| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 35/49] cfg80211: wext: avoid copying malformed SSIDs | Date | Sun, 27 Oct 2019 22:01:13 +0100 |
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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,
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