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net: bpfilter: use cleanup callback to release umh_info

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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: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Taehee Yoo 2019-01-09 02:24:34 +09:00 committed by David S. Miller
parent 73ab1cb2de
commit 5b4cb650e5
3 changed files with 44 additions and 23 deletions
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11
include/linux/bpfilter.h
View File

@ -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,
char __user *optval,
unsigned int optlen, bool is_set);
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

23
net/bpfilter/bpfilter_kern.c
View File

@ -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;
}

33
net/ipv4/bpfilter/sockopt.c
View File

@ -1,28 +1,37 @@
// 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);