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Subject[patch 066/108] cfg80211: fix in nl80211_set_reg()
2.6.30-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Luis R. Rodriguez <lrodriguez@atheros.com>

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@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
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;




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