net/netfilter/nft_range.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/init.h>
   8 #include <linux/module.h>
   9 #include <linux/netlink.h>
  10 #include <linux/netfilter.h>
  11 #include <linux/netfilter/nf_tables.h>
  12 #include <net/netfilter/nf_tables_core.h>
  13 #include <net/netfilter/nf_tables.h>
  14
  15 struct nft_range_expr {
  16         struct nft_data         data_from;
  17         struct nft_data         data_to;
  18         enum nft_registers      sreg:8;
  19         u8                      len;
  20         enum nft_range_ops      op:8;
  21 };
  22
  23 void nft_range_eval(const struct nft_expr *expr,
  24                     struct nft_regs *regs, const struct nft_pktinfo *pkt)
  25 {
  26         const struct nft_range_expr *priv = nft_expr_priv(expr);
  27         int d1, d2;
  28
  29         d1 = memcmp(&regs->data[priv->sreg], &priv->data_from, priv->len);
  30         d2 = memcmp(&regs->data[priv->sreg], &priv->data_to, priv->len);
  31         switch (priv->op) {
  32         case NFT_RANGE_EQ:
  33                 if (d1 < 0 || d2 > 0)
  34                         regs->verdict.code = NFT_BREAK;
  35                 break;
  36         case NFT_RANGE_NEQ:
  37                 if (d1 >= 0 && d2 <= 0)
  38                         regs->verdict.code = NFT_BREAK;
  39                 break;
  40         }
  41 }
  42
  43 static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
  44         [NFTA_RANGE_SREG]               = { .type = NLA_U32 },
  45         [NFTA_RANGE_OP]                 = { .type = NLA_U32 },
  46         [NFTA_RANGE_FROM_DATA]          = { .type = NLA_NESTED },
  47         [NFTA_RANGE_TO_DATA]            = { .type = NLA_NESTED },
  48 };
  49
  50 static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
  51                         const struct nlattr * const tb[])
  52 {
  53         struct nft_range_expr *priv = nft_expr_priv(expr);
  54         struct nft_data_desc desc_from, desc_to;
  55         int err;
  56         u32 op;
  57
  58         if (!tb[NFTA_RANGE_SREG]      ||
  59             !tb[NFTA_RANGE_OP]        ||
  60             !tb[NFTA_RANGE_FROM_DATA] ||
  61             !tb[NFTA_RANGE_TO_DATA])
  62                 return -EINVAL;
  63
  64         err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from),
  65                             &desc_from, tb[NFTA_RANGE_FROM_DATA]);
  66         if (err < 0)
  67                 return err;
  68
  69         if (desc_from.type != NFT_DATA_VALUE) {
  70                 err = -EINVAL;
  71                 goto err1;
  72         }
  73
  74         err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to),
  75                             &desc_to, tb[NFTA_RANGE_TO_DATA]);
  76         if (err < 0)
  77                 goto err1;
  78
  79         if (desc_to.type != NFT_DATA_VALUE) {
  80                 err = -EINVAL;
  81                 goto err2;
  82         }
  83
  84         if (desc_from.len != desc_to.len) {
  85                 err = -EINVAL;
  86                 goto err2;
  87         }
  88
  89         priv->sreg = nft_parse_register(tb[NFTA_RANGE_SREG]);
  90         err = nft_validate_register_load(priv->sreg, desc_from.len);
  91         if (err < 0)
  92                 goto err2;
  93
  94         err = nft_parse_u32_check(tb[NFTA_RANGE_OP], U8_MAX, &op);
  95         if (err < 0)
  96                 goto err2;
  97
  98         switch (op) {
  99         case NFT_RANGE_EQ:
 100         case NFT_RANGE_NEQ:
 101                 break;
 102         default:
 103                 err = -EINVAL;
 104                 goto err2;
 105         }
 106
 107         priv->op  = op;
 108         priv->len = desc_from.len;
 109         return 0;
 110 err2:
 111         nft_data_release(&priv->data_to, desc_to.type);
 112 err1:
 113         nft_data_release(&priv->data_from, desc_from.type);
 114         return err;
 115 }
 116
 117 static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr)
 118 {
 119         const struct nft_range_expr *priv = nft_expr_priv(expr);
 120
 121         if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg))
 122                 goto nla_put_failure;
 123         if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op)))
 124                 goto nla_put_failure;
 125
 126         if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from,
 127                           NFT_DATA_VALUE, priv->len) < 0 ||
 128             nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to,
 129                           NFT_DATA_VALUE, priv->len) < 0)
 130                 goto nla_put_failure;
 131         return 0;
 132
 133 nla_put_failure:
 134         return -1;
 135 }
 136
 137 static const struct nft_expr_ops nft_range_ops = {
 138         .type           = &nft_range_type,
 139         .size           = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)),
 140         .eval           = nft_range_eval,
 141         .init           = nft_range_init,
 142         .dump           = nft_range_dump,
 143 };
 144
 145 struct nft_expr_type nft_range_type __read_mostly = {
 146         .name           = "range",
 147         .ops            = &nft_range_ops,
 148         .policy         = nft_range_policy,
 149         .maxattr        = NFTA_RANGE_MAX,
 150         .owner          = THIS_MODULE,
 151 };