linux.git/include/uapi/asm-generic/fcntl.h, branch v7.2-rc2 Linux kernel source tree Merge tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs 2026-06-14T22:29:45+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-06-14T22:29:45+00:00 7e0e7bd60d4a812b694c477716597fcb038b00cb Pull misc vfs updates from Christian Brauner: "Features: - Reduce pipe->mutex contention by pre-allocating pages outside the lock in anon_pipe_write(). anon_pipe_write() called alloc_page() once per page while holding pipe->mutex. The allocation can sleep doing direct reclaim and runs memcg charging, which extends the critical section and stalls any concurrent reader on the same mutex. Now up to 8 pages are pre-allocated before the mutex is taken, leftovers are recycled into the per-pipe tmp_page[] cache before unlock, and any remainder is released after unlock, keeping the allocator out of the critical section on both sides. On a writers x readers sweep with 64KB writes against a 1 MB pipe throughput improves 6-28% and average write latency drops 5-22%; under memory pressure - when the cost of holding the mutex across reclaim is highest - throughput improves 21-48% and latency drops 17-33%. The microbenchmark is added to selftests. - uaccess/sockptr: fix the ignored_trailing logic in copy_struct_to_user() to behave as documented and the usize check in copy_struct_from_sockptr() for user pointers, and add copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr() helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC). - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real inode backing a dentry via d_real_inode(). On overlayfs the inode attached to the dentry doesn't carry the underlying device information; this is used by the filesystem restriction BPF program that was merged into systemd. - docs: add guidelines for submitting new filesystems, motivated by the maintenance burden abandoned and untestable filesystems impose on VFS developers, blocking infrastructure work like folio conversions and iomap migration. Fixes: - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() and drop the now-redundant assignments in callers. This began as a one-line dma-buf fix for a path_noexec() warning; a pseudo filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo() callers were audited: the only visible effect is on dma-buf where SB_I_NOEXEC silences the warning. - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs, qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a device with a sector size > PAGE_SIZE crashed roughly half of them; the rest had the same missing error handling pattern. Plus a follow-up releasing the superblock buffer_head when setting the minix v3 block size fails. - mount: honour SB_NOUSER in the new mount API. - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by switching the process-group paths of send_sigio() and send_sigurg() from read_lock(&tasklist_lock) to RCU, matching the single-PID path. - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing delegated NFS mounts (fsopen() in a container with the mount performed by a privileged daemon) that broke when non-init s_user_ns was tied to FS_USERNS_MOUNT. - selftests/namespaces: fix a hang in nsid_test where an unreaped grandchild kept the TAP pipe write-end open, a waitpid(-1) race in listns_efault_test, and a false FAIL on kernels without listns() where the tests should SKIP. - filelock: fix the break_lease() stub signature for CONFIG_FILE_LOCKING=n. - init/initramfs_test: wait for the async initramfs unpacking before running; the test and do_populate_rootfs() share the parser state. - fs/coredump: reduce redundant log noise in validate_coredump_safety(). - iomap: pass the correct length to fserror_report_io() in __iomap_write_begin(). - backing-file: fix the backing_file_open() kerneldoc. Cleanups: - initramfs: refactor the cpio hex header parsing to use hex2bin() instead of the hand-rolled simple_strntoul() which is reverted, and extend the initramfs KUnit tests to cover header fields with 0x prefixes. - Replace __get_free_pages() and friends with kmalloc()/kzalloc() across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2, isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the do_mounts init code - part of the larger work of replacing page allocator calls with kmalloc(). - Use clear_and_wake_up_bit() in unlock_buffer() and journal_end_buffer_io_sync() instead of open-coding the sequence. - Drop unused VFS exports: unexport drop_super_exclusive(), remove start_removing_user_path_at(), and fold __start_removing_path() into start_removing_path(). - fs/read_write: narrow the __kernel_write() export with EXPORT_SYMBOL_FOR_MODULES(). - vfs: uapi: retire octal and hex constants in favor of (1 << n) for the O_ flags. Finding a free bit for a new flag across the architectures was needlessly hard with the mixed bases. - dcache: add extra sanity checks of dead dentries in dentry_free() via a new DENTRY_WARN_ONCE() that also prints d_flags. - iov_iter: use kmemdup_array() in dup_iter() to harden the allocation against multiplication overflow. - fs/pipe: write to ->poll_usage only once. - vfs: remove an always-taken if-branch in find_next_fd(). - dcache: use kmalloc_flex() for struct external_name in __d_alloc(). - namei: use QSTR() instead of QSTR_INIT() in path_pts(). - sync_file_range: delete dead S_ISLNK code. - Comment fixes: retire a stale comment in fget_task_next() and fix assorted spelling mistakes" * tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits) backing-file: fix backing_file_open() kerneldoc parameter iomap: pass the correct len to fserror_report_io in __iomap_write_begin vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags bpf: add bpf_real_inode() kfunc fs/read_write: Do not export __kernel_write() to the entire world libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() mount: honour SB_NOUSER in the new mount API fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling selftests/pipe: add pipe_bench microbenchmark fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write fs: retire stale comment in fget_task_next() fs: fix spelling mistakes in comment bfs: replace get_zeroed_page() with kzalloc() binfmt_misc: replace __get_free_page() with kmalloc() configfs: replace __get_free_pages() with kzalloc() fs/namespace: use __getname() to allocate mntpath buffer fs/select: replace __get_free_page() with kmalloc() ... 
Pull misc vfs updates from Christian Brauner:
 "Features:

   - Reduce pipe->mutex contention by pre-allocating pages outside the
     lock in anon_pipe_write().

     anon_pipe_write() called alloc_page() once per page while holding
     pipe->mutex. The allocation can sleep doing direct reclaim and runs
     memcg charging, which extends the critical section and stalls any
     concurrent reader on the same mutex. Now up to 8 pages are
     pre-allocated before the mutex is taken, leftovers are recycled
     into the per-pipe tmp_page[] cache before unlock, and any remainder
     is released after unlock, keeping the allocator out of the critical
     section on both sides. On a writers x readers sweep with 64KB
     writes against a 1 MB pipe throughput improves 6-28% and average
     write latency drops 5-22%; under memory pressure - when the cost of
     holding the mutex across reclaim is highest - throughput improves
     21-48% and latency drops 17-33%. The microbenchmark is added to
     selftests.

   - uaccess/sockptr: fix the ignored_trailing logic in
     copy_struct_to_user() to behave as documented and the usize check
     in copy_struct_from_sockptr() for user pointers, and add
     copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr()
     helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC).

   - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real
     inode backing a dentry via d_real_inode(). On overlayfs the inode
     attached to the dentry doesn't carry the underlying device
     information; this is used by the filesystem restriction BPF program
     that was merged into systemd.

   - docs: add guidelines for submitting new filesystems, motivated by
     the maintenance burden abandoned and untestable filesystems impose
     on VFS developers, blocking infrastructure work like folio
     conversions and iomap migration.

  Fixes:

   - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
     and drop the now-redundant assignments in callers. This began as a
     one-line dma-buf fix for a path_noexec() warning; a pseudo
     filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo()
     callers were audited: the only visible effect is on dma-buf where
     SB_I_NOEXEC silences the warning.

   - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs,
     qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a
     device with a sector size > PAGE_SIZE crashed roughly half of them;
     the rest had the same missing error handling pattern. Plus a
     follow-up releasing the superblock buffer_head when setting the
     minix v3 block size fails.

   - mount: honour SB_NOUSER in the new mount API.

   - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by
     switching the process-group paths of send_sigio() and send_sigurg()
     from read_lock(&tasklist_lock) to RCU, matching the single-PID
     path.

   - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing
     delegated NFS mounts (fsopen() in a container with the mount
     performed by a privileged daemon) that broke when non-init
     s_user_ns was tied to FS_USERNS_MOUNT.

   - selftests/namespaces: fix a hang in nsid_test where an unreaped
     grandchild kept the TAP pipe write-end open, a waitpid(-1) race in
     listns_efault_test, and a false FAIL on kernels without listns()
     where the tests should SKIP.

   - filelock: fix the break_lease() stub signature for
     CONFIG_FILE_LOCKING=n.

   - init/initramfs_test: wait for the async initramfs unpacking before
     running; the test and do_populate_rootfs() share the parser state.

   - fs/coredump: reduce redundant log noise in
     validate_coredump_safety().

   - iomap: pass the correct length to fserror_report_io() in
     __iomap_write_begin().

   - backing-file: fix the backing_file_open() kerneldoc.

  Cleanups:

   - initramfs: refactor the cpio hex header parsing to use hex2bin()
     instead of the hand-rolled simple_strntoul() which is reverted, and
     extend the initramfs KUnit tests to cover header fields with 0x
     prefixes.

   - Replace __get_free_pages() and friends with kmalloc()/kzalloc()
     across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2,
     isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the
     do_mounts init code - part of the larger work of replacing page
     allocator calls with kmalloc().

   - Use clear_and_wake_up_bit() in unlock_buffer() and
     journal_end_buffer_io_sync() instead of open-coding the sequence.

   - Drop unused VFS exports: unexport drop_super_exclusive(), remove
     start_removing_user_path_at(), and fold __start_removing_path()
     into start_removing_path().

   - fs/read_write: narrow the __kernel_write() export with
     EXPORT_SYMBOL_FOR_MODULES().

   - vfs: uapi: retire octal and hex constants in favor of (1 << n) for
     the O_ flags. Finding a free bit for a new flag across the
     architectures was needlessly hard with the mixed bases.

   - dcache: add extra sanity checks of dead dentries in dentry_free()
     via a new DENTRY_WARN_ONCE() that also prints d_flags.

   - iov_iter: use kmemdup_array() in dup_iter() to harden the
     allocation against multiplication overflow.

   - fs/pipe: write to ->poll_usage only once.

   - vfs: remove an always-taken if-branch in find_next_fd().

   - dcache: use kmalloc_flex() for struct external_name in __d_alloc().

   - namei: use QSTR() instead of QSTR_INIT() in path_pts().

   - sync_file_range: delete dead S_ISLNK code.

   - Comment fixes: retire a stale comment in fget_task_next() and fix
     assorted spelling mistakes"

* tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits)
  backing-file: fix backing_file_open() kerneldoc parameter
  iomap: pass the correct len to fserror_report_io in __iomap_write_begin
  vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS
  filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n
  vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags
  bpf: add bpf_real_inode() kfunc
  fs/read_write: Do not export __kernel_write() to the entire world
  libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers
  libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
  mount: honour SB_NOUSER in the new mount API
  fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling
  selftests/pipe: add pipe_bench microbenchmark
  fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write
  fs: retire stale comment in fget_task_next()
  fs: fix spelling mistakes in comment
  bfs: replace get_zeroed_page() with kzalloc()
  binfmt_misc: replace __get_free_page() with kmalloc()
  configfs: replace __get_free_pages() with kzalloc()
  fs/namespace: use __getname() to allocate mntpath buffer
  fs/select: replace __get_free_page() with kmalloc()
  ...
vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags 2026-06-06T13:34:03+00:00 Jori Koolstra jkoolstra@xs4all.nl 2026-06-04T22:24:05+00:00 0da79c259ad0554b36761a7135d4f92eb7c46263 A recent build failure[1] exposed the diffculty of working with the current octal and hex definitions of O_ flags when trying to find a gap for a new flag. This difficulty is compounded by the fact that O_ flags may have architectural specific values. Replace the hex/octal #defines, which are hard to parse when looking for free bits, with explicit bit shifts like (1 << 11). Also, add comments that identify which architectures redefine some of the seemingly free ("cursed") bits in uapi/asm-generic/fcntl.h. These should not be used to define new O_ flags (for now, at least). The translastion was done with Claude Opus 4.8, and verified with a (non-AI) gawk script. The accounting of which architectures claim which bit-gaps in uapi/asm-generic/fcntl.h is also done by hand. [1]: https://lore.kernel.org/all/agruPPybCx8q2XcJ@sirena.org.uk/ Assisted-by: Claude:Opus 4.8 Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl> Link: https://patch.msgid.link/20260604222405.5382-1-jkoolstra@xs4all.nl Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> 
A recent build failure[1] exposed the diffculty of working with the
current octal and hex definitions of O_ flags when trying to find a gap
for a new flag. This difficulty is compounded by the fact that O_ flags
may have architectural specific values.

Replace the hex/octal #defines, which are hard to parse when looking for
free bits, with explicit bit shifts like (1 << 11). Also, add comments
that identify which architectures redefine some of the seemingly free
("cursed") bits in uapi/asm-generic/fcntl.h. These should not be used to
define new O_ flags (for now, at least).

The translastion was done with Claude Opus 4.8, and verified with a
(non-AI) gawk script. The accounting of which architectures claim
which bit-gaps in uapi/asm-generic/fcntl.h is also done by hand.

