1 files changed, 153 insertions, 0 deletions
diff --git a/net/netfilter/xt_bpf.c b/net/netfilter/xt_bpf.c
new file mode 100644
index 000000000..849ac552a
--- /dev/null
+++ b/net/netfilter/xt_bpf.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Xtables module to match packets using a BPF filter.
+ * Copyright 2013 Google Inc.
+ * Written by Willem de Bruijn <willemb@google.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/syscalls.h>
+#include <linux/skbuff.h>
+#include <linux/filter.h>
+#include <linux/bpf.h>
+
+#include <linux/netfilter/xt_bpf.h>
+#include <linux/netfilter/x_tables.h>
+
+MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
+MODULE_DESCRIPTION("Xtables: BPF filter match");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_bpf");
+MODULE_ALIAS("ip6t_bpf");
+
+static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len,
+				   struct bpf_prog **ret)
+{
+	struct sock_fprog_kern program;
+
+	if (len > XT_BPF_MAX_NUM_INSTR)
+		return -EINVAL;
+
+	program.len = len;
+	program.filter = insns;
+
+	if (bpf_prog_create(ret, &program)) {
+		pr_info_ratelimited("check failed: parse error\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret)
+{
+	struct bpf_prog *prog;
+
+	prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	*ret = prog;
+	return 0;
+}
+
+static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)
+{
+	if (strnlen(path, XT_BPF_PATH_MAX) == XT_BPF_PATH_MAX)
+		return -EINVAL;
+
+	*ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);
+	return PTR_ERR_OR_ZERO(*ret);
+}
+
+static int bpf_mt_check(const struct xt_mtchk_param *par)
+{
+	struct xt_bpf_info *info = par->matchinfo;
+
+	return __bpf_mt_check_bytecode(info->bpf_program,
+				       info->bpf_program_num_elem,
+				       &info->filter);
+}
+
+static int bpf_mt_check_v1(const struct xt_mtchk_param *par)
+{
+	struct xt_bpf_info_v1 *info = par->matchinfo;
+
+	if (info->mode == XT_BPF_MODE_BYTECODE)
+		return __bpf_mt_check_bytecode(info->bpf_program,
+					       info->bpf_program_num_elem,
+					       &info->filter);
+	else if (info->mode == XT_BPF_MODE_FD_ELF)
+		return __bpf_mt_check_fd(info->fd, &info->filter);
+	else if (info->mode == XT_BPF_MODE_PATH_PINNED)
+		return __bpf_mt_check_path(info->path, &info->filter);
+	else
+		return -EINVAL;
+}
+
+static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
+{
+	const struct xt_bpf_info *info = par->matchinfo;
+
+	return bpf_prog_run(info->filter, skb);
+}
+
+static bool bpf_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
+{
+	const struct xt_bpf_info_v1 *info = par->matchinfo;
+
+	return !!bpf_prog_run_save_cb(info->filter, (struct sk_buff *) skb);
+}
+
+static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
+{
+	const struct xt_bpf_info *info = par->matchinfo;
+
+	bpf_prog_destroy(info->filter);
+}
+
+static void bpf_mt_destroy_v1(const struct xt_mtdtor_param *par)
+{
+	const struct xt_bpf_info_v1 *info = par->matchinfo;
+
+	bpf_prog_destroy(info->filter);
+}
+
+static struct xt_match bpf_mt_reg[] __read_mostly = {
+	{
+		.name		= "bpf",
+		.revision	= 0,
+		.family		= NFPROTO_UNSPEC,
+		.checkentry	= bpf_mt_check,
+		.match		= bpf_mt,
+		.destroy	= bpf_mt_destroy,
+		.matchsize	= sizeof(struct xt_bpf_info),
+		.usersize	= offsetof(struct xt_bpf_info, filter),
+		.me		= THIS_MODULE,
+	},
+	{
+		.name		= "bpf",
+		.revision	= 1,
+		.family		= NFPROTO_UNSPEC,
+		.checkentry	= bpf_mt_check_v1,
+		.match		= bpf_mt_v1,
+		.destroy	= bpf_mt_destroy_v1,
+		.matchsize	= sizeof(struct xt_bpf_info_v1),
+		.usersize	= offsetof(struct xt_bpf_info_v1, filter),
+		.me		= THIS_MODULE,
+	},
+};
+
+static int __init bpf_mt_init(void)
+{
+	return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
+}
+
+static void __exit bpf_mt_exit(void)
+{
+	xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
+}
+
+module_init(bpf_mt_init);
+module_exit(bpf_mt_exit);