1 // SPDX-License-Identifier: GPL-2.0
2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
3 #include <linux/init.h>
4 #include <linux/module.h>
6 #include <linux/bpfilter.h>
7 #include <linux/sched.h>
8 #include <linux/sched/signal.h>
10 #include <linux/file.h>
13 extern char bpfilter_umh_start;
14 extern char bpfilter_umh_end;
16 static void shutdown_umh(void)
18 struct task_struct *tsk;
20 if (bpfilter_ops.stop)
23 tsk = get_pid_task(find_vpid(bpfilter_ops.info.pid), PIDTYPE_PID);
25 send_sig(SIGKILL, tsk, 1);
30 static void __stop_umh(void)
32 if (IS_ENABLED(CONFIG_INET))
36 static int __bpfilter_process_sockopt(struct sock *sk, int optname,
38 unsigned int optlen, bool is_set)
40 struct mbox_request req;
41 struct mbox_reply reply;
47 req.pid = current->pid;
49 req.addr = (long __force __user)optval;
51 if (!bpfilter_ops.info.pid)
53 n = kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),
55 if (n != sizeof(req)) {
56 pr_err("write fail %zd\n", n);
62 n = kernel_read(bpfilter_ops.info.pipe_from_umh, &reply, sizeof(reply),
64 if (n != sizeof(reply)) {
65 pr_err("read fail %zd\n", n);
75 static int start_umh(void)
79 /* fork usermode process */
80 err = fork_usermode_blob(&bpfilter_umh_start,
81 &bpfilter_umh_end - &bpfilter_umh_start,
85 bpfilter_ops.stop = false;
86 pr_info("Loaded bpfilter_umh pid %d\n", bpfilter_ops.info.pid);
88 /* health check that usermode process started correctly */
89 if (__bpfilter_process_sockopt(NULL, 0, NULL, 0, 0) != 0) {
97 static int __init load_umh(void)
101 mutex_lock(&bpfilter_ops.lock);
102 if (!bpfilter_ops.stop) {
107 if (!err && IS_ENABLED(CONFIG_INET)) {
108 bpfilter_ops.sockopt = &__bpfilter_process_sockopt;
109 bpfilter_ops.start = &start_umh;
112 mutex_unlock(&bpfilter_ops.lock);
116 static void __exit fini_umh(void)
118 mutex_lock(&bpfilter_ops.lock);
119 if (IS_ENABLED(CONFIG_INET)) {
121 bpfilter_ops.start = NULL;
122 bpfilter_ops.sockopt = NULL;
124 mutex_unlock(&bpfilter_ops.lock);
126 module_init(load_umh);
127 module_exit(fini_umh);
128 MODULE_LICENSE("GPL");