commit e438768ff9b22c83a968e14b79e8c83128e8bfe4
author Luis R. Rodriguez <mcgrof@do-not-panic.com> Tue Nov 05 09:18:01 2013 -0800
committer Johannes Berg <johannes.berg@intel.com> Mon Nov 25 20:51:02 2013 +0100
tree 956366ad035f64af8965c3a737eaa74598d1e1b6
parent cc493e4f5296f4da111f25ea4a216bb77270ccc6

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>

net/wireless/nl80211.c

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 04fa8bb..7b73132 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5100,6 +5100,9 @@
 			return -EINVAL;
 	}
 
+	if (!reg_is_valid_request(alpha2))
+		return -EINVAL;
+
 	size_of_regd = sizeof(struct ieee80211_regdomain) +
 		       num_rules * sizeof(struct ieee80211_reg_rule);
 

net/wireless/reg.c

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index b4b1687..d8f047a 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -450,7 +450,7 @@
 	return kobject_uevent(&reg_pdev->dev.kobj, KOBJ_CHANGE);
 }
 
-static bool reg_is_valid_request(const char *alpha2)
+bool reg_is_valid_request(const char *alpha2)
 {
 	struct regulatory_request *lr = get_last_request();
 

net/wireless/reg.h

diff --git a/net/wireless/reg.h b/net/wireless/reg.h
index 9677e3c..b4076ba 100644
--- a/net/wireless/reg.h
+++ b/net/wireless/reg.h
@@ -18,6 +18,7 @@
 
 extern const struct ieee80211_regdomain __rcu *cfg80211_regdomain;
 
+bool reg_is_valid_request(const char *alpha2);
 bool is_world_regdom(const char *alpha2);
 bool reg_supported_dfs_region(u8 dfs_region);