diff options
author | Lennart Poettering <lennart@poettering.net> | 2021-02-16 23:41:35 +0100 |
---|---|---|
committer | GitHub <noreply@github.com> | 2021-02-16 23:41:35 +0100 |
commit | b1b4e9204c8260956825e2b9733c95903e215e31 (patch) | |
tree | 7be4306eb4e6c39aa94358c47a24ed8b23a5414f /src/shared/firewall-util-nft.c | |
parent | bb1296b55a222cbab24d533006e730529009258c (diff) | |
parent | 79dd22409325e99f255806ddf874173615628cfe (diff) | |
download | systemd-b1b4e9204c8260956825e2b9733c95903e215e31.tar.gz |
Merge pull request #18007 from fw-strlen/ipv6_masq_and_dnat
Support ipv6 for masquerade and dnat in nspawn and networkd
Diffstat (limited to 'src/shared/firewall-util-nft.c')
-rw-r--r-- | src/shared/firewall-util-nft.c | 184 |
1 files changed, 151 insertions, 33 deletions
diff --git a/src/shared/firewall-util-nft.c b/src/shared/firewall-util-nft.c index 98dd7ff3b4..6b900f0d06 100644 --- a/src/shared/firewall-util-nft.c +++ b/src/shared/firewall-util-nft.c @@ -9,6 +9,7 @@ #include <linux/netfilter/nf_nat.h> #include <linux/netfilter_ipv4.h> #include <netinet/ip.h> +#include <netinet/ip6.h> #include "sd-netlink.h" @@ -17,6 +18,7 @@ #include "firewall-util-private.h" #include "in-addr-util.h" #include "macro.h" +#include "memory-util.h" #include "socket-util.h" #include "time-util.h" @@ -28,6 +30,9 @@ #define UDP_DPORT_OFFSET 2 +void nft_in6addr_to_range(const union in_addr_union *source, unsigned int prefixlen, + struct in6_addr *start, struct in6_addr *end); + static int nfnl_netlink_sendv(sd_netlink *nfnl, sd_netlink_message *messages[], size_t msgcount) { @@ -329,9 +334,13 @@ static int sd_nfnl_message_new_masq_rule(sd_netlink *nfnl, sd_netlink_message ** if (r < 0) return r; - /* 1st statement: ip saddr @masq_saddr. Place iph->saddr in reg1. */ - r = nfnl_add_expr_payload(m, NFT_PAYLOAD_NETWORK_HEADER, offsetof(struct iphdr, saddr), - sizeof(uint32_t), NFT_REG32_01); + /* 1st statement: ip saddr @masq_saddr. Place iph->saddr in reg1, resp. ipv6 in reg1..reg4. */ + if (family == AF_INET) + r = nfnl_add_expr_payload(m, NFT_PAYLOAD_NETWORK_HEADER, offsetof(struct iphdr, saddr), + sizeof(uint32_t), NFT_REG32_01); + else + r = nfnl_add_expr_payload(m, NFT_PAYLOAD_NETWORK_HEADER, offsetof(struct ip6_hdr, ip6_src.s6_addr), + sizeof(struct in6_addr), NFT_REG32_01); if (r < 0) return r; @@ -397,7 +406,7 @@ static int sd_nfnl_message_new_dnat_rule_pre(sd_netlink *nfnl, sd_netlink_messag if (r < 0) return r; - proto_reg = NFT_REG32_02; + proto_reg = family == AF_INET ? NFT_REG32_02 : NFT_REG32_05; r = nfnl_add_expr_dnat(m, family, NFT_REG32_01, proto_reg); if (r < 0) return r; @@ -411,9 +420,8 @@ static int sd_nfnl_message_new_dnat_rule_pre(sd_netlink *nfnl, sd_netlink_messag static int sd_nfnl_message_new_dnat_rule_out(sd_netlink *nfnl, sd_netlink_message **ret, int family, const char *chain) { - static const uint32_t zero, one = 1; + static const uint32_t zero = 0, one = 1; - uint32_t lonet = htobe32(0x7F000000), lomask = htobe32(0xff000000); _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL; enum nft_registers proto_reg; int r; @@ -426,19 +434,31 @@ static int sd_nfnl_message_new_dnat_rule_out(sd_netlink *nfnl, sd_netlink_messag if (r < 0) return r; - /* 1st statement: exclude 127.0.0.1/8: ip daddr != 127.0.0.1/8 */ - r = nfnl_add_expr_payload(m, NFT_PAYLOAD_NETWORK_HEADER, offsetof(struct iphdr, daddr), - sizeof(uint32_t), NFT_REG32_01); - if (r < 0) - return r; + /* 1st statement: exclude 127.0.0.1/8: ip daddr != 127.0.0.1/8, resp. avoid ::1 */ + if (family == AF_INET) { + uint32_t lonet = htobe32(UINT32_C(0x7F000000)), lomask = htobe32(UINT32_C(0xff000000)); - /* 1st statement (cont.): bitops/prefix */ - r = nfnl_add_expr_bitwise(m, NFT_REG32_01, NFT_REG32_01, &lomask, &zero, sizeof(lomask)); - if (r < 0) - return r; + r = nfnl_add_expr_payload(m, NFT_PAYLOAD_NETWORK_HEADER, offsetof(struct iphdr, daddr), + sizeof(lonet), NFT_REG32_01); + if (r < 0) + return r; + /* 1st statement (cont.): bitops/prefix */ + r = nfnl_add_expr_bitwise(m, NFT_REG32_01, NFT_REG32_01, &lomask, &zero, sizeof(lomask)); + if (r < 0) + return r; - /* 1st statement (cont.): compare reg1 with 127/8 */ - r = nfnl_add_expr_cmp(m, NFT_CMP_NEQ, NFT_REG32_01, &lonet, sizeof(lonet)); + /* 1st statement (cont.): compare reg1 with 127/8 */ + r = nfnl_add_expr_cmp(m, NFT_CMP_NEQ, NFT_REG32_01, &lonet, sizeof(lonet)); + } else { + struct in6_addr loaddr = IN6ADDR_LOOPBACK_INIT; + + r = nfnl_add_expr_payload(m, NFT_PAYLOAD_NETWORK_HEADER, offsetof(struct ip6_hdr, ip6_dst.s6_addr), + sizeof(loaddr), NFT_REG32_01); + if (r < 0) + return r; + + r = nfnl_add_expr_cmp(m, NFT_CMP_NEQ, NFT_REG32_01, &loaddr, sizeof(loaddr)); + } if (r < 0) return r; @@ -475,7 +495,7 @@ static int sd_nfnl_message_new_dnat_rule_out(sd_netlink *nfnl, sd_netlink_messag /* 4th statement: dnat connection to address/port retrieved by the * preceding expression. */ - proto_reg = NFT_REG32_02; + proto_reg = family == AF_INET ? NFT_REG32_02 : NFT_REG32_05; r = nfnl_add_expr_dnat(m, family, NFT_REG32_01, proto_reg); if (r < 0) return r; @@ -620,10 +640,11 @@ static uint32_t concat_types2(enum nft_key_types a, enum nft_key_types b) { #define NFT_INIT_MSGS 16 static int fw_nftables_init_family(sd_netlink *nfnl, int family) { sd_netlink_message *batch[NFT_INIT_MSGS] = {}; - size_t ip_type_size = sizeof(uint32_t); - int ip_type = TYPE_IPADDR, r; - size_t msgcnt = 0, i; + size_t msgcnt = 0, i, ip_type_size; uint32_t set_id = 0; + int ip_type, r; + + assert(IN_SET(family, AF_INET, AF_INET6)); r = sd_nfnl_message_batch_begin(nfnl, &batch[msgcnt]); if (r < 0) @@ -661,6 +682,14 @@ static int fw_nftables_init_family(sd_netlink *nfnl, int family) { if (r < 0) goto out_unref; + if (family == AF_INET) { + ip_type_size = sizeof(uint32_t); + ip_type = TYPE_IPADDR; + } else { + assert(family == AF_INET6); + ip_type_size = sizeof(struct in6_addr); + ip_type = TYPE_IP6ADDR; + } msgcnt++; assert(msgcnt < NFT_INIT_MSGS); /* set to store ip address ranges we should masquerade for */ @@ -731,6 +760,10 @@ int fw_nftables_init(FirewallContext *ctx) { if (r < 0) return r; + r = fw_nftables_init_family(nfnl, AF_INET6); + if (r < 0) + log_debug_errno(r, "Failed to init ipv6 NAT: %m"); + ctx->nfnl = TAKE_PTR(nfnl); return 0; } @@ -815,6 +848,73 @@ static int fw_nftables_recreate_table(sd_netlink *nfnl, int af, sd_netlink_messa return 0; } +void nft_in6addr_to_range(const union in_addr_union *source, unsigned int prefixlen, + struct in6_addr *ret_start, struct in6_addr *ret_end) { + uint8_t carry = 0; + int i, j; + + assert(prefixlen <= 128); + + for (i = 0, j = 15; i < 16; i++) { + uint8_t nm; + + nm = 0xFF; + if (prefixlen < 8) + nm = 0xFF << (8 - prefixlen); + + ret_start->s6_addr[i] = source->in6.s6_addr[i] & nm; + if (prefixlen <= 8 && j == 15) { + carry = 1u << (8 - prefixlen); + j = i; + } + + if (prefixlen >= 8) + prefixlen -= 8; + else + prefixlen = 0; + } + *ret_end = *ret_start; + + for (; j >= 0; j--) { + uint16_t overflow = ret_end->s6_addr[j] + carry; + + ret_end->s6_addr[j] = overflow; + if (overflow <= 0xff) + break; + carry = 1; + } + + if (memcmp(ret_start, ret_end, sizeof(*ret_start)) > 0) + zero(ret_end); +} + +static int nft_message_add_setelem_ip6range(sd_netlink_message *m, + const union in_addr_union *source, + unsigned int prefixlen) { + struct in6_addr start, end; + int