diff options
| author | Johannes Berg | 2017-01-02 11:19:29 +0100 |
|---|---|---|
| committer | Johannes Berg | 2017-01-02 11:28:25 +0100 |
| commit | 35f432a03e41d3bf08c51ede917f94e2288fbe8c (patch) | |
| tree | 67eed715e449fb7460f834c32edf723f2b4efa05 /net | |
| parent | eb7903bb83cc1db31a9124d4cc8a1bddebe26e33 (diff) | |
mac80211: initialize fast-xmit 'info' later
In ieee80211_xmit_fast(), 'info' is initialized to point to the skb
that's passed in, but that skb may later be replaced by a clone (if
it was shared), leading to an invalid pointer.
This can lead to use-after-free and also later crashes since the
real SKB's info->hw_queue doesn't get initialized properly.
Fix this by assigning info only later, when it's needed, after the
skb replacement (may have) happened.
Cc: stable@vger.kernel.org
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mac80211/tx.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 2c21b7039136..0d8b716e509e 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3287,7 +3287,7 @@ static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata, int extra_head = fast_tx->hdr_len - (ETH_HLEN - 2); int hw_headroom = sdata->local->hw.extra_tx_headroom; struct ethhdr eth; - struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); + struct ieee80211_tx_info *info; struct ieee80211_hdr *hdr = (void *)fast_tx->hdr; struct ieee80211_tx_data tx; ieee80211_tx_result r; @@ -3351,6 +3351,7 @@ static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata, memcpy(skb->data + fast_tx->da_offs, eth.h_dest, ETH_ALEN); memcpy(skb->data + fast_tx->sa_offs, eth.h_source, ETH_ALEN); + info = IEEE80211_SKB_CB(skb); memset(info, 0, sizeof(*info)); info->band = fast_tx->band; info->control.vif = &sdata->vif; |