diff mbox series

[v7,3/6] mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC

Message ID 20221209160453.3246150-4-jeffxu@google.com
State New
Headers
Series mm/memfd: introduce MFD_NOEXEC_SEAL and MFD_EXEC |

Commit Message

Jeff Xu Dec. 9, 2022, 4:04 p.m. UTC 
  From: Jeff Xu <jeffxu@google.com>

The new MFD_NOEXEC_SEAL and MFD_EXEC flags allows application to
set executable bit at creation time (memfd_create).

When MFD_NOEXEC_SEAL is set, memfd is created without executable bit
(mode:0666), and sealed with F_SEAL_EXEC, so it can't be chmod to
be executable (mode: 0777) after creation.

when MFD_EXEC flag is set, memfd is created with executable bit
(mode:0777), this is the same as the old behavior of memfd_create.

The new pid namespaced sysctl vm.memfd_noexec has 3 values:
0: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
        MFD_EXEC was set.
1: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
        MFD_NOEXEC_SEAL was set.
2: memfd_create() without MFD_NOEXEC_SEAL will be rejected.

The sysctl allows finer control of memfd_create for old-software
that doesn't set the executable bit, for example, a container with
vm.memfd_noexec=1 means the old-software will create non-executable
memfd by default. Also, the value of memfd_noexec is passed to child
namespace at creation time. For example, if the init namespace has
vm.memfd_noexec=2, all its children namespaces will be created with 2.

Signed-off-by: Jeff Xu <jeffxu@google.com>
Co-developed-by: Daniel Verkamp <dverkamp@chromium.org>
Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Reported-by: kernel test robot <lkp@intel.com>
---
 include/linux/pid_namespace.h | 19 +++++++++++
 include/uapi/linux/memfd.h    |  4 +++
 kernel/pid_namespace.c        |  5 +++
 kernel/pid_sysctl.h           | 59 +++++++++++++++++++++++++++++++++++
 mm/memfd.c                    | 48 ++++++++++++++++++++++++++--
 5 files changed, 133 insertions(+), 2 deletions(-)
 create mode 100644 kernel/pid_sysctl.h

Comments

Kees Cook Dec. 14, 2022, 6:53 p.m. UTC | #1 
On Fri, Dec 09, 2022 at 04:04:50PM +0000, jeffxu@chromium.org wrote:
> From: Jeff Xu <jeffxu@google.com>
> 
> The new MFD_NOEXEC_SEAL and MFD_EXEC flags allows application to
> set executable bit at creation time (memfd_create).
> 
> When MFD_NOEXEC_SEAL is set, memfd is created without executable bit
> (mode:0666), and sealed with F_SEAL_EXEC, so it can't be chmod to
> be executable (mode: 0777) after creation.
> 
> when MFD_EXEC flag is set, memfd is created with executable bit
> (mode:0777), this is the same as the old behavior of memfd_create.
> 
> The new pid namespaced sysctl vm.memfd_noexec has 3 values:
> 0: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
>         MFD_EXEC was set.
> 1: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
>         MFD_NOEXEC_SEAL was set.
> 2: memfd_create() without MFD_NOEXEC_SEAL will be rejected.
> 
> The sysctl allows finer control of memfd_create for old-software
> that doesn't set the executable bit, for example, a container with
> vm.memfd_noexec=1 means the old-software will create non-executable
> memfd by default. Also, the value of memfd_noexec is passed to child
> namespace at creation time. For example, if the init namespace has
> vm.memfd_noexec=2, all its children namespaces will be created with 2.
> 
> Signed-off-by: Jeff Xu <jeffxu@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>
SeongJae Park Dec. 16, 2022, 6:39 p.m. UTC | #2 
Hi Jeff,

> From: Jeff Xu <jeffxu@google.com>
> 
> The new MFD_NOEXEC_SEAL and MFD_EXEC flags allows application to
> set executable bit at creation time (memfd_create).
> 
> When MFD_NOEXEC_SEAL is set, memfd is created without executable bit
> (mode:0666), and sealed with F_SEAL_EXEC, so it can't be chmod to
> be executable (mode: 0777) after creation.
> 
> when MFD_EXEC flag is set, memfd is created with executable bit
> (mode:0777), this is the same as the old behavior of memfd_create.
> 
> The new pid namespaced sysctl vm.memfd_noexec has 3 values:
> 0: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
>         MFD_EXEC was set.
> 1: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
>         MFD_NOEXEC_SEAL was set.
> 2: memfd_create() without MFD_NOEXEC_SEAL will be rejected.
> 
> The sysctl allows finer control of memfd_create for old-software
> that doesn't set the executable bit, for example, a container with
> vm.memfd_noexec=1 means the old-software will create non-executable
> memfd by default. Also, the value of memfd_noexec is passed to child
> namespace at creation time. For example, if the init namespace has
> vm.memfd_noexec=2, all its children namespaces will be created with 2.
> 
> Signed-off-by: Jeff Xu <jeffxu@google.com>
> Co-developed-by: Daniel Verkamp <dverkamp@chromium.org>
> Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
> Reported-by: kernel test robot <lkp@intel.com>
> ---
[...]
> diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
> index f4f8cb0435b4..8a98b1af9376 100644
> --- a/kernel/pid_namespace.c
> +++ b/kernel/pid_namespace.c
> @@ -23,6 +23,7 @@
>  #include <linux/sched/task.h>
>  #include <linux/sched/signal.h>
>  #include <linux/idr.h>
> +#include "pid_sysctl.h"
>  
>  static DEFINE_MUTEX(pid_caches_mutex);
>  static struct kmem_cache *pid_ns_cachep;
> @@ -110,6 +111,8 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
>  	ns->ucounts = ucounts;
>  	ns->pid_allocated = PIDNS_ADDING;
>  
> +	initialize_memfd_noexec_scope(ns);
> +
>  	return ns;
>  
>  out_free_idr:
> @@ -455,6 +458,8 @@ static __init int pid_namespaces_init(void)
>  #ifdef CONFIG_CHECKPOINT_RESTORE
>  	register_sysctl_paths(kern_path, pid_ns_ctl_table);
>  #endif
> +
> +	register_pid_ns_sysctl_table_vm();
>  	return 0;
>  }
[...]
>  
> diff --git a/kernel/pid_sysctl.h b/kernel/pid_sysctl.h
> new file mode 100644
> index 000000000000..90a93161a122
> --- /dev/null
> +++ b/kernel/pid_sysctl.h
> @@ -0,0 +1,59 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef LINUX_PID_SYSCTL_H
> +#define LINUX_PID_SYSCTL_H
> +
> +#include <linux/pid_namespace.h>
> +
> +#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
> +static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns)
[...]
> +static inline void register_pid_ns_sysctl_table_vm(void)
> +{
> +	register_sysctl_paths(vm_path, pid_ns_ctl_table_vm);
> +}
> +#else
> +static inline void set_memfd_noexec_scope(struct pid_namespace *ns) {}
> +static inline void register_pid_ns_ctl_table_vm(void) {}
> +#endif
[...]

I found this patch makes build fails whne CONFIG_SYSCTL or CONFIG_MEMFD_CREATE
are not defined, as initialize_memfd_noexec_scope() and
register_pid_ns_sysctl_table_vm() are used from pid_namespace.c without the
configs protection.

I just posted a patch for that:
https://lore.kernel.org/linux-mm/20221216183314.169707-1-sj@kernel.org/

Could you please check?


