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* Merge tag 'fs.idmapped.v6.3' of ↵Linus Torvalds2023-02-201-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping Pull vfs idmapping updates from Christian Brauner: - Last cycle we introduced the dedicated struct mnt_idmap type for mount idmapping and the required infrastucture in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). As promised in last cycle's pull request message this converts everything to rely on struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevant on the mount level. Especially for non-vfs developers without detailed knowledge in this area this was a potential source for bugs. This finishes the conversion. Instead of passing the plain namespace around this updates all places that currently take a pointer to a mnt_userns with a pointer to struct mnt_idmap. Now that the conversion is done all helpers down to the really low-level helpers only accept a struct mnt_idmap argument instead of two namespace arguments. Conflating mount and other idmappings will now cause the compiler to complain loudly thus eliminating the possibility of any bugs. This makes it impossible for filesystem developers to mix up mount and filesystem idmappings as they are two distinct types and require distinct helpers that cannot be used interchangeably. Everything associated with struct mnt_idmap is moved into a single separate file. With that change no code can poke around in struct mnt_idmap. It can only be interacted with through dedicated helpers. That means all filesystems are and all of the vfs is completely oblivious to the actual implementation of idmappings. We are now also able to extend struct mnt_idmap as we see fit. For example, we can decouple it completely from namespaces for users that don't require or don't want to use them at all. We can also extend the concept of idmappings so we can cover filesystem specific requirements. In combination with the vfs{g,u}id_t work we finished in v6.2 this makes this feature substantially more robust and thus difficult to implement wrong by a given filesystem and also protects the vfs. - Enable idmapped mounts for tmpfs and fulfill a longstanding request. A long-standing request from users had been to make it possible to create idmapped mounts for tmpfs. For example, to share the host's tmpfs mount between multiple sandboxes. This is a prerequisite for some advanced Kubernetes cases. Systemd also has a range of use-cases to increase service isolation. And there are more users of this. However, with all of the other work going on this was way down on the priority list but luckily someone other than ourselves picked this up. As usual the patch is tiny as all the infrastructure work had been done multiple kernel releases ago. In addition to all the tests that we already have I requested that Rodrigo add a dedicated tmpfs testsuite for idmapped mounts to xfstests. It is to be included into xfstests during the v6.3 development cycle. This should add a slew of additional tests. * tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits) shmem: support idmapped mounts for tmpfs fs: move mnt_idmap fs: port vfs{g,u}id helpers to mnt_idmap fs: port fs{g,u}id helpers to mnt_idmap fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap fs: port i_{g,u}id_{needs_}update() to mnt_idmap quota: port to mnt_idmap fs: port privilege checking helpers to mnt_idmap fs: port inode_owner_or_capable() to mnt_idmap fs: port inode_init_owner() to mnt_idmap fs: port acl to mnt_idmap fs: port xattr to mnt_idmap fs: port ->permission() to pass mnt_idmap fs: port ->fileattr_set() to pass mnt_idmap fs: port ->set_acl() to pass mnt_idmap fs: port ->get_acl() to pass mnt_idmap fs: port ->tmpfile() to pass mnt_idmap fs: port ->rename() to pass mnt_idmap fs: port ->mknod() to pass mnt_idmap fs: port ->mkdir() to pass mnt_idmap ...
| * fs: port inode_owner_or_capable() to mnt_idmapChristian Brauner2023-01-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
* | filelock: move file locking definitions to separate header fileJeff Layton2023-01-111-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | The file locking definitions have lived in fs.h since the dawn of time, but they are only used by a small subset of the source files that include it. Move the file locking definitions to a new header file, and add the appropriate #include directives to the source files that need them. By doing this we trim down fs.h a bit and limit the amount of rebuilding that has to be done when we make changes to the file locking APIs. Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Howells <dhowells@redhat.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Acked-by: Chuck Lever <chuck.lever@oracle.com> Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Acked-by: Steve French <stfrench@microsoft.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Jeff Layton <jlayton@kernel.org>
* keep iocb_flags() result cached in struct fileAl Viro2022-06-101-0/+1
| | | | | | | | | | | | | * calculate at the time we set FMODE_OPENED (do_dentry_open() for normal opens, alloc_file() for pipe()/socket()/etc.) * update when handling F_SETFL * keep in a new field - file->f_iocb_flags; since that thing is needed only before the refcount reaches zero, we can put it into the same anon union where ->f_rcuhead and ->f_llist live - those are used only after refcount reaches zero. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: add FMODE_CAN_ODIRECT file flagNeilBrown2022-05-101-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently various places test if direct IO is possible on a file by checking for the existence of the direct_IO address space operation. This is a poor choice, as the direct_IO operation may not be used - it is only used if the generic_file_*_iter functions are called for direct IO and some filesystems - particularly NFS - don't do this. Instead, introduce a new f_mode flag: FMODE_CAN_ODIRECT and change the various places to check this (avoiding pointer dereferences). do_dentry_open() will set this flag if ->direct_IO is present, so filesystems do not need to be changed. NFS *is* changed, to set the flag explicitly and discard the direct_IO entry in the address_space_operations for files. Other filesystems which currently use noop_direct_IO could usefully be changed to set this flag instead. Link: https://lkml.kernel.org/r/164859778128.29473.15189737957277399416.stgit@noble.brown Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: NeilBrown <neilb@suse.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* fs: remove fs.f_write_hintChristoph Hellwig2022-03-091-18/+0
| | | | | | | | | | | | | | | | The value is now completely unused except for reporting it back through the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls for it. Trying to use the F_SET_FILE_RW_HINT and F_GET_FILE_RW_HINT fcntls will now return EINVAL, just like it would on a kernel that never supported this functionality in the first place. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220308060529.736277-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2021-09-031-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge misc updates from Andrew Morton: "173 patches. Subsystems affected by this series: ia64, ocfs2, block, and mm (debug, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock, oom-kill, migration, ksm, percpu, vmstat, and madvise)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits) mm/madvise: add MADV_WILLNEED to process_madvise() mm/vmstat: remove unneeded return value mm/vmstat: simplify the array size calculation mm/vmstat: correct some wrong comments mm/percpu,c: remove obsolete comments of pcpu_chunk_populated() selftests: vm: add COW time test for KSM pages selftests: vm: add KSM merging time test mm: KSM: fix data type selftests: vm: add KSM merging across nodes test selftests: vm: add KSM zero page merging test selftests: vm: add KSM unmerge test selftests: vm: add KSM merge test mm/migrate: correct kernel-doc notation mm: wire up syscall process_mrelease mm: introduce process_mrelease system call memblock: make memblock_find_in_range method private mm/mempolicy.c: use in_task() in mempolicy_slab_node() mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies mm/mempolicy: advertise new MPOL_PREFERRED_MANY mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY ...