[1]: https://lore.kernel.org/all/agruPPybCx8q2XcJ@sirena.org.uk/

Assisted-by: Claude:Opus 4.8
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Link: https://patch.msgid.link/20260604222405.5382-1-jkoolstra@xs4all.nl
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
vfs: add O_EMPTYPATH to openat(2)/openat2(2) 2026-05-21T08:53:33+00:00 Jori Koolstra jkoolstra@xs4all.nl 2026-04-24T11:46:02+00:00 31cf44efa6df72a524b40adefb80539f3a4e13ba To get an operable version of an O_PATH file descriptor, it is possible to use openat(fd, ".", O_DIRECTORY) for directories, but other files currently require going through open("/proc/<pid>/fd/<nr>"), which depends on a functioning procfs. This patch adds the O_EMPTYPATH flag to openat(2)/openat2(2). If passed, LOOKUP_EMPTY is set at path resolution time. Note: This implies that you cannot rely anymore on disabling procfs from being mounted (e.g. inside a container without procfs mounted and with CAP_SYS_ADMIN dropped) to prevent O_PATH fds from being re-opened read-write. Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl> Link: https://patch.msgid.link/20260424114611.1678641-2-jkoolstra@xs4all.nl Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> 
To get an operable version of an O_PATH file descriptor, it is possible
to use openat(fd, ".", O_DIRECTORY) for directories, but other files
currently require going through open("/proc/<pid>/fd/<nr>"), which
depends on a functioning procfs.

This patch adds the O_EMPTYPATH flag to openat(2)/openat2(2). If passed,
LOOKUP_EMPTY is set at path resolution time.

Note: This implies that you cannot rely anymore on disabling procfs from
being mounted (e.g. inside a container without procfs mounted and with
CAP_SYS_ADMIN dropped) to prevent O_PATH fds from being re-opened
read-write.

Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Link: https://patch.msgid.link/20260424114611.1678641-2-jkoolstra@xs4all.nl
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
fs: get rid of __FMODE_NONOTIFY kludge 2024-12-09T10:34:29+00:00 Al Viro viro@zeniv.linux.org.uk 2024-11-15T15:30:14+00:00 ebe559609d7829b52c6642b581860760984faf9d All it takes to get rid of the __FMODE_NONOTIFY kludge is switching fanotify from anon_inode_getfd() to anon_inode_getfile_fmode() and adding a dentry_open_nonotify() helper to be used by fanotify on the other path. That's it - no more weird shit in OPEN_FMODE(), etc. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Link: https://lore.kernel.org/linux-fsdevel/20241113043003.GH3387508@ZenIV/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/d1231137e7b661a382459e79a764259509a4115d.1731684329.git.josef@toxicpanda.com 
All it takes to get rid of the __FMODE_NONOTIFY kludge is switching
fanotify from anon_inode_getfd() to anon_inode_getfile_fmode() and adding
a dentry_open_nonotify() helper to be used by fanotify on the other path.
That's it - no more weird shit in OPEN_FMODE(), etc.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/linux-fsdevel/20241113043003.GH3387508@ZenIV/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/d1231137e7b661a382459e79a764259509a4115d.1731684329.git.josef@toxicpanda.com
open: return EINVAL for O_DIRECTORY | O_CREAT 2023-03-22T10:06:55+00:00 Christian Brauner brauner@kernel.org 2023-03-21T08:18:07+00:00 43b450632676fb60e9faeddff285d9fac94a4f58 After a couple of years and multiple LTS releases we received a report that the behavior of O_DIRECTORY | O_CREAT changed starting with v5.7. On kernels prior to v5.7 combinations of O_DIRECTORY, O_CREAT, O_EXCL had the following semantics: (1) open("/tmp/d", O_DIRECTORY | O_CREAT) * d doesn't exist: create regular file * d exists and is a regular file: ENOTDIR * d exists and is a directory: EISDIR (2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL) * d doesn't exist: create regular file * d exists and is a regular file: EEXIST * d exists and is a directory: EEXIST (3) open("/tmp/d", O_DIRECTORY | O_EXCL) * d doesn't exist: ENOENT * d exists and is a regular file: ENOTDIR * d exists and is a directory: open directory On kernels since to v5.7 combinations of O_DIRECTORY, O_CREAT, O_EXCL have the following semantics: (1) open("/tmp/d", O_DIRECTORY | O_CREAT) * d doesn't exist: ENOTDIR (create regular file) * d exists and is a regular file: ENOTDIR * d exists and is a directory: EISDIR (2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL) * d doesn't exist: ENOTDIR (create regular file) * d exists and is a regular file: EEXIST * d exists and is a directory: EEXIST (3) open("/tmp/d", O_DIRECTORY | O_EXCL) * d doesn't exist: ENOENT * d exists and is a regular file: ENOTDIR * d exists and is a directory: open directory This is a fairly substantial semantic change that userspace didn't notice until Pedro took the time to deliberately figure out corner cases. Since no one noticed this breakage we can somewhat safely assume that O_DIRECTORY | O_CREAT combinations are likely unused. The v5.7 breakage is especially weird because while ENOTDIR is returned indicating failure a regular file is actually created. This doesn't make a lot of sense. Time was spent finding potential users of this combination. Searching on codesearch.debian.net showed that codebases often express semantical expectations about O_DIRECTORY | O_CREAT which are completely contrary to what our code has done and currently does. The expectation often is that this particular combination would create and open a directory. This suggests users who tried to use that combination would stumble upon the counterintuitive behavior no matter if pre-v5.7 or post v5.7 and quickly realize neither semantics give them what they want. For some examples see the code examples in [1] to [3] and the discussion in [4]. There are various ways to address this issue. The lazy/simple option would be to restore the pre-v5.7 behavior and to just live with that bug forever. But since there's a real chance that the O_DIRECTORY | O_CREAT quirk isn't relied upon we should try to get away with murder(ing bad semantics) first. If we need to Frankenstein pre-v5.7 behavior later so be it. So let's simply return EINVAL categorically for O_DIRECTORY | O_CREAT combinations. In addition to cleaning up the old bug this also opens up the possiblity to make that flag combination do something more intuitive in the future. Starting with this commit the following semantics apply: (1) open("/tmp/d", O_DIRECTORY | O_CREAT) * d doesn't exist: EINVAL * d exists and is a regular file: EINVAL * d exists and is a directory: EINVAL (2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL) * d doesn't exist: EINVAL * d exists and is a regular file: EINVAL * d exists and is a directory: EINVAL (3) open("/tmp/d", O_DIRECTORY | O_EXCL) * d doesn't exist: ENOENT * d exists and is a regular file: ENOTDIR * d exists and is a directory: open directory One additional note, O_TMPFILE is implemented as: #define __O_TMPFILE 020000000 #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY) #define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT) For older kernels it was important to return an explicit error when O_TMPFILE wasn't supported. So O_TMPFILE requires that O_DIRECTORY is raised alongside __O_TMPFILE. It also enforced that O_CREAT wasn't specified. Since O_DIRECTORY | O_CREAT could be used to create a regular allowing that combination together with __O_TMPFILE would've meant that false positives were possible, i.e., that a regular file was created instead of a O_TMPFILE. This could've been used to trick userspace into thinking it operated on a O_TMPFILE when it wasn't. Now that we block O_DIRECTORY | O_CREAT completely the check for O_CREAT in the __O_TMPFILE branch via if ((flags & O_TMPFILE_MASK) != O_TMPFILE) can be dropped. Instead we can simply check verify that O_DIRECTORY is raised via if (!(flags & O_DIRECTORY)) and explain this in two comments. As Aleksa pointed out O_PATH is unaffected by this change since it always returned EINVAL if O_CREAT was specified - with or without O_DIRECTORY. Link: https://lore.kernel.org/lkml/20230320071442.172228-1-pedro.falcato@gmail.com Link: https://sources.debian.org/src/flatpak/1.14.4-1/subprojects/libglnx/glnx-dirfd.c/?hl=324#L324 [1] Link: https://sources.debian.org/src/flatpak-builder/1.2.3-1/subprojects/libglnx/glnx-shutil.c/?hl=251#L251 [2] Link: https://sources.debian.org/src/ostree/2022.7-2/libglnx/glnx-dirfd.c/?hl=324#L324 [3] Link: https://www.openwall.com/lists/oss-security/2014/11/26/14 [4] Reported-by: Pedro Falcato <pedro.falcato@gmail.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <brauner@kernel.org> 
After a couple of years and multiple LTS releases we received a report
that the behavior of O_DIRECTORY | O_CREAT changed starting with v5.7.

