cfg80211: add two missing NULL pointer checks

These pointers can be NULL, the is_mesh() case isn't
ever hit in the current kernel, but cmp_ies() can be
hit under certain conditions.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: stable@kernel.org [2.6.29, 2.6.30]
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/scan.c

@@ -118,7 +118,7 @@ static int cmp_ies(u8 num, u8 *ies1, size_t len1, u8 *ies2, size_t len2)
 
 	if (!ie1 && !ie2)
 		return 0;
-	if (!ie1)
+	if (!ie1 || !ie2)
 		return -1;
 
 	r = memcmp(ie1 + 2, ie2 + 2, min(ie1[1], ie2[1]));
@@ -171,6 +171,8 @@ static bool is_mesh(struct cfg80211_bss *a,
 	ie = find_ie(WLAN_EID_MESH_CONFIG,
 		     a->information_elements,
 		     a->len_information_elements);
+	if (!ie)
+		return false;
 	if (ie[1] != IEEE80211_MESH_CONFIG_LEN)
 		return false;