| * memcg: enable accounting for fasync_cacheVasily Averin2021-09-031-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fasync_struct is used by almost all character device drivers to set up the fasync queue, and for regular files by the file lease code. This structure is quite small but long-living and it can be assigned for any open file. It makes sense to account for its allocations to restrict the host's memory consumption from inside the memcg-limited container. Link: https://lkml.kernel.org/r/1b408625-d71c-0b26-b0b6-9baf00f93e69@virtuozzo.com Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrei Vagin <avagin@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Roman Gushchin <guro@fb.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Yutian Yang <nglaive@gmail.com> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | fcntl: fix potential deadlock for &fasync_struct.fa_lockDesmond Cheong Zhi Xi2021-08-211-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is an existing lock hierarchy of &dev->event_lock --> &fasync_struct.fa_lock --> &f->f_owner.lock from the following call chain: input_inject_event(): spin_lock_irqsave(&dev->event_lock,...); input_handle_event(): input_pass_values(): input_to_handler(): evdev_events(): evdev_pass_values(): spin_lock(&client->buffer_lock); __pass_event(): kill_fasync(): kill_fasync_rcu(): read_lock(&fa->fa_lock); send_sigio(): read_lock_irqsave(&fown->lock,...); &dev->event_lock is HARDIRQ-safe, so interrupts have to be disabled while grabbing &fasync_struct.fa_lock, otherwise we invert the lock hierarchy. However, since kill_fasync which calls kill_fasync_rcu is an exported symbol, it may not necessarily be called with interrupts disabled. As kill_fasync_rcu may be called with interrupts disabled (for example, in the call chain above), we replace calls to read_lock/read_unlock on &fasync_struct.fa_lock in kill_fasync_rcu with read_lock_irqsave/read_unlock_irqrestore. Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> Signed-off-by: Jeff Layton <jlayton@kernel.org>
* | fcntl: fix potential deadlocks for &fown_struct.lockDesmond Cheong Zhi Xi2021-08-211-6/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Syzbot reports a potential deadlock in do_fcntl: ======================================================== WARNING: possible irq lock inversion dependency detected 5.12.0-syzkaller #0 Not tainted -------------------------------------------------------- syz-executor132/8391 just changed the state of lock: ffff888015967bf8 (&f->f_owner.lock){.+..}-{2:2}, at: f_getown_ex fs/fcntl.c:211 [inline] ffff888015967bf8 (&f->f_owner.lock){.+..}-{2:2}, at: do_fcntl+0x8b4/0x1200 fs/fcntl.c:395 but this lock was taken by another, HARDIRQ-safe lock in the past: (&dev->event_lock){-...}-{2:2} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Chain exists of: &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&f->f_owner.lock); local_irq_disable(); lock(&dev->event_lock); lock(&new->fa_lock); <Interrupt> lock(&dev->event_lock); *** DEADLOCK *** This happens because there is a lock hierarchy of &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock from the following call chain: input_inject_event(): spin_lock_irqsave(&dev->event_lock,...); input_handle_event(): input_pass_values(): input_to_handler(): evdev_events(): evdev_pass_values(): spin_lock(&client->buffer_lock); __pass_event(): kill_fasync(): kill_fasync_rcu(): read_lock(&fa->fa_lock); send_sigio(): read_lock_irqsave(&fown->lock,...); However, since &dev->event_lock is HARDIRQ-safe, interrupts have to be disabled while grabbing &f->f_owner.lock, otherwise we invert the lock hierarchy. Hence, we replace calls to read_lock/read_unlock on &f->f_owner.lock, with read_lock_irq/read_unlock_irq. Reported-and-tested-by: syzbot+e6d5398a02c516ce5e70@syzkaller.appspotmail.com Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> Signed-off-by: Jeff Layton <jlayton@kernel.org>
* fcntl: Fix unreachable code in do_fcntl()Gustavo A. R. Silva2021-07-121-1/+1
| | | | | | | | | | | | | | | Fix the following warning: fs/fcntl.c:373:3: warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough] fallthrough; ^ include/linux/compiler_attributes.h:210:41: note: expanded from macro 'fallthrough' # define fallthrough __attribute__((__fallthrough__)) by placing the fallthrough; statement inside ifdeffery. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* Merge tag 'idmapped-mounts-v5.12' of ↵Linus Torvalds2021-02-231-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull idmapped mounts from Christian Brauner: "This introduces idmapped mounts which has been in the making for some time. Simply put, different mounts can expose the same file or directory with different ownership. This initial implementation comes with ports for fat, ext4 and with Christoph's port for xfs with more filesystems being actively worked on by independent people and maintainers. Idmapping mounts handle a wide range of long standing use-cases. Here are just a few: - Idmapped mounts make it possible to easily share files between multiple users or multiple machines especially in complex scenarios. For example, idmapped mounts will be used in the implementation of portable home directories in systemd-homed.service(8) where they allow users to move their home directory to an external storage device and use it on multiple computers where they are assigned different uids and gids. This effectively makes it possible to assign random uids and gids at login time. - It is possible to share files from the host with unprivileged containers without having to change ownership permanently through chown(2). - It is possible to idmap a container's rootfs and without having to mangle every file. For example, Chromebooks use it to share the user's Download folder with their unprivileged containers in their Linux subsystem. - It is possible to share files between containers with non-overlapping idmappings. - Filesystem that lack a proper concept of ownership such as fat can use idmapped mounts to implement discretionary access (DAC) permission checking. - They allow users to efficiently changing ownership on a per-mount basis without having to (recursively) chown(2) all files. In contrast to chown (2) changing ownership of large sets of files is instantenous with idmapped mounts. This is especially useful when ownership of a whole root filesystem of a virtual machine or container is changed. With idmapped mounts a single syscall mount_setattr syscall will be sufficient to change the ownership of all files. - Idmapped mounts always take the current ownership into account as idmappings specify what a given uid or gid is supposed to be mapped to. This contrasts with the chown(2) syscall which cannot by itself take the current ownership of the files it changes into account. It simply changes the ownership to the specified uid and gid. This is especially problematic when recursively chown(2)ing a large set of files which is commong with the aforementioned portable home directory and container and vm scenario. - Idmapped mounts allow to change ownership locally, restricting it to specific mounts, and temporarily as the ownership changes only apply as long as the mount exists. Several userspace projects have either already put up patches and pull-requests for this feature or will do so should you decide to pull this: - systemd: In a wide variety of scenarios but especially right away in their implementation of portable home directories. https://systemd.io/HOME_DIRECTORY/ - container runtimes: containerd, runC, LXD:To share data between host and unprivileged containers, unprivileged and privileged containers, etc. The pull request for idmapped mounts support in containerd, the default Kubernetes runtime is already up for quite a while now: https://github.com/containerd/containerd/pull/4734 - The virtio-fs developers and several users have expressed interest in using this feature with virtual machines once virtio-fs is ported. - ChromeOS: Sharing host-directories with unprivileged containers. I've tightly synced with all those projects and all of those listed here have also expressed their need/desire for this feature on the mailing list. For more info on how people use this there's a bunch of talks about this too. Here's just two recent ones: https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf https://fosdem.org/2021/schedule/event/containers_idmap/ This comes with an extensive xfstests suite covering both ext4 and xfs: https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts It covers truncation, creation, opening, xattrs, vfscaps, setid execution, setgid inheritance and more both with idmapped and non-idmapped mounts. It already helped to discover an unrelated xfs setgid inheritance bug which has since been fixed in mainline. It will be sent for inclusion with the xfstests project should you decide to merge this. In order to support per-mount idmappings vfsmounts are marked with user namespaces. The idmapping of the user namespace will be used to map the ids of vfs objects when they are accessed through that mount. By default all vfsmounts are marked with the initial user namespace. The initial user namespace is used to indicate that a mount is not idmapped. All operations behave as before and this is verified in the testsuite. Based on prior discussions we want to attach the whole user namespace and not just a dedicated idmapping struct. This allows us to reuse all the helpers that already exist for dealing with idmappings instead of introducing a whole new range of helpers. In addition, if we decide in the future that we are confident enough to enable unprivileged users to setup idmapped mounts the permission checking can take into account whether the caller is privileged in the user namespace the mount is currently marked with. The user namespace the mount will be marked with can be specified by passing a file descriptor refering to the user namespace as an argument to the new mount_setattr() syscall together with the new MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern of extensibility. The following conditions must be met in order to create an idmapped mount: - The caller must currently have the CAP_SYS_ADMIN capability in the user namespace the underlying filesystem has been mounted in. - The underlying filesystem must support idmapped mounts. - The mount must not already be idmapped. This also implies that the idmapping of a mount cannot be altered once it has been idmapped. - The mount must be a detached/anonymous mount, i.e. it must have been created by calling open_tree() with the OPEN_TREE_CLONE flag and it must not already have been visible in the filesystem. The last two points guarantee easier semantics for userspace and the kernel and make the implementation significantly simpler. By default vfsmounts are marked with the initial user namespace and no behavioral or performance changes are observed. The manpage with a detailed description can be found here: https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8 In order to support idmapped mounts, filesystems need to be changed and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The patches to convert individual filesystem are not very large or complicated overall as can be seen from the included fat, ext4, and xfs ports. Patches for other filesystems are actively worked on and will be sent out separately. The xfstestsuite can be used to verify that port has been done correctly. The mount_setattr() syscall is motivated independent of the idmapped mounts patches and it's been around since July 2019. One of the most valuable features of the new mount api is the ability to perform mounts based on file descriptors only. Together with the lookup restrictions available in the openat2() RESOLVE_* flag namespace which we added in v5.6 this is the first time we are close to hardened and race-free (e.g. symlinks) mounting and path resolution. While userspace has started porting to the new mount api to mount proper filesystems and create new bind-mounts it is currently not possible to change mount options of an already existing bind mount in the new mount api since the mount_setattr() syscall is missing. With the addition of the mount_setattr() syscall we remove this last restriction and userspace can now fully port to the new mount api, covering every use-case the old mount api could. We also add the crucial ability to recursively change mount options for a whole mount tree, both removing and adding mount options at the same time. This syscall has been requested multiple times by various people and projects. There is a simple tool available at https://github.com/brauner/mount-idmapped that allows to create idmapped mounts so people can play with this patch series. I'll add support for the regular mount binary should you decide to pull this in the following weeks: Here's an example to a simple idmapped mount of another user's home directory: u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt u1001@f2-vm:/$ ls -al /home/ubuntu/ total 28 drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 . drwxr-xr-x 4 root root 4096 Oct 28 04:00 .. -rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile -rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ ls -al /mnt/ total 28 drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 . drwxr-xr-x 29 root root 4096 Oct 28 22:01 .. -rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile -rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ touch /mnt/my-file u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file u1001@f2-vm:/$ ls -al /mnt/my-file -rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file u1001@f2-vm:/$ ls -al /home/ubuntu/my-file -rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file u1001@f2-vm:/$ getfacl /mnt/my-file getfacl: Removing leading '/' from absolute path names # file: mnt/my-file # owner: u1001 # group: u1001 user::rw- user:u1001:rwx group::rw- mask::rwx other::r-- u1001@f2-vm:/$ getfacl /home/ubuntu/my-file getfacl: Removing leading '/' from absolute path names # file: home/ubuntu/my-file # owner: ubuntu # group: ubuntu user::rw- user:ubuntu:rwx group::rw- mask::rwx other::r--" * tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits) xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl xfs: support idmapped mounts ext4: support idmapped mounts fat: handle idmapped mounts tests: add mount_setattr() selftests fs: introduce MOUNT_ATTR_IDMAP fs: add mount_setattr() fs: add attr_flags_to_mnt_flags helper fs: split out functions to hold writers namespace: only take read lock in do_reconfigure_mnt() mount: make {lock,unlock}_mount_hash() static namespace: take lock_mount_hash() directly when changing flags nfs: do not export idmapped mounts overlayfs: do not mount on top of idmapped mounts ecryptfs: do not mount on top of idmapped mounts ima: handle idmapped mounts apparmor: handle idmapped mounts fs: make helpers idmap mount aware exec: handle idmapped mounts would_dump: handle idmapped mounts ...
