| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 58/93] mac80211: Reject malformed SSID elements | Date | Sun, 27 Oct 2019 22:01:10 +0100 |
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From: Will Deacon <will@kernel.org>
commit 4152561f5da3fca92af7179dd538ea89e248f9d0 upstream.
Although this shouldn't occur in practice, it's a good idea to bounds check the length field of the SSID element prior to using it for things like allocations or memcpy operations.
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/20191004095132.15777-1-will@kernel.org Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/mac80211/mlme.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -2554,7 +2554,8 @@ struct sk_buff *ieee80211_ap_probereq_ge rcu_read_lock(); ssid = ieee80211_bss_get_ie(cbss, WLAN_EID_SSID); - if (WARN_ON_ONCE(ssid == NULL)) + if (WARN_ONCE(!ssid || ssid[1] > IEEE80211_MAX_SSID_LEN, + "invalid SSID element (len=%d)", ssid ? ssid[1] : -1)) ssid_len = 0; else ssid_len = ssid[1]; @@ -5039,7 +5040,7 @@ int ieee80211_mgd_assoc(struct ieee80211 rcu_read_lock(); ssidie = ieee80211_bss_get_ie(req->bss, WLAN_EID_SSID); - if (!ssidie) { + if (!ssidie || ssidie[1] > sizeof(assoc_data->ssid)) { rcu_read_unlock(); kfree(assoc_data); return -EINVAL;
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