On kernels prior to v5.7 combinations of O_DIRECTORY, O_CREAT, O_EXCL
had the following semantics:

(1) open("/tmp/d", O_DIRECTORY | O_CREAT)
    * d doesn't exist:                create regular file
    * d exists and is a regular file: ENOTDIR
    * d exists and is a directory:    EISDIR

(2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL)
    * d doesn't exist:                create regular file
    * d exists and is a regular file: EEXIST
    * d exists and is a directory:    EEXIST

(3) open("/tmp/d", O_DIRECTORY | O_EXCL)
    * d doesn't exist:                ENOENT
    * d exists and is a regular file: ENOTDIR
    * d exists and is a directory:    open directory

On kernels since to v5.7 combinations of O_DIRECTORY, O_CREAT, O_EXCL
have the following semantics:

(1) open("/tmp/d", O_DIRECTORY | O_CREAT)
    * d doesn't exist:                ENOTDIR (create regular file)
    * d exists and is a regular file: ENOTDIR
    * d exists and is a directory:    EISDIR

(2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL)
    * d doesn't exist:                ENOTDIR (create regular file)
    * d exists and is a regular file: EEXIST
    * d exists and is a directory:    EEXIST

(3) open("/tmp/d", O_DIRECTORY | O_EXCL)
    * d doesn't exist:                ENOENT
    * d exists and is a regular file: ENOTDIR
    * d exists and is a directory:    open directory

This is a fairly substantial semantic change that userspace didn't
notice until Pedro took the time to deliberately figure out corner
cases. Since no one noticed this breakage we can somewhat safely assume
that O_DIRECTORY | O_CREAT combinations are likely unused.

The v5.7 breakage is especially weird because while ENOTDIR is returned
indicating failure a regular file is actually created. This doesn't make
a lot of sense.

Time was spent finding potential users of this combination. Searching on
codesearch.debian.net showed that codebases often express semantical
expectations about O_DIRECTORY | O_CREAT which are completely contrary
to what our code has done and currently does.

The expectation often is that this particular combination would create
and open a directory. This suggests users who tried to use that
combination would stumble upon the counterintuitive behavior no matter
if pre-v5.7 or post v5.7 and quickly realize neither semantics give them
what they want. For some examples see the code examples in [1] to [3]
and the discussion in [4].

There are various ways to address this issue. The lazy/simple option
would be to restore the pre-v5.7 behavior and to just live with that bug
forever. But since there's a real chance that the O_DIRECTORY | O_CREAT
quirk isn't relied upon we should try to get away with murder(ing bad
semantics) first. If we need to Frankenstein pre-v5.7 behavior later so
be it.

So let's simply return EINVAL categorically for O_DIRECTORY | O_CREAT
combinations. In addition to cleaning up the old bug this also opens up
the possiblity to make that flag combination do something more intuitive
in the future.

Starting with this commit the following semantics apply:

(1) open("/tmp/d", O_DIRECTORY | O_CREAT)
    * d doesn't exist:                EINVAL
    * d exists and is a regular file: EINVAL
    * d exists and is a directory:    EINVAL

(2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL)
    * d doesn't exist:                EINVAL
    * d exists and is a regular file: EINVAL
    * d exists and is a directory:    EINVAL

(3) open("/tmp/d", O_DIRECTORY | O_EXCL)
    * d doesn't exist:                ENOENT
    * d exists and is a regular file: ENOTDIR
    * d exists and is a directory:    open directory

One additional note, O_TMPFILE is implemented as:

    #define __O_TMPFILE    020000000
    #define O_TMPFILE      (__O_TMPFILE | O_DIRECTORY)
    #define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT)

For older kernels it was important to return an explicit error when
O_TMPFILE wasn't supported. So O_TMPFILE requires that O_DIRECTORY is
raised alongside __O_TMPFILE. It also enforced that O_CREAT wasn't
specified. Since O_DIRECTORY | O_CREAT could be used to create a regular
allowing that combination together with __O_TMPFILE would've meant that
false positives were possible, i.e., that a regular file was created
instead of a O_TMPFILE. This could've been used to trick userspace into
thinking it operated on a O_TMPFILE when it wasn't.

Now that we block O_DIRECTORY | O_CREAT completely the check for O_CREAT
in the __O_TMPFILE branch via if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
can be dropped. Instead we can simply check verify that O_DIRECTORY is
raised via if (!(flags & O_DIRECTORY)) and explain this in two comments.