| * fcntl: handle idmapped mountsChristian Brauner2021-01-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable the setfl() helper to handle idmapped mounts by passing down the mount's user namespace. 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/20210121131959.646623-20-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
| * inode: make init and permission helpers idmapped mount awareChristian Brauner2021-01-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The inode_owner_or_capable() helper determines whether the caller is the owner of the inode or is capable with respect to that inode. Allow it to handle idmapped mounts. If the inode is accessed through an idmapped mount it according to 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. Similarly, allow the inode_init_owner() helper to handle idmapped mounts. It initializes a new inode on idmapped mounts by mapping the fsuid and fsgid of the caller from the mount's user namespace. 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/20210121131959.646623-7-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
* | fcntl: make F_GETOWN(EX) return 0 on dead owner taskPavel Tikhomirov2021-02-081-6/+13
|/ | | | | | | | | | | | | | | | | | | | | | | Currently there is no way to differentiate the file with alive owner from the file with dead owner but pid of the owner reused. That's why CRIU can't actually know if it needs to restore file owner or not, because if it restores owner but actual owner was dead, this can introduce unexpected signals to the "false"-owner (which reused the pid). Let's change the api, so that F_GETOWN(EX) returns 0 in case actual owner is dead already. This comports with the POSIX spec, which states that a PID of 0 indicates that no signal will be sent. Cc: Jeff Layton <jlayton@kernel.org> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Andrei Vagin <avagin@gmail.com> Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Signed-off-by: Jeff Layton <jlayton@kernel.org>
* fcntl: Fix potential deadlock in send_sig{io, urg}()Boqun Feng2020-11-051-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Syzbot reports a potential deadlock found by the newly added recursive read deadlock detection in lockdep: [...] ======================================================== [...] WARNING: possible irq lock inversion dependency detected [...] 5.9.0-rc2-syzkaller #0 Not tainted [...] -------------------------------------------------------- [...] syz-executor.1/10214 just changed the state of lock: [...] ffff88811f506338 (&f->f_owner.lock){.+..}-{2:2}, at: send_sigurg+0x1d/0x200 [...] but this lock was taken by another, HARDIRQ-safe lock in the past: [...] (&dev->event_lock){-...}-{2:2} [...] [...] [...] and interrupts could create inverse lock ordering between them. [...] [...] [...] other info that might help us debug this: [...] Chain exists of: [...] &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock [...] [...] Possible interrupt unsafe locking scenario: [...] [...] CPU0 CPU1 [...] ---- ---- [...] lock(&f->f_owner.lock); [...] local_irq_disable(); [...] lock(&dev->event_lock); [...] lock(&new->fa_lock); [...] <Interrupt> [...] lock(&dev->event_lock); [...] [...] *** DEADLOCK *** The corresponding deadlock case is as followed: CPU 0 CPU 1 CPU 2 read_lock(&fown->lock); spin_lock_irqsave(&dev->event_lock, ...) write_lock_irq(&filp->f_owner.lock); // wait for the lock read_lock(&fown-lock); // have to wait until the writer release // due to the fairness <interrupted> spin_lock_irqsave(&dev->event_lock); // wait for the lock The lock dependency on CPU 1 happens if there exists a call sequence: input_inject_event(): spin_lock_irqsave(&dev->event_lock,...); input_handle_event(): input_pass_values(): input_to_handler(): handler->event(): // evdev_event() evdev_pass_values(): spin_lock(&client->buffer_lock); __pass_event(): kill_fasync(): kill_fasync_rcu(): read_lock(&fa->fa_lock); send_sigio(): read_lock(&fown->lock); To fix this, make the reader in send_sigurg() and send_sigio() use read_lock_irqsave() and read_lock_irqrestore(). Reported-by: syzbot+22e87cdf94021b984aa6@syzkaller.appspotmail.com Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Jeff Layton <jlayton@kernel.org>
* treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva2020-08-241-2/+2
| | | | | | | | | | Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* fcntl: Distribute switch variables for initializationKees Cook2020-03-031-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Variables declared in a switch statement before any case statements cannot be automatically initialized with compiler instrumentation (as they are not part of any execution flow). With GCC's proposed automatic stack variable initialization feature, this triggers a warning (and they don't get initialized). Clang's automatic stack variable initialization (via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also doesn't initialize such variables[1]. Note that these warnings (or silent skipping) happen before the dead-store elimination optimization phase, so even when the automatic initializations are later elided in favor of direct initializations, the warnings remain. To avoid these problems, move such variables into the "case" where they're used or lift them up into the main function body. fs/fcntl.c: In function ‘send_sigio_to_task’: fs/fcntl.c:738:20: warning: statement will never be executed [-Wswitch-unreachable] 738 | kernel_siginfo_t si; | ^~ [1] https://bugs.llvm.org/show_bug.cgi?id=44916 Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jeff Layton <jlayton@kernel.org>
* Merge branch 'work.misc' of ↵Linus Torvalds2019-12-081-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs cleanups from Al Viro: "No common topic, just three cleanups". * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: make __d_alloc() static fs/namespace: add __user to open_tree and move_mount syscalls fs/fnctl: fix missing __user in fcntl_rw_hint()
