From 51b0a5d8c21a91801bbef9bcc8639dc0b206c6cd Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 26 Sep 2014 14:35:14 +0200 Subject: [PATCH] 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 --- include/net/netfilter/ipv4/nf_reject.h | 1 + include/net/netfilter/nft_reject.h | 9 +-- include/uapi/linux/netfilter/nf_tables.h | 21 +++++++ net/bridge/netfilter/nft_reject_bridge.c | 95 ++++++++++++++++++++++++++++++-- net/ipv4/netfilter/nft_reject_ipv4.c | 1 - net/netfilter/nft_reject.c | 37 +++++++++++++ net/netfilter/nft_reject_inet.c | 94 +++++++++++++++++++++++++++++-- 7 files changed, 241 insertions(+), 17 deletions(-) diff --git a/include/net/netfilter/ipv4/nf_reject.h b/include/net/netfilter/ipv4/nf_reject.h index f713b5a..8ce0638 100644 --- a/include/net/netfilter/ipv4/nf_reject.h +++ b/include/net/netfilter/ipv4/nf_reject.h @@ -5,6 +5,7 @@ #include #include #include +#include static inline void nf_send_unreach(struct sk_buff *skb_in, int code) { diff --git a/include/net/netfilter/nft_reject.h b/include/net/netfilter/nft_reject.h index 36b0da2..60fa153 100644 --- a/include/net/netfilter/nft_reject.h +++ b/include/net/netfilter/nft_reject.h @@ -14,12 +14,7 @@ int nft_reject_init(const struct nft_ctx *ctx, int nft_reject_dump(struct sk_buff *skb, const struct nft_expr *expr); -void nft_reject_ipv4_eval(const struct nft_expr *expr, - struct nft_data data[NFT_REG_MAX + 1], - const struct nft_pktinfo *pkt); - -void nft_reject_ipv6_eval(const struct nft_expr *expr, - struct nft_data data[NFT_REG_MAX + 1], - const struct nft_pktinfo *pkt); +int nft_reject_icmp_code(u8 code); +int nft_reject_icmpv6_code(u8 code); #endif diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index b72ccfe..c26df67 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -749,13 +749,34 @@ enum nft_queue_attributes { * * @NFT_REJECT_ICMP_UNREACH: reject using ICMP unreachable * @NFT_REJECT_TCP_RST: reject using TCP RST + * @NFT_REJECT_ICMPX_UNREACH: abstracted ICMP unreachable for bridge and inet */ enum nft_reject_types { NFT_REJECT_ICMP_UNREACH, NFT_REJECT_TCP_RST, + NFT_REJECT_ICMPX_UNREACH, }; /** + * enum nft_reject_code - Generic reject codes for IPv4/IPv6 + * + * @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: administratively prohibited + * + * These codes are mapped to real ICMP and ICMPv6 codes. + */ +enum nft_reject_inet_code { + NFT_REJECT_ICMPX_NO_ROUTE = 0, + NFT_REJECT_ICMPX_PORT_UNREACH, + NFT_REJECT_ICMPX_HOST_UNREACH, + NFT_REJECT_ICMPX_ADMIN_PROHIBITED, + __NFT_REJECT_ICMPX_MAX +}; +#define NFT_REJECT_ICMPX_MAX (__NFT_REJECT_ICMPX_MAX + 1) + +/** * enum nft_reject_attributes - nf_tables reject expression netlink attributes * * @NFTA_REJECT_TYPE: packet type to use (NLA_U32: nft_reject_types) diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c index ee3ffe9..a764795 100644 --- a/net/bridge/netfilter/nft_reject_bridge.c +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -14,21 +14,106 @@ #include #include #include +#include +#include static void nft_reject_bridge_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 (eth_hdr(pkt->skb)->h_proto) { case htons(ETH_P_IP): - 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 htons(ETH_P_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; default: /* No explicit way to reject this protocol, drop it. */ - data[NFT_REG_VERDICT].verdict = NF_DROP; break; } + data[NFT_REG_VERDICT].verdict = NF_DROP; +} + +static int nft_reject_bridge_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_bridge_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_bridge_type; @@ -36,8 +121,8 @@ static const struct nft_expr_ops nft_reject_bridge_ops = { .type = &nft_reject_bridge_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_reject)), .eval = nft_reject_bridge_eval, - .init = nft_reject_init, - .dump = nft_reject_dump, + .init = nft_reject_bridge_init, + .dump = nft_reject_bridge_dump, }; static struct nft_expr_type nft_reject_bridge_type __read_mostly = { diff --git a/net/ipv4/netfilter/nft_reject_ipv4.c b/net/ipv4/netfilter/nft_reject_ipv4.c index e79718a..ed33299 100644 --- a/net/ipv4/netfilter/nft_reject_ipv4.c +++ b/net/ipv4/netfilter/nft_reject_ipv4.c @@ -16,7 +16,6 @@ #include #include #include -#include #include #include 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 = { -- 2.7.4