diff options
| -rw-r--r-- | include/linux/bpfilter.h | 15 | ||||
| -rw-r--r-- | include/uapi/linux/bpfilter.h | 21 | ||||
| -rw-r--r-- | net/Kconfig | 2 | ||||
| -rw-r--r-- | net/Makefile | 1 | ||||
| -rw-r--r-- | net/bpfilter/Kconfig | 16 | ||||
| -rw-r--r-- | net/bpfilter/Makefile | 30 | ||||
| -rw-r--r-- | net/bpfilter/bpfilter_kern.c | 111 | ||||
| -rw-r--r-- | net/bpfilter/main.c | 63 | ||||
| -rw-r--r-- | net/bpfilter/msgfmt.h | 17 | ||||
| -rw-r--r-- | net/ipv4/Makefile | 2 | ||||
| -rw-r--r-- | net/ipv4/bpfilter/Makefile | 2 | ||||
| -rw-r--r-- | net/ipv4/bpfilter/sockopt.c | 42 | ||||
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 17 |
13 files changed, 339 insertions, 0 deletions
diff --git a/include/linux/bpfilter.h b/include/linux/bpfilter.h new file mode 100644 index 000000000000..687b1760bb9f --- /dev/null +++ b/include/linux/bpfilter.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_BPFILTER_H +#define _LINUX_BPFILTER_H + +#include <uapi/linux/bpfilter.h> + +struct sock; +int bpfilter_ip_set_sockopt(struct sock *sk, int optname, char *optval, + unsigned int optlen); +int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char *optval, + int *optlen); +extern int (*bpfilter_process_sockopt)(struct sock *sk, int optname, + char __user *optval, + unsigned int optlen, bool is_set); +#endif diff --git a/include/uapi/linux/bpfilter.h b/include/uapi/linux/bpfilter.h new file mode 100644 index 000000000000..2ec3cc99ea4c --- /dev/null +++ b/include/uapi/linux/bpfilter.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _UAPI_LINUX_BPFILTER_H +#define _UAPI_LINUX_BPFILTER_H + +#include <linux/if.h> + +enum { + BPFILTER_IPT_SO_SET_REPLACE = 64, + BPFILTER_IPT_SO_SET_ADD_COUNTERS = 65, + BPFILTER_IPT_SET_MAX, +}; + +enum { + BPFILTER_IPT_SO_GET_INFO = 64, + BPFILTER_IPT_SO_GET_ENTRIES = 65, + BPFILTER_IPT_SO_GET_REVISION_MATCH = 66, + BPFILTER_IPT_SO_GET_REVISION_TARGET = 67, + BPFILTER_IPT_GET_MAX, +}; + +#endif /* _UAPI_LINUX_BPFILTER_H */ diff --git a/net/Kconfig b/net/Kconfig index df8d45ef47d8..ba554cedb615 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -202,6 +202,8 @@ source "net/bridge/netfilter/Kconfig" endif +source "net/bpfilter/Kconfig" + source "net/dccp/Kconfig" source "net/sctp/Kconfig" source "net/rds/Kconfig" diff --git a/net/Makefile b/net/Makefile index 77aaddedbd29..bdaf53925acd 100644 --- a/net/Makefile +++ b/net/Makefile @@ -20,6 +20,7 @@ obj-$(CONFIG_TLS) += tls/ obj-$(CONFIG_XFRM) += xfrm/ obj-$(CONFIG_UNIX) += unix/ obj-$(CONFIG_NET) += ipv6/ +obj-$(CONFIG_BPFILTER) += bpfilter/ obj-$(CONFIG_PACKET) += packet/ obj-$(CONFIG_NET_KEY) += key/ obj-$(CONFIG_BRIDGE) += bridge/ diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig new file mode 100644 index 000000000000..60725c5f79db --- /dev/null +++ b/net/bpfilter/Kconfig @@ -0,0 +1,16 @@ +menuconfig BPFILTER + bool "BPF based packet filtering framework (BPFILTER)" + default n + depends on NET && BPF + help + This builds experimental bpfilter framework that is aiming to + provide netfilter compatible functionality via BPF + +if BPFILTER +config BPFILTER_UMH + tristate "bpfilter kernel module with user mode helper" + default m + help + This builds bpfilter kernel module with embedded user mode helper +endif + diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile new file mode 100644 index 000000000000..2af752c8ef5e --- /dev/null +++ b/net/bpfilter/Makefile @@ -0,0 +1,30 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the Linux BPFILTER layer. +# + +hostprogs-y := bpfilter_umh +bpfilter_umh-objs := main.o +HOSTCFLAGS += -I. -Itools/include/ +ifeq ($(CONFIG_BPFILTER_UMH), y) +# builtin bpfilter_umh should be compiled with -static +# since rootfs isn't mounted at the time of __init +# function is called and do_execv won't find elf interpreter +HOSTLDFLAGS += -static +endif + +# a bit of elf magic to convert bpfilter_umh binary into a binary blob +# inside bpfilter_umh.o elf file referenced by +# _binary_net_bpfilter_bpfilter_umh_start symbol +# which bpfilter_kern.c passes further into umh blob loader at run-time +quiet_cmd_copy_umh = GEN $@ + cmd_copy_umh = echo ':' > $(obj)/.bpfilter_umh.o.cmd; \ + $(OBJCOPY) -I binary -O $(CONFIG_OUTPUT_FORMAT) \ + -B `$(OBJDUMP) -f $<|grep architecture|cut -d, -f1|cut -d' ' -f2` \ + --rename-section .data=.init.rodata $< $@ + +$(obj)/bpfilter_umh.o: $(obj)/bpfilter_umh + $(call cmd,copy_umh) + +obj-$(CONFIG_BPFILTER_UMH) += bpfilter.o +bpfilter-objs += bpfilter_kern.o bpfilter_umh.o diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c new file mode 100644 index 000000000000..7596314b61c7 --- /dev/null +++ b/net/bpfilter/bpfilter_kern.