Thanks,
SJ
Jeff Xu Dec. 16, 2022, 7:03 p.m. UTC | #3 
On Fri, Dec 16, 2022 at 10:39 AM SeongJae Park <sj@kernel.org> wrote:
>
> Hi Jeff,
>
> > From: Jeff Xu <jeffxu@google.com>
> >
> > The new MFD_NOEXEC_SEAL and MFD_EXEC flags allows application to
> > set executable bit at creation time (memfd_create).
> >
> > When MFD_NOEXEC_SEAL is set, memfd is created without executable bit
> > (mode:0666), and sealed with F_SEAL_EXEC, so it can't be chmod to
> > be executable (mode: 0777) after creation.
> >
> > when MFD_EXEC flag is set, memfd is created with executable bit
> > (mode:0777), this is the same as the old behavior of memfd_create.
> >
> > The new pid namespaced sysctl vm.memfd_noexec has 3 values:
> > 0: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
> >         MFD_EXEC was set.
> > 1: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
> >         MFD_NOEXEC_SEAL was set.
> > 2: memfd_create() without MFD_NOEXEC_SEAL will be rejected.
> >
> > The sysctl allows finer control of memfd_create for old-software
> > that doesn't set the executable bit, for example, a container with
> > vm.memfd_noexec=1 means the old-software will create non-executable
> > memfd by default. Also, the value of memfd_noexec is passed to child
> > namespace at creation time. For example, if the init namespace has
> > vm.memfd_noexec=2, all its children namespaces will be created with 2.
> >
> > Signed-off-by: Jeff Xu <jeffxu@google.com>
> > Co-developed-by: Daniel Verkamp <dverkamp@chromium.org>
> > Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
> > Reported-by: kernel test robot <lkp@intel.com>
> > ---
> [...]
> > diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
> > index f4f8cb0435b4..8a98b1af9376 100644
> > --- a/kernel/pid_namespace.c
> > +++ b/kernel/pid_namespace.c
> > @@ -23,6 +23,7 @@
> >  #include <linux/sched/task.h>
> >  #include <linux/sched/signal.h>
> >  #include <linux/idr.h>
> > +#include "pid_sysctl.h"
> >
> >  static DEFINE_MUTEX(pid_caches_mutex);
> >  static struct kmem_cache *pid_ns_cachep;
> > @@ -110,6 +111,8 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
> >       ns->ucounts = ucounts;
> >       ns->pid_allocated = PIDNS_ADDING;
> >
> > +     initialize_memfd_noexec_scope(ns);
> > +
> >       return ns;
> >
> >  out_free_idr:
> > @@ -455,6 +458,8 @@ static __init int pid_namespaces_init(void)
> >  #ifdef CONFIG_CHECKPOINT_RESTORE
> >       register_sysctl_paths(kern_path, pid_ns_ctl_table);
> >  #endif
> > +
> > +     register_pid_ns_sysctl_table_vm();
> >       return 0;
> >  }
> [...]
> >
> > diff --git a/kernel/pid_sysctl.h b/kernel/pid_sysctl.h
> > new file mode 100644
> > index 000000000000..90a93161a122
> > --- /dev/null
> > +++ b/kernel/pid_sysctl.h
> > @@ -0,0 +1,59 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef LINUX_PID_SYSCTL_H
> > +#define LINUX_PID_SYSCTL_H
> > +
> > +#include <linux/pid_namespace.h>
> > +
> > +#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
> > +static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns)
> [...]
> > +static inline void register_pid_ns_sysctl_table_vm(void)
> > +{
> > +     register_sysctl_paths(vm_path, pid_ns_ctl_table_vm);
> > +}
> > +#else
> > +static inline void set_memfd_noexec_scope(struct pid_namespace *ns) {}
> > +static inline void register_pid_ns_ctl_table_vm(void) {}
> > +#endif
> [...]
>
> I found this patch makes build fails whne CONFIG_SYSCTL or CONFIG_MEMFD_CREATE
> are not defined, as initialize_memfd_noexec_scope() and
> register_pid_ns_sysctl_table_vm() are used from pid_namespace.c without the
> configs protection.
>
> I just posted a patch for that:
> https://lore.kernel.org/linux-mm/20221216183314.169707-1-sj@kernel.org/
>
> Could you please check?
>
Hi SeongJae,
Thanks for the patch ! I responded to the other thread.

