| Message ID | 1307468546-16915-1-git-send-email-coelho@ti.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Tue, 2011-06-07 at 20:42 +0300, Luciano Coelho wrote: > 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> > --- This should also go to stable, but since it won't apply directly there, I'll wait till it's applied upstream and then backport it to stable kernels.
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 1c57036..c859f50 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -3412,11 +3412,11 @@ 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++; } @@ -3578,12 +3578,11 @@ 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++;
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> --- net/wireless/nl80211.c | 9 ++++----- 1 files changed, 4 insertions(+), 5 deletions(-)