korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-09-21 20:22:13 +08:00
Code Issues Packages Projects Releases Wiki Activity

pidfd: prevent creation of pidfds for kthreads

Browse Source 
It's currently possible to create pidfds for kthreads but it is unclear
what that is supposed to mean. Until we have use-cases for it and we
figured out what behavior we want block the creation of pidfds for
kthreads.

Link: https://lore.kernel.org/r/20240731-gleis-mehreinnahmen-6bbadd128383@brauner
Fixes: 32fcb426ec ("pid: add pidfd_open()")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2024-07-31 12:01:12 +02:00
parent 889ced4c93
commit 3b5bbe798b
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 22 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
kernel/fork.c
View File

@ -2053,11 +2053,24 @@ static int __pidfd_prepare(struct pid *pid, unsigned int flags, struct file **re
*/
int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret)
{
bool thread = flags & PIDFD_THREAD;
if (!pid || !pid_has_task(pid, thread ? PIDTYPE_PID : PIDTYPE_TGID))
if (!pid)
return -EINVAL;
scoped_guard(rcu) {
struct task_struct *tsk;
if (flags & PIDFD_THREAD)
tsk = pid_task(pid, PIDTYPE_PID);
else
tsk = pid_task(pid, PIDTYPE_TGID);
if (!tsk)
return -EINVAL;
/* Don't create pidfds for kernel threads for now. */
if (tsk->flags & PF_KTHREAD)
return -EINVAL;
}
return __pidfd_prepare(pid, flags, ret);
}
@ -2403,6 +2416,12 @@ __latent_entropy struct task_struct *copy_process(
if (clone_flags & CLONE_PIDFD) {
int flags = (clone_flags & CLONE_THREAD) ? PIDFD_THREAD : 0;
/* Don't create pidfds for kernel threads for now. */
if (args->kthread) {
retval = -EINVAL;
goto bad_fork_free_pid;
}
/* Note that no task has been attached to @pid yet. */
retval = __pidfd_prepare(pid, flags, &pidfile);
if (retval < 0)