net/netfilter/nft_socket.c

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #include <linux/module.h>
0003 #include <linux/netfilter/nf_tables.h>
0004 #include <net/netfilter/nf_tables.h>
0005 #include <net/netfilter/nf_tables_core.h>
0006 #include <net/netfilter/nf_socket.h>
0007 #include <net/inet_sock.h>
0008 #include <net/tcp.h>
0009
0010 struct nft_socket {
0011     enum nft_socket_keys        key:8;
0012     u8              level;
0013     u8              len;
0014     union {
0015         u8          dreg;
0016     };
0017 };
0018
0019 static void nft_socket_wildcard(const struct nft_pktinfo *pkt,
0020                 struct nft_regs *regs, struct sock *sk,
0021                 u32 *dest)
0022 {
0023     switch (nft_pf(pkt)) {
0024     case NFPROTO_IPV4:
0025         nft_reg_store8(dest, inet_sk(sk)->inet_rcv_saddr == 0);
0026         break;
0027 #if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
0028     case NFPROTO_IPV6:
0029         nft_reg_store8(dest, ipv6_addr_any(&sk->sk_v6_rcv_saddr));
0030         break;
0031 #endif
0032     default:
0033         regs->verdict.code = NFT_BREAK;
0034         return;
0035     }
0036 }
0037
0038 #ifdef CONFIG_SOCK_CGROUP_DATA
0039 static noinline bool
0040 nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo *pkt, u32 level)
0041 {
0042     struct cgroup *cgrp;
0043
0044     if (!sk_fullsock(sk))
0045         return false;
0046
0047     cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
0048     if (level > cgrp->level)
0049         return false;
0050
0051     memcpy(dest, &cgrp->ancestor_ids[level], sizeof(u64));
0052
0053     return true;
0054 }
0055 #endif
0056
0057 static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)
0058 {
0059     const struct net_device *indev = nft_in(pkt);
0060     const struct sk_buff *skb = pkt->skb;
0061     struct sock *sk = NULL;
0062
0063     if (!indev)
0064         return NULL;
0065
0066     switch (nft_pf(pkt)) {
0067     case NFPROTO_IPV4:
0068         sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, indev);
0069         break;
0070 #if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
0071     case NFPROTO_IPV6:
0072         sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, indev);
0073         break;
0074 #endif
0075     default:
0076         WARN_ON_ONCE(1);
0077         break;
0078     }
0079
0080     return sk;
0081 }
0082
0083 static void nft_socket_eval(const struct nft_expr *expr,
0084                 struct nft_regs *regs,
0085                 const struct nft_pktinfo *pkt)
0086 {
0087     const struct nft_socket *priv = nft_expr_priv(expr);
0088     struct sk_buff *skb = pkt->skb;
0089     struct sock *sk = skb->sk;
0090     u32 *dest = &regs->data[priv->dreg];
0091
0092     if (sk && !net_eq(nft_net(pkt), sock_net(sk)))
0093         sk = NULL;
0094
0095     if (!sk)
0096         sk = nft_socket_do_lookup(pkt);
0097
0098     if (!sk) {
0099         regs->verdict.code = NFT_BREAK;
0100         return;
0101     }
0102
0103     switch(priv->key) {
0104     case NFT_SOCKET_TRANSPARENT:
0105         nft_reg_store8(dest, inet_sk_transparent(sk));
0106         break;
0107     case NFT_SOCKET_MARK:
0108         if (sk_fullsock(sk)) {
0109             *dest = sk->sk_mark;
0110         } else {
0111             regs->verdict.code = NFT_BREAK;
0112             return;
0113         }
0114         break;
0115     case NFT_SOCKET_WILDCARD:
0116         if (!sk_fullsock(sk)) {
0117             regs->verdict.code = NFT_BREAK;
0118             return;
0119         }
0120         nft_socket_wildcard(pkt, regs, sk, dest);
0121         break;
0122 #ifdef CONFIG_SOCK_CGROUP_DATA
0123     case NFT_SOCKET_CGROUPV2:
0124         if (!nft_sock_get_eval_cgroupv2(dest, sk, pkt, priv->level)) {
0125             regs->verdict.code = NFT_BREAK;
0126             return;
0127         }
0128         break;
0129 #endif
0130     default:
0131         WARN_ON(1);
0132         regs->verdict.code = NFT_BREAK;
0133     }
0134
0135     if (sk != skb->sk)
0136         sock_gen_put(sk);
0137 }
0138
0139 static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {
0140     [NFTA_SOCKET_KEY]       = { .type = NLA_U32 },
0141     [NFTA_SOCKET_DREG]      = { .type = NLA_U32 },
0142     [NFTA_SOCKET_LEVEL]     = { .type = NLA_U32 },
0143 };
0144
0145 static int nft_socket_init(const struct nft_ctx *ctx,
0146                const struct nft_expr *expr,
0147                const struct nlattr * const tb[])
