Merge branch 'bpfilter'

Alexei Starovoitov says:

====================
bpfilter

v2->v3:
- followed Luis's suggestion and significantly simplied first patch
  with shmem_kernel_file_setup+kernel_write. Added kdoc for new helper
- fixed typos and race to access pipes with mutex
- tested with bpfilter being 'builtin'. CONFIG_BPFILTER_UMH=y|m both work.
  Interesting to see a usermode executable being embedded inside vmlinux.
- it doesn't hurt to enable bpfilter in .config.
  ip_setsockopt commands sent to usermode via pipes and -ENOPROTOOPT is
  returned from userspace, so kernel falls back to original iptables code

v1->v2:
this patch set is almost a full rewrite of the earlier umh modules approach
The v1 of patches and follow up discussion was covered by LWN:
https://lwn.net/Articles/749108/

I believe the v2 addresses all issues brought up by Andy and others.
Mainly there are zero changes to kernel/module.c
Instead of teaching module loading logic to recognize special
umh module, let normal kernel modules execute part of its own
.init.rodata as a new user space process (Andy's idea)
Patch 1 introduces this new helper:
int fork_usermode_blob(void *data, size_t len, struct umh_info *info);
Input:
  data + len == executable file
Output:
  struct umh_info {
       struct file *pipe_to_umh;
       struct file *pipe_from_umh;
       pid_t pid;
  };

Advantages vs v1:
- the embedded user mode executable is stored as .init.rodata inside
  normal kernel module. These pages are freed when .ko finishes loading
- the elf file is copied into tmpfs file. The user mode process is swappable.
- the communication between user mode process and 'parent' kernel module
  is done via two unix pipes, hence protocol is not exposed to
  user space
- impossible to launch umh on its own (that was the main issue of v1)
  and impossible to be man-in-the-middle due to pipes
- bpfilter.ko consists of tiny kernel part that passes the data
  between kernel and umh via pipes and much bigger umh part that
  doing all the work
- 'lsmod' shows bpfilter.ko as usual.
  'rmmod bpfilter' removes kernel module and kills corresponding umh
- signed bpfilter.ko covers the whole image including umh code

Few issues:
- the user can still attach to the process and debug it with
  'gdb /proc/pid/exe pid', but 'gdb -p pid' doesn't work.
  (a bit worse comparing to v1)
- tinyconfig will notice a small increase in .text
  +766 | TEXT | 7c8b94806bec umh: introduce fork_usermode_blob() helper
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

fs/exec.c

@@ -1706,14 +1706,13 @@ static int exec_binprm(struct linux_binprm *bprm)
 /*
  * sys_execve() executes a new program.
  */
-static int do_execveat_common(int fd, struct filename *filename,
+static int __do_execve_file(int fd, struct filename *filename,
 			    struct user_arg_ptr argv,
 			    struct user_arg_ptr envp,
-			      int flags)
+			    int flags, struct file *file)
 {
 	char *pathbuf = NULL;
 	struct linux_binprm *bprm;
-	struct file *file;
 	struct files_struct *displaced;
 	int retval;
 
@@ -1752,6 +1751,7 @@ static int do_execveat_common(int fd, struct filename *filename,
 	check_unsafe_exec(bprm);
 	current->in_execve = 1;
 
+	if (!file)
 		file = do_open_execat(fd, filename, flags);
 	retval = PTR_ERR(file);
 	if (IS_ERR(file))
@@ -1760,7 +1760,9 @@ static int do_execveat_common(int fd, struct filename *filename,
 	sched_exec();
 
 	bprm->file = file;
-	if (fd == AT_FDCWD || filename->name[0] == '/') {
+	if (!filename) {
+		bprm->filename = "none";
+	} else if (fd == AT_FDCWD || filename->name[0] == '/') {
 		bprm->filename = filename->name;
 	} else {
 		if (filename->name[0] == '\0')
@@ -1826,6 +1828,7 @@ static int do_execveat_common(int fd, struct filename *filename,
 	task_numa_free(current);
 	free_bprm(bprm);
 	kfree(pathbuf);
+	if (filename)
 		putname(filename);
 	if (displaced)
 		put_files_struct(displaced);
@@ -1849,10 +1852,27 @@ static int do_execveat_common(int fd, struct filename *filename,
 	if (displaced)
 		reset_files_struct(displaced);
 out_ret:
+	if (filename)
 		putname(filename);
 	return retval;
 }
 
