1 /* 2 * Copyright (c) 2012-2016 Pablo Neira Ayuso <[email protected]> 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 */ 8 9 #include <linux/init.h> 10 #include <linux/module.h> 11 #include <linux/skbuff.h> 12 #include <linux/netlink.h> 13 #include <linux/netfilter.h> 14 #include <linux/netfilter/nf_tables.h> 15 #include <net/netfilter/nf_tables.h> 16 17 #define nft_objref_priv(expr) *((struct nft_object **)nft_expr_priv(expr)) 18 19 static void nft_objref_eval(const struct nft_expr *expr, 20 struct nft_regs *regs, 21 const struct nft_pktinfo *pkt) 22 { 23 struct nft_object *obj = nft_objref_priv(expr); 24 25 obj->type->eval(obj, regs, pkt); 26 } 27 28 static int nft_objref_init(const struct nft_ctx *ctx, 29 const struct nft_expr *expr, 30 const struct nlattr * const tb[]) 31 { 32 struct nft_object *obj = nft_objref_priv(expr); 33 u8 genmask = nft_genmask_next(ctx->net); 34 u32 objtype; 35 36 if (!tb[NFTA_OBJREF_IMM_NAME] || 37 !tb[NFTA_OBJREF_IMM_TYPE]) 38 return -EINVAL; 39 40 objtype = ntohl(nla_get_be32(tb[NFTA_OBJREF_IMM_TYPE])); 41 obj = nf_tables_obj_lookup(ctx->table, tb[NFTA_OBJREF_IMM_NAME], objtype, 42 genmask); 43 if (IS_ERR(obj)) 44 return -ENOENT; 45 46 nft_objref_priv(expr) = obj; 47 obj->use++; 48 49 return 0; 50 } 51 52 static int nft_objref_dump(struct sk_buff *skb, const struct nft_expr *expr) 53 { 54 const struct nft_object *obj = nft_objref_priv(expr); 55 56 if (nla_put_string(skb, NFTA_OBJREF_IMM_NAME, obj->name) || 57 nla_put_be32(skb, NFTA_OBJREF_IMM_TYPE, htonl(obj->type->type))) 58 goto nla_put_failure; 59 60 return 0; 61 62 nla_put_failure: 63 return -1; 64 } 65 66 static void nft_objref_destroy(const struct nft_ctx *ctx, 67 const struct nft_expr *expr) 68 { 69 struct nft_object *obj = nft_objref_priv(expr); 70 71 obj->use--; 72 } 73 74 static struct nft_expr_type nft_objref_type; 75 static const struct nft_expr_ops nft_objref_ops = { 76 .type = &nft_objref_type, 77 .size = NFT_EXPR_SIZE(sizeof(struct nft_object *)), 78 .eval = nft_objref_eval, 79 .init = nft_objref_init, 80 .destroy = nft_objref_destroy, 81 .dump = nft_objref_dump, 82 }; 83 84 struct nft_objref_map { 85 struct nft_set *set; 86 enum nft_registers sreg:8; 87 struct nft_set_binding binding; 88 }; 89 90 static void nft_objref_map_eval(const struct nft_expr *expr, 91 struct nft_regs *regs, 92 const struct nft_pktinfo *pkt) 93 { 94 struct nft_objref_map *priv = nft_expr_priv(expr); 95 const struct nft_set *set = priv->set; 96 const struct nft_set_ext *ext; 97 struct nft_object *obj; 98 bool found; 99 100 found = set->ops->lookup(nft_net(pkt), set, ®s->data[priv->sreg], 101 &ext); 102 if (!found) { 103 regs->verdict.code = NFT_BREAK; 104 return; 105 } 106 obj = *nft_set_ext_obj(ext); 107 obj->type->eval(obj, regs, pkt); 108 } 109 110 static int nft_objref_map_init(const struct nft_ctx *ctx, 111 const struct nft_expr *expr, 112 const struct nlattr * const tb[]) 113 { 114 struct nft_objref_map *priv = nft_expr_priv(expr); 115 u8 genmask = nft_genmask_next(ctx->net); 116 struct nft_set *set; 117 int err; 118 119 set = nft_set_lookup(ctx->net, ctx->table, tb[NFTA_OBJREF_SET_NAME], 120 tb[NFTA_OBJREF_SET_ID], genmask); 121 if (IS_ERR(set)) 122 return PTR_ERR(set); 123 124 if (!