2C_RDWR: {
 		struct i2c_rdwr_ioctl_data rdwr_arg;
 		struct i2c_msg *rdwr_pa;
+		int res;
 
 		if (copy_from_user(&rdwr_arg,
 				   (struct i2c_rdwr_ioctl_data __user *)arg,
@@ -467,7 +464,9 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		if (IS_ERR(rdwr_pa))
 			return PTR_ERR(rdwr_pa);
 
-		return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
+		res = i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
+		kfree(rdwr_pa);
+		return res;
 	}
 
 	case I2C_SMBUS: {
@@ -540,7 +539,7 @@ static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned lo
 		struct i2c_rdwr_ioctl_data32 rdwr_arg;
 		struct i2c_msg32 __user *p;
 		struct i2c_msg *rdwr_pa;
-		int i;
+		int i, res;
 
 		if (copy_from_user(&rdwr_arg,
 				   (struct i2c_rdwr_ioctl_data32 __user *)arg,
@@ -573,7 +572,9 @@ static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned lo
 			};
 		}
 
-		return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
+		res = i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
+		kfree(rdwr_pa);
+		return res;
 	}
 	case I2C_SMBUS: {
 		struct i2c_smbus_ioctl_data32	data32;
-- 
2.47.0.277.g8800431eea-goog