user/sven/linux.git/drivers/base/devtmpfs.c, branch v6.2.7

devtmpfs: fix the dangling pointer of global devtmpfsd thread

2022-06-27T14:41:13Z

When the devtmpfs fails to mount, a dangling pointer still remains in global. Specifically, the err variable is passed by a pointer to the devtmpfsd. When the devtmpfsd exits, it sets the error and completes the setup_done. In this situation, the thread pointer is not set to null. After the devtmpfsd exited, the devtmpfs can wakes up the destroyed devtmpfsd thread by wake_up_process if a device change event comes. Signed-off-by: Yangxi Xiang Link: https://lore.kernel.org/r/20220627120409.11174-1-xyangxi5@gmail.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2022-03-28T19:41:28Z

Pull driver core updates from Greg KH: "Here is the set of driver core changes for 5.18-rc1. Not much here, primarily it was a bunch of cleanups and small updates: - kobj_type cleanups for default_groups - documentation updates - firmware loader minor changes - component common helper added and take advantage of it in many drivers (the largest part of this pull request). All of these have been in linux-next for a while with no reported problems" * tag 'driver-core-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (54 commits) Documentation: update stable review cycle documentation drivers/base/dd.c : Remove the initial value of the global variable Documentation: update stable tree link Documentation: add link to stable release candidate tree devres: fix typos in comments Documentation: add note block surrounding security patch note samples/kobject: Use sysfs_emit instead of sprintf base: soc: Make soc_device_match() simpler and easier to read driver core: dd: fix return value of __setup handler driver core: Refactor sysfs and drv/bus remove hooks driver core: Refactor multiple copies of device cleanup scripts: get_abi.pl: Fix typo in help message kernfs: fix typos in comments kernfs: remove unneeded #if 0 guard ALSA: hda/realtek: Make use of the helper component_compare_dev_name video: omapfb: dss: Make use of the helper component_compare_dev power: supply: ab8500: Make use of the helper component_compare_dev ASoC: codecs: wcd938x: Make use of the helper component_compare/release_of iommu/mediatek: Make use of the helper component_compare/release_of drm: of: Make use of the helper component_release_of ...

devtmpfs: drop redundant fs parameters from internal fs

2022-02-04T14:38:01Z

The internal_fs_type is mounted via vfs_kernel_mount() and is never registered as a filesystem, thus specifying the parameters is redundant as those params will not be validated by fs_validate_description(). Both {shmem,ramfs}_fs_parameters are anyway validated when those respective filesystems are first registered, so there is no reason to pass them to devtmpfs too, drop them. Reviewed-by: Christoph Hellwig Acked-by: Christian Brauner Signed-off-by: Anthony Iliopoulos Link: https://lore.kernel.org/r/20220119220248.32225-1-ailiop@suse.com Signed-off-by: Greg Kroah-Hartman

block: remove genhd.h

2022-02-02T14:49:59Z

There is no good reason to keep genhd.h separate from the main blkdev.h header that includes it. So fold the contents of genhd.h into blkdev.h and remove genhd.h entirely. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20220124093913.742411-4-hch@lst.de Signed-off-by: Jens Axboe

devtmpfs regression fix: reconfigure on each mount

2022-01-17T07:40:29Z

Prior to Linux v5.4 devtmpfs used mount_single() which treats the given mount options as "remount" options, so it updates the configuration of the single super_block on each mount. Since that was changed, the mount options used for devtmpfs are ignored. This is a regression which affect systemd - which mounts devtmpfs with "-o mode=755,size=4m,nr_inodes=1m". This patch restores the "remount" effect by calling reconfigure_single() Fixes: d401727ea0d7 ("devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single()") Acked-by: Christian Brauner Cc: Al Viro Signed-off-by: NeilBrown Signed-off-by: Linus Torvalds

devtmpfs: mount with noexec and nosuid

2021-12-30T12:54:42Z

devtmpfs is writable. Add the noexec and nosuid as default mount flags to prevent code execution from /dev. The systems who don't use systemd and who rely on CONFIG_DEVTMPFS_MOUNT=y are the ones to be protected by this patch. Other systems are fine with the udev solution. No sane program should be relying on executing from /dev. So this patch reduces the attack surface. It doesn't prevent any specific attack, but it reduces the possibility that someone can use /dev as a place to put executable code. Chrome OS has been carrying this patch for several years. It seems trivial and simple solution to improve the protection of /dev when CONFIG_DEVTMPFS_MOUNT=y. Original patch: https://lore.kernel.org/lkml/20121120215059.GA1859@www.outflux.net/ Cc: ellyjones@chromium.org Cc: Kay Sievers Cc: Roland Eggner Co-developed-by: Muhammad Usama Anjum Signed-off-by: Kees Cook Signed-off-by: Muhammad Usama Anjum Link: https://lore.kernel.org/r/YcMfDOyrg647RCmd@debian-BULLSEYE-live-builder-AMD64 Signed-off-by: Greg Kroah-Hartman

devtmpfs: actually reclaim some init memory

2021-03-23T13:57:35Z

Currently gcc seems to inline devtmpfs_setup() into devtmpfsd(), so its memory footprint isn't reclaimed as intended. Mark it noinline to make sure it gets put in .init.text. While here, setup_done can also be put in .init.data: After complete() releases the internal spinlock, the completion object is never touched again by that thread, and the waiting thread doesn't proceed until it observes ->done while holding that spinlock. This is now the same pattern as for kthreadd_done in init/main.c: complete() is done in a __ref function, while the corresponding wait_for_completion() is in an __init function. Reviewed-by: Christoph Hellwig Signed-off-by: Rasmus Villemoes Link: https://lore.kernel.org/r/20210312103027.2701413-2-linux@rasmusvillemoes.dk Signed-off-by: Greg Kroah-Hartman

devtmpfs: fix placement of complete() call

2021-03-23T13:57:35Z

Calling complete() from within the __init function is wrong - theoretically, the init process could proceed all the way to freeing the init mem before the devtmpfsd thread gets to execute the return instruction in devtmpfs_setup(). In practice, it seems to be harmless as gcc inlines devtmpfs_setup() into devtmpfsd(). So the calls of the __init functions init_chdir() etc. actually happen from devtmpfs_setup(), but the __ref on that one silences modpost (it's all right, because those calls happen before the complete()). But it does make the __init annotation of the setup function moot, which we'll fix in a subsequent patch. Fixes: bcbacc4909f1 ("devtmpfs: refactor devtmpfsd()") Reviewed-by: Christoph Hellwig Signed-off-by: Rasmus Villemoes Link: https://lore.kernel.org/r/20210312103027.2701413-1-linux@rasmusvillemoes.dk Signed-off-by: Greg Kroah-Hartman

namei: prepare for idmapped mounts

2021-01-24T13:27:18Z

The various vfs_*() helpers are called by filesystems or by the vfs itself to perform core operations such as create, link, mkdir, mknod, rename, rmdir, tmpfile and unlink. Enable them to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace and pass it down. Afterwards the checks and operations are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-15-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner

attr: handle idmapped mounts

2021-01-24T13:27:16Z

When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner