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Subject[PATCH net 2/4] net: bpfilter: use cleanup callback to release umh_info
Date
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>
---
include/linux/bpfilter.h | 11 ++++++++---
net/bpfilter/bpfilter_kern.c | 23 ++++++++++-------------
net/ipv4/bpfilter/sockopt.c | 33 ++++++++++++++++++++++++++-------
3 files changed, 44 insertions(+), 23 deletions(-)

diff --git a/include/linux/bpfilter.h b/include/linux/bpfilter.h
index f02cee0225d4..70ffeed280e9 100644
--- 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 7acfc83087d5..a68940b74c01 100644
--- 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 5e04ed25bc0e..c326cfbc0f62 100644
--- 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);
--
2.17.1
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