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/init.h> +#include <linux/module.h> +#include <linux/umh.h> +#include <linux/bpfilter.h> +#include <linux/sched.h> +#include <linux/sched/signal.h> +#include <linux/fs.h> +#include <linux/file.h> +#include "msgfmt.h" + +#define UMH_start _binary_net_bpfilter_bpfilter_umh_start +#define UMH_end _binary_net_bpfilter_bpfilter_umh_end + +extern char UMH_start; +extern char UMH_end; + +static struct umh_info info; +/* since ip_getsockopt() can run in parallel, serialize access to umh */ +static DEFINE_MUTEX(bpfilter_lock); + +static void shutdown_umh(struct umh_info *info) +{ + struct task_struct *tsk; + + tsk = pid_task(find_vpid(info->pid), PIDTYPE_PID); + if (tsk) + force_sig(SIGKILL, tsk); + fput(info->pipe_to_umh); + fput(info->pipe_from_umh); +} + +static void __stop_umh(void) +{ + if (bpfilter_process_sockopt) { + bpfilter_process_sockopt = NULL; + shutdown_umh(&info); + } +} + +static void stop_umh(void) +{ + mutex_lock(&bpfilter_lock); + __stop_umh(); + mutex_unlock(&bpfilter_lock); +} + +static int __bpfilter_process_sockopt(struct sock *sk, int optname, + char __user *optval, + unsigned int optlen, bool is_set) +{ + struct mbox_request req; + struct mbox_reply reply; + loff_t pos; + ssize_t n; + int ret; + + req.is_set = is_set; + req.pid = current->pid; + req.cmd = optname; + req.addr = (long)optval; + req.len = optlen; + mutex_lock(&bpfilter_lock); + n = __kernel_write(info.pipe_to_umh, &req, sizeof(req), &pos); + if (n != sizeof(req)) { + pr_err("write fail %zd\n", n); + __stop_umh(); + ret = -EFAULT; + goto out; + } + pos = 0; + n = kernel_read(info.pipe_from_umh, &reply, sizeof(reply), &pos); + if (n != sizeof(reply)) { + pr_err("read fail %zd\n", n); + __stop_umh(); + ret = -EFAULT; + goto out; + } + ret = reply.status; +out: + mutex_unlock(&bpfilter_lock); + return ret; +} + +static int __init load_umh(void) +{ + int err; + + /* fork usermode process */ + err = fork_usermode_blob(&UMH_start, &UMH_end - &UMH_start, &info); + if (err) + return err; + pr_info("Loaded bpfilter_umh pid %d\n", info.pid); + + /* health check that usermode process started correctly */ + if (__bpfilter_process_sockopt(NULL, 0, 0, 0, 0) != 0) { + stop_umh(); + return -EFAULT; + } + bpfilter_process_sockopt = &__bpfilter_process_sockopt; + return 0; +} + +static void __exit fini_umh(void) +{ + stop_umh(); +} +module_init(load_umh); +module_exit(fini_umh); +MODULE_LICENSE("GPL"); diff --git a/net/bpfilter/main.c b/net/bpfilter/main.c new file mode 100644 index 000000000000..81bbc1684896 --- /dev/null +++ b/net/bpfilter/main.c @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <sys/uio.h> +#include <errno.h> +#include <stdio.h> +#include <sys/socket.h> +#include <fcntl.h> +#include <unistd.h> +#include "include/uapi/linux/bpf.h" +#include <asm/unistd.h> +#include "msgfmt.h" + +int debug_fd; + +static int handle_get_cmd(struct mbox_request *cmd) +{ + switch (cmd->cmd) { + case 0: + return 0; + default: + break; + } + return -ENOPROTOOPT; +} + +static int handle_set_cmd(struct mbox_request *cmd) +{ + return -ENOPROTOOPT; +} + +static void loop(void) +{ + while (1) { + struct mbox_request req; + struct mbox_reply reply; + int n; + + n = read(0, &req, sizeof(req)); + if (n != sizeof(req)) { + dprintf(debug_fd, "invalid request %d\n", n); + return; + } + + reply.status = req.is_set ? + handle_set_cmd(&req) : + handle_get_cmd(&req); + + n = write(1, &reply, sizeof(reply)); + if (n != sizeof(reply)) { + dprintf(debug_fd, "reply failed %d\n", n); + return; + } + } +} + +int main(void) +{ + debug_fd = open("/dev/console", 00000002 | 00000100); + dprintf(debug_fd, "Started bpfilter\n"); + loop(); + close(debug_fd); + return 0; +} diff --git a/net/bpfilter/msgfmt.h b/net/bpfilter/msgfmt.h new file mode 100644 index 000000000000..98d121c62945 --- /dev/null +++ b/net/bpfilter/msgfmt.