mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-30 06:10:56 +00:00
Code Issues Releases Wiki Activity
No description
1202155 commits 105 branches 5097 tags 5.6 GiB
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%
Find a file
Aleksa Sarai a4f0d04142 selftests: memfd: error out test process when child test fails 
[ Upstream commit 99f34659e7 ]

Patch series "memfd: cleanups for vm.memfd_noexec", v2.

The most critical issue with vm.memfd_noexec=2 (the fact that passing
MFD_EXEC would bypass it entirely[1]) has been fixed in Andrew's
tree[2], but there are still some outstanding issues that need to be
addressed:

 * vm.memfd_noexec=2 shouldn't reject old-style memfd_create(2) syscalls
   because it will make it far to difficult to ever migrate. Instead it
   should imply MFD_EXEC.

 * The dmesg warnings are pr_warn_once(), which on most systems means
   that they will be used up by systemd or some other boot process and
   userspace developers will never see it.

   - For the !(flags & (MFD_EXEC | MFD_NOEXEC_SEAL)) case, outputting a
     rate-limited message to the kernel log is necessary to tell
     userspace that they should add the new flags.

     Arguably the most ideal way to deal with the spam concern[3,4]
     while still prompting userspace to switch to the new flags would be
     to only log the warning once per task or something similar.
     However, adding something to task_struct for tracking this would be
     needless bloat for a single pr_warn_ratelimited().

     So just switch to pr_info_ratelimited() to avoid spamming the log
     with something that isn't a real warning. There's lots of
     info-level stuff in dmesg, it seems really unlikely that this
     should be an actual problem. Most programs are already switching to
     the new flags anyway.

   - For the vm.memfd_noexec=2 case, we need to log a warning for every
     failure because otherwise userspace will have no idea why their
     previously working program started returning -EACCES (previously
     -EINVAL) from memfd_create(2). pr_warn_once() is simply wrong here.

 * The racheting mechanism for vm.memfd_noexec makes it incredibly
   unappealing for most users to enable the sysctl because enabling it
   on &init_pid_ns means you need a system reboot to unset it. Given the
   actual security threat being protected against, CAP_SYS_ADMIN users
   being restricted in this way makes little sense.

   The argument for this ratcheting by the original author was that it
   allows you to have a hierarchical setting that cannot be unset by
   child pidnses, but this is not accurate -- changing the parent
   pidns's vm.memfd_noexec setting to be more restrictive didn't affect
   children.

   Instead, switch the vm.memfd_noexec sysctl to be properly
   hierarchical and allow CAP_SYS_ADMIN users (in the pidns's owning
   userns) to lower the setting as long as it is not lower than the
   parent's effective setting. This change also makes it so that
   changing a parent pidns's vm.memfd_noexec will affect all
   descendants, providing a properly hierarchical setting. The
   performance impact of this is incredibly minimal since the maximum
   depth of pidns is 32 and it is only checked during memfd_create(2)
   and unshare(CLONE_NEWPID).

 * The memfd selftests would not exit with a non-zero error code when
   certain tests that ran in a forked process (specifically the ones
   related to MFD_EXEC and MFD_NOEXEC_SEAL) failed.

[1]: https://lore.kernel.org/all/ZJwcsU0vI-nzgOB_@codewreck.org/
[2]: https://lore.kernel.org/all/20230705063315.3680666-1-jeffxu@google.com/
[3]: https://lore.kernel.org/Y5yS8wCnuYGLHMj4@x1n/
[4]: https://lore.kernel.org/f185bb42-b29c-977e-312e-3349eea15383@linuxfoundation.org/

This patch (of 5):

Before this change, a test runner using this self test would see a return
code of 0 when the tests using a child process (namely the MFD_NOEXEC_SEAL
and MFD_EXEC tests) failed, masking test failures.

Link: https://lkml.kernel.org/r/20230814-memfd-vm-noexec-uapi-fixes-v2-0-7ff9e3e10ba6@cyphar.com
Link: https://lkml.kernel.org/r/20230814-memfd-vm-noexec-uapi-fixes-v2-1-7ff9e3e10ba6@cyphar.com
Fixes: 11f75a0144 ("selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Jeff Xu <jeffxu@google.com>
Cc: "Christian Brauner (Microsoft)" <brauner@kernel.org>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-13 09:53:09 +02:00
arch nmi_backtrace: allow excluding an arbitrary CPU 2023-09-13 09:53:08 +02:00
block block-6.5-2023-08-19 2023-08-19 17:31:46 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: api - Use work queue in crypto_destroy_instance 2023-09-13 09:53:05 +02:00
Documentation dt-bindings: sc16is7xx: Add property to change GPIO function 2023-09-06 21:22:25 +01:00
drivers wifi: rtw89: 8852b: rfk: fine tune IQK parameters to improve performance on 2GHz band 2023-09-13 09:53:09 +02:00
fs fs: ocfs2: namei: check return value of ocfs2_add_entry() 2023-09-13 09:53:08 +02:00
include nmi_backtrace: allow excluding an arbitrary CPU 2023-09-13 09:53:08 +02:00
init sched/psi: Select KERNFS as needed 2023-09-13 09:52:59 +02:00
io_uring io_uring/parisc: Adjust pgoff in io_uring mmap() for parisc 2023-08-08 12:37:01 -06:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel watchdog/hardlockup: avoid large stack frames in watchdog_hardlockup_check() 2023-09-13 09:53:08 +02:00
lib nmi_backtrace: allow excluding an arbitrary CPU 2023-09-13 09:53:08 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm net-memcg: Fix scope of sockmem pressure indicators 2023-09-13 09:53:07 +02:00
net net: annotate data-races around sk->sk_lingertime 2023-09-13 09:53:08 +02:00
rust rust: macros: vtable: fix HAS_* redefinition (gen_const_name) 2023-08-09 21:15:07 +02:00
samples samples: ftrace: Replace bti assembly with hint for older compiler 2023-08-21 22:03:58 -04:00
scripts scripts/gdb: fix 'lx-lsmod' show the wrong size 2023-09-13 09:53:08 +02:00
security vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing 2023-09-13 09:52:58 +02:00
sound ALSA: usb-audio: Fix init call orders for UAC1 2023-09-06 21:22:23 +01:00
tools selftests: memfd: error out test process when child test fails 2023-09-13 09:53:09 +02:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-07-29 11:05:28 -04:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Revert ".gitignore: ignore *.cover and *.mbx" 2023-07-04 15:05:12 -07:00
.mailmap mailmap: add entries for Simon Horman 2023-08-16 09:53:10 +01:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS sound fixes for 6.5 2023-08-25 08:48:14 -07:00
Makefile kbuild: rust_is_available: remove -v option 2023-09-13 09:53:05 +02:00
README

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.