[PATCH AUTOSEL 4.20 29/52] cfg80211: prevent speculation on cfg80211_classify8021d() return
From: Sasha Levin <sashal@kernel.org>
Date: 2019-03-11 19:56:21
Also in:
linux-wireless, lkml, stable
Subsystem:
802.11 (including cfg80211/nl80211), the rest · Maintainers:
Johannes Berg, Linus Torvalds
From: Johannes Berg <redacted> [ Upstream commit 1fc9b7253382ce1a83d9a3e63e88d656eb63f263 ] It's possible that the caller of cfg80211_classify8021d() uses the value to index an array, like mac80211 in ieee80211_downgrade_queue(). Prevent speculation on the return value. Signed-off-by: Johannes Berg <redacted> Signed-off-by: Luca Coelho <redacted> Signed-off-by: Johannes Berg <redacted> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/wireless/util.c | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-)
diff --git a/net/wireless/util.c b/net/wireless/util.c
index d473bd135da8..d8b7eb75bade 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c@@ -5,7 +5,7 @@ * Copyright 2007-2009 Johannes Berg <johannes@sipsolutions.net> * Copyright 2013-2014 Intel Mobile Communications GmbH * Copyright 2017 Intel Deutschland GmbH - * Copyright (C) 2018 Intel Corporation + * Copyright (C) 2018-2019 Intel Corporation */ #include <linux/export.h> #include <linux/bitops.h>
@@ -19,6 +19,7 @@ #include <linux/mpls.h> #include <linux/gcd.h> #include <linux/bitfield.h> +#include <linux/nospec.h> #include "core.h" #include "rdev-ops.h"
@@ -715,20 +716,25 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb, { unsigned int dscp; unsigned char vlan_priority; + unsigned int ret; /* skb->priority values from 256->263 are magic values to * directly indicate a specific 802.1d priority. This is used * to allow 802.1d priority to be passed directly in from VLAN * tags, etc. */ - if (skb->priority >= 256 && skb->priority <= 263) - return skb->priority - 256; + if (skb->priority >= 256 && skb->priority <= 263) { + ret = skb->priority - 256; + goto out; + } if (skb_vlan_tag_present(skb)) { vlan_priority = (skb_vlan_tag_get(skb) & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; - if (vlan_priority > 0) - return vlan_priority; + if (vlan_priority > 0) { + ret = vlan_priority; + goto out; + } } switch (skb->protocol) {
@@ -747,8 +753,9 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb, if (!mpls) return 0; - return (ntohl(mpls->entry) & MPLS_LS_TC_MASK) + ret = (ntohl(mpls->entry) & MPLS_LS_TC_MASK) >> MPLS_LS_TC_SHIFT; + goto out; } case htons(ETH_P_80221): /* 802.21 is always network control traffic */
@@ -761,18 +768,24 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb, unsigned int i, tmp_dscp = dscp >> 2; for (i = 0; i < qos_map->num_des; i++) { - if (tmp_dscp == qos_map->dscp_exception[i].dscp) - return qos_map->dscp_exception[i].up; + if (tmp_dscp == qos_map->dscp_exception[i].dscp) { + ret = qos_map->dscp_exception[i].up; + goto out; + } } for (i = 0; i < 8; i++) { if (tmp_dscp >= qos_map->up[i].low && - tmp_dscp <= qos_map->up[i].high) - return i; + tmp_dscp <= qos_map->up[i].high) { + ret = i; + goto out; + } } } - return dscp >> 5; + ret = dscp >> 5; +out: + return array_index_nospec(ret, IEEE80211_NUM_TIDS); } EXPORT_SYMBOL(cfg80211_classify8021d);
--
2.19.1