Commit Graph

445 Commits

Author SHA1 Message Date
Andrey Albershteyn
be7efb2d20
fs: introduce file_getattr and file_setattr syscalls
Introduce file_getattr() and file_setattr() syscalls to manipulate inode
extended attributes. The syscalls takes pair of file descriptor and
pathname. Then it operates on inode opened accroding to openat()
semantics. The struct file_attr is passed to obtain/change extended
attributes.

This is an alternative to FS_IOC_FSSETXATTR ioctl with a difference
that file don't need to be open as we can reference it with a path
instead of fd. By having this we can manipulated inode extended
attributes not only on regular files but also on special ones. This
is not possible with FS_IOC_FSSETXATTR ioctl as with special files
we can not call ioctl() directly on the filesystem inode using fd.

This patch adds two new syscalls which allows userspace to get/set
extended inode attributes on special files by using parent directory
and a path - *at() like syscall.

CC: linux-api@vger.kernel.org
CC: linux-fsdevel@vger.kernel.org
CC: linux-xfs@vger.kernel.org
Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
Link: https://lore.kernel.org/20250630-xattrat-syscall-v6-6-c4e3bc35227b@kernel.org
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-02 17:05:17 +02:00
Linus Torvalds
fd101da676 vfs-6.15-rc1.mount
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Merge tag 'vfs-6.15-rc1.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs mount updates from Christian Brauner:

 - Mount notifications

   The day has come where we finally provide a new api to listen for
   mount topology changes outside of /proc/<pid>/mountinfo. A mount
   namespace file descriptor can be supplied and registered with
   fanotify to listen for mount topology changes.

   Currently notifications for mount, umount and moving mounts are
   generated. The generated notification record contains the unique
   mount id of the mount.

   The listmount() and statmount() api can be used to query detailed
   information about the mount using the received unique mount id.

   This allows userspace to figure out exactly how the mount topology
   changed without having to generating diffs of /proc/<pid>/mountinfo
   in userspace.

 - Support O_PATH file descriptors with FSCONFIG_SET_FD in the new mount
   api

 - Support detached mounts in overlayfs

   Since last cycle we support specifying overlayfs layers via file
   descriptors. However, we don't allow detached mounts which means
   userspace cannot user file descriptors received via
   open_tree(OPEN_TREE_CLONE) and fsmount() directly. They have to
   attach them to a mount namespace via move_mount() first.

   This is cumbersome and means they have to undo mounts via umount().
   Allow them to directly use detached mounts.

 - Allow to retrieve idmappings with statmount

   Currently it isn't possible to figure out what idmapping has been
   attached to an idmapped mount. Add an extension to statmount() which
   allows to read the idmapping from the mount.

 - Allow creating idmapped mounts from mounts that are already idmapped

   So far it isn't possible to allow the creation of idmapped mounts
   from already idmapped mounts as this has significant lifetime
   implications. Make the creation of idmapped mounts atomic by allow to
   pass struct mount_attr together with the open_tree_attr() system call
   allowing to solve these issues without complicating VFS lookup in any
   way.

   The system call has in general the benefit that creating a detached
   mount and applying mount attributes to it becomes an atomic operation
   for userspace.

 - Add a way to query statmount() for supported options

   Allow userspace to query which mount information can be retrieved
   through statmount().

 - Allow superblock owners to force unmount

* tag 'vfs-6.15-rc1.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (21 commits)
  umount: Allow superblock owners to force umount
  selftests: add tests for mount notification
  selinux: add FILE__WATCH_MOUNTNS
  samples/vfs: fix printf format string for size_t
  fs: allow changing idmappings
  fs: add kflags member to struct mount_kattr
  fs: add open_tree_attr()
  fs: add copy_mount_setattr() helper
  fs: add vfs_open_tree() helper
  statmount: add a new supported_mask field
  samples/vfs: add STATMOUNT_MNT_{G,U}IDMAP
  selftests: add tests for using detached mount with overlayfs
  samples/vfs: check whether flag was raised
  statmount: allow to retrieve idmappings
  uidgid: add map_id_range_up()
  fs: allow detached mounts in clone_private_mount()
  selftests/overlayfs: test specifying layers as O_PATH file descriptors
  fs: support O_PATH fds with FSCONFIG_SET_FD
  vfs: add notifications for mount attach and detach
  fanotify: notify on mount attach and detach
  ...
2025-03-24 09:34:10 -07:00
Yuichiro Tsuji
29d80d506b
open: Fix return type of several functions from long to int
Fix the return type of several functions from long to int to match its actu
al behavior. These functions only return int values. This change improves
type consistency across the filesystem code and aligns the function signatu
re with its existing implementation and usage.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yuichiro Tsuji <yuichtsu@amazon.com>
Link: https://lore.kernel.org/r/20250121070844.4413-2-yuichtsu@amazon.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21 10:25:32 +01:00
Christian Brauner
c4a16820d9
fs: add open_tree_attr()
Add open_tree_attr() which allow to atomically create a detached mount
tree and set mount options on it. If OPEN_TREE_CLONE is used this will
allow the creation of a detached mount with a new set of mount options
without it ever being exposed to userspace without that set of mount
options applied.