r; + + nft_in6addr_to_range(source, prefixlen, &start, &end); + + r = sd_nfnl_nft_message_add_setelem(m, 0, &start, sizeof(start), NULL, 0); + if (r < 0) + return r; + + r = sd_nfnl_nft_message_add_setelem_end(m); + if (r < 0) + return r; + + r = sd_nfnl_nft_message_add_setelem(m, 1, &end, sizeof(end), NULL, 0); + if (r < 0) + return r; + + r = sd_netlink_message_append_u32(m, NFTA_SET_ELEM_FLAGS, htobe32(NFT_SET_ELEM_INTERVAL_END)); + if (r < 0) + return r; + + return sd_nfnl_nft_message_add_setelem_end(m); +} + #define NFT_MASQ_MSGS 3 int fw_nftables_add_masquerade( @@ -831,6 +931,8 @@ int fw_nftables_add_masquerade( if (!source || source_prefixlen == 0) return -EINVAL; + if (af == AF_INET6 && source_prefixlen < 8) + return -EINVAL; again: r = sd_nfnl_message_batch_begin(ctx->nfnl, &transaction[0]); if (r < 0) @@ -844,7 +946,11 @@ again: if (r < 0) goto out_unref; - r = nft_message_add_setelem_iprange(transaction[tsize], source, source_prefixlen); + if (af == AF_INET) + r = nft_message_add_setelem_iprange(transaction[tsize], source, source_prefixlen); + else + r = nft_message_add_setelem_ip6range(transaction[tsize], source, source_prefixlen); + if (r < 0) goto out_unref; @@ -881,7 +987,7 @@ int fw_nftables_add_local_dnat( const union in_addr_union *remote, uint16_t remote_port, const union in_addr_union *previous_remote) { - uint32_t data[2], key[2]; + uint32_t data[5], key[2], dlen; sd_netlink_message *transaction[NFT_DNAT_MSGS] = {}; bool retry = true; size_t tsize; @@ -889,9 +995,6 @@ int fw_nftables_add_local_dnat( assert(add || !previous_remote); - if (af != AF_INET) - return -EAFNOSUPPORT; - if (!IN_SET(protocol, IPPROTO_TCP, IPPROTO_UDP)) return -EPROTONOSUPPORT; @@ -908,7 +1011,14 @@ again: if (remote_port <= 0) return -EINVAL; - data[1] = htobe16(remote_port); + if (af == AF_INET) { + dlen = 8; + data[1] = htobe16(remote_port); + } else { + assert(af == AF_INET6); + dlen = sizeof(data); + data[4] = htobe16(remote_port); + } r = sd_nfnl_message_batch_begin(ctx->nfnl, &transaction[0]); if (r < 0) @@ -916,23 +1026,29 @@ again: tsize = 1; /* If a previous remote is set, remove its entry */ - if (add && previous_remote && previous_remote->in.s_addr != remote->in.s_addr) { - data[0] = previous_remote->in.s_addr; + if (add && previous_remote && !in_addr_equal(af, previous_remote, remote)) { + if (af == AF_INET) + data[0] = previous_remote->in.s_addr; + else + memcpy(data, &previous_remote->in6, sizeof(previous_remote->in6)); - r = nft_del_element(ctx->nfnl, &transaction[tsize], af, NFT_SYSTEMD_DNAT_MAP_NAME, key, sizeof(key), data, sizeof(data)); + r = nft_del_element(ctx->nfnl, &transaction[tsize], af, NFT_SYSTEMD_DNAT_MAP_NAME, key, sizeof(key), data, dlen); if (r < 0) goto out_unref; tsize++; } - data[0] = remote->in.s_addr; + if (af == AF_INET) + data[0] = remote->in.s_addr; + else + memcpy(data, &remote->in6, sizeof(remote->in6)); assert(tsize < NFT_DNAT_MSGS); if (add) - nft_add_element(ctx->nfnl, &transaction[tsize], af, NFT_SYSTEMD_DNAT_MAP_NAME, key, sizeof(key), data, sizeof(data)); + nft_add_element(ctx->nfnl, &transaction[tsize], af, NFT_SYSTEMD_DNAT_MAP_NAME, key, sizeof(key), data, dlen); else - nft_del_element(ctx->nfnl, &transaction[tsize], af, NFT_SYSTEMD_DNAT_MAP_NAME, key, sizeof(key), data, sizeof(data)); + nft_del_element(ctx->nfnl, &transaction[tsize], af, NFT_SYSTEMD_DNAT_MAP_NAME, key, sizeof(key), data, dlen); tsize++; assert(tsize < NFT_DNAT_MSGS); @@ -949,6 +1065,8 @@ again: int tmp = fw_nftables_recreate_table(ctx->nfnl, af, transaction, tsize); if (tmp == 0) { + /* table created anew; previous address already gone */ + previous_remote = NULL; retry = false; goto again; } |