[PATCH net 7/9] batman-adv: mcast: ensure unshared skb for multicast packets
Simon Wunderlich <[email protected]>
| Newsgroups | org.open-mesh.lists.batman,org.kernel.vger.netdev,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
From: Sven Eckelmann <[email protected]> When a packet is transmitted via a batman-adv interface and has already enough room for the header then nothing will make sure that the skbuff is unshared. But it is not allowed to modify a currently shared skbuff. Always make sure that the pskb_expand_head() is not only called for a too small header but also for shared skbuffs. Cc: [email protected] Fixes: 90039133221e ("batman-adv: mcast: implement multicast packet generation") Signed-off-by: Sven Eckelmann <[email protected]> Signed-off-by: Simon Wunderlich <[email protected]> --- net/batman-adv/multicast_forw.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/batman-adv/multicast_forw.c b/net/batman-adv/multicast_forw.c index bae2a81109767..3927d28dcbb89 100644 --- a/net/batman-adv/multicast_forw.c +++ b/net/batman-adv/multicast_forw.c @@ -1105,8 +1105,7 @@ static int batadv_mcast_forw_expand_head(struct batadv_priv *bat_priv, return -EINVAL; } - if (skb_headroom(skb) < hdr_size && - pskb_expand_head(skb, hdr_size, 0, GFP_ATOMIC) < 0) + if (skb_cow(skb, hdr_size) < 0) return -ENOMEM; return 0; -- 2.47.3