diff options
| -rw-r--r-- | include/linux/netfilter_bridge/ebt_nat.h | 1 | ||||
| -rw-r--r-- | include/linux/netfilter_bridge/ebtables.h | 4 | ||||
| -rw-r--r-- | net/bridge/netfilter/ebt_mark.c | 6 | ||||
| -rw-r--r-- | net/bridge/netfilter/ebt_snat.c | 27 |
4 files changed, 32 insertions, 6 deletions
diff --git a/include/linux/netfilter_bridge/ebt_nat.h b/include/linux/netfilter_bridge/ebt_nat.h index 26fd90d..435b886 100644 --- a/include/linux/netfilter_bridge/ebt_nat.h +++ b/include/linux/netfilter_bridge/ebt_nat.h @@ -1,6 +1,7 @@ #ifndef __LINUX_BRIDGE_EBT_NAT_H #define __LINUX_BRIDGE_EBT_NAT_H +#define NAT_ARP_BIT (0x00000010) struct ebt_nat_info { unsigned char mac[ETH_ALEN]; diff --git a/include/linux/netfilter_bridge/ebtables.h b/include/linux/netfilter_bridge/ebtables.h index e6ea70d..8777526 100644 --- a/include/linux/netfilter_bridge/ebtables.h +++ b/include/linux/netfilter_bridge/ebtables.h @@ -26,6 +26,10 @@ #define EBT_CONTINUE -3 #define EBT_RETURN -4 #define NUM_STANDARD_TARGETS 4 +/* ebtables target modules store the verdict inside an int. We can + * reclaim a part of this int for backwards compatible extensions. + * The 4 lsb are more than enough to store the verdict. */ +#define EBT_VERDICT_BITS 0x0000000F struct ebt_counter { diff --git a/net/bridge/netfilter/ebt_mark.c b/net/bridge/netfilter/ebt_mark.c index 2458638..62d23c7 100644 --- a/net/bridge/netfilter/ebt_mark.c +++ b/net/bridge/netfilter/ebt_mark.c @@ -33,7 +33,7 @@ static int ebt_target_mark(struct sk_buff **pskb, unsigned int hooknr, else (*pskb)->mark ^= info->mark; - return info->target | -16; + return info->target | ~EBT_VERDICT_BITS; } static int ebt_target_mark_check(const char *tablename, unsigned int hookmask, @@ -44,13 +44,13 @@ static int ebt_target_mark_check(const char *tablename, unsigned int hookmask, if (datalen != EBT_ALIGN(sizeof(struct ebt_mark_t_info))) return -EINVAL; - tmp = info->target | -16; + tmp = info->target | ~EBT_VERDICT_BITS; if (BASE_CHAIN && tmp == EBT_RETURN) return -EINVAL; CLEAR_BASE_CHAIN_BIT; if (tmp < -NUM_STANDARD_TARGETS || tmp >= 0) return -EINVAL; - tmp = info->target & -16; + tmp = info->target & ~EBT_VERDICT_BITS; if (tmp != MARK_SET_VALUE && tmp != MARK_OR_VALUE && tmp != MARK_AND_VALUE && tmp != MARK_XOR_VALUE) return -EINVAL; diff --git a/net/bridge/netfilter/ebt_snat.c b/net/bridge/netfilter/ebt_snat.c index cbb33e2..a507221 100644 --- a/net/bridge/netfilter/ebt_snat.c +++ b/net/bridge/netfilter/ebt_snat.c @@ -12,6 +12,8 @@ #include <linux/netfilter_bridge/ebt_nat.h> #include <linux/module.h> #include <net/sock.h> +#include <linux/if_arp.h> +#include <net/arp.h> static int ebt_target_snat(struct sk_buff **pskb, unsigned int hooknr, const struct net_device *in, const struct net_device *out, @@ -31,24 +33,43 @@ static int ebt_target_snat(struct sk_buff **pskb, unsigned int hooknr, *pskb = nskb; } memcpy(eth_hdr(*pskb)->h_source, info->mac, ETH_ALEN); - return info->target; + if (!(info->target & NAT_ARP_BIT) && + eth_hdr(*pskb)->h_proto == htons(ETH_P_ARP)) { + struct arphdr _ah, *ap; + + ap = skb_header_pointer(*pskb, 0, sizeof(_ah), &_ah); + if (ap == NULL) + return EBT_DROP; + if (ap->ar_hln != ETH_ALEN) + goto out; + if (skb_store_bits(*pskb, sizeof(_ah), info->mac,ETH_ALEN)) + return EBT_DROP; + } +out: + return info->target | ~EBT_VERDICT_BITS; } static int ebt_target_snat_check(const char *tablename, unsigned int hookmask, const struct ebt_entry *e, void *data, unsigned int datalen) { struct ebt_nat_info *info = (struct ebt_nat_info *) data; + int tmp; if (datalen != EBT_ALIGN(sizeof(struct ebt_nat_info))) return -EINVAL; - if (BASE_CHAIN && info->target == EBT_RETURN) + tmp = info->target | ~EBT_VERDICT_BITS; + if (BASE_CHAIN && tmp == EBT_RETURN) return -EINVAL; CLEAR_BASE_CHAIN_BIT; if (strcmp(tablename, "nat")) return -EINVAL; if (hookmask & ~(1 << NF_BR_POST_ROUTING)) return -EINVAL; - if (INVALID_TARGET) + + if (tmp < -NUM_STANDARD_TARGETS || tmp >= 0) + return -EINVAL; + tmp = info->target | EBT_VERDICT_BITS; + if ((tmp & ~NAT_ARP_BIT) != ~NAT_ARP_BIT) return -EINVAL; return 0; } |