Link: https://lore.kernel.org/r/20250128-work-mnt_idmap-update-v2-v1-3-c25feb0d2eb3@kernel.org
Reviewed-by: "Seth Forshee (DigitalOcean)" <sforshee@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-12 12:12:28 +01:00
Christian Göttsche
6140be90ec fs/xattr: add *at family syscalls
Add the four syscalls setxattrat(), getxattrat(), listxattrat() and
removexattrat().  Those can be used to operate on extended attributes,
especially security related ones, either relative to a pinned directory
or on a file descriptor without read access, avoiding a
/proc/<pid>/fd/<fd> detour, requiring a mounted procfs.

One use case will be setfiles(8) setting SELinux file contexts
("security.selinux") without race conditions and without a file
descriptor opened with read access requiring SELinux read permission.

Use the do_{name}at() pattern from fs/open.c.

Pass the value of the extended attribute, its length, and for
setxattrat(2) the command (XATTR_CREATE or XATTR_REPLACE) via an added
struct xattr_args to not exceed six syscall arguments and not
merging the AT_* and XATTR_* flags.

[AV: fixes by Christian Brauner folded in, the entire thing rebased on
top of {filename,file}_...xattr() primitives, treatment of empty
pathnames regularized.  As the result, AT_EMPTY_PATH+NULL handling
is cheap, so f...(2) can use it]

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Link: https://lore.kernel.org/r/20240426162042.191916-1-cgoettsche@seltendoof.de
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
CC: x86@kernel.org
CC: linux-alpha@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.org
CC: linux-ia64@vger.kernel.org
CC: linux-m68k@lists.linux-m68k.org
CC: linux-mips@vger.kernel.org
CC: linux-parisc@vger.kernel.org
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-s390@vger.kernel.org
CC: linux-sh@vger.kernel.org
CC: sparclinux@vger.kernel.org
CC: linux-fsdevel@vger.kernel.org
CC: audit@vger.kernel.org
CC: linux-arch@vger.kernel.org
CC: linux-api@vger.kernel.org
CC: linux-security-module@vger.kernel.org
CC: selinux@vger.kernel.org
[brauner: slight tweaks]
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-06 12:59:44 -05:00
Aleksa Sarai
4356d575ef fhandle: expose u64 mount id to name_to_handle_at(2)
Now that we provide a unique 64-bit mount ID interface in statx(2), we
can now provide a race-free way for name_to_handle_at(2) to provide a
file handle and corresponding mount without needing to worry about
racing with /proc/mountinfo parsing or having to open a file just to do
statx(2).

While this is not necessary if you are using AT_EMPTY_PATH and don't
care about an extra statx(2) call, users that pass full paths into
name_to_handle_at(2) need to know which mount the file handle comes from
(to make sure they don't try to open_by_handle_at a file handle from a
different filesystem) and switching to AT_EMPTY_PATH would require
allocating a file for every name_to_handle_at(2) call, turning

  err = name_to_handle_at(-EBADF, "/foo/bar/baz", &handle, &mntid,
                          AT_HANDLE_MNT_ID_UNIQUE);

into

  int fd = openat(-EBADF, "/foo/bar/baz", O_PATH | O_CLOEXEC);
  err1 = name_to_handle_at(fd, "", &handle, &unused_mntid, AT_EMPTY_PATH);
  err2 = statx(fd, "", AT_EMPTY_PATH, STATX_MNT_ID_UNIQUE, &statxbuf);
  mntid = statxbuf.stx_mnt_id;
  close(fd);

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20240828-exportfs-u64-mount-id-v3-2-10c2c4c16708@cyphar.com
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-05 11:39:17 +02:00
Linus Torvalds
91bd008d4e Probes updates for v6.11:
Uprobes:
 - x86/shstk: Make return uprobe work with shadow stack.
 - Add uretprobe syscall which speeds up the uretprobe 10-30% faster. This
   syscall is automatically used from user-space trampolines which are
   generated by the uretprobe. If this syscall is used by normal
   user program, it will cause SIGILL. Note that this is currently only
   implemented on x86_64.
   (This also has 2 fixes for adjusting the syscall number to avoid conflict
    with new *attrat syscalls.)
 - uprobes/perf: fix user stack traces in the presence of pending uretprobe.
   This corrects the uretprobe's trampoline address in the stacktrace with
   correct return address.
 - selftests/x86: Add a return uprobe with shadow stack test.
 - selftests/bpf: Add uretprobe syscall related tests.
   . test case for register integrity check.
   . test case with register changing case.
   . test case for uretprobe syscall without uprobes (expected to be failed).
   . test case for uretprobe with shadow stack.
 - selftests/bpf: add test validating uprobe/uretprobe stack traces
 - MAINTAINERS: Add uprobes entry. This does not specify the tree but to
   clarify who maintains and reviews the uprobes.
 
 Kprobes:
 - tracing/kprobes: Test case cleanups. Replace redundant WARN_ON_ONCE() +
   pr_warn() with WARN_ONCE() and remove unnecessary code from selftest.
 - tracing/kprobes: Add symbol counting check when module loads. This
   checks the uniqueness of the probed symbol on modules. The same check
   has already done for kernel symbols.
   (This also has a fix for build error with CONFIG_MODULES=n)
 
 Cleanup:
 - Add MODULE_DESCRIPTION() macros for fprobe and kprobe examples.
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Merge tag 'probes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:
 "Uprobes:

   - x86/shstk: Make return uprobe work with shadow stack

   - Add uretprobe syscall which speeds up the uretprobe 10-30% faster.
     This syscall is automatically used from user-space trampolines
     which are generated by the uretprobe. If this syscall is used by
     normal user program, it will cause SIGILL. Note that this is
     currently only implemented on x86_64.