+static int do_execveat_common(int fd, struct filename *filename,
+			      struct user_arg_ptr argv,
+			      struct user_arg_ptr envp,
+			      int flags)
+{
+	return __do_execve_file(fd, filename, argv, envp, flags, NULL);
+}
+
+int do_execve_file(struct file *file, void *__argv, void *__envp)
+{
+	struct user_arg_ptr argv = { .ptr.native = __argv };
+	struct user_arg_ptr envp = { .ptr.native = __envp };
+
+	return __do_execve_file(AT_FDCWD, NULL, argv, envp, 0, file);
+}
+
 int do_execve(struct filename *filename,
 	const char __user *const __user *__argv,
 	const char __user *const __user *__envp)

include/linux/binfmts.h

@@ -150,5 +150,6 @@ extern int do_execveat(int, struct filename *,
 		       const char __user * const __user *,
 		       const char __user * const __user *,
 		       int);
+int do_execve_file(struct file *file, void *__argv, void *__envp);
 
 #endif /* _LINUX_BINFMTS_H */

include/linux/bpfilter.h

+/* 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

include/linux/umh.h

@@ -22,8 +22,10 @@ struct subprocess_info {
 	const char *path;
 	char **argv;
 	char **envp;
+	struct file *file;
 	int wait;
 	int retval;
+	pid_t pid;
 	int (*init)(struct subprocess_info *info, struct cred *new);
 	void (*cleanup)(struct subprocess_info *info);
 	void *data;
@@ -38,6 +40,16 @@ call_usermodehelper_setup(const char *path, char **argv, char **envp,
 			  int (*init)(struct subprocess_info *info, struct cred *new),
 			  void (*cleanup)(struct subprocess_info *), void *data);
 
+struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
+			  int (*init)(struct subprocess_info *info, struct cred *new),
+			  void (*cleanup)(struct subprocess_info *), void *data);
+struct umh_info {
+	struct file *pipe_to_umh;
+	struct file *pipe_from_umh;
+	pid_t pid;
+};
+int fork_usermode_blob(void *data, size_t len, struct umh_info *info);
+
 extern int
 call_usermodehelper_exec(struct subprocess_info *info, int wait);
 

include/uapi/linux/bpfilter.h

+/* 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 */

kernel/umh.c

@@ -25,6 +25,8 @@
 #include <linux/ptrace.h>
 #include <linux/async.h>
 #include <linux/uaccess.h>
+#include <linux/shmem_fs.h>
+#include <linux/pipe_fs_i.h>
 
 #include <trace/events/module.h>
 
@@ -97,6 +99,10 @@ static int call_usermodehelper_exec_async(void *data)
 
 	commit_creds(new);
 
+	if (sub_info->file)
+		retval = do_execve_file(sub_info->file,
+					sub_info->argv, sub_info->envp);
+	else
 		retval = do_execve(getname_kernel(sub_info->path),
 				   (const char __user *const __user *)sub_info->argv,
 				   (const char __user *const __user *)sub_info->envp);
@@ -185,6 +191,8 @@ static void call_usermodehelper_exec_work(struct work_struct *work)
 		if (pid < 0) {
 			sub_info->retval = pid;
 			umh_complete(sub_info);
+		} else {
+			sub_info->pid = pid;
 		}
 	}
 }
@@ -393,6 +401,117 @@ struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
 }
 EXPORT_SYMBOL(call_usermodehelper_setup);
 
+struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
+		int (*init)(struct subprocess_info *info, struct cred *new),
+		void (*cleanup)(struct subprocess_info *info), void *data)
+{
+	struct subprocess_info *sub_info;
+
+	sub_info = kzalloc(sizeof(struct subprocess_info), GFP_KERNEL);
+	if (!sub_info)
+		return NULL;
+
+	INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
+	sub_info->path = "none";
+	sub_info->file = file;
+	sub_info->init = init;
+	sub_info->cleanup = cleanup;
+	sub_info->data = data;
+	return sub_info;
+}
+
+static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
+{
+	struct umh_info *umh_info = info->data;
+	struct file *from_umh[2];
+	struct file *to_umh[2];
+	int err;
+
+	/* create pipe to send data to umh */
+	err = create_pipe_files(to_umh, 0);
+	if (err)
+		return err;
+	err = replace_fd(0, to_umh[0], 0);
+	fput(to_umh[0]);
+	if (err < 0) {
+		fput(to_umh[1]);
+		return err;
+	}
+
+	/* create pipe to receive data from umh */
+	err = create_pipe_files(from_umh, 0);
+	if (err) {
+		fput(to_umh[1]);
+		replace_fd(0, NULL, 0);
+		return err;
+	}
+	err = replace_fd(1, from_umh[1], 0);
+	fput(from_umh[1]);
+	if (err < 0) {
+		fput(to_umh[1]);
+		replace_fd(0, NULL, 0);
+		fput(from_umh[0]);
+		return err;
+	}
+
+	umh_info->pipe_to_umh = to_umh[1];
+	umh_info->pipe_from_umh = from_umh[0];
+	return 0;
+}
+
+static void umh_save_pid(struct subprocess_info *info)
+{
+	struct umh_info *umh_info = info->data;
+
+	umh_info->pid = info->pid;
+}
+
+/**
+ * fork_usermode_blob - fork a blob of bytes as a usermode process
+ * @data: a blob of bytes that can be do_execv-ed as a file
+ * @len: length of the blob
+ * @info: information about usermode process (shouldn't be NULL)
+ *
+ * Returns either negative error or zero which indicates success
+ * in executing a blob of bytes as a usermode process. In such
+ * case 'struct umh_info *info' is populated with two pipes
+ * and a pid of the process. The caller is responsible for health
+ * check of the user process, killing it via pid, and closing the
+ * pipes when user process is no longer needed.
+ */
+int fork_usermode_blob(void *data, size_t len, struct umh_info *info)
+{
+	struct subprocess_info *sub_info;
+	struct file *file;
+	ssize_t written;
+	loff_t pos = 0;
+	int err;
+
+	file = shmem_kernel_file_setup("", len, 0);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	written = kernel_write(file, data, len, &pos);
+	if (written != len) {
+		err = written;
+		if (err >= 0)
+			err = -ENOMEM;
+		goto out;
+	}
+
+	err = -ENOMEM;
+	sub_info = call_usermodehelper_setup_file(file, umh_pipe_setup,
+						  umh_save_pid, info);
+	if (!sub_info)
+		goto out;
+
+	err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
+out:
+	fput(file);
+	return err;
+}
+EXPORT_SYMBOL_GPL(fork_usermode_blob);
+
 /**
  * call_usermodehelper_exec - start a usermode application
  * @sub_info: information about the subprocessa

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"

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/

net/bpfilter/Kconfig

+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
+

net/bpfilter/Makefile

+# 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

net/bpfilter/bpfilter_kern.c

+// 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");

net/bpfilter/main.c

+// 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;
+}

net/bpfilter/msgfmt.h

+/* 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

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

net/ipv4/bpfilter/Makefile

+obj-$(CONFIG_BPFILTER) += sockopt.o
+

net/ipv4/bpfilter/sockopt.c

+// 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);
+}

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 &&