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authorTaehee Yoo <ap420073@gmail.com>2019-01-09 02:23:56 +0900
committerDavid S. Miller <davem@davemloft.net>2019-01-11 18:05:40 -0800
commit73ab1cb2de9e3efe7f818d5453de271e5371df1d (patch)
tree597da57b75e0bceceea75e1cbf9980068bc5dc54 /kernel/umh.c
parent2ff33d6637393fe9348357285931811b76e1402f (diff)
umh: add exit routine for UMH process
A UMH process which is created by the fork_usermode_blob() such as bpfilter needs to release members of the umh_info when process is terminated. But the do_exit() does not release members of the umh_info. hence module which uses UMH needs own code to detect whether UMH process is terminated or not. But this implementation needs extra code for checking the status of UMH process. it eventually makes the code more complex. The new PF_UMH flag is added and it is used to identify UMH processes. The exit_umh() does not release members of the umh_info. Hence umh_info->cleanup callback should release both members of the umh_info and the private data. Suggested-by: David S. Miller <davem@davemloft.net> Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/umh.c')
-rw-r--r--kernel/umh.c33
1 files changed, 31 insertions, 2 deletions
diff --git a/kernel/umh.c b/kernel/umh.c
index 0baa672e023c..d937cbad903a 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -37,6 +37,8 @@ static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
static DEFINE_SPINLOCK(umh_sysctl_lock);
static DECLARE_RWSEM(umhelper_sem);
+static LIST_HEAD(umh_list);
+static DEFINE_MUTEX(umh_list_lock);
static void call_usermodehelper_freeinfo(struct subprocess_info *info)
{
@@ -100,10 +102,12 @@ static int call_usermodehelper_exec_async(void *data)
commit_creds(new);
sub_info->pid = task_pid_nr(current);
- if (sub_info->file)
+ if (sub_info->file) {
retval = do_execve_file(sub_info->file,
sub_info->argv, sub_info->envp);
- else
+ if (!retval)
+ current->flags |= PF_UMH;
+ } else
retval = do_execve(getname_kernel(sub_info->path),
(const char __user *const __user *)sub_info->argv,
(const char __user *const __user *)sub_info->envp);
@@ -517,6 +521,11 @@ int fork_usermode_blob(void *data, size_t len, struct umh_info *info)
goto out;
err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
+ if (!err) {
+ mutex_lock(&umh_list_lock);
+ list_add(&info->list, &umh_list);
+ mutex_unlock(&umh_list_lock);
+ }
out:
fput(file);
return err;
@@ -679,6 +688,26 @@ static int proc_cap_handler(struct ctl_table *table, int write,
return 0;
}
+void __exit_umh(struct task_struct *tsk)
+{
+ struct umh_info *info;
+ pid_t pid = tsk->pid;
+
+ mutex_lock(&umh_list_lock);
+ list_for_each_entry(info, &umh_list, list) {
+ if (info->pid == pid) {
+ list_del(&info->list);
+ mutex_unlock(&umh_list_lock);
+ goto out;
+ }
+ }
+ mutex_unlock(&umh_list_lock);
+ return;
+out:
+ if (info->cleanup)
+ info->cleanup(info);
+}
+
struct ctl_table usermodehelper_table[] = {
{
.procname = "bset",

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