netfilter: require Ethernet MAC header before using eth_hdr() `ip6t_eui64`, `xt_mac`, the `bitmap:ip,mac`, `hash:ip,mac`, and `hash:mac` ipset types, and `nf_log_syslog` access `eth_hdr(skb)` after either assuming that the skb is associated with an Ethernet device or checking only that the `ETH_HLEN` bytes at `skb_mac_header(skb)` lie between `skb->head` and `skb->data`. Make these paths first verify that the skb is associated with an Ethernet device, that the MAC header was set, and that it spans at least a full Ethernet header before accessing `eth_hdr(skb)`. Suggested-by: Florian Westphal <fw@strlen.de> Tested-by: Ren Wei <enjou1224z@gmail.com> Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Signed-off-by: Florian Westphal <fw@strlen.de>
diff --git a/net/ipv6/netfilter/ip6t_eui64.c b/net/ipv6/netfilter/ip6t_eui64.c index da69a27..bbb684f 100644 --- a/net/ipv6/netfilter/ip6t_eui64.c +++ b/net/ipv6/netfilter/ip6t_eui64.c
@@ -7,6 +7,7 @@ #include <linux/module.h> #include <linux/skbuff.h> #include <linux/ipv6.h> +#include <linux/if_arp.h> #include <linux/if_ether.h> #include <linux/netfilter/x_tables.h> @@ -21,8 +22,10 @@ eui64_mt6(const struct sk_buff *skb, struct xt_action_param *par) { unsigned char eui64[8]; - if (!(skb_mac_header(skb) >= skb->head && - skb_mac_header(skb) + ETH_HLEN <= skb->data)) { + if (!skb->dev || skb->dev->type != ARPHRD_ETHER) + return false; + + if (!skb_mac_header_was_set(skb) || skb_mac_header_len(skb) < ETH_HLEN) { par->hotdrop = true; return false; }
diff --git a/net/netfilter/ipset/ip_set_bitmap_ipmac.c b/net/netfilter/ipset/ip_set_bitmap_ipmac.c index 2c625e0..752f59e 100644 --- a/net/netfilter/ipset/ip_set_bitmap_ipmac.c +++ b/net/netfilter/ipset/ip_set_bitmap_ipmac.c
@@ -11,6 +11,7 @@ #include <linux/etherdevice.h> #include <linux/skbuff.h> #include <linux/errno.h> +#include <linux/if_arp.h> #include <linux/if_ether.h> #include <linux/netlink.h> #include <linux/jiffies.h> @@ -220,8 +221,8 @@ bitmap_ipmac_kadt(struct ip_set *set, const struct sk_buff *skb, return -IPSET_ERR_BITMAP_RANGE; /* Backward compatibility: we don't check the second flag */ - if (skb_mac_header(skb) < skb->head || - (skb_mac_header(skb) + ETH_HLEN) > skb->data) + if (!skb->dev || skb->dev->type != ARPHRD_ETHER || + !skb_mac_header_was_set(skb) || skb_mac_header_len(skb) < ETH_HLEN) return -EINVAL; e.id = ip_to_id(map, ip);
diff --git a/net/netfilter/ipset/ip_set_hash_ipmac.c b/net/netfilter/ipset/ip_set_hash_ipmac.c index 467c59a..b9a2681 100644 --- a/net/netfilter/ipset/ip_set_hash_ipmac.c +++ b/net/netfilter/ipset/ip_set_hash_ipmac.c
@@ -11,6 +11,7 @@ #include <linux/skbuff.h> #include <linux/errno.h> #include <linux/random.h> +#include <linux/if_arp.h> #include <linux/if_ether.h> #include <net/ip.h> #include <net/ipv6.h> @@ -89,8 +90,8 @@ hash_ipmac4_kadt(struct ip_set *set, const struct sk_buff *skb, struct hash_ipmac4_elem e = { .ip = 0, { .foo[0] = 0, .foo[1] = 0 } }; struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set); - if (skb_mac_header(skb) < skb->head || - (skb_mac_header(skb) + ETH_HLEN) > skb->data) + if (!skb->dev || skb->dev->type != ARPHRD_ETHER || + !skb_mac_header_was_set(skb) || skb_mac_header_len(skb) < ETH_HLEN) return -EINVAL; if (opt->flags & IPSET_DIM_TWO_SRC) @@ -205,8 +206,8 @@ hash_ipmac6_kadt(struct ip_set *set, const struct sk_buff *skb, }; struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set); - if (skb_mac_header(skb) < skb->head || - (skb_mac_header(skb) + ETH_HLEN) > skb->data) + if (!skb->dev || skb->dev->type != ARPHRD_ETHER || + !skb_mac_header_was_set(skb) || skb_mac_header_len(skb) < ETH_HLEN) return -EINVAL; if (opt->flags & IPSET_DIM_TWO_SRC)
diff --git a/net/netfilter/ipset/ip_set_hash_mac.c b/net/netfilter/ipset/ip_set_hash_mac.c index 7188147..41a1225 100644 --- a/net/netfilter/ipset/ip_set_hash_mac.c +++ b/net/netfilter/ipset/ip_set_hash_mac.c
@@ -8,6 +8,7 @@ #include <linux/etherdevice.h> #include <linux/skbuff.h> #include <linux/errno.h> +#include <linux/if_arp.h> #include <linux/if_ether.h> #include <net/netlink.h> @@ -77,8 +78,8 @@ hash_mac4_kadt(struct ip_set *set, const struct sk_buff *skb, struct hash_mac4_elem e = { { .foo[0] = 0, .foo[1] = 0 } }; struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set); - if (skb_mac_header(skb) < skb->head || - (skb_mac_header(skb) + ETH_HLEN) > skb->data) + if (!skb->dev || skb->dev->type != ARPHRD_ETHER || + !skb_mac_header_was_set(skb) || skb_mac_header_len(skb) < ETH_HLEN) return -EINVAL; if (opt->flags & IPSET_DIM_ONE_SRC)
diff --git a/net/netfilter/nf_log_syslog.c b/net/netfilter/nf_log_syslog.c index 0507d67..7a8952b 100644 --- a/net/netfilter/nf_log_syslog.c +++ b/net/netfilter/nf_log_syslog.c
@@ -78,7 +78,10 @@ dump_arp_packet(struct nf_log_buf *m, else logflags = NF_LOG_DEFAULT_MASK; - if (logflags & NF_LOG_MACDECODE) { + if ((logflags & NF_LOG_MACDECODE) && + skb->dev && skb->dev->type == ARPHRD_ETHER && + skb_mac_header_was_set(skb) && + skb_mac_header_len(skb) >= ETH_HLEN) { nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM ", eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest); nf_log_dump_vlan(m, skb); @@ -797,6 +800,9 @@ static void dump_mac_header(struct nf_log_buf *m, switch (dev->type) { case ARPHRD_ETHER: + if (!skb_mac_header_was_set(skb) || skb_mac_header_len(skb) < ETH_HLEN) + return; + nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM ", eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest); nf_log_dump_vlan(m, skb);
diff --git a/net/netfilter/xt_mac.c b/net/netfilter/xt_mac.c index 81649da..4798cd2 100644 --- a/net/netfilter/xt_mac.c +++ b/net/netfilter/xt_mac.c
@@ -29,9 +29,7 @@ static bool mac_mt(const struct sk_buff *skb, struct xt_action_param *par) if (skb->dev == NULL || skb->dev->type != ARPHRD_ETHER) return false; - if (skb_mac_header(skb) < skb->head) - return false; - if (skb_mac_header(skb) + ETH_HLEN > skb->data) + if (!skb_mac_header_was_set(skb) || skb_mac_header_len(skb) < ETH_HLEN) return false; ret = ether_addr_equal(eth_hdr(skb)->h_source, info->srcaddr); ret ^= info->invert;