From 57a27e1d6a3bb9ad4efeebd3a8c71156d6207536 Mon Sep 17 00:00:00 2001 From: Luciano Coelho Date: Tue, 7 Jun 2011 20:42:26 +0300 Subject: [PATCH] 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 Signed-off-by: Luciano Coelho Signed-off-by: John W. Linville --- net/wireless/nl80211.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 88a565f130a5..98fa8eb6cc4b 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -3406,11 +3406,11 @@ 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) { + 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 @@ static int nl80211_start_sched_scan(struct sk_buff *skb, 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++; -- 2.34.1