From: Will Deacon will@kernel.org
commit 4ac2813cc867ae563a1ba5a9414bfb554e5796fa upstream.
Ensure the SSID element is bounds-checked prior to invoking memcpy() with its length field, when copying to userspace.
Cc: stable@vger.kernel.org Cc: Kees Cook keescook@chromium.org Reported-by: Nicolas Waisman nico@semmle.com Signed-off-by: Will Deacon will@kernel.org Link: https://lore.kernel.org/r/20191004095132.15777-2-will@kernel.org [adjust commit log a bit] Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/wireless/wext-sme.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/net/wireless/wext-sme.c +++ b/net/wireless/wext-sme.c @@ -224,6 +224,7 @@ int cfg80211_mgd_wext_giwessid(struct ne struct iw_point *data, char *ssid) { struct wireless_dev *wdev = dev->ieee80211_ptr; + int ret = 0;
/* call only for station! */ if (WARN_ON(wdev->iftype != NL80211_IFTYPE_STATION)) @@ -241,7 +242,10 @@ int cfg80211_mgd_wext_giwessid(struct ne if (ie) { data->flags = 1; data->length = ie[1]; - memcpy(ssid, ie + 2, data->length); + if (data->length > IW_ESSID_MAX_SIZE) + ret = -EINVAL; + else + memcpy(ssid, ie + 2, data->length); } rcu_read_unlock(); } else if (wdev->wext.connect.ssid && wdev->wext.connect.ssid_len) { @@ -251,7 +255,7 @@ int cfg80211_mgd_wext_giwessid(struct ne } wdev_unlock(wdev);
- return 0; + return ret; }
int cfg80211_mgd_wext_siwap(struct net_device *dev,