     (This also has two fixes for adjusting the syscall number to avoid
     conflict with new *attrat syscalls.)

   - uprobes/perf: fix user stack traces in the presence of pending
     uretprobe. This corrects the uretprobe's trampoline address in the
     stacktrace with correct return address

   - selftests/x86: Add a return uprobe with shadow stack test

   - selftests/bpf: Add uretprobe syscall related tests.
      - test case for register integrity check
      - test case with register changing case
      - test case for uretprobe syscall without uprobes (expected to fail)
      - test case for uretprobe with shadow stack

   - selftests/bpf: add test validating uprobe/uretprobe stack traces

   - MAINTAINERS: Add uprobes entry. This does not specify the tree but
     to clarify who maintains and reviews the uprobes

  Kprobes:

   - tracing/kprobes: Test case cleanups.

     Replace redundant WARN_ON_ONCE() + pr_warn() with WARN_ONCE() and
     remove unnecessary code from selftest

   - tracing/kprobes: Add symbol counting check when module loads.

     This checks the uniqueness of the probed symbol on modules. The
     same check has already done for kernel symbols

     (This also has a fix for build error with CONFIG_MODULES=n)

  Cleanup:

   - Add MODULE_DESCRIPTION() macros for fprobe and kprobe examples"

* tag 'probes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  MAINTAINERS: Add uprobes entry
  selftests/bpf: Change uretprobe syscall number in uprobe_syscall test
  uprobe: Change uretprobe syscall scope and number
  tracing/kprobes: Fix build error when find_module() is not available
  tracing/kprobes: Add symbol counting check when module loads
  selftests/bpf: add test validating uprobe/uretprobe stack traces
  perf,uprobes: fix user stack traces in the presence of pending uretprobes
  tracing/kprobe: Remove cleanup code unrelated to selftest
  tracing/kprobe: Integrate test warnings into WARN_ONCE
  selftests/bpf: Add uretprobe shadow stack test
  selftests/bpf: Add uretprobe syscall call from user space test
  selftests/bpf: Add uretprobe syscall test for regs changes
  selftests/bpf: Add uretprobe syscall test for regs integrity
  selftests/x86: Add return uprobe shadow stack test
  uprobe: Add uretprobe syscall to speed up return probe
  uprobe: Wire up uretprobe system call
  x86/shstk: Make return uprobe work with shadow stack
  samples: kprobes: add missing MODULE_DESCRIPTION() macros
  fprobe: add missing MODULE_DESCRIPTION() macro
2024-07-18 12:19:20 -07:00
Arnd Bergmann
63e2f40c9e syscalls: fix sys_fanotify_mark prototype
My earlier fix missed an incorrect function prototype that shows up on
native 32-bit builds:

In file included from fs/notify/fanotify/fanotify_user.c:14:
include/linux/syscalls.h:248:25: error: conflicting types for 'sys_fanotify_mark'; have 'long int(int,  unsigned int,  u32,  u32,  int,  const char *)' {aka 'long int(int,  unsigned int,  unsigned int,  unsigned int,  int,  const char *)'}
 1924 | SYSCALL32_DEFINE6(fanotify_mark,
      | ^~~~~~~~~~~~~~~~~
include/linux/syscalls.h:862:17: note: previous declaration of 'sys_fanotify_mark' with type 'long int(int,  unsigned int,  u64,  int, const char *)' {aka 'long int(int,  unsigned int,  long long unsigned int,  int,  const char *)'}

On x86 and powerpc, the prototype is also wrong but hidden in an #ifdef,
so it never caused problems.

Add another alternative declaration that matches the conditional function
definition.

Fixes: 403f17a330 ("parisc: use generic sys_fanotify_mark implementation")
Cc: stable@vger.kernel.org
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-07-01 14:52:12 +02:00
Arnd Bergmann
0fa8ab5f35 linux/syscalls.h: add missing __user annotations
A couple of declarations in linux/syscalls.h are missing __user
annotations on their pointers, which can lead to warnings from
sparse because these don't match the implementation that have
the correct address space annotations.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-06-25 15:57:38 +02:00
Arnd Bergmann
4b8e88e563 ftruncate: pass a signed offset
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: 3f6d078d4a ("fix compat truncate/ftruncate")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-06-24 18:29:20 +02:00
Jiri Olsa
190fec72df uprobe: Wire up uretprobe system call
Wiring up uretprobe system call, which comes in following changes.
We need to do the wiring before, because the uretprobe implementation
needs the syscall number.

Note at the moment uretprobe syscall is supported only for native
64-bit process.

Link: https://lore.kernel.org/all/20240611112158.40795-3-jolsa@kernel.org/

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-06-12 08:44:27 +09:00
Jeff Xu
8be7258aad mseal: add mseal syscall
The new mseal() is an syscall on 64 bit CPU, and with following signature:

int mseal(void addr, size_t len, unsigned long flags)
addr/len: memory range.
flags: reserved.

mseal() blocks following operations for the given memory range.

1> Unmapping, moving to another location, and shrinking the size,
   via munmap() and mremap(), can leave an empty space, therefore can
   be replaced with a VMA with a new set of attributes.

2> Moving or expanding a different VMA into the current location,
   via mremap().

3> Modifying a VMA via mmap(MAP_FIXED).

