This code has a check for "if (rc != len) {" so it will fail if the
simple_write_to_buffer() does not completely fill the buffer. In
particular it will fail if "*ppos != 0". Although this code works, it is
more complicated than necessary. Just use strndup_user() instead.
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
drivers/net/wireless/ath/wil6210/debugfs.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
index fe84362718de..591ba7f61c64 100644
--- a/drivers/net/wireless/ath/wil6210/debugfs.c
+++ b/drivers/net/wireless/ath/wil6210/debugfs.c
@@ -1937,18 +1937,15 @@ static ssize_t wil_link_stats_write(struct file *file, const char __user *buf,
struct wil6210_priv *wil = s->private;
int cid, interval, rc, i;
struct wil6210_vif *vif;
- char *kbuf = kmalloc(len + 1, GFP_KERNEL);
+ char *kbuf;
- if (!kbuf)
- return -ENOMEM;
+ if (*ppos != 0)
+ return -EINVAL;
- rc = simple_write_to_buffer(kbuf, len, ppos, buf, len);
- if (rc != len) {
- kfree(kbuf);
- return rc >= 0 ? -EIO : rc;
- }
+ kbuf = strndup_user(buf, len + 1);
+ if (IS_ERR(kbuf))
+ return -ENOMEM;
- kbuf[len] = '\0';
/* specify cid (use -1 for all cids) and snapshot interval in ms */
rc = sscanf(kbuf, "%d %d", &cid, &interval);
kfree(kbuf);
--
2.35.1
