nl80211: fix check for valid SSID size in scan operations

commit 208c72f4fe44fe09577e7975ba0e7fa0278f3d03 upstream.

In both trigger_scan and sched_scan operations, we were checking for
the SSID length before assigning the value correctly.  Since the
memory was just kzalloc'ed, the check was always failing and SSID with
over 32 characters were allowed to go through.

This was causing a buffer overflow when copying the actual SSID to the
proper place.

This bug has been there since 2.6.29-rc4.

[PG: 34 codebase does not have nl80211_start_sched_scan part]

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 030cf153bea252e28893e7d976f776faa355aa14..0ba104fa35209791ae34cc3b3b936f4b83c81b72 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3072,12 +3072,12 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
        i = 0;
        if (info->attrs[NL80211_ATTR_SCAN_SSIDS]) {
                nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS], tmp) {
+                       request->ssids[i].ssid_len = nla_len(attr);
                        if (request->ssids[i].ssid_len > IEEE80211_MAX_SSID_LEN) {
                                err = -EINVAL;
                                goto out_free;
                        }
                        memcpy(request->ssids[i].ssid, nla_data(attr), nla_len(attr));
-                       request->ssids[i].ssid_len = nla_len(attr);
                        i++;
                }
        }