diff options
Diffstat (limited to 'net/bridge')
| -rw-r--r-- | net/bridge/br_netfilter.c | 107 |
1 files changed, 78 insertions, 29 deletions
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index 137f23259a9..77f7b5fda45 100644 --- a/net/bridge/br_netfilter.c +++ b/net/bridge/br_netfilter.c @@ -209,6 +209,72 @@ static inline void nf_bridge_update_protocol(struct sk_buff *skb) skb->protocol = htons(ETH_P_PPP_SES); } +/* When handing a packet over to the IP layer + * check whether we have a skb that is in the + * expected format + */ + +int br_parse_ip_options(struct sk_buff *skb) +{ + struct ip_options *opt; + struct iphdr *iph; + struct net_device *dev = skb->dev; + u32 len; + + iph = ip_hdr(skb); + opt = &(IPCB(skb)->opt); + + /* Basic sanity checks */ + if (iph->ihl < 5 || iph->version != 4) + goto inhdr_error; + + if (!pskb_may_pull(skb, iph->ihl*4)) + goto inhdr_error; + + iph = ip_hdr(skb); + if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) + goto inhdr_error; + + len = ntohs(iph->tot_len); + if (skb->len < len) { + IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INTRUNCATEDPKTS); + goto drop; + } else if (len < (iph->ihl*4)) + goto inhdr_error; + + if (pskb_trim_rcsum(skb, len)) { + IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS); + goto drop; + } + + /* Zero out the CB buffer if no options present */ + if (iph->ihl == 5) { + memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); + return 0; + } + + opt->optlen = iph->ihl*4 - sizeof(struct iphdr); + if (ip_options_compile(dev_net(dev), opt, skb)) + goto inhdr_error; + + /* Check correct handling of SRR option */ + if (unlikely(opt->srr)) { + struct in_device *in_dev = __in_dev_get_rcu(dev); + if (in_dev && !IN_DEV_SOURCE_ROUTE(in_dev)) + goto drop; + + if (ip_options_rcv_srr(skb)) + goto drop; + } + + return 0; + +inhdr_error: + IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INHDRERRORS); +drop: + return -1; +} + /* Fill in the header for fragmented IP packets handled by * the IPv4 connection tracking code. */ @@ -549,7 +615,6 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff *skb, { struct net_bridge_port *p; struct net_bridge *br; - struct iphdr *iph; __u32 len = nf_bridge_encap_header_len(skb); if (unlikely(!pskb_may_pull(skb, len))) @@ -578,28 +643,9 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff *skb, nf_bridge_pull_encap_header_rcsum(skb); - if (!pskb_may_pull(skb, sizeof(struct iphdr))) - goto inhdr_error; - - iph = ip_hdr(skb); - if (iph->ihl < 5 || iph->version != 4) - goto inhdr_error; - - if (!pskb_may_pull(skb, 4 * iph->ihl)) - goto inhdr_error; - - iph = ip_hdr(skb); - if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0) - goto inhdr_error; - - len = ntohs(iph->tot_len); - if (skb->len < len || len < 4 * iph->ihl) - goto inhdr_error; - - pskb_trim_rcsum(skb, len); - - /* BUG: Should really parse the IP options here. */ - memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); + if (br_parse_ip_options(skb)) + /* Drop invalid packet */ + goto out; nf_bridge_put(skb->nf_bridge); if (!nf_bridge_alloc(skb)) @@ -614,8 +660,6 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff *skb, return NF_STOLEN; -inhdr_error: -// IP_INC_STATS_BH(IpInHdrErrors); out: return NF_DROP; } @@ -759,14 +803,19 @@ static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff *skb, #if defined(CONFIG_NF_CONNTRACK_IPV4) || defined(CONFIG_NF_CONNTRACK_IPV4_MODULE) static int br_nf_dev_queue_xmit(struct sk_buff *skb) { + int ret; + if (skb->nfct != NULL && skb->protocol == htons(ETH_P_IP) && skb->len + nf_bridge_mtu_reduction(skb) > skb->dev->mtu && !skb_is_gso(skb)) { - /* BUG: Should really parse the IP options here. */ - memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); - return ip_fragment(skb, br_dev_queue_push_xmit); + if (br_parse_ip_options(skb)) + /* Drop invalid packet */ + return NF_DROP; + ret = ip_fragment(skb, br_dev_queue_push_xmit); } else - return br_dev_queue_push_xmit(skb); + ret = br_dev_queue_push_xmit(skb); + + return ret; } #else static int br_nf_dev_queue_xmit(struct sk_buff *skb) |