| * fs/fnctl: fix missing __user in fcntl_rw_hint()Ben Dooks2019-10-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The fcntl_rw_hint() has a missing __user annotation in the code when assinging argp. Add this to fix the following sparse warnings: fs/fcntl.c:280:22: warning: incorrect type in initializer (different address spaces) fs/fcntl.c:280:22: expected unsigned long long [usertype] *argp fs/fcntl.c:280:22: got unsigned long long [noderef] [usertype] <asn:1> * fs/fcntl.c:287:34: warning: incorrect type in argument 1 (different address spaces) fs/fcntl.c:287:34: expected void [noderef] <asn:1> *to fs/fcntl.c:287:34: got unsigned long long [usertype] *argp fs/fcntl.c:291:40: warning: incorrect type in argument 2 (different address spaces) fs/fcntl.c:291:40: expected void const [noderef] <asn:1> *from fs/fcntl.c:291:40: got unsigned long long [usertype] *argp fs/fcntl.c:303:34: warning: incorrect type in argument 1 (different address spaces) fs/fcntl.c:303:34: expected void [noderef] <asn:1> *to fs/fcntl.c:303:34: got unsigned long long [usertype] *argp fs/fcntl.c:307:40: warning: incorrect type in argument 2 (different address spaces) fs/fcntl.c:307:40: expected void const [noderef] <asn:1> *from fs/fcntl.c:307:40: got unsigned long long [usertype] *argp Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fcntl: fix typo in RWH_WRITE_LIFE_NOT_SET r/w hint nameEugene Syromiatnikov2019-10-251-1/+1
|/ | | | | | | | | | | | | | | | | | | According to commit message in the original commit c75b1d9421f8 ("fs: add fcntl() interface for setting/getting write life time hints"), as well as userspace library[1] and man page update[2], R/W hint constants are intended to have RWH_* prefix. However, RWF_WRITE_LIFE_NOT_SET retained "RWF_*" prefix used in the early versions of the proposed patch set[3]. Rename it and provide the old name as a synonym for the new one for backward compatibility. [1] https://github.com/axboe/fio/commit/bd553af6c849 [2] https://github.com/mkerrisk/man-pages/commit/580082a186fd [3] https://www.mail-archive.com/linux-block@vger.kernel.org/msg09638.html Fixes: c75b1d9421f8 ("fs: add fcntl() interface for setting/getting write life time hints") Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* fs: mark expected switch fall-throughsGustavo A. R. Silva2019-04-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. This patch fixes the following warnings: fs/affs/affs.h:124:38: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/configfs/dir.c:1692:11: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/configfs/dir.c:1694:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ceph/file.c:249:3: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext4/hash.c:233:15: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext4/hash.c:246:15: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext2/inode.c:1237:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext2/inode.c:1244:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext4/indirect.c:1182:6: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext4/indirect.c:1188:6: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext4/indirect.c:1432:6: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ext4/indirect.c:1440:6: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/f2fs/node.c:618:8: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/f2fs/node.c:620:8: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/btrfs/ref-verify.c:522:15: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/gfs2/bmap.c:711:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/gfs2/bmap.c:722:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/jffs2/fs.c:339:6: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/nfsd/nfs4proc.c:429:12: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ufs/util.h:62:6: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/ufs/util.h:43:6: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/fcntl.c:770:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/seq_file.c:319:10: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/libfs.c:148:11: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/libfs.c:150:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/signalfd.c:178:7: warning: this statement may fall through [-Wimplicit-fallthrough=] fs/locks.c:1473:16: warning: this statement may fall through [-Wimplicit-fallthrough=] Warning level 3 was used: -Wimplicit-fallthrough=3 This patch is part of the ongoing efforts to enabling -Wimplicit-fallthrough. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
* signal: Distinguish between kernel_siginfo and siginfoEric W. Biederman2018-10-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Linus recently observed that if we did not worry about the padding member in struct siginfo it is only about 48 bytes, and 48 bytes is much nicer than 128 bytes for allocating on the stack and copying around in the kernel. The obvious thing of only adding the padding when userspace is including siginfo.h won't work as there are sigframe definitions in the kernel that embed struct siginfo. So split siginfo in two; kernel_siginfo and siginfo. Keeping the traditional name for the userspace definition. While the version that is used internally to the kernel and ultimately will not be padded to 128 bytes is called kernel_siginfo. The definition of struct kernel_siginfo I have put in include/signal_types.h A set of buildtime checks has been added to verify the two structures have the same field offsets. To make it easy to verify the change kernel_siginfo retains the same size as siginfo. The reduction in size comes in a following change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Don't send signals to tasks that don't existEric W. Biederman2018-08-161-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | Recently syzbot reported crashes in send_sigio_to_task and send_sigurg_to_task in linux-next. Despite finding a reproducer syzbot apparently did not bisected this or otherwise track down the offending commit in linux-next. I happened to see this report and examined the code because I had recently changed these functions as part of making PIDTYPE_TGID a real pid type so that fork would does not need to restart when receiving a signal. By examination I see that I spotted a bug in the code that could explain the reported crashes. When I took Oleg's suggestion and optimized send_sigurg and send_sigio to only send to a single task when type is PIDTYPE_PID or PIDTYPE_TGID I failed to handle pids that no longer point to tasks. The macro do_each_pid_task simply iterates for zero iterations. With pid_task an explicit NULL test is needed. Update the code to include the missing NULL test. Fixes: 019191342fec ("signal: Use PIDTYPE_TGID to clearly store where file signals will be sent") Reported-by: syzkaller-bugs@googlegroups.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Pass pid type into do_send_sig_infoEric W. Biederman2018-07-211-3/+3
