rtnetlink: Correct nested IFLA_VF_VLAN_LIST attribute validation

jira LE-1907
cve CVE-2024-36017
Rebuild_History Non-Buildable kernel-4.18.0-553.16.1.el8_10
commit-author Roded Zats <[email protected]>
commit 1aec77b

Each attribute inside a nested IFLA_VF_VLAN_LIST is assumed to be a
struct ifla_vf_vlan_info so the size of such attribute needs to be at least
of sizeof(struct ifla_vf_vlan_info) which is 14 bytes.
The current size validation in do_setvfinfo is against NLA_HDRLEN (4 bytes)
which is less than sizeof(struct ifla_vf_vlan_info) so this validation
is not enough and a too small attribute might be cast to a
struct ifla_vf_vlan_info, this might result in an out of bands
read access when accessing the saved (casted) entry in ivvl.

Fixes: 79aab09 ("net: Update API for VF vlan protocol 802.1ad support")
	Signed-off-by: Roded Zats <[email protected]>
	Reviewed-by: Donald Hunter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
	Signed-off-by: Jakub Kicinski <[email protected]>
(cherry picked from commit 1aec77b)
	Signed-off-by: Jonathan Maple <[email protected]>

Author: PlaidCat

net/core/rtnetlink.c

@@ -2364,7 +2364,7 @@ static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
 
 		nla_for_each_nested(attr, tb[IFLA_VF_VLAN_LIST], rem) {
 			if (nla_type(attr) != IFLA_VF_VLAN_INFO ||
-			    nla_len(attr) < NLA_HDRLEN) {
+			    nla_len(attr) < sizeof(struct ifla_vf_vlan_info)) {
 				return -EINVAL;
 			}
 			if (len >= MAX_VLAN_LIST_LEN)