4> Size expansion, via mremap(), does not appear to pose any specific
   risks to sealed VMAs. It is included anyway because the use case is
   unclear. In any case, users can rely on merging to expand a sealed VMA.

5> mprotect() and pkey_mprotect().

6> Some destructive madvice() behaviors (e.g. MADV_DONTNEED) for anonymous
   memory, when users don't have write permission to the memory. Those
   behaviors can alter region contents by discarding pages, effectively a
   memset(0) for anonymous memory.

Following input during RFC are incooperated into this patch:

Jann Horn: raising awareness and providing valuable insights on the
destructive madvise operations.
Linus Torvalds: assisting in defining system call signature and scope.
Liam R. Howlett: perf optimization.
Theo de Raadt: sharing the experiences and insight gained from
  implementing mimmutable() in OpenBSD.

Finally, the idea that inspired this patch comes from Stephen Röttger's
work in Chrome V8 CFI.

[jeffxu@chromium.org: add branch prediction hint, per Pedro]
  Link: https://lkml.kernel.org/r/20240423192825.1273679-2-jeffxu@chromium.org
Link: https://lkml.kernel.org/r/20240415163527.626541-3-jeffxu@chromium.org
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Stephen Röttger <sroettger@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Amer Al Shanawany <amer.shanawany@gmail.com>
Cc: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-23 19:40:26 -07:00
Casey Schaufler
a5a858f622 lsm: use 32-bit compatible data types in LSM syscalls
Change the size parameters in lsm_list_modules(), lsm_set_self_attr()
and lsm_get_self_attr() from size_t to u32. This avoids the need to
have different interfaces for 32 and 64 bit systems.

Cc: stable@vger.kernel.org
Fixes: a04a119808 ("LSM: syscalls for current process attributes")
Fixes: ad4aff9ec2 ("LSM: Create lsm_list_modules system call")
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reported-and-reviewed-by: Dmitry V. Levin <ldv@strace.io>
[PM: subject and metadata tweaks, syscall.h fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-03-14 11:31:26 -04:00
Richard Palethorpe
56062d60f1 x86/entry/ia32: Ensure s32 is sign extended to s64
Presently ia32 registers stored in ptregs are unconditionally cast to
unsigned int by the ia32 stub. They are then cast to long when passed to
__se_sys*, but will not be sign extended.

This takes the sign of the syscall argument into account in the ia32
stub. It still casts to unsigned int to avoid implementation specific
behavior. However then casts to int or unsigned int as necessary. So that
the following cast to long sign extends the value.

This fixes the io_pgetevents02 LTP test when compiled with -m32. Presently
the systemcall io_pgetevents_time64() unexpectedly accepts -1 for the
maximum number of events.

It doesn't appear other systemcalls with signed arguments are effected
because they all have compat variants defined and wired up.

Fixes: ebeb8c82ff ("syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION and x32")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240110130122.3836513-1-nik.borisov@suse.com
Link: https://lore.kernel.org/ltp/20210921130127.24131-1-rpalethorpe@suse.com/
2024-01-24 11:49:19 +01:00
Christian Brauner
ba5afb9a84
fs: rework listmount() implementation
Linus pointed out that there's error handling and naming issues in the
that we should rewrite:

* Perform the access checks for the buffer before actually doing any
  work instead of doing it during the iteration.
* Rename the arguments to listmount() and do_listmount() to clarify what
  the arguments are used for.
* Get rid of the pointless ctr variable and overflow checking.
* Get rid of the pointless speculation check.

Link: https://lore.kernel.org/r/CAHk-=wjh6Cypo8WC-McXgSzCaou3UXccxB+7PVeSuGR8AjCphg@mail.gmail.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-01-13 13:06:25 +01:00
Linus Torvalds
063a7ce32d lsm/stable-6.8 PR 20240105
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Merge tag 'lsm-pr-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull security module updates from Paul Moore:

 - Add three new syscalls: lsm_list_modules(), lsm_get_self_attr(), and
   lsm_set_self_attr().

   The first syscall simply lists the LSMs enabled, while the second and
   third get and set the current process' LSM attributes. Yes, these
   syscalls may provide similar functionality to what can be found under
   /proc or /sys, but they were designed to support multiple,
   simultaneaous (stacked) LSMs from the start as opposed to the current
   /proc based solutions which were created at a time when only one LSM
   was allowed to be active at a given time.

   We have spent considerable time discussing ways to extend the
   existing /proc interfaces to support multiple, simultaneaous LSMs and
   even our best ideas have been far too ugly to support as a kernel
   API; after +20 years in the kernel, I felt the LSM layer had
   established itself enough to justify a handful of syscalls.

   Support amongst the individual LSM developers has been nearly
   unanimous, with a single objection coming from Tetsuo (TOMOYO) as he
   is worried that the LSM_ID_XXX token concept will make it more
   difficult for out-of-tree LSMs to survive. Several members of the LSM
   community have demonstrated the ability for out-of-tree LSMs to
   continue to exist by picking high/unused LSM_ID values as well as
   pointing out that many kernel APIs rely on integer identifiers, e.g.
   syscalls (!), but unfortunately Tetsuo's objections remain.

   My personal opinion is that while I have no interest in penalizing
   out-of-tree LSMs, I'm not going to penalize in-tree development to
   support out-of-tree development, and I view this as a necessary step
   forward to support the push for expanded LSM stacking and reduce our
   reliance on /proc and /sys which has occassionally been problematic
   for some container users. Finally, we have included the linux-api
   folks on (all?) recent revisions of the patchset and addressed all of
   their concerns.

