[PATCH] base: devcoredump: Replace simple_strtol with kstrtol

The disabled_store() function uses simple_strtol(), which is marked
obsolete. simple_strtol() does not provide error handling on invalid
input - it silently returns a partial parse result or 0, which the
'if (tmp != 1) return -EINVAL' check then accepts as a legitimate
non-1 value.

Replace simple_strtol(buf, NULL, 10) with kstrtol(buf, 10, &tmp),
which returns an error code on invalid input. This makes the write-once
lockdown attribute stricter: malformed input (e.g. trailing garbage)
now returns -EINVAL instead of being silently treated as a non-1 value
that the caller wanted to reject anyway.

The behaviour for the legitimate '1' input is unchanged.

Signed-off-by: Jiangshan Yi <[email protected]>
---
 drivers/base/devcoredump.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c
index 8bb1763083dd..f346729bee1b 100644
--- a/drivers/base/devcoredump.c
+++ b/drivers/base/devcoredump.c
@@ -210,7 +210,12 @@ static ssize_t disabled_show(const struct class *class, const struct class_attri
 static ssize_t disabled_store(const struct class *class, const struct class_attribute *attr,
 			      const char *buf, size_t count)
 {
-	long tmp = simple_strtol(buf, NULL, 10);
+	long tmp;
+	int ret;
+
+	ret = kstrtol(buf, 10, &tmp);
+	if (ret < 0)
+		return ret;
 
 	/*
 	 * This essentially makes the attribute write-once, since you can't
-- 
2.25.1