![Fabrice Fontaine](/assets/img/avatar_default.png)
hostapd before 2.10 and wpa_supplicant before 2.10 allow an incorrect indication of disconnection in certain situations because source address validation is mishandled. This is a denial of service that should have been prevented by PMF (aka management frame protection). The attacker must send a crafted 802.11 frame from a location that is within the 802.11 communications range. Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
78 lines
2.9 KiB
Diff
78 lines
2.9 KiB
Diff
From 8c07fa9eda13e835f3f968b2e1c9a8be3a851ff9 Mon Sep 17 00:00:00 2001
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From: Jouni Malinen <j@w1.fi>
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Date: Thu, 29 Aug 2019 11:52:04 +0300
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Subject: [PATCH] AP: Silently ignore management frame from unexpected source
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address
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Do not process any received Management frames with unexpected/invalid SA
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so that we do not add any state for unexpected STA addresses or end up
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sending out frames to unexpected destination. This prevents unexpected
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sequences where an unprotected frame might end up causing the AP to send
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out a response to another device and that other device processing the
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unexpected response.
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In particular, this prevents some potential denial of service cases
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where the unexpected response frame from the AP might result in a
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connected station dropping its association.
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Signed-off-by: Jouni Malinen <j@w1.fi>
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Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
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[Retrieved from:
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https://w1.fi/security/2019-7/0001-AP-Silently-ignore-management-frame-from-unexpected-.patch]
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---
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src/ap/drv_callbacks.c | 13 +++++++++++++
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src/ap/ieee802_11.c | 12 ++++++++++++
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2 files changed, 25 insertions(+)
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diff --git a/src/ap/drv_callbacks.c b/src/ap/drv_callbacks.c
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index 31587685fe3b..34ca379edc3d 100644
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--- a/src/ap/drv_callbacks.c
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+++ b/src/ap/drv_callbacks.c
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@@ -131,6 +131,19 @@ int hostapd_notif_assoc(struct hostapd_data *hapd, const u8 *addr,
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"hostapd_notif_assoc: Skip event with no address");
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return -1;
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}
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+
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+ if (is_multicast_ether_addr(addr) ||
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+ is_zero_ether_addr(addr) ||
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+ os_memcmp(addr, hapd->own_addr, ETH_ALEN) == 0) {
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+ /* Do not process any frames with unexpected/invalid SA so that
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+ * we do not add any state for unexpected STA addresses or end
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+ * up sending out frames to unexpected destination. */
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+ wpa_printf(MSG_DEBUG, "%s: Invalid SA=" MACSTR
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+ " in received indication - ignore this indication silently",
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+ __func__, MAC2STR(addr));
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+ return 0;
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+ }
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+
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random_add_randomness(addr, ETH_ALEN);
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hostapd_logger(hapd, addr, HOSTAPD_MODULE_IEEE80211,
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diff --git a/src/ap/ieee802_11.c b/src/ap/ieee802_11.c
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index c85a28db44b7..e7065372e158 100644
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--- a/src/ap/ieee802_11.c
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+++ b/src/ap/ieee802_11.c
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@@ -4626,6 +4626,18 @@ int ieee802_11_mgmt(struct hostapd_data *hapd, const u8 *buf, size_t len,
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fc = le_to_host16(mgmt->frame_control);
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stype = WLAN_FC_GET_STYPE(fc);
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+ if (is_multicast_ether_addr(mgmt->sa) ||
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+ is_zero_ether_addr(mgmt->sa) ||
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+ os_memcmp(mgmt->sa, hapd->own_addr, ETH_ALEN) == 0) {
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+ /* Do not process any frames with unexpected/invalid SA so that
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+ * we do not add any state for unexpected STA addresses or end
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+ * up sending out frames to unexpected destination. */
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+ wpa_printf(MSG_DEBUG, "MGMT: Invalid SA=" MACSTR
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+ " in received frame - ignore this frame silently",
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+ MAC2STR(mgmt->sa));
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+ return 0;
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+ }
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+
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if (stype == WLAN_FC_STYPE_BEACON) {
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handle_beacon(hapd, mgmt, len, fi);
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return 1;
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--
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2.20.1
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