As Aleksa pointed out O_PATH is unaffected by this change since it
always returned EINVAL if O_CREAT was specified - with or without
O_DIRECTORY.

Link: https://lore.kernel.org/lkml/20230320071442.172228-1-pedro.falcato@gmail.com
Link: https://sources.debian.org/src/flatpak/1.14.4-1/subprojects/libglnx/glnx-dirfd.c/?hl=324#L324 [1]
Link: https://sources.debian.org/src/flatpak-builder/1.2.3-1/subprojects/libglnx/glnx-shutil.c/?hl=251#L251 [2]
Link: https://sources.debian.org/src/ostree/2022.7-2/libglnx/glnx-dirfd.c/?hl=324#L324 [3]
Link: https://www.openwall.com/lists/oss-security/2014/11/26/14 [4]
Reported-by: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
tools: Fixed MIPS builds due to struct flock re-definition 2022-07-20T10:55:33+00:00 Florian Fainelli f.fainelli@gmail.com 2022-07-15T18:55:49+00:00 9b31e60800d8fa69027baf9ec7f03a0c5b145079 Building perf for MIPS failed after 9f79b8b72339 ("uapi: simplify __ARCH_FLOCK{,64}_PAD a little") with the following error: CC /home/fainelli/work/buildroot/output/bmips/build/linux-custom/tools/perf/trace/beauty/fcntl.o In file included from ../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:77, from ../include/uapi/linux/fcntl.h:5, from trace/beauty/fcntl.c:10: ../include/uapi/asm-generic/fcntl.h:188:8: error: redefinition of 'struct flock' struct flock { ^~~~~ In file included from ../include/uapi/linux/fcntl.h:5, from trace/beauty/fcntl.c:10: ../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:63:8: note: originally defined here struct flock { ^~~~~ This is due to the local copy under tools/include/uapi/asm-generic/fcntl.h including the toolchain's kernel headers which already define 'struct flock' and define HAVE_ARCH_STRUCT_FLOCK to future inclusions make a decision as to whether re-defining 'struct flock' is appropriate or not. Make sure what do not re-define 'struct flock' when HAVE_ARCH_STRUCT_FLOCK is already defined. Fixes: 9f79b8b72339 ("uapi: simplify __ARCH_FLOCK{,64}_PAD a little") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> [arnd: sync with include/uapi/asm-generic/fcntl.h as well] Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
Building perf for MIPS failed after 9f79b8b72339 ("uapi: simplify
__ARCH_FLOCK{,64}_PAD a little") with the following error:

  CC
/home/fainelli/work/buildroot/output/bmips/build/linux-custom/tools/perf/trace/beauty/fcntl.o
In file included from
../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:77,
                 from ../include/uapi/linux/fcntl.h:5,
                 from trace/beauty/fcntl.c:10:
../include/uapi/asm-generic/fcntl.h:188:8: error: redefinition of
'struct flock'
 struct flock {
        ^~~~~
In file included from ../include/uapi/linux/fcntl.h:5,
                 from trace/beauty/fcntl.c:10:
../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:63:8:
note: originally defined here
 struct flock {
        ^~~~~

This is due to the local copy under
tools/include/uapi/asm-generic/fcntl.h including the toolchain's kernel
headers which already define 'struct flock' and define
HAVE_ARCH_STRUCT_FLOCK to future inclusions make a decision as to
whether re-defining 'struct flock' is appropriate or not.

Make sure what do not re-define 'struct flock'
when HAVE_ARCH_STRUCT_FLOCK is already defined.

Fixes: 9f79b8b72339 ("uapi: simplify __ARCH_FLOCK{,64}_PAD a little")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[arnd: sync with include/uapi/asm-generic/fcntl.h as well]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
uapi: always define F_GETLK64/F_SETLK64/F_SETLKW64 in fcntl.h 2022-04-26T20:35:20+00:00 Christoph Hellwig hch@lst.de 2022-04-05T07:12:56+00:00 306f7cc1e9061313c46d19e9bdffc819880794c1 The F_GETLK64/F_SETLK64/F_SETLKW64 fcntl opcodes are only implemented for the 32-bit syscall APIs, but are also needed for compat handling on 64-bit kernels. Consolidate them in unistd.h instead of definining the internal compat definitions in compat.h, which is rather error prone (e.g. parisc gets the values wrong currently). Note that before this change they were never visible to userspace due to the fact that CONFIG_64BIT is only set for kernel builds. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Guo Ren <guoren@kernel.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Tested-by: Heiko Stuebner <heiko@sntech.de> Link: https://lore.kernel.org/r/20220405071314.3225832-3-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> 
The F_GETLK64/F_SETLK64/F_SETLKW64 fcntl opcodes are only implemented
for the 32-bit syscall APIs, but are also needed for compat handling
on 64-bit kernels.

