linux/include/uapi
Jeff Xu 105ff5339f mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC
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>
2023-01-18 17:12:37 -08:00
..
asm-generic uapi: Add missing _UAPI prefix to <asm-generic/types.h> include guard 2022-12-01 16:22:06 +01:00
drm drm/msm updates for 6.2 2022-11-30 17:02:27 +10:00
linux mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC 2023-01-18 17:12:37 -08:00
misc This tag contains habanalabs driver changes for v6.2: 2022-11-29 13:19:29 +01:00
mtd This pull request contains updates for UBI and UBIFS 2022-10-14 18:23:23 -07:00
rdma RDMA/rxe: Extend rxe user ABI to support flush 2022-12-09 19:36:01 -04:00
scsi scsi: scsi_transport_fc: Adjust struct fc_nl_event flex array usage 2022-09-25 12:52:48 -04:00
sound ASoC: Updates for v6.2 2022-12-06 11:13:26 +01:00
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