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.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index da657d8231140fbad9cb3f0058d2794fb4bdf5d4..d1f58e5250f689caa68f3f3fba002a88b928a675 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3179,12 +3179,12 @@ 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++;
                }
        }