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authorPablo Neira Ayuso <pablo@netfilter.org>2016-09-23 16:23:33 +0300
committerPablo Neira Ayuso <pablo@netfilter.org>2016-09-26 00:16:42 +0300
commit0f3cd9b3697708c86a825ae3cedabf7be6fd3e72 (patch)
tree14b59bebf1a6dc16a961864a93febfbacc4d3715 /net/netfilter
parent7a682575ad4829b4de3e672a6ad5f73a05826b82 (diff)
downloadlinux-0f3cd9b3697708c86a825ae3cedabf7be6fd3e72.tar.xz
netfilter: nf_tables: add range expression
Inverse ranges != [a,b] are not currently possible because rules are composites of && operations, and we need to express this: data < a || data > b This patch adds a new range expression. Positive ranges can be already through two cmp expressions: cmp(sreg, data, >=) cmp(sreg, data, <=) This new range expression provides an alternative way to express this. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/Makefile3
-rw-r--r--net/netfilter/nf_tables_core.c7
-rw-r--r--net/netfilter/nft_range.c138
3 files changed, 146 insertions, 2 deletions
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 0c8581100ac6..c23c3c84416f 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -71,8 +71,9 @@ obj-$(CONFIG_NF_DUP_NETDEV) += nf_dup_netdev.o
# nf_tables
nf_tables-objs += nf_tables_core.o nf_tables_api.o nf_tables_trace.o
-nf_tables-objs += nft_immediate.o nft_cmp.o nft_lookup.o nft_dynset.o
+nf_tables-objs += nft_immediate.o nft_cmp.o nft_range.o
nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o
+nf_tables-objs += nft_lookup.o nft_dynset.o
obj-$(CONFIG_NF_TABLES) += nf_tables.o
obj-$(CONFIG_NF_TABLES_INET) += nf_tables_inet.o
diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c
index 67259cefef06..7c94ce0080d5 100644
--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -263,8 +263,13 @@ int __init nf_tables_core_module_init(void)
if (err < 0)
goto err7;
- return 0;
+ err = nft_range_module_init();
+ if (err < 0)
+ goto err8;
+ return 0;
+err8:
+ nft_dynset_module_exit();
err7:
nft_payload_module_exit();
err6:
diff --git a/net/netfilter/nft_range.c b/net/netfilter/nft_range.c
new file mode 100644
index 000000000000..c6d5358482d1
--- /dev/null
+++ b/net/netfilter/nft_range.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+#include <net/netfilter/nf_tables.h>
+
+struct nft_range_expr {
+ struct nft_data data_from;
+ struct nft_data data_to;
+ enum nft_registers sreg:8;
+ u8 len;
+ enum nft_range_ops op:8;
+};
+
+static void nft_range_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
+{
+ const struct nft_range_expr *priv = nft_expr_priv(expr);
+ bool mismatch;
+ int d1, d2;
+
+ d1 = memcmp(&regs->data[priv->sreg], &priv->data_from, priv->len);
+ d2 = memcmp(&regs->data[priv->sreg], &priv->data_to, priv->len);
+ switch (priv->op) {
+ case NFT_RANGE_EQ:
+ mismatch = (d1 < 0 || d2 > 0);
+ break;
+ case NFT_RANGE_NEQ:
+ mismatch = (d1 >= 0 && d2 <= 0);
+ break;
+ }
+
+ if (mismatch)
+ regs->verdict.code = NFT_BREAK;
+}
+
+static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
+ [NFTA_RANGE_SREG] = { .type = NLA_U32 },
+ [NFTA_RANGE_OP] = { .type = NLA_U32 },
+ [NFTA_RANGE_FROM_DATA] = { .type = NLA_NESTED },
+ [NFTA_RANGE_TO_DATA] = { .type = NLA_NESTED },
+};
+
+static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+ const struct nlattr * const tb[])
+{
+ struct nft_range_expr *priv = nft_expr_priv(expr);
+ struct nft_data_desc desc_from, desc_to;
+ int err;
+
+ err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from),
+ &desc_from, tb[NFTA_RANGE_FROM_DATA]);
+ if (err < 0)
+ return err;
+
+ err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to),
+ &desc_to, tb[NFTA_RANGE_TO_DATA]);
+ if (err < 0)
+ goto err1;
+
+ if (desc_from.len != desc_to.len) {
+ err = -EINVAL;
+ goto err2;
+ }
+
+ priv->sreg = nft_parse_register(tb[NFTA_RANGE_SREG]);
+ err = nft_validate_register_load(priv->sreg, desc_from.len);
+ if (err < 0)
+ goto err2;
+
+ priv->op = ntohl(nla_get_be32(tb[NFTA_RANGE_OP]));
+ priv->len = desc_from.len;
+ return 0;
+err2:
+ nft_data_uninit(&priv->data_to, desc_to.type);
+err1:
+ nft_data_uninit(&priv->data_from, desc_from.type);
+ return err;
+}
+
+static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+ const struct nft_range_expr *priv = nft_expr_priv(expr);
+
+ if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg))
+ goto nla_put_failure;
+ if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op)))
+ goto nla_put_failure;
+
+ if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from,
+ NFT_DATA_VALUE, priv->len) < 0 ||
+ nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to,
+ NFT_DATA_VALUE, priv->len) < 0)
+ goto nla_put_failure;
+ return 0;
+
+nla_put_failure:
+ return -1;
+}
+
+static struct nft_expr_type nft_range_type;
+static const struct nft_expr_ops nft_range_ops = {
+ .type = &nft_range_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)),
+ .eval = nft_range_eval,
+ .init = nft_range_init,
+ .dump = nft_range_dump,
+};
+
+static struct nft_expr_type nft_range_type __read_mostly = {
+ .name = "range",
+ .ops = &nft_range_ops,
+ .policy = nft_range_policy,
+ .maxattr = NFTA_RANGE_MAX,
+ .owner = THIS_MODULE,
+};
+
+int __init nft_range_module_init(void)
+{
+ return nft_register_expr(&nft_range_type);
+}
+
+void nft_range_module_exit(void)
+{
+ nft_unregister_expr(&nft_range_type);
+}