| | | | | | | | This passes the information we already have at the call sight into do_send_sig_info. Ultimately allowing for better handling of signals sent to a group of processes during fork. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Pass pid type into send_sigio_to_task & send_sigurg_to_taskEric W. Biederman2018-07-211-17/+9
| | | | | | | This information is already present and using it directly simplifies the logic of the code. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Use PIDTYPE_TGID to clearly store where file signals will be sentEric W. Biederman2018-07-211-22/+32
| | | | | | | | | | | | | | | | | | | | | When f_setown is called a pid and a pid type are stored. Replace the use of PIDTYPE_PID with PIDTYPE_TGID as PIDTYPE_TGID goes to the entire thread group. Replace the use of PIDTYPE_MAX with PIDTYPE_PID as PIDTYPE_PID now is only for a thread. Update the users of __f_setown to use PIDTYPE_TGID instead of PIDTYPE_PID. For now the code continues to capture task_pid (when task_tgid would really be appropriate), and iterate on PIDTYPE_PID (even when type == PIDTYPE_TGID) out of an abundance of caution to preserve existing behavior. Oleg Nesterov suggested using the test to ensure we use PIDTYPE_PID for tgid lookup also be used to avoid taking the tasklist lock. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* mm: restructure memfd codeMike Kravetz2018-06-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the addition of memfd hugetlbfs support, we now have the situation where memfd depends on TMPFS -or- HUGETLBFS. Previously, memfd was only supported on tmpfs, so it made sense that the code resided in shmem.c. In the current code, memfd is only functional if TMPFS is defined. If HUGETLFS is defined and TMPFS is not defined, then memfd functionality will not be available for hugetlbfs. This does not cause BUGs, just a lack of potentially desired functionality. Code is restructured in the following way: - include/linux/memfd.h is a new file containing memfd specific definitions previously contained in shmem_fs.h. - mm/memfd.c is a new file containing memfd specific code previously contained in shmem.c. - memfd specific code is removed from shmem_fs.h and shmem.c. - A new config option MEMFD_CREATE is added that is defined if TMPFS or HUGETLBFS is defined. No functional changes are made to the code: restructuring only. Link: http://lkml.kernel.org/r/20180415182119.4517-4-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Marc-Andr Lureau <marcandre.lureau@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fasync: Fix deadlock between task-context and interrupt-context kill_fasync()Kirill Tkhai2018-05-011-8/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I observed the following deadlock between them: [task 1] [task 2] [task 3] kill_fasync() mm_update_next_owner() copy_process() spin_lock_irqsave(&fa->fa_lock) read_lock(&tasklist_lock) write_lock_irq(&tasklist_lock) send_sigio() <IRQ> ... read_lock(&fown->lock) kill_fasync() ... read_lock(&tasklist_lock) spin_lock_irqsave(&fa->fa_lock) ... Task 1 can't acquire read locked tasklist_lock, since there is already task 3 expressed its wish to take the lock exclusive. Task 2 holds the read locked lock, but it can't take the spin lock. Also, there is possible another deadlock (which I haven't observed): [task 1] [task 2] f_getown() kill_fasync() read_lock(&f_own->lock) spin_lock_irqsave(&fa->fa_lock,) <IRQ> send_sigio() write_lock_irq(&f_own->lock) kill_fasync() read_lock(&fown->lock) spin_lock_irqsave(&fa->fa_lock,) Actually, we do not need exclusive fa->fa_lock in kill_fasync_rcu(), as it guarantees fa->fa_file->f_owner integrity only. It may seem, that it used to give a task a small possibility to receive two sequential signals, if there are two parallel kill_fasync() callers, and task handles the first signal fastly, but the behaviour won't become different, since there is exclusive sighand lock in do_send_sig_info(). The patch converts fa_lock into rwlock_t, and this fixes two above deadlocks, as rwlock is allowed to be taken from interrupt handler by qrwlock design. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Jeff Layton <jlayton@redhat.com>
* fs: add do_compat_fcntl64() helper; remove in-kernel call to compat syscallDominik Brodowski2018-04-021-3/+9
| | | | | | | | | | | | | Using the fs-internal do_compat_fcntl64() helper allows us to get rid of the fs-internal call to the compat_sys_fcntl64() syscall. This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* vfs: do bulk POLL* -> EPOLL* replacementLinus Torvalds2018-02-111-6/+6
| | | | | | | | | | | | | | | | | | | | | | | This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.poll2' of ↵Linus Torvalds2018-02-111-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more poll annotation updates from Al Viro: "This is preparation to solving the problems you've mentioned in the original poll series. After this series, the kernel is ready for running for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done as a for bulk search-and-replace. After that, the kernel is ready to apply the patch to unify {de,}mangle_poll(), and then get rid of kernel-side POLL... uses entirely, and we should be all done with that stuff. Basically, that's what you suggested wrt KPOLL..., except that we can use EPOLL... instead - they already are arch-independent (and equal to what is currently kernel-side POLL...). After the preparations (in this series) switch to returning EPOLL... from ->poll() instances is completely mechanical and kernel-side POLL... can go away. The last step (killing kernel-side POLL... and unifying {de,}mangle_poll() has to be done after the search-and-replace job, since we need userland-side POLL... for unified {de,}mangle_poll(), thus the cherry-pick at the last step. After that we will have: - POLL{IN,OUT,...} *not* in __poll_t, so any stray instances of ->poll() still using those will be caught by sparse. - eventpoll.c and select.c warning-free wrt __poll_t - no more kernel-side definitions of POLL... - userland ones are visible through the entire kernel (and used pretty much only for mangle/demangle) - same behavior as after the first series (i.e. sparc et.al. epoll(2) working correctly)" * 'work.poll2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: annotate ep_scan_ready_list() ep_send_events_proc(): return result via esed->res preparation to switching ->poll() to returning EPOLL... add EPOLLNVAL, annotate EPOLL... and event_poll->event use linux/poll.h instead of asm/poll.h xen: fix poll misannotation smc: missing poll annotations
