diff options
| author | Johannes Berg <johannes.berg@intel.com> | 2017-01-02 11:19:29 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-01-12 11:39:07 +0100 |
| commit | 5e7598a625eead50e6d783797de828fe22e86f25 (patch) | |
| tree | ac6e4d45ccfd7a2f2a158d5292366d221445e02c /net/mac80211 | |
| parent | 3c4eef31670361212d4f762c9420fa9a4ff160c0 (diff) | |
mac80211: initialize fast-xmit 'info' later
commit 35f432a03e41d3bf08c51ede917f94e2288fbe8c upstream.
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.
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/mac80211')
| -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 bd5f4be89435..dd190ff3daea 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3262,7 +3262,7 @@ 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; @@ -3326,6 +3326,7 @@ 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; |