The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 3b5bbe798b2451820e74243b738268f51901e7d0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024081910-grid-bobsled-6cb3@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
3b5bbe798b24 ("pidfd: prevent creation of pidfds for kthreads")
83b290c9e3b5 ("pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together")
64bef697d33b ("pidfd: implement PIDFD_THREAD flag for pidfd_open()")
21e25205d7f9 ("pidfd: don't do_notify_pidfd() if !thread_group_empty()")
cdefbf2324ce ("pidfd: cleanup the usage of __pidfd_prepare's flags")
932562a6045e ("rseq: Split out rseq.h from sched.h")
cba6167f0adb ("restart_block: Trim includes")
f038cc1379c0 ("locking/seqlock: Split out seqlock_types.h")
53d31ba842d9 ("posix-cpu-timers: Split out posix-timers_types.h")
f995443f01b4 ("locking/seqlock: Simplify SEQCOUNT_LOCKNAME()")
58390c8ce1bd ("Merge tag 'iommu-updates-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3b5bbe798b2451820e74243b738268f51901e7d0 Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner(a)kernel.org>
Date: Wed, 31 Jul 2024 12:01:12 +0200
Subject: [PATCH] pidfd: prevent creation of pidfds for kthreads
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: 32fcb426ec00 ("pid: add pidfd_open()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index cc760491f201..18bdc87209d0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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)
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 3b5bbe798b2451820e74243b738268f51901e7d0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024081909-comment-hypocrisy-a802@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
3b5bbe798b24 ("pidfd: prevent creation of pidfds for kthreads")
83b290c9e3b5 ("pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together")
64bef697d33b ("pidfd: implement PIDFD_THREAD flag for pidfd_open()")
21e25205d7f9 ("pidfd: don't do_notify_pidfd() if !thread_group_empty()")
cdefbf2324ce ("pidfd: cleanup the usage of __pidfd_prepare's flags")
932562a6045e ("rseq: Split out rseq.h from sched.h")
cba6167f0adb ("restart_block: Trim includes")
f038cc1379c0 ("locking/seqlock: Split out seqlock_types.h")
53d31ba842d9 ("posix-cpu-timers: Split out posix-timers_types.h")
f995443f01b4 ("locking/seqlock: Simplify SEQCOUNT_LOCKNAME()")
58390c8ce1bd ("Merge tag 'iommu-updates-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3b5bbe798b2451820e74243b738268f51901e7d0 Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner(a)kernel.org>
Date: Wed, 31 Jul 2024 12:01:12 +0200
Subject: [PATCH] pidfd: prevent creation of pidfds for kthreads
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: 32fcb426ec00 ("pid: add pidfd_open()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index cc760491f201..18bdc87209d0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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)
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 3b5bbe798b2451820e74243b738268f51901e7d0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024081908-dork-steadfast-6a68@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
3b5bbe798b24 ("pidfd: prevent creation of pidfds for kthreads")
83b290c9e3b5 ("pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together")
64bef697d33b ("pidfd: implement PIDFD_THREAD flag for pidfd_open()")
21e25205d7f9 ("pidfd: don't do_notify_pidfd() if !thread_group_empty()")
cdefbf2324ce ("pidfd: cleanup the usage of __pidfd_prepare's flags")
932562a6045e ("rseq: Split out rseq.h from sched.h")
cba6167f0adb ("restart_block: Trim includes")
f038cc1379c0 ("locking/seqlock: Split out seqlock_types.h")
53d31ba842d9 ("posix-cpu-timers: Split out posix-timers_types.h")
f995443f01b4 ("locking/seqlock: Simplify SEQCOUNT_LOCKNAME()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3b5bbe798b2451820e74243b738268f51901e7d0 Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner(a)kernel.org>
Date: Wed, 31 Jul 2024 12:01:12 +0200
Subject: [PATCH] pidfd: prevent creation of pidfds for kthreads
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: 32fcb426ec00 ("pid: add pidfd_open()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index cc760491f201..18bdc87209d0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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)