[patch 066/108] cfg80211: fix in nl80211_set_reg()

[Greg KH]

2.6.30-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx>

commit 61405e97788b1bc4e7c5be5b4ec04a73fc11bac2 upstream.

There is a race on access to last_request and its alpha2
through reg_is_valid_request() and us possibly processing
first another regulatory request on another CPU. We avoid
this improbably race by locking with the cfg80211_mutex as
we should have done in the first place. While at it add
the assert on locking on reg_is_valid_request().

Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/wireless/nl80211.c |    5 ++++-
 net/wireless/reg.c     |    2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2388,6 +2388,8 @@ static int nl80211_set_reg(struct sk_buf
 			return -EINVAL;
 	}
 
+	mutex_lock(&cfg80211_mutex);
+
 	if (!reg_is_valid_request(alpha2)) {
 		r = -EINVAL;
 		goto bad_reg;
@@ -2425,13 +2427,14 @@ static int nl80211_set_reg(struct sk_buf
 
 	BUG_ON(rule_idx != num_rules);
 
-	mutex_lock(&cfg80211_mutex);
 	r = set_regdom(rd);
+
 	mutex_unlock(&cfg80211_mutex);
 
 	return r;
 
  bad_reg:
+	mutex_unlock(&cfg80211_mutex);
 	kfree(rd);
 	return r;
 }
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -389,6 +389,8 @@ static int call_crda(const char *alpha2)
 /* Used by nl80211 before kmalloc'ing our regulatory domain */
 bool reg_is_valid_request(const char *alpha2)
 {
+	assert_cfg80211_lock();
+
 	if (!last_request)
 		return false;
 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/