[PATCH 1/2] EDAC/device_sysfs: Use kstrtouint for poll_msec to prevent truncation

[Jad Keskes]

The poll_msec sysfs store uses simple_strtoul() which accepts an
unsigned long, but the target field (poll_msec) is unsigned int. On
64-bit systems, a value > UINT_MAX is silently truncated when stored.

Fix the mismatch by using kstrtouint() instead. This rejects values
> UINT_MAX at parse time, making truncation impossible. Also add a
check for value < 1 to reject the 0-delay case, which would cause the
poll work to spin without delay and consume 100% CPU.

Fixes: e27e3dac6517 ("drivers/edac: add edac_device class")
Signed-off-by: Jad Keskes <inasj268@xxxxxxxxx>
---
 drivers/edac/edac_device_sysfs.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/edac/edac_device_sysfs.c b/drivers/edac/edac_device_sysfs.c
index ac678b4a21fc..e2ee5c6c56d3 100644
--- a/drivers/edac/edac_device_sysfs.c
+++ b/drivers/edac/edac_device_sysfs.c
@@ -90,14 +90,21 @@ static ssize_t edac_device_ctl_poll_msec_store(struct edac_device_ctl_info
 					*ctl_info, const char *data,
 					size_t count)
 {
-	unsigned long value;
+	unsigned int value;
+	int ret;
 
 	/* get the value and enforce that it is non-zero, must be at least
 	 * one millisecond for the delay period, between scans
 	 * Then cancel last outstanding delay for the work request
 	 * and set a new one.
 	 */
-	value = simple_strtoul(data, NULL, 0);
+	ret = kstrtouint(data, 0, &value);
+	if (ret < 0)
+		return ret;
+
+	if (value < 1)
+		return -EINVAL;
+
 	edac_device_reset_delay_period(ctl_info, value);
 
 	return count;
-- 
2.55.0