Andrew,
From a process point of view, should I update this patch to V9 to
include the fix ?
or add a patch directly on top in the mm-unstable branch.

Thanks
Jeff

>
> Thanks,
> SJ
Andrew Morton Dec. 16, 2022, 7:21 p.m. UTC | #4 
On Fri, 16 Dec 2022 11:03:06 -0800 Jeff Xu <jeffxu@google.com> wrote:

> >
> > I just posted a patch for that:
> > https://lore.kernel.org/linux-mm/20221216183314.169707-1-sj@kernel.org/
> >
> > Could you please check?
> >
> Hi SeongJae,
> Thanks for the patch ! I responded to the other thread.
> 
> Andrew,
> >From a process point of view, should I update this patch to V9 to
> include the fix ?
> or add a patch directly on top in the mm-unstable branch.

A little fixup patch wouild be preferable.

But I added the below yesterday, so I think we're all good?

--- a/kernel/pid_sysctl.h~mm-memfd-add-mfd_noexec_seal-and-mfd_exec-fix
+++ a/kernel/pid_sysctl.h
@@ -52,8 +52,10 @@ static inline void register_pid_ns_sysct
 	register_sysctl_paths(vm_path, pid_ns_ctl_table_vm);
 }
 #else
+static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns) {}
 static inline void set_memfd_noexec_scope(struct pid_namespace *ns) {}
 static inline void register_pid_ns_ctl_table_vm(void) {}
+static inline void register_pid_ns_sysctl_table_vm(void) {}
 #endif
 
 #endif /* LINUX_PID_SYSCTL_H */
SeongJae Park Dec. 16, 2022, 7:31 p.m. UTC | #5 
Hi Jeff and Andrew,

On Fri, 16 Dec 2022 11:21:02 -0800 Andrew Morton <akpm@linux-foundation.org> wrote:

> On Fri, 16 Dec 2022 11:03:06 -0800 Jeff Xu <jeffxu@google.com> wrote:
> 
> > >
> > > I just posted a patch for that:
> > > https://lore.kernel.org/linux-mm/20221216183314.169707-1-sj@kernel.org/
> > >
> > > Could you please check?
> > >
> > Hi SeongJae,
> > Thanks for the patch ! I responded to the other thread.

Thank you for the quick and nice response, Jeff :)

> > 
> > Andrew,
> > >From a process point of view, should I update this patch to V9 to
> > include the fix ?
> > or add a patch directly on top in the mm-unstable branch.
> 
> A little fixup patch wouild be preferable.
> 
> But I added the below yesterday, so I think we're all good?

Good, thank you.  I should be more patient until you push it, but I was unable
to resist ;)


Thanks,
SJ

> 
> --- a/kernel/pid_sysctl.h~mm-memfd-add-mfd_noexec_seal-and-mfd_exec-fix
> +++ a/kernel/pid_sysctl.h
> @@ -52,8 +52,10 @@ static inline void register_pid_ns_sysct
>  	register_sysctl_paths(vm_path, pid_ns_ctl_table_vm);
>  }
>  #else
> +static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns) {}
>  static inline void set_memfd_noexec_scope(struct pid_namespace *ns) {}
>  static inline void register_pid_ns_ctl_table_vm(void) {}
> +static inline void register_pid_ns_sysctl_table_vm(void) {}
>  #endif
>  
>  #endif /* LINUX_PID_SYSCTL_H */
> _
diff mbox series

Patch

diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 07481bb87d4e..c758809d5bcf 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -16,6 +16,21 @@ 
 
 struct fs_pin;
 
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
+/*
+ * sysctl for vm.memfd_noexec
+ * 0: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL
+ *	acts like MFD_EXEC was set.
+ * 1: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL
+ *	acts like MFD_NOEXEC_SEAL was set.
+ * 2: memfd_create() without MFD_NOEXEC_SEAL will be
+ *	rejected.
+ */
+#define MEMFD_NOEXEC_SCOPE_EXEC			0
+#define MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL		1
+#define MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED	2
+#endif
+
 struct pid_namespace {
 	struct idr idr;
 	struct rcu_head rcu;
@@ -31,6 +46,10 @@  struct pid_namespace {
 	struct ucounts *ucounts;
 	int reboot;	/* group exit code if this pidns was rebooted */
 	struct ns_common ns;
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
+	/* sysctl for vm.memfd_noexec */
+	int memfd_noexec_scope;
+#endif
 } __randomize_layout;
 
 extern struct pid_namespace init_pid_ns;
diff --git a/include/uapi/linux/memfd.h b/include/uapi/linux/memfd.h
index 7a8a26751c23..273a4e15dfcf 100644
--- a/include/uapi/linux/memfd.h
+++ b/include/uapi/linux/memfd.h
@@ -8,6 +8,10 @@ 
 #define MFD_CLOEXEC		0x0001U
 #define MFD_ALLOW_SEALING	0x0002U
 #define MFD_HUGETLB		0x0004U
+/* not executable and sealed to prevent changing to executable. */
+#define MFD_NOEXEC_SEAL		0x0008U
+/* executable */
+#define MFD_EXEC		0x0010U
 
 /*
  * Huge page size encoding when MFD_HUGETLB is specified, and a huge page
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index f4f8cb0435b4..8a98b1af9376 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -23,6 +23,7 @@ 
 #include <linux/sched/task.h>
 #include <linux/sched/signal.h>
 #include <linux/idr.h>
+#include "pid_sysctl.h"
 
 static DEFINE_MUTEX(pid_caches_mutex);
 static struct kmem_cache *pid_ns_cachep;
@@ -110,6 +111,8 @@  static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
 	ns->ucounts = ucounts;
 	ns->pid_allocated = PIDNS_ADDING;
 
+	initialize_memfd_noexec_scope(ns);
+
 	return ns;
 
 out_free_idr:
@@ -455,6 +458,8 @@  static __init int pid_namespaces_init(void)
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	register_sysctl_paths(kern_path, pid_ns_ctl_table);
 #endif
+
+	register_pid_ns_sysctl_table_vm();
 	return 0;
 }
 
diff --git a/kernel/pid_sysctl.h b/kernel/pid_sysctl.h
new file mode 100644
index 000000000000..90a93161a122
--- /dev/null
+++ b/kernel/pid_sysctl.h
@@ -0,0 +1,59 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_PID_SYSCTL_H
+#define LINUX_PID_SYSCTL_H
+
+#include <linux/pid_namespace.h>
+
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
+static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns)
+{
+	ns->memfd_noexec_scope =
+		task_active_pid_ns(current)->memfd_noexec_scope;
+}
+
+static int pid_mfd_noexec_dointvec_minmax(struct ctl_table *table,
+	int write, void *buf, size_t *lenp, loff_t *ppos)
+{
+	struct pid_namespace *ns = task_active_pid_ns(current);
+	struct ctl_table table_copy;
+
+	if (write && !ns_capable(ns->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	table_copy = *table;
+	if (ns != &init_pid_ns)
+		table_copy.data = &ns->memfd_noexec_scope;
+
+	/*
+	 * set minimum to current value, the effect is only bigger
+	 * value is accepted.
+	 */
+	if (*(int *)table_copy.data > *(int *)table_copy.extra1)
+		table_copy.extra1 = table_copy.data;
+
+	return proc_dointvec_minmax(&table_copy, write, buf, lenp, ppos);
+}
+
+static struct ctl_table pid_ns_ctl_table_vm[] = {
+	{
+		.procname	= "memfd_noexec",
+		.data		= &init_pid_ns.memfd_noexec_scope,
+		.maxlen		= sizeof(init_pid_ns.memfd_noexec_scope),
+		.mode		= 0644,
+		.proc_handler	= pid_mfd_noexec_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
+	},
+	{ }
+};
+static struct ctl_path vm_path[] = { { .procname = "vm", }, { } };
+static inline void register_pid_ns_sysctl_table_vm(void)
+{
+	register_sysctl_paths(vm_path, pid_ns_ctl_table_vm);
+}
+#else
+static inline void set_memfd_noexec_scope(struct pid_namespace *ns) {}
+static inline void register_pid_ns_ctl_table_vm(void) {}
+#endif
+
+#endif /* LINUX_PID_SYSCTL_H */
diff --git a/mm/memfd.c b/mm/memfd.c
index 4ebeab94aa74..ec70675a7069 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -18,6 +18,7 @@ 
 #include <linux/hugetlb.h>
 #include <linux/shmem_fs.h>
 #include <linux/memfd.h>
+#include <linux/pid_namespace.h>
 #include <uapi/linux/memfd.h>
 