 - Add a new security_file_ioctl_compat() LSM hook to handle the 32-bit
   ioctls on 64-bit systems problem.

   This patch includes support for all of the existing LSMs which
   provide ioctl hooks, although it turns out only SELinux actually
   cares about the individual ioctls. It is worth noting that while
   Casey (Smack) and Tetsuo (TOMOYO) did not give explicit ACKs to this
   patch, they did both indicate they are okay with the changes.

 - Fix a potential memory leak in the CALIPSO code when IPv6 is disabled
   at boot.

   While it's good that we are fixing this, I doubt this is something
   users are seeing in the wild as you need to both disable IPv6 and
   then attempt to configure IPv6 labeled networking via
   NetLabel/CALIPSO; that just doesn't make much sense.

   Normally this would go through netdev, but Jakub asked me to take
   this patch and of all the trees I maintain, the LSM tree seemed like
   the best fit.

 - Update the LSM MAINTAINERS entry with additional information about
   our process docs, patchwork, bug reporting, etc.

   I also noticed that the Lockdown LSM is missing a dedicated
   MAINTAINERS entry so I've added that to the pull request. I've been
   working with one of the major Lockdown authors/contributors to see if
   they are willing to step up and assume a Lockdown maintainer role;
   hopefully that will happen soon, but in the meantime I'll continue to
   look after it.

 - Add a handful of mailmap entries for Serge Hallyn and myself.

* tag 'lsm-pr-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (27 commits)
  lsm: new security_file_ioctl_compat() hook
  lsm: Add a __counted_by() annotation to lsm_ctx.ctx
  calipso: fix memory leak in netlbl_calipso_add_pass()
  selftests: remove the LSM_ID_IMA check in lsm/lsm_list_modules_test
  MAINTAINERS: add an entry for the lockdown LSM
  MAINTAINERS: update the LSM entry
  mailmap: add entries for Serge Hallyn's dead accounts
  mailmap: update/replace my old email addresses
  lsm: mark the lsm_id variables are marked as static
  lsm: convert security_setselfattr() to use memdup_user()
  lsm: align based on pointer length in lsm_fill_user_ctx()
  lsm: consolidate buffer size handling into lsm_fill_user_ctx()
  lsm: correct error codes in security_getselfattr()
  lsm: cleanup the size counters in security_getselfattr()
  lsm: don't yet account for IMA in LSM_CONFIG_COUNT calculation
  lsm: drop LSM_ID_IMA
  LSM: selftests for Linux Security Module syscalls
  SELinux: Add selfattr hooks
  AppArmor: Add selfattr hooks
  Smack: implement setselfattr and getselfattr hooks
  ...
2024-01-09 12:57:46 -08:00
Miklos Szeredi
b4c2bea8ce
add listmount(2) syscall
Add way to query the children of a particular mount.  This is a more
flexible way to iterate the mount tree than having to parse
/proc/self/mountinfo.

Lookup the mount by the new 64bit mount ID. If a mount needs to be
queried based on path, then statx(2) can be used to first query the
mount ID belonging to the path.

Return an array of new (64bit) mount ID's. Without privileges only
mounts are listed which are reachable from the task's root.

Folded into this patch are several later improvements. Keeping them
separate would make the history pointlessly confusing:

* Recursive listing of mounts is the default now (cf. [1]).
* Remove explicit LISTMOUNT_UNREACHABLE flag (cf. [1]) and fail if mount
  is unreachable from current root. This also makes permission checking
  consistent with statmount() (cf. [3]).
* Start listing mounts in unique mount ID order (cf. [2]) to allow
  continuing listmount() from a midpoint.
* Allow to continue listmount(). The @request_mask parameter is renamed
  and to @param to be usable by both statmount() and listmount().
  If @param is set to a mount id then listmount() will continue listing
  mounts from that id on. This allows listing mounts in multiple
  listmount invocations without having to resize the buffer. If @param
  is zero then the listing starts from the beginning (cf. [4]).
* Don't return EOVERFLOW, instead return the buffer size which allows to
  detect a full buffer as well (cf. [4]).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://lore.kernel.org/r/20231025140205.3586473-6-mszeredi@redhat.com
Reviewed-by: Ian Kent <raven@themaw.net>
Link: https://lore.kernel.org/r/20231128160337.29094-2-mszeredi@redhat.com [1] (folded)
Link: https://lore.kernel.org/r/20231128160337.29094-3-mszeredi@redhat.com [2] (folded)
Link: https://lore.kernel.org/r/20231128160337.29094-4-mszeredi@redhat.com [3] (folded)
Link: https://lore.kernel.org/r/20231128160337.29094-5-mszeredi@redhat.com [4] (folded)
[Christian Brauner <brauner@kernel.org>: various smaller fixes]
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-14 11:49:17 +01:00
Miklos Szeredi
46eae99ef7
add statmount(2) syscall
Add a way to query attributes of a single mount instead of having to parse
the complete /proc/$PID/mountinfo, which might be huge.

Lookup the mount the new 64bit mount ID.  If a mount needs to be queried
based on path, then statx(2) can be used to first query the mount ID
belonging to the path.

Design is based on a suggestion by Linus:

  "So I'd suggest something that is very much like "statfsat()", which gets
   a buffer and a length, and returns an extended "struct statfs" *AND*
   just a string description at the end."

