[PATCH] platform/x86: dell_rbu: avoid uninit value usage in packet_size_write()

[Fedor Pchelkin]

Ensure the temp value has been properly parsed from the user-provided
buffer and initialized to be used in later operations.  While at it,
prefer a convenient kstrtoul() helper.

Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.

Fixes: ad6ce87e5bd4 ("[PATCH] dell_rbu: changes in packet update mechanism")
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
---
 drivers/platform/x86/dell/dell_rbu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/dell/dell_rbu.c b/drivers/platform/x86/dell/dell_rbu.c
index eb50f1d75d0c..225c318d4b44 100644
--- a/drivers/platform/x86/dell/dell_rbu.c
+++ b/drivers/platform/x86/dell/dell_rbu.c
@@ -619,9 +619,12 @@ static ssize_t packet_size_write(struct file *filp, struct kobject *kobj,
 				 char *buffer, loff_t pos, size_t count)
 {
 	unsigned long temp;
+
+	if (kstrtoul(buffer, 10, &temp))
+		return -EINVAL;
+
 	spin_lock(&rbu_data.lock);
 	packet_empty_list();
-	sscanf(buffer, "%lu", &temp);
 	if (temp < 0xffffffff)
 		rbu_data.packetsize = temp;
 
-- 
2.53.0