[PATCH 4/4] nl80211: use for_each_element() in validate_ie_attr()

[Johannes Berg <johannes@sipsolutions.net>]

From: Johannes Berg <johannes.berg@intel.com>

This makes for much simpler code, simply walk through all
the elements and check that the last one found ends with
the end of the data. This works because if any element is
malformed the walk is aborted, we end up with a mismatch.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/wireless/nl80211.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index a3cc039b9f55..5d85f6032f84 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -203,29 +203,17 @@ cfg80211_get_dev_from_info(struct net *netns, struct genl_info *info)
 static int validate_ie_attr(const struct nlattr *attr,
 			    struct netlink_ext_ack *extack)
 {
-	const u8 *pos;
-	int len;
+	const u8 *data = nla_data(attr);
+	unsigned int len = nla_len(attr);
+	struct element *elem;
 
-	pos = nla_data(attr);
-	len = nla_len(attr);
-
-	while (len) {
-		u8 elemlen;
-
-		if (len < 2)
-			goto error;
-		len -= 2;
-
-		elemlen = pos[1];
-		if (elemlen > len)
-			goto error;
-
-		len -= elemlen;
-		pos += 2 + elemlen;
+	for_each_element(elem, data, len) {
+		/* nothing */
 	}
 
-	return 0;
-error:
+	if (for_each_element_completed(elem, data, len))
+		return 0;
+
 	NL_SET_ERR_MSG_ATTR(extack, attr, "malformed information elements");
 	return -EINVAL;
 }
-- 
2.17.2