nl80211: fix overflow in ssid_len
When one of the SSID's length passed in a scan or sched_scan request
is larger than 255, there will be an overflow in the u8 that is used
to store the length before checking. This causes the check to fail
and we overrun the buffer when copying the SSID.
Fix this by checking the nl80211 attribute length before copying it to
the struct.
This is a follow up for the previous commit
208c72f4fe44fe09577e7975ba0e7fa0278f3d03, which didn't fix the problem
entirely.
Reported-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 88a565f..98fa8eb 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3406,11 +3406,11 @@
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) {
+ if (nla_len(attr) > IEEE80211_MAX_SSID_LEN) {
err = -EINVAL;
goto out_free;
}
+ request->ssids[i].ssid_len = nla_len(attr);
memcpy(request->ssids[i].ssid, nla_data(attr), nla_len(attr));
i++;
}
@@ -3572,12 +3572,11 @@
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) {
+ if (nla_len(attr) > IEEE80211_MAX_SSID_LEN) {
err = -EINVAL;
goto out_free;
}
+ request->ssids[i].ssid_len = nla_len(attr);
memcpy(request->ssids[i].ssid, nla_data(attr),
nla_len(attr));
i++;