From: Ryder Lee <ryder.lee@xxxxxxxxxxxx> [ Upstream commit a4926abb787e2ef3ee2997e6ca8844d859478647 ] Add a missing skb_shared check into 802.3 path to prevent potential use-after-free from happening. This also uses skb_share_check() instead of open-coding in tx path. Signed-off-by: Ryder Lee <ryder.lee@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/e7a73aaf7742b17e43421c56625646dfc5c4d2cb.1653571902.git.ryder.lee@xxxxxxxxxxxx Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/mac80211/tx.c | 36 +++++++++++++----------------------- 1 file changed, 13 insertions(+), 23 deletions(-) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index bbbcc678c655..36e1eb9b2fff 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -2811,19 +2811,10 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata, /* * If the skb is shared we need to obtain our own copy. */ - if (skb_shared(skb)) { - struct sk_buff *tmp_skb = skb; - - /* can't happen -- skb is a clone if info_id != 0 */ - WARN_ON(info_id); - - skb = skb_clone(skb, GFP_ATOMIC); - kfree_skb(tmp_skb); - - if (!skb) { - ret = -ENOMEM; - goto free; - } + skb = skb_share_check(skb, GFP_ATOMIC); + if (unlikely(!skb)) { + ret = -ENOMEM; + goto free; } hdr.frame_control = fc; @@ -3526,15 +3517,9 @@ static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata, /* after this point (skb is modified) we cannot return false */ - if (skb_shared(skb)) { - struct sk_buff *tmp_skb = skb; - - skb = skb_clone(skb, GFP_ATOMIC); - kfree_skb(tmp_skb); - - if (!skb) - return true; - } + skb = skb_share_check(skb, GFP_ATOMIC); + if (unlikely(!skb)) + return true; if ((hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) && ieee80211_amsdu_aggregate(sdata, sta, fast_tx, skb)) @@ -4244,7 +4229,7 @@ static void ieee80211_8023_xmit(struct ieee80211_sub_if_data *sdata, struct net_device *dev, struct sta_info *sta, struct ieee80211_key *key, struct sk_buff *skb) { - struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); + struct ieee80211_tx_info *info; struct ieee80211_local *local = sdata->local; struct tid_ampdu_tx *tid_tx; u8 tid; @@ -4259,6 +4244,11 @@ static void ieee80211_8023_xmit(struct ieee80211_sub_if_data *sdata, test_bit(SDATA_STATE_OFFCHANNEL, &sdata->state)) goto out_free; + skb = skb_share_check(skb, GFP_ATOMIC); + if (unlikely(!skb)) + return; + + info = IEEE80211_SKB_CB(skb); memset(info, 0, sizeof(*info)); tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK; -- 2.35.1
