mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Jeff Xu](/assets/img/avatar_default.png)
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. [akpm@linux-foundation.org: add stub functions to fix build] [akpm@linux-foundation.org: remove unneeded register_pid_ns_ctl_table_vm() stub, per Jeff] [akpm@linux-foundation.org: s/pr_warn_ratelimited/pr_warn_once/, per review] [akpm@linux-foundation.org: fix CONFIG_SYSCTL=n warning] Link: https://lkml.kernel.org/r/20221215001205.51969-4-jeffxu@google.com 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> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Jorge Lucangeli Obes <jorgelo@chromium.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
39 lines
1.4 KiB
C
39 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
|
|
#ifndef _UAPI_LINUX_MEMFD_H
|
|
#define _UAPI_LINUX_MEMFD_H
|
|
|
|
#include <asm-generic/hugetlb_encode.h>
|
|
|
|
/* flags for memfd_create(2) (unsigned int) */
|
|
#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
|
|
* size other than the default is desired. See hugetlb_encode.h.
|
|
* All known huge page size encodings are provided here. It is the
|
|
* responsibility of the application to know which sizes are supported on
|
|
* the running system. See mmap(2) man page for details.
|
|
*/
|
|
#define MFD_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
|
|
#define MFD_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK
|
|
|
|
#define MFD_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB
|
|
#define MFD_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB
|
|
#define MFD_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB
|
|
#define MFD_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB
|
|
#define MFD_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB
|
|
#define MFD_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB
|
|
#define MFD_HUGE_32MB HUGETLB_FLAG_ENCODE_32MB
|
|
#define MFD_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB
|
|
#define MFD_HUGE_512MB HUGETLB_FLAG_ENCODE_512MB
|
|
#define MFD_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB
|
|
#define MFD_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
|
|
#define MFD_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
|
|
|
|
#endif /* _UAPI_LINUX_MEMFD_H */
|