| * use linux/poll.h instead of asm/poll.hAl Viro2018-02-011-1/+1
| | | | | | | | | | | | | | | | | | The only place that has any business including asm/poll.h is linux/poll.h. Fortunately, asm/poll.h had only been included in 3 places beyond that one, and all of them are trivial to switch to using linux/poll.h. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | shmem: rename functions that are memfd-relatedMarc-André Lureau2018-02-011-1/+1
|/ | | | | | | | | | | | | | | Those functions are called for memfd files, backed by shmem or hugetlb (the next patches will handle hugetlb). Link: http://lkml.kernel.org/r/20171107122800.25517-3-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'misc.poll' of ↵Linus Torvalds2018-01-311-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull poll annotations from Al Viro: "This introduces a __bitwise type for POLL### bitmap, and propagates the annotations through the tree. Most of that stuff is as simple as 'make ->poll() instances return __poll_t and do the same to local variables used to hold the future return value'. Some of the obvious brainos found in process are fixed (e.g. POLLIN misspelled as POLL_IN). At that point the amount of sparse warnings is low and most of them are for genuine bugs - e.g. ->poll() instance deciding to return -EINVAL instead of a bitmap. I hadn't touched those in this series - it's large enough as it is. Another problem it has caught was eventpoll() ABI mess; select.c and eventpoll.c assumed that corresponding POLL### and EPOLL### were equal. That's true for some, but not all of them - EPOLL### are arch-independent, but POLL### are not. The last commit in this series separates userland POLL### values from the (now arch-independent) kernel-side ones, converting between them in the few places where they are copied to/from userland. AFAICS, this is the least disruptive fix preserving poll(2) ABI and making epoll() work on all architectures. As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and it will trigger only on what would've triggered EPOLLWRBAND on other architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered at all on sparc. With this patch they should work consistently on all architectures" * 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits) make kernel-side POLL... arch-independent eventpoll: no need to mask the result of epi_item_poll() again eventpoll: constify struct epoll_event pointers debugging printk in sg_poll() uses %x to print POLL... bitmap annotate poll(2) guts 9p: untangle ->poll() mess ->si_band gets POLL... bitmap stored into a user-visible long field ring_buffer_poll_wait() return value used as return value of ->poll() the rest of drivers/*: annotate ->poll() instances media: annotate ->poll() instances fs: annotate ->poll() instances ipc, kernel, mm: annotate ->poll() instances net: annotate ->poll() instances apparmor: annotate ->poll() instances tomoyo: annotate ->poll() instances sound: annotate ->poll() instances acpi: annotate ->poll() instances crypto: annotate ->poll() instances block: annotate ->poll() instances x86: annotate ->poll() instances ...
| * make kernel-side POLL... arch-independentAl Viro2017-11-301-1/+1
| | | | | | | | | | | | mangle/demangle on the way to/from userland Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * ->si_band gets POLL... bitmap stored into a user-visible long fieldAl Viro2017-11-281-2/+2
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | signal: Ensure generic siginfos the kernel sends have all bits initializedEric W. Biederman2018-01-121-0/+1
|/ | | | | | | | | | | | | | | | | Call clear_siginfo to ensure stack allocated siginfos are fully initialized before being passed to the signal sending functions. This ensures that if there is the kind of confusion documented by TRAP_FIXME, FPE_FIXME, or BUS_FIXME the kernel won't send unitialized data to userspace when the kernel generates a signal with SI_USER but the copy to userspace assumes it is a different kind of signal, and different fields are initialized. This also prepares the way for turning copy_siginfo_to_user into a copy_to_user, by removing the need in many cases to perform a field by field copy simply to skip the uninitialized fields. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* fcntl: don't cap l_start and l_end values for F_GETLK64 in compat syscallJeff Layton2017-11-151-6/+5
| | | | | | | | | | | | | | | | Currently, we're capping the values too low in the F_GETLK64 case. The fields in that structure are 64-bit values, so we shouldn't need to do any sort of fixup there. Make sure we check that assumption at build time in the future however by ensuring that the sizes we're copying will fit. With this, we no longer need COMPAT_LOFF_T_MAX either, so remove it. Fixes: 94073ad77fff2 (fs/locks: don't mess with the address limit in compat_fcntl64) Reported-by: Vitaly Lipatov <lav@etersoft.ru> Signed-off-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: David Howells <dhowells@redhat.com>
* fcntl: don't leak fd reference when fixup_compat_flock failsJeff Layton2017-11-151-3/+2
| | | | | | | | Currently we just return err here, but we need to put the fd reference first. Fixes: 94073ad77fff (fs/locks: don't mess with the address limit in compat_fcntl64) Signed-off-by: Jeff Layton <jlayton@redhat.com>
* Merge branch 'linus' into locking/core, to resolve conflictsIngo Molnar2017-11-071-0/+1
|\ | | | | | | | | | | | | | | | | | | Conflicts: include/linux/compiler-clang.h include/linux/compiler-gcc.h include/linux/compiler-intel.h include/uapi/linux/stddef.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns ↵Mark Rutland2017-10-251-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* fcntl: Don't set si_code to SI_SIGIO when sig == SIGPOLLEric W. Biederman2017-09-191-1/+1
