cfg80211: check regulatory request alpha2 early

Currently nl80211 allows userspace to send the kernel
a bogus regulatory domain with at most 32 rules set
and it won't reject it until after its allocated
memory. Let's be smart about it and take advantage
that the last_request is now available under RTNL
and check if the alpha2 matches an expected request
and reject any bogus userspace requests prior to
hitting the memory allocator.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 04fa8bb1b4bb..7b73132910b7 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5100,6 +5100,9 @@ static int nl80211_set_reg(struct sk_buff *skb, struct genl_info *info)
                         return -EINVAL;
         }
 
+        if (!reg_is_valid_request(alpha2))
+                return -EINVAL;
+
         size_of_regd = sizeof(struct ieee80211_regdomain) +
                        num_rules * sizeof(struct ieee80211_reg_rule);