linux-kernel - [PATCH] hwmon: (pmbus/ibm-cffps) Prevent writing on_off

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Message-Id: <1578411640-16929-1-git-send-email-eajames@linux.ibm.com>
Date:   Tue,  7 Jan 2020 09:40:40 -0600
From:   Eddie James <eajames@...ux.ibm.com>
To:     linux-hwmon@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, jdelvare@...e.com,
        linux@...ck-us.net, dan.carpenter@...cle.com,
        Eddie James <eajames@...ux.ibm.com>
Subject: [PATCH] hwmon: (pmbus/ibm-cffps) Prevent writing on_off_config with bad data

If the user write parameters resulted in no bytes being written to the
temporary buffer, then ON_OFF_CONFIG will be written with uninitialized
data. Prevent this by bailing out in this case.

Signed-off-by: Eddie James <eajames@...ux.ibm.com>
---
 drivers/hwmon/pmbus/ibm-cffps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
index 1c91ee1f9926..3795fe55b84f 100644
--- a/drivers/hwmon/pmbus/ibm-cffps.c
+++ b/drivers/hwmon/pmbus/ibm-cffps.c
@@ -250,7 +250,7 @@ static ssize_t ibm_cffps_debugfs_write(struct file *file,
 		pmbus_set_page(psu->client, 0);
 
 		rc = simple_write_to_buffer(&data, 1, ppos, buf, count);
-		if (rc < 0)
+		if (rc <= 0)
 			return rc;
 
 		rc = i2c_smbus_write_byte_data(psu->client,
-- 
2.24.0