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Commit 5b4cb650 authored by Taehee Yoo's avatar Taehee Yoo Committed by David S. Miller
Browse files

net: bpfilter: use cleanup callback to release umh_info 



Now, UMH process is killed, do_exit() calls the umh_info->cleanup callback
to release members of the umh_info.
This patch makes bpfilter_umh's cleanup routine to use the
umh_info->cleanup callback.

Signed-off-by: default avatarTaehee Yoo <ap420073@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 73ab1cb2

include/linux/bpfilter.h

+8 −3
Original line number Diff line number Diff line
@@ -3,13 +3,18 @@ 
#define _LINUX_BPFILTER_H



#include <uapi/linux/bpfilter.h>

#include <linux/umh.h>



struct sock;

int bpfilter_ip_set_sockopt(struct sock *sk, int optname, char __user *optval,

			    unsigned int optlen);

int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval,

			    int __user *optlen);

extern int (*bpfilter_process_sockopt)(struct sock *sk, int optname,

struct bpfilter_umh_ops {

	struct umh_info info;

	int (*sockopt)(struct sock *sk, int optname,

		       char __user *optval,

		       unsigned int optlen, bool is_set);

};

extern struct bpfilter_umh_ops bpfilter_ops;

#endif

net/bpfilter/bpfilter_kern.c

+10 −13
Original line number Diff line number Diff line
@@ -13,7 +13,6 @@ 
extern char bpfilter_umh_start;

extern char bpfilter_umh_end;



static struct umh_info info;

/* since ip_getsockopt() can run in parallel, serialize access to umh */

static DEFINE_MUTEX(bpfilter_lock);
@@ -28,16 +27,13 @@ static void shutdown_umh(struct umh_info *info) 
		force_sig(SIGKILL, tsk);

		put_task_struct(tsk);

	}

	fput(info->pipe_to_umh);

	fput(info->pipe_from_umh);

	info->pid = 0;

}



static void __stop_umh(void)

{

	if (IS_ENABLED(CONFIG_INET)) {

		bpfilter_process_sockopt = NULL;

		shutdown_umh(&info);

		bpfilter_ops.sockopt = NULL;

		shutdown_umh(&bpfilter_ops.info);

	}

}
@@ -64,9 +60,10 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname, 
	req.addr = (long __force __user)optval;

	req.len = optlen;

	mutex_lock(&bpfilter_lock);

	if (!info.pid)

	if (!bpfilter_ops.info.pid)

		goto out;

	n = __kernel_write(info.pipe_to_umh, &req, sizeof(req), &pos);

	n = __kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),

			   &pos);

	if (n != sizeof(req)) {

		pr_err("write fail %zd\n", n);

		__stop_umh();
@@ -74,7 +71,8 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname, 
		goto out;

	}

	pos = 0;

	n = kernel_read(info.pipe_from_umh, &reply, sizeof(reply), &pos);

	n = kernel_read(bpfilter_ops.info.pipe_from_umh, &reply, sizeof(reply),

			&pos);

	if (n != sizeof(reply)) {

		pr_err("read fail %zd\n", n);

		__stop_umh();
@@ -92,13 +90,12 @@ static int __init load_umh(void) 
	int err;



	/* fork usermode process */

	info.cmdline = "bpfilter_umh";

	err = fork_usermode_blob(&bpfilter_umh_start,

				 &bpfilter_umh_end - &bpfilter_umh_start,

				 &info);

				 &bpfilter_ops.info);

	if (err)

		return err;

	pr_info("Loaded bpfilter_umh pid %d\n", info.pid);

	pr_info("Loaded bpfilter_umh pid %d\n", bpfilter_ops.info.pid);



	/* health check that usermode process started correctly */

	if (__bpfilter_process_sockopt(NULL, 0, NULL, 0, 0) != 0) {
@@ -106,7 +103,7 @@ static int __init load_umh(void) 
		return -EFAULT;

	}

	if (IS_ENABLED(CONFIG_INET))

		bpfilter_process_sockopt = &__bpfilter_process_sockopt;

		bpfilter_ops.sockopt = &__bpfilter_process_sockopt;



	return 0;

}

net/ipv4/bpfilter/sockopt.c

+26 −7
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/init.h>

#include <linux/module.h>

#include <linux/uaccess.h>

#include <linux/bpfilter.h>

#include <uapi/linux/bpf.h>

#include <linux/wait.h>

#include <linux/kmod.h>

#include <linux/fs.h>

#include <linux/file.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);

struct bpfilter_umh_ops bpfilter_ops;

EXPORT_SYMBOL_GPL(bpfilter_ops);



static void bpfilter_umh_cleanup(struct umh_info *info)

{

	fput(info->pipe_to_umh);

	fput(info->pipe_from_umh);

	info->pid = 0;

}



static int bpfilter_mbox_request(struct sock *sk, int optname,

				 char __user *optval,

				 unsigned int optlen, bool is_set)

{

	if (!bpfilter_process_sockopt) {

	if (!bpfilter_ops.sockopt) {

		int err = request_module("bpfilter");



		if (err)

			return err;

		if (!bpfilter_process_sockopt)

		if (!bpfilter_ops.sockopt)

			return -ECHILD;

	}

	return bpfilter_process_sockopt(sk, optname, optval, optlen, is_set);

	return bpfilter_ops.sockopt(sk, optname, optval, optlen, is_set);

}



int bpfilter_ip_set_sockopt(struct sock *sk, int optname, char __user *optval,
@@ -41,3 +50,13 @@ int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval, 


	return bpfilter_mbox_request(sk, optname, optval, len, false);

}



static int __init bpfilter_sockopt_init(void)

{

	bpfilter_ops.info.cmdline = "bpfilter_umh";

	bpfilter_ops.info.cleanup = &bpfilter_umh_cleanup;



	return 0;

}



module_init(bpfilter_sockopt_init);