The interface closely mimics that of statx.

Handle ASCII attributes by appending after the end of the structure (as per
above suggestion).  Pointers to strings are stored in u64 members to make
the structure the same regardless of pointer size.  Strings are nul
terminated.

Link: https://lore.kernel.org/all/CAHk-=wh5YifP7hzKSbwJj94+DZ2czjrZsczy6GBimiogZws=rg@mail.gmail.com/
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://lore.kernel.org/r/20231025140205.3586473-5-mszeredi@redhat.com
Reviewed-by: Ian Kent <raven@themaw.net>
[Christian Brauner <brauner@kernel.org>: various minor changes]
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-11 19:11:02 +01:00
Casey Schaufler
ad4aff9ec2 LSM: Create lsm_list_modules system call
Create a system call to report the list of Linux Security Modules
that are active on the system. The list is provided as an array
of LSM ID numbers.

The calling application can use this list determine what LSM
specific actions it might take. That might include choosing an
output format, determining required privilege or bypassing
security module specific behavior.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12 22:54:42 -05:00
Casey Schaufler
a04a119808 LSM: syscalls for current process attributes
Create a system call lsm_get_self_attr() to provide the security
module maintained attributes of the current process.
Create a system call lsm_set_self_attr() to set a security
module maintained attribute of the current process.
Historically these attributes have been exposed to user space via
entries in procfs under /proc/self/attr.

The attribute value is provided in a lsm_ctx structure. The structure
identifies the size of the attribute, and the attribute value. The format
of the attribute value is defined by the security module. A flags field
is included for LSM specific information. It is currently unused and must
be 0. The total size of the data, including the lsm_ctx structure and any
padding, is maintained as well.

struct lsm_ctx {
        __u64 id;
        __u64 flags;
        __u64 len;
        __u64 ctx_len;
        __u8 ctx[];
};

Two new LSM hooks are used to interface with the LSMs.
security_getselfattr() collects the lsm_ctx values from the
LSMs that support the hook, accounting for space requirements.
security_setselfattr() identifies which LSM the attribute is
intended for and passes it along.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12 22:54:42 -05:00
Linus Torvalds
1e0c505e13 asm-generic updates for v6.7
The ia64 architecture gets its well-earned retirement as planned,
 now that there is one last (mostly) working release that will
 be maintained as an LTS kernel.
 
 The architecture specific system call tables are updated for
 the added map_shadow_stack() syscall and to remove references
 to the long-gone sys_lookup_dcookie() syscall.
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Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull ia64 removal and asm-generic updates from Arnd Bergmann:

 - The ia64 architecture gets its well-earned retirement as planned,
   now that there is one last (mostly) working release that will be
   maintained as an LTS kernel.

 - The architecture specific system call tables are updated for the
   added map_shadow_stack() syscall and to remove references to the
   long-gone sys_lookup_dcookie() syscall.

* tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  hexagon: Remove unusable symbols from the ptrace.h uapi
  asm-generic: Fix spelling of architecture
  arch: Reserve map_shadow_stack() syscall number for all architectures
  syscalls: Cleanup references to sys_lookup_dcookie()
  Documentation: Drop or replace remaining mentions of IA64
  lib/raid6: Drop IA64 support
  Documentation: Drop IA64 from feature descriptions
  kernel: Drop IA64 support from sig_fault handlers
  arch: Remove Itanium (IA-64) architecture
2023-11-01 15:28:33 -10:00
Sohil Mehta
ccab211af3 syscalls: Cleanup references to sys_lookup_dcookie()
commit 'be65de6b03aa ("fs: Remove dcookies support")' removed the
syscall definition for lookup_dcookie.  However, syscall tables still
point to the old sys_lookup_dcookie() definition. Update syscall tables
of all architectures to directly point to sys_ni_syscall() instead.

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org> # for perf
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2023-10-03 19:51:37 +02:00
peterz@infradead.org
0f4b5f9722 futex: Add sys_futex_requeue()
Finish off the 'simple' futex2 syscall group by adding
sys_futex_requeue(). Unlike sys_futex_{wait,wake}() its arguments are
too numerous to fit into a regular syscall. As such, use struct
futex_waitv to pass the 'source' and 'destination' futexes to the
syscall.

This syscall implements what was previously known as FUTEX_CMP_REQUEUE
and uses {val, uaddr, flags} for source and {uaddr, flags} for
destination.

This design explicitly allows requeueing between different types of
futex by having a different flags word per uaddr.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230921105248.511860556@noisy.programming.kicks-ass.net
2023-09-21 19:22:10 +02:00
peterz@infradead.org
cb8c4312af futex: Add sys_futex_wait()
To complement sys_futex_waitv()/wake(), add sys_futex_wait(). This
syscall implements what was previously known as FUTEX_WAIT_BITSET
except it uses 'unsigned long' for the value and bitmask arguments,
takes timespec and clockid_t arguments for the absolute timeout and
uses FUTEX2 flags.

The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230921105248.164324363@noisy.programming.kicks-ass.net
2023-09-21 19:22:08 +02:00
peterz@infradead.org
9f6c532f59 futex: Add sys_futex_wake()
To complement sys_futex_waitv() add sys_futex_wake(). This syscall
implements what was previously known as FUTEX_WAKE_BITSET except it
uses 'unsigned long' for the bitmask and takes FUTEX2 flags.

