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: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/bpfilter.h b/include/linux/bpfilter.h
index f02cee0..70ffeed 100644 (file)
--- a/include/linux/bpfilter.h
+++ b/include/linux/bpfilter.h
@@ -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

diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 7acfc83..a68940b 100644 (file)
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -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;
 }

diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c
index 5e04ed2..c326cfb 100644 (file)
--- a/net/ipv4/bpfilter/sockopt.c
+++ b/net/ipv4/bpfilter/sockopt.c
@@ -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);