kernel/linux.git/fs/open.c, branch v6.6.132

allow finish_no_open(file, ERR_PTR(-E...))

2025-11-24T09:29:40+00:00

[ Upstream commit fe91e078b60d1beabf5cef4a37c848457a6d2dfb ] ... allowing any ->lookup() return value to be passed to it. Reviewed-by: NeilBrown Signed-off-by: Al Viro Signed-off-by: Sasha Levin

openat2: explicitly return -E2BIG for (usize > PAGE_SIZE)

2024-11-01T00:58:32+00:00

commit f92f0a1b05698340836229d791b3ffecc71b265a upstream. While we do currently return -EFAULT in this case, it seems prudent to follow the behaviour of other syscalls like clone3. It seems quite unlikely that anyone depends on this error code being EFAULT, but we can always revert this if it turns out to be an issue. Cc: stable@vger.kernel.org # v5.6+ Fixes: fddb5d430ad9 ("open: introduce openat2(2) syscall") Signed-off-by: Aleksa Sarai Link: https://lore.kernel.org/r/20241010-extensible-structs-check_fields-v3-3-d2833dfe6edd@cyphar.com Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman

ftruncate: pass a signed offset

2024-07-05T07:34:04+00:00

commit 4b8e88e563b5f666446d002ad0dc1e6e8e7102b0 upstream. The old ftruncate() syscall, using the 32-bit off_t misses a sign extension when called in compat mode on 64-bit architectures. As a result, passing a negative length accidentally succeeds in truncating to file size between 2GiB and 4GiB. Changing the type of the compat syscall to the signed compat_off_t changes the behavior so it instead returns -EINVAL. The native entry point, the truncate() syscall and the corresponding loff_t based variants are all correct already and do not suffer from this mistake. Fixes: 3f6d078d4acc ("fix compat truncate/ftruncate") Reviewed-by: Christian Brauner Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

cred: get rid of CONFIG_DEBUG_CREDENTIALS

2023-12-20T16:01:51+00:00

commit ae1914174a63a558113e80d24ccac2773f9f7b2b upstream. This code is rarely (never?) enabled by distros, and it hasn't caught anything in decades. Let's kill off this legacy debug code. Suggested-by: Linus Torvalds Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

Merge tag 'v6.6-vfs.fchmodat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2023-08-28T18:25:27+00:00

Pull fchmodat2 system call from Christian Brauner: "This adds the fchmodat2() system call. It is a revised version of the fchmodat() system call, adding a missing flag argument. Support for both AT_SYMLINK_NOFOLLOW and AT_EMPTY_PATH are included. Adding this system call revision has been a longstanding request but so far has always fallen through the cracks. While the kernel implementation of fchmodat() does not have a flag argument the libc provided POSIX-compliant fchmodat(3) version does. Both glibc and musl have to implement a workaround in order to support AT_SYMLINK_NOFOLLOW (see [1] and [2]). The workaround is brittle because it relies not just on O_PATH and O_NOFOLLOW semantics and procfs magic links but also on our rather inconsistent symlink semantics. This gives userspace a proper fchmodat2() system call that libcs can use to properly implement fchmodat(3) and allows them to get rid of their hacks. In this case it will immediately benefit them as the current workaround is already defunct because of aformentioned inconsistencies. In addition to AT_SYMLINK_NOFOLLOW, give userspace the ability to use AT_EMPTY_PATH with fchmodat2(). This is already possible with fchownat() so there's no reason to not also support it for fchmodat2(). The implementation is simple and comes with selftests. Implementation of the system call and wiring up the system call are done as separate patches even though they could arguably be one patch. But in case there are merge conflicts from other system call additions it can be beneficial to have separate patches" Link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=17eca54051ee28ba1ec3f9aed170a62630959143;hb=a492b1e5ef7ab50c6fdd4e4e9879ea5569ab0a6c#l35 [1] Link: https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c?id=718f363bc2067b6487900eddc9180c84e7739f80#n28 [2] * tag 'v6.6-vfs.fchmodat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: selftests: fchmodat2: remove duplicate unneeded defines fchmodat2: add support for AT_EMPTY_PATH selftests: Add fchmodat2 selftest arch: Register fchmodat2, usually as syscall 452 fs: Add fchmodat2() Non-functional cleanup of a "__user * filename"

Merge tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2023-08-28T17:17:14+00:00

