Ensure the SSID element is bounds-checked prior to invoking memcpy() with its length field.
Cc: <[email protected]> Cc: Johannes Berg <[email protected]> Cc: Kees Cook <[email protected]> Reported-by: Nicolas Waisman <[email protected]> Signed-off-by: Will Deacon <[email protected]> --- net/wireless/wext-sme.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c index c67d7a82ab13..3fd2cc7fc36a 100644 --- a/net/wireless/wext-sme.c +++ b/net/wireless/wext-sme.c @@ -201,6 +201,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, struct iw_request_info *info, struct iw_point *data, char *ssid) { + int ret = 0; struct wireless_dev *wdev = dev->ieee80211_ptr; /* call only for station! */ @@ -219,7 +220,10 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, 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) { @@ -229,7 +233,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, } wdev_unlock(wdev); - return 0; + return ret; } int cfg80211_mgd_wext_siwap(struct net_device *dev, -- 2.23.0.581.g78d2f28ef7-goog
