From 2c16d60332643e90d4fa244f4a706c454b8c7569 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Tue, 6 Dec 2016 16:25:02 -0500 Subject: [PATCH] netfilter: xt_bpf: support ebpf Add support for attaching an eBPF object by file descriptor. The iptables binary can be called with a path to an elf object or a pinned bpf object. Also pass the mode and path to the kernel to be able to return it later for iptables dump and save. Signed-off-by: Willem de Bruijn Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/xt_bpf.h | 21 ++++++ net/netfilter/xt_bpf.c | 96 ++++++++++++++++++++++----- 2 files changed, 101 insertions(+), 16 deletions(-) diff --git a/include/uapi/linux/netfilter/xt_bpf.h b/include/uapi/linux/netfilter/xt_bpf.h index 1fad2c27ac32..b97725af2ac0 100644 --- a/include/uapi/linux/netfilter/xt_bpf.h +++ b/include/uapi/linux/netfilter/xt_bpf.h @@ -2,9 +2,11 @@ #define _XT_BPF_H #include +#include #include #define XT_BPF_MAX_NUM_INSTR 64 +#define XT_BPF_PATH_MAX (XT_BPF_MAX_NUM_INSTR * sizeof(struct sock_filter)) struct bpf_prog; @@ -16,4 +18,23 @@ struct xt_bpf_info { struct bpf_prog *filter __attribute__((aligned(8))); }; +enum xt_bpf_modes { + XT_BPF_MODE_BYTECODE, + XT_BPF_MODE_FD_PINNED, + XT_BPF_MODE_FD_ELF, +}; + +struct xt_bpf_info_v1 { + __u16 mode; + __u16 bpf_program_num_elem; + __s32 fd; + union { + struct sock_filter bpf_program[XT_BPF_MAX_NUM_INSTR]; + char path[XT_BPF_PATH_MAX]; + }; + + /* only used in the kernel */ + struct bpf_prog *filter __attribute__((aligned(8))); +}; + #endif /*_XT_BPF_H */ diff --git a/net/netfilter/xt_bpf.c b/net/netfilter/xt_bpf.c index dffee9d47ec4..2dedaa23ab0a 100644 --- a/net/netfilter/xt_bpf.c +++ b/net/netfilter/xt_bpf.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include @@ -20,15 +21,15 @@ MODULE_LICENSE("GPL"); MODULE_ALIAS("ipt_bpf"); MODULE_ALIAS("ip6t_bpf"); -static int bpf_mt_check(const struct xt_mtchk_param *par) +static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len, + struct bpf_prog **ret) { - struct xt_bpf_info *info = par->matchinfo; struct sock_fprog_kern program; - program.len = info->bpf_program_num_elem; - program.filter = info->bpf_program; + program.len = len; + program.filter = insns; - if (bpf_prog_create(&info->filter, &program)) { + if (bpf_prog_create(ret, &program)) { pr_info("bpf: check failed: parse error\n"); return -EINVAL; } @@ -36,6 +37,42 @@ static int bpf_mt_check(const struct xt_mtchk_param *par) 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(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_PINNED || + info->mode == XT_BPF_MODE_FD_ELF) + return __bpf_mt_check_fd(info->fd, &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; @@ -43,31 +80,58 @@ static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par) 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), - .me = THIS_MODULE, +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), + .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), + .me = THIS_MODULE, + }, }; static int __init bpf_mt_init(void) { - return xt_register_match(&bpf_mt_reg); + return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg)); } static void __exit bpf_mt_exit(void) { - xt_unregister_match(&bpf_mt_reg); + xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg)); } module_init(bpf_mt_init); -- 2.30.2