Pull misc vfs updates from Christian Brauner: "This contains the usual miscellaneous features, cleanups, and fixes for vfs and individual filesystems. Features: - Block mode changes on symlinks and rectify our broken semantics - Report file modifications via fsnotify() for splice - Allow specifying an explicit timeout for the "rootwait" kernel command line option. This allows to timeout and reboot instead of always waiting indefinitely for the root device to show up - Use synchronous fput for the close system call Cleanups: - Get rid of open-coded lockdep workarounds for async io submitters and replace it all with a single consolidated helper - Simplify epoll allocation helper - Convert simple_write_begin and simple_write_end to use a folio - Convert page_cache_pipe_buf_confirm() to use a folio - Simplify __range_close to avoid pointless locking - Disable per-cpu buffer head cache for isolated cpus - Port ecryptfs to kmap_local_page() api - Remove redundant initialization of pointer buf in pipe code - Unexport the d_genocide() function which is only used within core vfs - Replace printk(KERN_ERR) and WARN_ON() with WARN() Fixes: - Fix various kernel-doc issues - Fix refcount underflow for eventfds when used as EFD_SEMAPHORE - Fix a mainly theoretical issue in devpts - Check the return value of __getblk() in reiserfs - Fix a racy assert in i_readcount_dec - Fix integer conversion issues in various functions - Fix LSM security context handling during automounts that prevented NFS superblock sharing" * tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (39 commits) cachefiles: use kiocb_{start,end}_write() helpers ovl: use kiocb_{start,end}_write() helpers aio: use kiocb_{start,end}_write() helpers io_uring: use kiocb_{start,end}_write() helpers fs: create kiocb_{start,end}_write() helpers fs: add kerneldoc to file_{start,end}_write() helpers io_uring: rename kiocb_end_write() local helper splice: Convert page_cache_pipe_buf_confirm() to use a folio libfs: Convert simple_write_begin and simple_write_end to use a folio fs/dcache: Replace printk and WARN_ON by WARN fs/pipe: remove redundant initialization of pointer buf fs: Fix kernel-doc warnings devpts: Fix kernel-doc warnings doc: idmappings: fix an error and rephrase a paragraph init: Add support for rootwait timeout parameter vfs: fix up the assert in i_readcount_dec fs: Fix one kernel-doc comment docs: filesystems: idmappings: clarify from where idmappings are taken fs/buffer.c: disable per-CPU buffer_head cache for isolated CPUs vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing ...

fs: Fix kernel-doc warnings

2023-08-19T10:12:12+00:00

These have a variety of causes and a corresponding variety of solutions. Signed-off-by: "Matthew Wilcox (Oracle)" Message-Id: <20230818200824.2720007-1-willy@infradead.org> Signed-off-by: Christian Brauner

fs: use __fput_sync in close(2)

2023-08-08T17:36:51+00:00

close(2) is a special case which guarantees a shallow kernel stack, making delegation to task_work machinery unnecessary. Said delegation is problematic as it involves atomic ops and interrupt masking trips, none of which are cheap on x86-64. Forcing close(2) to do it looks like an oversight in the original work. Moreover presence of CONFIG_RSEQ adds an additional overhead as fput() -> task_work_add(..., TWA_RESUME) -> set_notify_resume() makes the thread returning to userspace land in resume_user_mode_work(), where rseq_handle_notify_resume takes a SMAP round-trip if rseq is enabled for the thread (and it is by default with contemporary glibc). Sample result when benchmarking open1_processes -t 1 from will-it-scale (that's an open + close loop) + tmpfs on /tmp, running on the Sapphire Rapid CPU (ops/s): stock+RSEQ: 1329857 stock-RSEQ: 1421667 (+7%) patched: 1523521 (+14.5% / +7%) (with / without rseq) Patched result is the same regardless of rseq as the codepath is avoided. Signed-off-by: Linus Torvalds Signed-off-by: Christian Brauner

open: make RESOLVE_CACHED correctly test for O_TMPFILE

2023-08-06T13:08:35+00:00

O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old fast-path check for RESOLVE_CACHED would reject all users passing O_DIRECTORY with -EAGAIN, when in fact the intended test was to check for __O_TMPFILE. Cc: stable@vger.kernel.org # v5.12+ Fixes: 99668f618062 ("fs: expose LOOKUP_CACHED through openat2() RESOLVE_CACHED") Signed-off-by: Aleksa Sarai Message-Id: <20230806-resolve_cached-o_tmpfile-v1-1-7ba16308465e@cyphar.com> Signed-off-by: Christian Brauner

fchmodat2: add support for AT_EMPTY_PATH

2023-07-28T14:43:05+00:00

This allows userspace to avoid going through /proc/self/fd when dealing with all types of file descriptors for chmod(), and makes fchmodat2() a proper superset of all other chmod syscalls. The primary difference between fchmodat2(AT_EMPTY_PATH) and fchmod() is that fchmod() doesn't operate on O_PATH file descriptors by design. To quote open(2): > O_PATH (since Linux 2.6.39) > [...] > The file itself is not opened, and other file operations (e.g., > read(2), write(2), fchmod(2), fchown(2), fgetxattr(2), ioctl(2), > mmap(2)) fail with the error EBADF. However, procfs has allowed userspace to do this operation ever since the introduction of O_PATH through magic-links, so adding this feature is only an improvement for programs that have to mess around with /proc/self/fd/$n today to get this behaviour. In addition, fchownat(AT_EMPTY_PATH) has existed since the introduction of O_PATH and allows chown() operations directly on O_PATH descriptors. Signed-off-by: Aleksa Sarai Acked-by: Alexey Gladkov Message-Id: <20230728-fchmodat2-at_empty_path-v1-1-f3add31d3516@cyphar.com> Signed-off-by: Christian Brauner