The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230921105247.936205525@noisy.programming.kicks-ass.net
2023-09-21 19:22:07 +02:00
Linus Torvalds
df57721f9a Add x86 shadow stack support
Convert IBT selftest to asm to fix objtool warning
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Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 shadow stack support from Dave Hansen:
 "This is the long awaited x86 shadow stack support, part of Intel's
  Control-flow Enforcement Technology (CET).

  CET consists of two related security features: shadow stacks and
  indirect branch tracking. This series implements just the shadow stack
  part of this feature, and just for userspace.

  The main use case for shadow stack is providing protection against
  return oriented programming attacks. It works by maintaining a
  secondary (shadow) stack using a special memory type that has
  protections against modification. When executing a CALL instruction,
  the processor pushes the return address to both the normal stack and
  to the special permission shadow stack. Upon RET, the processor pops
  the shadow stack copy and compares it to the normal stack copy.

  For more information, refer to the links below for the earlier
  versions of this patch set"

Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/

* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
  x86/shstk: Change order of __user in type
  x86/ibt: Convert IBT selftest to asm
  x86/shstk: Don't retry vm_munmap() on -EINTR
  x86/kbuild: Fix Documentation/ reference
  x86/shstk: Move arch detail comment out of core mm
  x86/shstk: Add ARCH_SHSTK_STATUS
  x86/shstk: Add ARCH_SHSTK_UNLOCK
  x86: Add PTRACE interface for shadow stack
  selftests/x86: Add shadow stack test
  x86/cpufeatures: Enable CET CR4 bit for shadow stack
  x86/shstk: Wire in shadow stack interface
  x86: Expose thread features in /proc/$PID/status
  x86/shstk: Support WRSS for userspace
  x86/shstk: Introduce map_shadow_stack syscall
  x86/shstk: Check that signal frame is shadow stack mem
  x86/shstk: Check that SSP is aligned on sigreturn
  x86/shstk: Handle signals for shadow stack
  x86/shstk: Introduce routines modifying shstk
  x86/shstk: Handle thread shadow stack
  x86/shstk: Add user-mode shadow stack support
  ...
2023-08-31 12:20:12 -07:00
Linus Torvalds
6bfce7759c A single update to the core entry code, which removes the empty user
address limit check which is a leftover of the removed TIF_FSCHECK.
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Merge tag 'core-entry-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core entry code update from Thomas Gleixner:
 "A single update to the core entry code, which removes the empty user
  address limit check which is a leftover of the removed TIF_FSCHECK"

* tag 'core-entry-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Remove empty addr_limit_user_check()
2023-08-28 14:04:55 -07:00
Mark Rutland
1dfe3a5a7c entry: Remove empty addr_limit_user_check()
Back when set_fs() was a generic API for altering the address limit,
addr_limit_user_check() was a safety measure to prevent userspace being
able to issue syscalls with an unbound limit.

With the the removal of set_fs() as a generic API, the last user of
addr_limit_user_check() was removed in commit:

  b5a5a01d8e ("arm64: uaccess: remove addr_limit_user_check()")

... as since that commit, no architecture defines TIF_FSCHECK, and hence
addr_limit_user_check() always expands to nothing.

Remove addr_limit_user_check(), updating the comment in
exit_to_user_mode_prepare() to no longer refer to it. At the same time,
the comment is reworded to be a little more generic so as to cover
kmap_assert_nomap() in addition to lockdep_sys_exit().

No functional change.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230821163526.2319443-1-mark.rutland@arm.com
2023-08-23 10:32:39 +02:00
Rick Edgecombe
c35559f94e x86/shstk: Introduce map_shadow_stack syscall
When operating with shadow stacks enabled, the kernel will automatically
allocate shadow stacks for new threads, however in some cases userspace
will need additional shadow stacks. The main example of this is the
ucontext family of functions, which require userspace allocating and
pivoting to userspace managed stacks.

Unlike most other user memory permissions, shadow stacks need to be
provisioned with special data in order to be useful. They need to be setup
with a restore token so that userspace can pivot to them via the RSTORSSP
instruction. But, the security design of shadow stacks is that they
should not be written to except in limited circumstances. This presents a
problem for userspace, as to how userspace can provision this special
data, without allowing for the shadow stack to be generally writable.

Previously, a new PROT_SHADOW_STACK was attempted, which could be
mprotect()ed from RW permissions after the data was provisioned. This was
found to not be secure enough, as other threads could write to the
shadow stack during the writable window.

The kernel can use a special instruction, WRUSS, to write directly to
userspace shadow stacks. So the solution can be that memory can be mapped
as shadow stack permissions from the beginning (never generally writable
in userspace), and the kernel itself can write the restore token.

First, a new madvise() flag was explored, which could operate on the
PROT_SHADOW_STACK memory. This had a couple of downsides:
1. Extra checks were needed in mprotect() to prevent writable memory from
   ever becoming PROT_SHADOW_STACK.
2. Extra checks/vma state were needed in the new madvise() to prevent
   restore tokens being written into the middle of pre-used shadow stacks.
   It is ideal to prevent restore tokens being added at arbitrary
   locations, so the check was to make sure the shadow stack had never been
   written to.
3. It stood out from the rest of the madvise flags, as more of direct
   action than a hint at future desired behavior.

