From 51b0a5d8c21a91801bbef9bcc8639dc0b206c6cd Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 26 Sep 2014 14:35:14 +0200 Subject: netfilter: nft_reject: introduce icmp code abstraction for inet and bridge This patch introduces the NFT_REJECT_ICMPX_UNREACH type which provides an abstraction to the ICMP and ICMPv6 codes that you can use from the inet and bridge tables, they are: * NFT_REJECT_ICMPX_NO_ROUTE: no route to host - network unreachable * NFT_REJECT_ICMPX_PORT_UNREACH: port unreachable * NFT_REJECT_ICMPX_HOST_UNREACH: host unreachable * NFT_REJECT_ICMPX_ADMIN_PROHIBITED: administratevely prohibited You can still use the specific codes when restricting the rule to match the corresponding layer 3 protocol. I decided to not overload the existing NFT_REJECT_ICMP_UNREACH to have different semantics depending on the table family and to allow the user to specify ICMP family specific codes if they restrict it to the corresponding family. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_reject.c | 37 ++++++++++++++++ net/netfilter/nft_reject_inet.c | 94 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 127 insertions(+), 4 deletions(-) (limited to 'net/netfilter') diff --git a/net/netfilter/nft_reject.c b/net/netfilter/nft_reject.c index f3448c2..ec8a456 100644 --- a/net/netfilter/nft_reject.c +++ b/net/netfilter/nft_reject.c @@ -17,6 +17,8 @@ #include #include #include +#include +#include const struct nla_policy nft_reject_policy[NFTA_REJECT_MAX + 1] = { [NFTA_REJECT_TYPE] = { .type = NLA_U32 }, @@ -70,5 +72,40 @@ nla_put_failure: } EXPORT_SYMBOL_GPL(nft_reject_dump); +static u8 icmp_code_v4[NFT_REJECT_ICMPX_MAX] = { + [NFT_REJECT_ICMPX_NO_ROUTE] = ICMP_NET_UNREACH, + [NFT_REJECT_ICMPX_PORT_UNREACH] = ICMP_PORT_UNREACH, + [NFT_REJECT_ICMPX_HOST_UNREACH] = ICMP_HOST_UNREACH, + [NFT_REJECT_ICMPX_ADMIN_PROHIBITED] = ICMP_PKT_FILTERED, +}; + +int nft_reject_icmp_code(u8 code) +{ + if (code > NFT_REJECT_ICMPX_MAX) + return -EINVAL; + + return icmp_code_v4[code]; +} + +EXPORT_SYMBOL_GPL(nft_reject_icmp_code); + + +static u8 icmp_code_v6[NFT_REJECT_ICMPX_MAX] = { + [NFT_REJECT_ICMPX_NO_ROUTE] = ICMPV6_NOROUTE, + [NFT_REJECT_ICMPX_PORT_UNREACH] = ICMPV6_PORT_UNREACH, + [NFT_REJECT_ICMPX_HOST_UNREACH] = ICMPV6_ADDR_UNREACH, + [NFT_REJECT_ICMPX_ADMIN_PROHIBITED] = ICMPV6_ADM_PROHIBITED, +}; + +int nft_reject_icmpv6_code(u8 code) +{ + if (code > NFT_REJECT_ICMPX_MAX) + return -EINVAL; + + return icmp_code_v6[code]; +} + +EXPORT_SYMBOL_GPL(nft_reject_icmpv6_code); + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Patrick McHardy "); diff --git a/net/netfilter/nft_reject_inet.c b/net/netfilter/nft_reject_inet.c index b718a52..7b5f9d5 100644 --- a/net/netfilter/nft_reject_inet.c +++ b/net/netfilter/nft_reject_inet.c @@ -14,17 +14,103 @@ #include #include #include +#include +#include static void nft_reject_inet_eval(const struct nft_expr *expr, struct nft_data data[NFT_REG_MAX + 1], const struct nft_pktinfo *pkt) { + struct nft_reject *priv = nft_expr_priv(expr); + struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out); + switch (pkt->ops->pf) { case NFPROTO_IPV4: - return nft_reject_ipv4_eval(expr, data, pkt); + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + nf_send_unreach(pkt->skb, priv->icmp_code); + break; + case NFT_REJECT_TCP_RST: + nf_send_reset(pkt->skb, pkt->ops->hooknum); + break; + case NFT_REJECT_ICMPX_UNREACH: + nf_send_unreach(pkt->skb, + nft_reject_icmp_code(priv->icmp_code)); + break; + } + break; case NFPROTO_IPV6: - return nft_reject_ipv6_eval(expr, data, pkt); + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + nf_send_unreach6(net, pkt->skb, priv->icmp_code, + pkt->ops->hooknum); + break; + case NFT_REJECT_TCP_RST: + nf_send_reset6(net, pkt->skb, pkt->ops->hooknum); + break; + case NFT_REJECT_ICMPX_UNREACH: + nf_send_unreach6(net, pkt->skb, + nft_reject_icmpv6_code(priv->icmp_code), + pkt->ops->hooknum); + break; + } + break; + } + data[NFT_REG_VERDICT].verdict = NF_DROP; +} + +static int nft_reject_inet_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_reject *priv = nft_expr_priv(expr); + int icmp_code; + + if (tb[NFTA_REJECT_TYPE] == NULL) + return -EINVAL; + + priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE])); + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + case NFT_REJECT_ICMPX_UNREACH: + if (tb[NFTA_REJECT_ICMP_CODE] == NULL) + return -EINVAL; + + icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]); + if (priv->type == NFT_REJECT_ICMPX_UNREACH && + icmp_code > NFT_REJECT_ICMPX_MAX) + return -EINVAL; + + priv->icmp_code = icmp_code; + break; + case NFT_REJECT_TCP_RST: + break; + default: + return -EINVAL; } + return 0; +} + +static int nft_reject_inet_dump(struct sk_buff *skb, + const struct nft_expr *expr) +{ + const struct nft_reject *priv = nft_expr_priv(expr); + + if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type))) + goto nla_put_failure; + + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + case NFT_REJECT_ICMPX_UNREACH: + if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code)) + goto nla_put_failure; + break; + } + + return 0; + +nla_put_failure: + return -1; } static struct nft_expr_type nft_reject_inet_type; @@ -32,8 +118,8 @@ static const struct nft_expr_ops nft_reject_inet_ops = { .type = &nft_reject_inet_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_reject)), .eval = nft_reject_inet_eval, - .init = nft_reject_init, - .dump = nft_reject_dump, + .init = nft_reject_inet_init, + .dump = nft_reject_inet_dump, }; static struct nft_expr_type nft_reject_inet_type __read_mostly = { -- cgit v1.1