nl80211: use for_each_element() in validate_ie_attr() (9f308616) · Commits · 戴 / test

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

+8 −20

Original line number	Diff line number	Diff line
		@@ -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;

		pos = nla_data(attr);
		len = nla_len(attr);

		while (len) {
		u8 elemlen;

		if (len < 2)
		goto error;
		len -= 2;
		const u8 *data = nla_data(attr);
		unsigned int len = nla_len(attr);
		struct element *elem;

		elemlen = pos[1];
		if (elemlen > len)
		goto error;

		len -= elemlen;
		pos += 2 + elemlen;
		for_each_element(elem, data, len) {
		/* nothing */
		}

		if (for_each_element_completed(elem, data, len))
		return 0;
		error:

		NL_SET_ERR_MSG_ATTR(extack, attr, "malformed information elements");
		return -EINVAL;
		}

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