From 9af9c676bc7420cd272aacb6aa1b7b174d34cfb9 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 348052b8d3477d22e25227e367351bf71434b6fb, 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 88a565f130a5a..98fa8eb6cc4be 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++; -- 2.39.5