 /*
@@ -263,12 +264,14 @@  long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
 #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1)
 #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN)
 
-#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB)
+#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | MFD_NOEXEC_SEAL | MFD_EXEC)
 
 SYSCALL_DEFINE2(memfd_create,
 		const char __user *, uname,
 		unsigned int, flags)
 {
+	char comm[TASK_COMM_LEN];
+	struct pid_namespace *ns;
 	unsigned int *file_seals;
 	struct file *file;
 	int fd, error;
@@ -285,6 +288,39 @@  SYSCALL_DEFINE2(memfd_create,
 			return -EINVAL;
 	}
 
+	/* Invalid if both EXEC and NOEXEC_SEAL are set.*/
+	if ((flags & MFD_EXEC) && (flags & MFD_NOEXEC_SEAL))
+		return -EINVAL;
+
+	if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
+#ifdef CONFIG_SYSCTL
+		int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
+
+		ns = task_active_pid_ns(current);
+		if (ns)
+			sysctl = ns->memfd_noexec_scope;
+
+		switch (sysctl) {
+		case MEMFD_NOEXEC_SCOPE_EXEC:
+			flags |= MFD_EXEC;
+			break;
+		case MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL:
+			flags |= MFD_NOEXEC_SEAL;
+			break;
+		default:
+			pr_warn_ratelimited(
+				"memfd_create(): MFD_NOEXEC_SEAL is enforced, pid=%d '%s'\n",
+				task_pid_nr(current), get_task_comm(comm, current));
+			return -EINVAL;
+		}
+#else
+		flags |= MFD_EXEC;
+#endif
+		pr_warn_ratelimited(
+			"memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=%d '%s'\n",
+			task_pid_nr(current), get_task_comm(comm, current));
+	}
+
 	/* length includes terminating zero */
 	len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1);
 	if (len <= 0)
@@ -328,7 +364,15 @@  SYSCALL_DEFINE2(memfd_create,
 	file->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
 	file->f_flags |= O_LARGEFILE;
 
-	if (flags & MFD_ALLOW_SEALING) {
+	if (flags & MFD_NOEXEC_SEAL) {
+		struct inode *inode = file_inode(file);
+
+		inode->i_mode &= ~0111;
+		file_seals = memfd_file_seals_ptr(file);
+		*file_seals &= ~F_SEAL_SEAL;
+		*file_seals |= F_SEAL_EXEC;
+	} else if (flags & MFD_ALLOW_SEALING) {
+		/* MFD_EXEC and MFD_ALLOW_SEALING are set */
 		file_seals = memfd_file_seals_ptr(file);
 		*file_seals &= ~F_SEAL_SEAL;
 	}