| | | | | | | | | | | When fixing things to avoid ambiguous cases I had a thinko and included SIGPOLL/SIGIO in with all of the other signals that have signal specific si_codes. Which is completely wrong. Fix that. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* fcntl: Don't use ambiguous SIG_POLL si_codesEric W. Biederman2017-07-241-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a weird and problematic intersection of features that when they all come together result in ambiguous siginfo values, that we can not support properly. - Supporting fcntl(F_SETSIG,...) with arbitrary valid signals. - Using positive values for POLL_IN, POLL_OUT, POLL_MSG, ..., etc that imply they are signal specific si_codes and using the aforementioned arbitrary signal to deliver them. - Supporting injection of arbitrary siginfo values for debugging and checkpoint/restore. The result is that just looking at siginfo si_codes of 1 to 6 are ambigious. It could either be a signal specific si_code or it could be a generic si_code. For most of the kernel this is a non-issue but for sending signals with siginfo it is impossible to play back the kernel signals and get the same result. Strictly speaking when the si_code was changed from SI_SIGIO to POLL_IN and friends between 2.2 and 2.4 this functionality was not ambiguous, as only real time signals were supported. Before 2.4 was released the kernel began supporting siginfo with non realtime signals so they could give details of why the signal was sent. The result is that if F_SETSIG is set to one of the signals with signal specific si_codes then user space can not know why the signal was sent. I grepped through a bunch of userspace programs using debian code search to get a feel for how often people choose a signal that results in an ambiguous si_code. I only found one program doing so and it was using SIGCHLD to test the F_SETSIG functionality, and did not appear to be a real world usage. Therefore the ambiguity does not appears to be a real world problem in practice. Remove the ambiguity while introducing the smallest chance of breakage by changing the si_code to SI_SIGIO when signals with signal specific si_codes are targeted. Fixes: v2.3.40 -- Added support for queueing non-rt signals Fixes: v2.3.21 -- Changed the si_code from SI_SIGIO Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* vfs: fix flock compat thinkoLinus Torvalds2017-07-071-15/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | Michael Ellerman reported that commit 8c6657cb50cb ("Switch flock copyin/copyout primitives to copy_{from,to}_user()") broke his networking on a bunch of PPC machines (64-bit kernel, 32-bit userspace). The reason is a brown-paper bug by that commit, which had the arguments to "copy_flock_fields()" in the wrong order, breaking the compat handling for file locking. Apparently very few people run 32-bit user space on x86 any more, so the PPC people got the honor of noticing this "feature". Michael also sent a minimal diff that just changed the order of the arguments in that macro. This is not that minimal diff. This not only changes the order of the arguments in the macro, it also changes them to be pointers (to be consistent with all the other uses of those pointers), and makes the functions that do all of this also have the proper "const" attribution on the source pointers in order to make issues like that (using the source as a destination) be really obvious. Reported-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.misc-set_fs' of ↵Linus Torvalds2017-07-051-93/+138
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc user access cleanups from Al Viro: "The first pile is assorted getting rid of cargo-culted access_ok(), cargo-culted set_fs() and field-by-field copyouts. The same description applies to a lot of stuff in other branches - this is just the stuff that didn't fit into a more specific topical branch" * 'work.misc-set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Switch flock copyin/copyout primitives to copy_{from,to}_user() fs/fcntl: return -ESRCH in f_setown when pid/pgid can't be found fs/fcntl: f_setown, avoid undefined behaviour fs/fcntl: f_setown, allow returning error lpfc debugfs: get rid of pointless access_ok() adb: get rid of pointless access_ok() isdn: get rid of pointless access_ok() compat statfs: switch to copy_to_user() fs/locks: don't mess with the address limit in compat_fcntl64 nfsd_readlink(): switch to vfs_get_link() drbd: ->sendpage() never needed set_fs() fs/locks: pass kernel struct flock to fcntl_getlk/setlk fs: locks: Fix some troubles at kernel-doc comments
| * Switch flock copyin/copyout primitives to copy_{from,to}_user()Al Viro2017-06-271-30/+29
| | | | | | | | | | | | | | | | ... and lose HAVE_ARCH_...; if copy_{to,from}_user() on an architecture sucks badly enough to make it a problem, we have a worse problem. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fs/fcntl: return -ESRCH in f_setown when pid/pgid can't be foundJeff Layton2017-06-141-5/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current implementation of F_SETOWN doesn't properly vet the argument passed in and only returns an error if INT_MIN is passed in. If the argument doesn't specify a valid pid/pgid, then we just end up cleaning out the file->f_owner structure. What we really want is to only clean that out only in the case where userland passed in an argument of 0. For anything else, we want to return ESRCH if it doesn't refer to a valid pid. The relevant POSIX spec page is here: http://pubs.opengroup.org/onlinepubs/9699919799/functions/fcntl.html Cc: Jiri Slaby <jslaby@suse.cz> Cc: zhong jiang <zhongjiang@huawei.com> Signed-off-by: Jeff Layton <jlayton@redhat.com>
| * fs/fcntl: f_setown, avoid undefined behaviourJiri Slaby2017-06-141-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fcntl(0, F_SETOWN, 0x80000000) triggers: UBSAN: Undefined behaviour in fs/fcntl.c:118:7 negation of -2147483648 cannot be represented in type 'int': CPU: 1 PID: 18261 Comm: syz-executor Not tainted 4.8.1-0-syzkaller #1 ... Call Trace: ... [<ffffffffad8f0868>] ? f_setown+0x1d8/0x200 [<ffffffffad8f19a9>] ? SyS_fcntl+0x999/0xf30 [<ffffffffaed1fb00>] ? entry_SYSCALL_64_fastpath+0x23/0xc1 Fix that by checking the arg parameter properly (against INT_MAX) before "who = -who". And return immediatelly with -EINVAL in case it is wrong. Note that according to POSIX we can return EINVAL: http://pubs.opengroup.org/onlinepubs/9699919799/functions/fcntl.html [EINVAL] The cmd argument is F_SETOWN and the value of the argument is not valid as a process or process group identifier. [v2] returns an error, v1 used to fail silently [v3] implement proper check for the bad value INT_MIN Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Jeff Layton <jlayton@poochiereds.net> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Jeff Layton <jlayton@redhat.com>
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