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wifi: mac80211_hwsim: fix race condition in pending packet

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A pending packet uses a cookie as an unique key, but it can be duplicated
because it didn't use atomic operators.

And also, a pending packet can be null in hwsim_tx_info_frame_received_nl
due to race condition with mac80211_hwsim_stop.

For this,
 * Use an atomic type and operator for a cookie
 * Add a lock around the loop for pending packets

Signed-off-by: Jeongik Cha <jeongik@google.com>
Link: https://lore.kernel.org/r/20220704084354.3556326-1-jeongik@google.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Jeongik Cha 2022-07-04 17:43:54 +09:00 committed by Johannes Berg
parent 37babce912
commit 4ee186fa7e
1 changed files with 8 additions and 6 deletions
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14
drivers/net/wireless/mac80211_hwsim.c
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@ -687,7 +687,7 @@ struct mac80211_hwsim_data {
bool ps_poll_pending;
struct dentry *debugfs;
uintptr_t pending_cookie;
atomic64_t pending_cookie;
struct sk_buff_head pending; /* packets pending */
/*
* Only radios in the same group can communicate together (the
@ -1358,7 +1358,7 @@ static void mac80211_hwsim_tx_frame_nl(struct ieee80211_hw *hw,
int i;
struct hwsim_tx_rate tx_attempts[IEEE80211_TX_MAX_RATES];
struct hwsim_tx_rate_flag tx_attempts_flags[IEEE80211_TX_MAX_RATES];
uintptr_t cookie;
u64 cookie;
if (data->ps != PS_DISABLED)
hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PM);
@ -1427,8 +1427,7 @@ static void mac80211_hwsim_tx_frame_nl(struct ieee80211_hw *hw,
goto nla_put_failure;
/* We create a cookie to identify this skb */
data->pending_cookie++;
cookie = data->pending_cookie;
cookie = (u64)atomic64_inc_return(&data->pending_cookie);
info->rate_driver_data[0] = (void *)cookie;
if (nla_put_u64_64bit(skb, HWSIM_ATTR_COOKIE, cookie, HWSIM_ATTR_PAD))
goto nla_put_failure;
@ -4178,6 +4177,7 @@ static int hwsim_tx_info_frame_received_nl(struct sk_buff *skb_2,
const u8 *src;
unsigned int hwsim_flags;
int i;
unsigned long flags;
bool found = false;
if (!info->attrs[HWSIM_ATTR_ADDR_TRANSMITTER] ||
@ -4205,18 +4205,20 @@ static int hwsim_tx_info_frame_received_nl(struct sk_buff *skb_2,
}
/* look for the skb matching the cookie passed back from user */
spin_lock_irqsave(&data2->pending.lock, flags);
skb_queue_walk_safe(&data2->pending, skb, tmp) {
u64 skb_cookie;
txi = IEEE80211_SKB_CB(skb);
skb_cookie = (u64)(uintptr_t)txi->rate_driver_data[0];
skb_cookie = (u64)txi->rate_driver_data[0];
if (skb_cookie == ret_skb_cookie) {
skb_unlink(skb, &data2->pending);
__skb_unlink(skb, &data2->pending);
found = true;
break;
}
}
spin_unlock_irqrestore(&data2->pending.lock, flags);
/* not found */
if (!found)