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _NET_BPFILTER_MSGFMT_H +#define _NET_BPFILTER_MSGFMT_H + +struct mbox_request { + __u64 addr; + __u32 len; + __u32 is_set; + __u32 cmd; + __u32 pid; +}; + +struct mbox_reply { + __u32 status; +}; + +#endif diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index b379520f9133..7018f91c5a39 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -16,6 +16,8 @@ obj-y := route.o inetpeer.o protocol.o \ inet_fragment.o ping.o ip_tunnel_core.o gre_offload.o \ metrics.o +obj-$(CONFIG_BPFILTER) += bpfilter/ + obj-$(CONFIG_NET_IP_TUNNEL) += ip_tunnel.o obj-$(CONFIG_SYSCTL) += sysctl_net_ipv4.o obj-$(CONFIG_PROC_FS) += proc.o diff --git a/net/ipv4/bpfilter/Makefile b/net/ipv4/bpfilter/Makefile new file mode 100644 index 000000000000..ce262d76cc48 --- /dev/null +++ b/net/ipv4/bpfilter/Makefile @@ -0,0 +1,2 @@ +obj-$(CONFIG_BPFILTER) += sockopt.o + diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c new file mode 100644 index 000000000000..42a96d2d8d05 --- /dev/null +++ b/net/ipv4/bpfilter/sockopt.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/uaccess.h> +#include <linux/bpfilter.h> +#include <uapi/linux/bpf.h> +#include <linux/wait.h> +#include <linux/kmod.h> + +int (*bpfilter_process_sockopt)(struct sock *sk, int optname, + char __user *optval, + unsigned int optlen, bool is_set); +EXPORT_SYMBOL_GPL(bpfilter_process_sockopt); + +int bpfilter_mbox_request(struct sock *sk, int optname, char __user *optval, + unsigned int optlen, bool is_set) +{ + if (!bpfilter_process_sockopt) { + int err = request_module("bpfilter"); + + if (err) + return err; + if (!bpfilter_process_sockopt) + return -ECHILD; + } + return bpfilter_process_sockopt(sk, optname, optval, optlen, is_set); +} + +int bpfilter_ip_set_sockopt(struct sock *sk, int optname, char __user *optval, + unsigned int optlen) +{ + return bpfilter_mbox_request(sk, optname, optval, optlen, true); +} + +int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval, + int __user *optlen) +{ + int len; + + if (get_user(len, optlen)) + return -EFAULT; + + return bpfilter_mbox_request(sk, optname, optval, len, false); +} diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 5ad2d8ed3a3f..e0791faacb24 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -47,6 +47,8 @@ #include <linux/errqueue.h> #include <linux/uaccess.h> +#include <linux/bpfilter.h> + /* * SOL_IP control messages. */ @@ -1244,6 +1246,11 @@ int ip_setsockopt(struct sock *sk, int level, return -ENOPROTOOPT; err = do_ip_setsockopt(sk, level, optname, optval, optlen); +#ifdef CONFIG_BPFILTER + if (optname >= BPFILTER_IPT_SO_SET_REPLACE && + optname < BPFILTER_IPT_SET_MAX) + err = bpfilter_ip_set_sockopt(sk, optname, optval, optlen); +#endif #ifdef CONFIG_NETFILTER /* we need to exclude all possible ENOPROTOOPTs except default case */ if (err == -ENOPROTOOPT && optname != IP_HDRINCL && @@ -1552,6 +1559,11 @@ int ip_getsockopt(struct sock *sk, int level, int err; err = do_ip_getsockopt(sk, level, optname, optval, optlen, 0); +#ifdef CONFIG_BPFILTER + if (optname >= BPFILTER_IPT_SO_GET_INFO && + optname < BPFILTER_IPT_GET_MAX) + err = bpfilter_ip_get_sockopt(sk, optname, optval, optlen); +#endif #ifdef CONFIG_NETFILTER /* we need to exclude all possible ENOPROTOOPTs except default case */ if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS && @@ -1584,6 +1596,11 @@ int compat_ip_getsockopt(struct sock *sk, int level, int optname, err = do_ip_getsockopt(sk, level, optname, optval, optlen, MSG_CMSG_COMPAT); +#ifdef CONFIG_BPFILTER + if (optname >= BPFILTER_IPT_SO_GET_INFO && + optname < BPFILTER_IPT_GET_MAX) + err = bpfilter_ip_get_sockopt(sk, optname, optval, optlen); +#endif #ifdef CONFIG_NETFILTER /* we need to exclude all possible ENOPROTOOPTs except default case */ if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS && |