[ Upstream commit 9d1bc24b52fb8c5d859f9a47084bf1179470e04c ]
bond_xmit_roundrobin() checks for IGMP packets but it parses the IP header even before checking skb->protocol.
We should validate the IP header with pskb_may_pull() before using iph->protocol.
Reported-and-tested-by: syzbot+e5be16aa39ad6e755391@syzkaller.appspotmail.com Fixes: a2fd940f4cff ("bonding: fix broken multicast with round-robin mode") Cc: Jay Vosburgh j.vosburgh@gmail.com Cc: Veaceslav Falico vfalico@gmail.com Cc: Andy Gospodarek andy@greyhouse.net Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/bonding/bond_main.c | 37 ++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 799fc38c5c34..b0aab3a0a1bf 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -3866,8 +3866,8 @@ static netdev_tx_t bond_xmit_roundrobin(struct sk_buff *skb, struct net_device *bond_dev) { struct bonding *bond = netdev_priv(bond_dev); - struct iphdr *iph = ip_hdr(skb); struct slave *slave; + int slave_cnt; u32 slave_id;
/* Start with the curr_active_slave that joined the bond as the @@ -3876,23 +3876,32 @@ static netdev_tx_t bond_xmit_roundrobin(struct sk_buff *skb, * send the join/membership reports. The curr_active_slave found * will send all of this type of traffic. */ - if (iph->protocol == IPPROTO_IGMP && skb->protocol == htons(ETH_P_IP)) { - slave = rcu_dereference(bond->curr_active_slave); - if (slave) - bond_dev_queue_xmit(bond, skb, slave->dev); - else - bond_xmit_slave_id(bond, skb, 0); - } else { - int slave_cnt = READ_ONCE(bond->slave_cnt); + if (skb->protocol == htons(ETH_P_IP)) { + int noff = skb_network_offset(skb); + struct iphdr *iph;
- if (likely(slave_cnt)) { - slave_id = bond_rr_gen_slave_id(bond); - bond_xmit_slave_id(bond, skb, slave_id % slave_cnt); - } else { - bond_tx_drop(bond_dev, skb); + if (unlikely(!pskb_may_pull(skb, noff + sizeof(*iph)))) + goto non_igmp; + + iph = ip_hdr(skb); + if (iph->protocol == IPPROTO_IGMP) { + slave = rcu_dereference(bond->curr_active_slave); + if (slave) + bond_dev_queue_xmit(bond, skb, slave->dev); + else + bond_xmit_slave_id(bond, skb, 0); + return NETDEV_TX_OK; } }
+non_igmp: + slave_cnt = READ_ONCE(bond->slave_cnt); + if (likely(slave_cnt)) { + slave_id = bond_rr_gen_slave_id(bond); + bond_xmit_slave_id(bond, skb, slave_id % slave_cnt); + } else { + bond_tx_drop(bond_dev, skb); + } return NETDEV_TX_OK; }