Consolidate them in unistd.h instead of definining the internal compat
definitions in compat.h, which is rather error prone (e.g. parisc
gets the values wrong currently).

Note that before this change they were never visible to userspace due
to the fact that CONFIG_64BIT is only set for kernel builds.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-3-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
uapi: simplify __ARCH_FLOCK{,64}_PAD a little 2022-04-26T20:35:14+00:00 Christoph Hellwig hch@lst.de 2022-04-05T07:12:55+00:00 9f79b8b7233942e9c4b071f1f331f17e7282bbfa Don't bother to define the symbols empty, just don't use them. That makes the intent a little more clear. Remove the unused HAVE_ARCH_STRUCT_FLOCK64 define and merge the 32-bit mips struct flock into the generic one. Add a new __ARCH_FLOCK_EXTRA_SYSID macro following the style of __ARCH_FLOCK_PAD to avoid having a separate definition just for one architecture. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Guo Ren <guoren@kernel.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Tested-by: Heiko Stuebner <heiko@sntech.de> Link: https://lore.kernel.org/r/20220405071314.3225832-2-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> 
Don't bother to define the symbols empty, just don't use them.
That makes the intent a little more clear.

Remove the unused HAVE_ARCH_STRUCT_FLOCK64 define and merge the
32-bit mips struct flock into the generic one.

Add a new __ARCH_FLOCK_EXTRA_SYSID macro following the style of
__ARCH_FLOCK_PAD to avoid having a separate definition just for
one architecture.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-2-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
locks: remove LOCK_MAND flock lock support 2021-09-10T20:21:44+00:00 Jeff Layton jlayton@kernel.org 2021-09-10T19:36:29+00:00 90f7d7a0d0d68623b5f7df5621a8d54d9518fcc4 As best I can tell, the logic for these has been broken for a long time (at least before the move to git), such that they never conflict with anything. Also, nothing checks for these flags and prevented opens or read/write behavior on the files. They don't seem to do anything. Given that, we can rip these symbols out of the kernel, and just make flock(2) return 0 when LOCK_MAND is set in order to preserve existing behavior. Cc: Matthew Wilcox <willy@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Jeff Layton <jlayton@kernel.org> 
As best I can tell, the logic for these has been broken for a long time
(at least before the move to git), such that they never conflict with
anything. Also, nothing checks for these flags and prevented opens or
read/write behavior on the files. They don't seem to do anything.

Given that, we can rip these symbols out of the kernel, and just make
flock(2) return 0 when LOCK_MAND is set in order to preserve existing
behavior.

Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
License cleanup: add SPDX license identifier to uapi header files with no license 2017-11-02T10:19:54+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2017-11-01T14:08:43+00:00 6f52b16c5b29b89d92c0e7236f4655dc8491ad70 Many user space API headers are missing licensing information, which makes it hard for compliance tools to determine the correct license. By default are files without license information under the default license of the kernel, which is GPLV2. Marking them GPLV2 would exclude them from being included in non GPLV2 code, which is obviously not intended. The user space API headers fall under the syscall exception which is in the kernels COPYING file: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". otherwise syscall usage would not be possible. Update the files which contain no license information with an SPDX license identifier. The chosen identifier is 'GPL-2.0 WITH Linux-syscall-note' which is the officially assigned identifier for the Linux syscall exception. SPDX license identifiers are 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. See the previous patch in this series for the methodology of how this patch was researched. 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> 
Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.

By default are files without license information under the default
license of the kernel, which is GPLV2.  Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:

   NOTE! This copyright does *not* cover user programs that use kernel
   services by normal system calls - this is merely considered normal use
   of the kernel, and does *not* fall under the heading of "derived work".

otherwise syscall usage would not be possible.

Update the files which contain no license information with an SPDX
license identifier.  The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception.  SPDX license identifiers are 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.  See the previous patch in this series for the
methodology of how this patch was researched.

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>