0148 {
0149     struct nft_socket *priv = nft_expr_priv(expr);
0150     unsigned int len;
0151
0152     if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY])
0153         return -EINVAL;
0154
0155     switch(ctx->family) {
0156     case NFPROTO_IPV4:
0157 #if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
0158     case NFPROTO_IPV6:
0159 #endif
0160     case NFPROTO_INET:
0161         break;
0162     default:
0163         return -EOPNOTSUPP;
0164     }
0165
0166     priv->key = ntohl(nla_get_be32(tb[NFTA_SOCKET_KEY]));
0167     switch(priv->key) {
0168     case NFT_SOCKET_TRANSPARENT:
0169     case NFT_SOCKET_WILDCARD:
0170         len = sizeof(u8);
0171         break;
0172     case NFT_SOCKET_MARK:
0173         len = sizeof(u32);
0174         break;
0175 #ifdef CONFIG_CGROUPS
0176     case NFT_SOCKET_CGROUPV2: {
0177         unsigned int level;
0178
0179         if (!tb[NFTA_SOCKET_LEVEL])
0180             return -EINVAL;
0181
0182         level = ntohl(nla_get_be32(tb[NFTA_SOCKET_LEVEL]));
0183         if (level > 255)
0184             return -EOPNOTSUPP;
0185
0186         priv->level = level;
0187         len = sizeof(u64);
0188         break;
0189     }
0190 #endif
0191     default:
0192         return -EOPNOTSUPP;
0193     }
0194
0195     priv->len = len;
0196     return nft_parse_register_store(ctx, tb[NFTA_SOCKET_DREG], &priv->dreg,
0197                     NULL, NFT_DATA_VALUE, len);
0198 }
0199
0200 static int nft_socket_dump(struct sk_buff *skb,
0201                const struct nft_expr *expr)
0202 {
0203     const struct nft_socket *priv = nft_expr_priv(expr);
0204
0205     if (nla_put_be32(skb, NFTA_SOCKET_KEY, htonl(priv->key)))
0206         return -1;
0207     if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg))
0208         return -1;
0209     if (priv->key == NFT_SOCKET_CGROUPV2 &&
0210         nla_put_be32(skb, NFTA_SOCKET_LEVEL, htonl(priv->level)))
0211         return -1;
0212     return 0;
0213 }
0214
0215 static bool nft_socket_reduce(struct nft_regs_track *track,
0216                   const struct nft_expr *expr)
0217 {
0218     const struct nft_socket *priv = nft_expr_priv(expr);
0219     const struct nft_socket *socket;
0220
0221     if (!nft_reg_track_cmp(track, expr, priv->dreg)) {
0222         nft_reg_track_update(track, expr, priv->dreg, priv->len);
0223         return false;
0224     }
0225
0226     socket = nft_expr_priv(track->regs[priv->dreg].selector);
0227     if (priv->key != socket->key ||
0228         priv->dreg != socket->dreg ||
0229         priv->level != socket->level) {
0230         nft_reg_track_update(track, expr, priv->dreg, priv->len);
0231         return false;
0232     }
0233
0234     if (!track->regs[priv->dreg].bitwise)
0235         return true;
0236
0237     return nft_expr_reduce_bitwise(track, expr);
0238 }
0239
0240 static int nft_socket_validate(const struct nft_ctx *ctx,
0241                    const struct nft_expr *expr,
0242                    const struct nft_data **data)
0243 {
0244     return nft_chain_validate_hooks(ctx->chain,
0245                     (1 << NF_INET_PRE_ROUTING) |
0246                     (1 << NF_INET_LOCAL_IN) |
0247                     (1 << NF_INET_LOCAL_OUT));
0248 }
0249
0250 static struct nft_expr_type nft_socket_type;
0251 static const struct nft_expr_ops nft_socket_ops = {
0252     .type       = &nft_socket_type,
0253     .size       = NFT_EXPR_SIZE(sizeof(struct nft_socket)),
0254     .eval       = nft_socket_eval,
0255     .init       = nft_socket_init,
0256     .dump       = nft_socket_dump,
0257     .validate   = nft_socket_validate,
0258     .reduce     = nft_socket_reduce,
0259 };
0260
0261 static struct nft_expr_type nft_socket_type __read_mostly = {
0262     .name       = "socket",
0263     .ops        = &nft_socket_ops,
0264     .policy     = nft_socket_policy,
0265     .maxattr    = NFTA_SOCKET_MAX,
0266     .owner      = THIS_MODULE,
0267 };
0268
0269 static int __init nft_socket_module_init(void)
0270 {
0271     return nft_register_expr(&nft_socket_type);
0272 }
0273
0274 static void __exit nft_socket_module_exit(void)
0275 {
0276     nft_unregister_expr(&nft_socket_type);
0277 }
0278
0279 module_init(nft_socket_module_init);
0280 module_exit(nft_socket_module_exit);
0281
0282 MODULE_LICENSE("GPL");
0283 MODULE_AUTHOR("Máté Eckl");
0284 MODULE_DESCRIPTION("nf_tables socket match module");
0285 MODULE_ALIAS_NFT_EXPR("socket");