[236/244] cfg80211: Fix validation of AKM suites

[Greg KH]

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

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

From: Jouni Malinen <jouni@xxxxxxxxxxxxxxxx>

commit 1b9ca0272ffae212e726380f66777b30a56ed7a5 upstream.

Incorrect variable was used in validating the akm_suites array from
NL80211_ATTR_AKM_SUITES. In addition, there was no explicit
validation of the array length (we only have room for
NL80211_MAX_NR_AKM_SUITES).

This can result in a buffer write overflow for stack variables with
arbitrary data from user space. The nl80211 commands using the affected
functionality require GENL_ADMIN_PERM, so this is only exposed to admin
users.

Signed-off-by: Jouni Malinen <jouni@xxxxxxxxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/wireless/nl80211.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4044,9 +4044,12 @@ static int nl80211_crypto_settings(struc
 		if (len % sizeof(u32))
 			return -EINVAL;
 
+		if (settings->n_akm_suites > NL80211_MAX_NR_AKM_SUITES)
+			return -EINVAL;
+
 		memcpy(settings->akm_suites, data, len);
 
-		for (i = 0; i < settings->n_ciphers_pairwise; i++)
+		for (i = 0; i < settings->n_akm_suites; i++)
 			if (!nl80211_valid_akm_suite(settings->akm_suites[i]))
 				return -EINVAL;
 	}


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