(set->flags & NFT_SET_OBJECT)) 125 return -EINVAL; 126 127 priv->sreg = nft_parse_register(tb[NFTA_OBJREF_SET_SREG]); 128 err = nft_validate_register_load(priv->sreg, set->klen); 129 if (err < 0) 130 return err; 131 132 priv->binding.flags = set->flags & NFT_SET_OBJECT; 133 134 err = nf_tables_bind_set(ctx, set, &priv->binding); 135 if (err < 0) 136 return err; 137 138 priv->set = set; 139 return 0; 140 } 141 142 static int nft_objref_map_dump(struct sk_buff *skb, const struct nft_expr *expr) 143 { 144 const struct nft_objref_map *priv = nft_expr_priv(expr); 145 146 if (nft_dump_register(skb, NFTA_OBJREF_SET_SREG, priv->sreg) || 147 nla_put_string(skb, NFTA_OBJREF_SET_NAME, priv->set->name)) 148 goto nla_put_failure; 149 150 return 0; 151 152 nla_put_failure: 153 return -1; 154 } 155 156 static void nft_objref_map_destroy(const struct nft_ctx *ctx, 157 const struct nft_expr *expr) 158 { 159 struct nft_objref_map *priv = nft_expr_priv(expr); 160 161 nf_tables_unbind_set(ctx, priv->set, &priv->binding); 162 } 163 164 static struct nft_expr_type nft_objref_type; 165 static const struct nft_expr_ops nft_objref_map_ops = { 166 .type = &nft_objref_type, 167 .size = NFT_EXPR_SIZE(sizeof(struct nft_objref_map)), 168 .eval = nft_objref_map_eval, 169 .init = nft_objref_map_init, 170 .destroy = nft_objref_map_destroy, 171 .dump = nft_objref_map_dump, 172 }; 173 174 static const struct nft_expr_ops * 175 nft_objref_select_ops(const struct nft_ctx *ctx, 176 const struct nlattr * const tb[]) 177 { 178 if (tb[NFTA_OBJREF_SET_SREG] && 179 (tb[NFTA_OBJREF_SET_NAME] || 180 tb[NFTA_OBJREF_SET_ID])) 181 return &nft_objref_map_ops; 182 else if (tb[NFTA_OBJREF_IMM_NAME] && 183 tb[NFTA_OBJREF_IMM_TYPE]) 184 return &nft_objref_ops; 185 186 return ERR_PTR(-EOPNOTSUPP); 187 } 188 189 static const struct nla_policy nft_objref_policy[NFTA_OBJREF_MAX + 1] = { 190 [NFTA_OBJREF_IMM_NAME] = { .type = NLA_STRING, 191 .len = NFT_OBJ_MAXNAMELEN - 1 }, 192 [NFTA_OBJREF_IMM_TYPE] = { .type = NLA_U32 }, 193 [NFTA_OBJREF_SET_SREG] = { .type = NLA_U32 }, 194 [NFTA_OBJREF_SET_NAME] = { .type = NLA_STRING, 195 .len = NFT_SET_MAXNAMELEN - 1 }, 196 [NFTA_OBJREF_SET_ID] = { .type = NLA_U32 }, 197 }; 198 199 static struct nft_expr_type nft_objref_type __read_mostly = { 200 .name = "objref", 201 .select_ops = nft_objref_select_ops, 202 .policy = nft_objref_policy, 203 .maxattr = NFTA_OBJREF_MAX, 204 .owner = THIS_MODULE, 205 }; 206 207 static int __init nft_objref_module_init(void) 208 { 209 return nft_register_expr(&nft_objref_type); 210 } 211 212 static void __exit nft_objref_module_exit(void) 213 { 214 nft_unregister_expr(&nft_objref_type); 215 } 216 217 module_init(nft_objref_module_init); 218 module_exit(nft_objref_module_exit); 219 220 MODULE_LICENSE("GPL"); 221 MODULE_AUTHOR("Pablo Neira Ayuso <[email protected]>"); 222 MODULE_ALIAS_NFT_EXPR("objref"); 223