From cb17ed29a7a5fea8c9bf70e8a05757d71650e025 Mon Sep 17 00:00:00 2001
From: Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
Date: Thu, 23 Jul 2020 14:01:53 +0400
Subject: [PATCH] mac80211: parse radiotap header when selecting Tx queue
Git-commit: cb17ed29a7a5fea8c9bf70e8a05757d71650e025
Patch-mainline: v5.9-rc1
References: jsc#SLE-13430
Already parse the radiotap header in ieee80211_monitor_select_queue.
In a subsequent commit this will allow us to add a radiotap flag that
influences the queue on which injected packets will be sent.
This also fixes the incomplete validation of the injected frame in
Ieee80211_monitor_select_queue: currently an out of bounds memory
access may occur in in the called function ieee80211_select_queue_80211
if the 802.11 header is too small.
Note that in ieee80211_monitor_start_xmit the radiotap header is parsed
again, which is necessairy because ieee80211_monitor_select_queue is not
always called beforehand.
Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
Link: https://lore.kernel.org/r/20200723100153.31631-6-Mathy.Vanhoef@kuleuven.be
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
include/net/mac80211.h | 8 ++++++++
net/mac80211/iface.c | 15 ++++++++++----
net/mac80211/tx.c | 54 ++++++++++++++++++++++----------------------------
3 files changed, 43 insertions(+), 34 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 21ce821a25e7..6e26f0ba6fd0 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -6238,6 +6238,14 @@ bool ieee80211_tx_prepare_skb(struct ieee80211_hw *hw,
struct ieee80211_vif *vif, struct sk_buff *skb,
int band, struct ieee80211_sta **sta);
+/**
+ * Sanity-check and parse the radiotap header of injected frames
+ * @skb: packet injected by userspace
+ * @dev: the &struct device of this 802.11 device
+ */
+bool ieee80211_parse_tx_radiotap(struct sk_buff *skb,
+ struct net_device *dev);
+
/**
* struct ieee80211_noa_data - holds temporary data for tracking P2P NoA state
*
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 570f818384e8..9740ae8fa697 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1183,17 +1183,24 @@ static u16 ieee80211_monitor_select_queue(struct net_device *dev,
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_local *local = sdata->local;
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr;
- struct ieee80211_radiotap_header *rtap = (void *)skb->data;
+ int len_rthdr;
if (local->hw.queues < IEEE80211_NUM_ACS)
return 0;
- if (skb->len < 4 ||
- skb->len < le16_to_cpu(rtap->it_len) + 2 /* frame control */)
+ /* reset flags and info before parsing radiotap header */
+ memset(info, 0, sizeof(*info));
+
+ if (!ieee80211_parse_tx_radiotap(skb, dev))
return 0; /* doesn't matter, frame will be dropped */
- hdr = (void *)((u8 *)skb->data + le16_to_cpu(rtap->it_len));
+ len_rthdr = ieee80211_get_radiotap_len(skb->data);
+ hdr = (struct ieee80211_hdr *)(skb->data + len_rthdr);
+ if (skb->len < len_rthdr + 2 ||
+ skb->len < len_rthdr + ieee80211_hdrlen(hdr->frame_control))
+ return 0; /* doesn't matter, frame will be dropped */
return ieee80211_select_queue_80211(sdata, skb, hdr);
}
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 7fb4afaa9410..ec35a92df8ed 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2015,9 +2015,10 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
ieee80211_tx(sdata, sta, skb, false);
}
-static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
- struct sk_buff *skb)
+bool ieee80211_parse_tx_radiotap(struct sk_buff *skb,
+ struct net_device *dev)
{
+ struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_radiotap_iterator iterator;
struct ieee80211_radiotap_header *rthdr =
(struct ieee80211_radiotap_header *) skb->data;
@@ -2036,6 +2037,18 @@ static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
u8 vht_mcs = 0, vht_nss = 0;
int i;
+ /* check for not even having the fixed radiotap header part */
+ if (unlikely(skb->len < sizeof(struct ieee80211_radiotap_header)))
+ return false; /* too short to be possibly valid */
+
+ /* is it a header version we can trust to find length from? */
+ if (unlikely(rthdr->it_version))
+ return false; /* only version 0 is supported */
+
+ /* does the skb contain enough to deliver on the alleged length? */
+ if (unlikely(skb->len < ieee80211_get_radiotap_len(skb->data)))
+ return false; /* skb too short for claimed rt header extent */
+
info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
IEEE80211_TX_CTL_DONTFRAG;
@@ -2189,13 +2202,6 @@ static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
local->hw.max_rate_tries);
}
- /*
- * remove the radiotap header
- * iterator->_max_length was sanity-checked against
- * skb->len by iterator init
- */
- skb_pull(skb, iterator._max_length);
-
return true;
}
@@ -2204,8 +2210,6 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_chanctx_conf *chanctx_conf;
- struct ieee80211_radiotap_header *prthdr =
- (struct ieee80211_radiotap_header *)skb->data;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr;
struct ieee80211_sub_if_data *tmp_sdata, *sdata;
@@ -2213,21 +2217,17 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
u16 len_rthdr;
int hdrlen;
- /* check for not even having the fixed radiotap header part */
- if (unlikely(skb->len < sizeof(struct ieee80211_radiotap_header)))
- goto fail; /* too short to be possibly valid */
+ memset(info, 0, sizeof(*info));
+ info->flags = IEEE80211_TX_CTL_REQ_TX_STATUS |
+ IEEE80211_TX_CTL_INJECTED;
- /* is it a header version we can trust to find length from? */
- if (unlikely(prthdr->it_version))
- goto fail; /* only version 0 is supported */
+ /* Sanity-check and process the injection radiotap header */
+ if (!ieee80211_parse_tx_radiotap(skb, dev))
+ goto fail;
- /* then there must be a radiotap header with a length we can use */
+ /* we now know there is a radiotap header with a length we can use */
len_rthdr = ieee80211_get_radiotap_len(skb->data);
- /* does the skb contain enough to deliver on the alleged length? */
- if (unlikely(skb->len < len_rthdr))
- goto fail; /* skb too short for claimed rt header extent */
-
/*
* fix up the pointers accounting for the radiotap
* header still being in there. We are being given
@@ -2273,11 +2273,6 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
skb->priority = *p & IEEE80211_QOS_CTL_TAG1D_MASK;
}
- memset(info, 0, sizeof(*info));
-
- info->flags = IEEE80211_TX_CTL_REQ_TX_STATUS |
- IEEE80211_TX_CTL_INJECTED;
-
rcu_read_lock();
/*
@@ -2343,9 +2338,8 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
info->band = chandef->chan->band;
- /* process and remove the injection radiotap header */
- if (!ieee80211_parse_tx_radiotap(local, skb))
- goto fail_rcu;
+ /* remove the injection radiotap header */
+ skb_pull(skb, len_rthdr);
ieee80211_xmit(sdata, NULL, skb);
rcu_read_unlock();
--
2.16.4