So rather than repurpose two existing syscalls (mmap, madvise) that don't
quite fit, just implement a new map_shadow_stack syscall to allow
userspace to map and setup new shadow stacks in one step. While ucontext
is the primary motivator, userspace may have other unforeseen reasons to
setup its own shadow stacks using the WRSS instruction. Towards this
provide a flag so that stacks can be optionally setup securely for the
common case of ucontext without enabling WRSS. Or potentially have the
kernel set up the shadow stack in some new way.

The following example demonstrates how to create a new shadow stack with
map_shadow_stack:
void *shstk = map_shadow_stack(addr, stack_size, SHADOW_STACK_SET_TOKEN);

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-35-rick.p.edgecombe%40intel.com
2023-08-02 15:01:51 -07:00
Alexey Gladkov
09da082b07
fs: Add fchmodat2()
On the userspace side fchmodat(3) is implemented as a wrapper
function which implements the POSIX-specified interface. This
interface differs from the underlying kernel system call, which does not
have a flags argument. Most implementations require procfs [1][2].

There doesn't appear to be a good userspace workaround for this issue
but the implementation in the kernel is pretty straight-forward.

The new fchmodat2() syscall allows to pass the AT_SYMLINK_NOFOLLOW flag,
unlike existing fchmodat.

[1] https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=17eca54051ee28ba1ec3f9aed170a62630959143;hb=a492b1e5ef7ab50c6fdd4e4e9879ea5569ab0a6c#l35
[2] https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c?id=718f363bc2067b6487900eddc9180c84e7739f80#n28

Co-developed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Message-Id: <f2a846ef495943c5d101011eebcf01179d0c7b61.1689092120.git.legion@kernel.org>
[brauner: pre reviews, do flag conversion in do_fchmodat() directly]
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-27 12:24:09 +02:00
Palmer Dabbelt
06a0213977 Non-functional cleanup of a "__user * filename"
The next patch defines a very similar interface, which I copied from
this definition.  Since I'm touching it anyway I don't see any reason
not to just go fix this one up.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Message-Id: <ef644540cfd8717f30bcc5e4c32f06c80b6c156e.1689092120.git.legion@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-11 18:55:49 +02:00
Linus Torvalds
7b82e90411 asm-generic updates for 6.5
These are cleanups for architecture specific header files:
 
  - the comments in include/linux/syscalls.h have gone out of sync
    and are really pointless, so these get removed
 
  - The asm/bitsperlong.h header no longer needs to be architecture
    specific on modern compilers, so use a generic version for newer
    architectures that use new enough userspace compilers
 
  - A cleanup for virt_to_pfn/virt_to_bus to have proper type
    checking, forcing the use of pointers
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Merge tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic updates from Arnd Bergmann:
 "These are cleanups for architecture specific header files:

   - the comments in include/linux/syscalls.h have gone out of sync and
     are really pointless, so these get removed

   - The asm/bitsperlong.h header no longer needs to be architecture
     specific on modern compilers, so use a generic version for newer
     architectures that use new enough userspace compilers

   - A cleanup for virt_to_pfn/virt_to_bus to have proper type checking,
     forcing the use of pointers"

* tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  syscalls: Remove file path comments from headers
  tools arch: Remove uapi bitsperlong.h of hexagon and microblaze
  asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch
  m68k/mm: Make pfn accessors static inlines
  arm64: memory: Make virt_to_pfn() a static inline
  ARM: mm: Make virt_to_pfn() a static inline
  asm-generic/page.h: Make pfn accessors static inlines
  xen/netback: Pass (void *) to virt_to_page()
  netfs: Pass a pointer to virt_to_page()
  cifs: Pass a pointer to virt_to_page() in cifsglob
  cifs: Pass a pointer to virt_to_page()
  riscv: mm: init: Pass a pointer to virt_to_page()
  ARC: init: Pass a pointer to virt_to_pfn() in init
  m68k: Pass a pointer to virt_to_pfn() virt_to_page()
  fs/proc/kcore.c: Pass a pointer to virt_addr_valid()
2023-07-06 10:06:04 -07:00
Linus Torvalds
6e17c6de3d - Yosry Ahmed brought back some cgroup v1 stats in OOM logs.
- Yosry has also eliminated cgroup's atomic rstat flushing.
 
 - Nhat Pham adds the new cachestat() syscall.  It provides userspace
   with the ability to query pagecache status - a similar concept to
   mincore() but more powerful and with improved usability.
 
 - Mel Gorman provides more optimizations for compaction, reducing the
   prevalence of page rescanning.
 
 - Lorenzo Stoakes has done some maintanance work on the get_user_pages()
   interface.
 
 - Liam Howlett continues with cleanups and maintenance work to the maple
   tree code.  Peng Zhang also does some work on maple tree.
 
 - Johannes Weiner has done some cleanup work on the compaction code.
 
 - David Hildenbrand has contributed additional selftests for
   get_user_pages().
 
 - Thomas Gleixner has contributed some maintenance and optimization work
   for the vmalloc code.
 
 - Baolin Wang has provided some compaction cleanups,
 
 - SeongJae Park continues maintenance work on the DAMON code.
 
 - Huang Ying has done some maintenance on the swap code's usage of
   device refcounting.
 
 - Christoph Hellwig has some cleanups for the filemap/directio code.
 
 - Ryan Roberts provides two patch series which yield some
   rationalization of the kernel's access to pte entries - use the provided
   APIs rather than open-coding accesses.
 
 - Lorenzo Stoakes has some fixes to the interaction between pagecache
   and directio access to file mappings.
 
 - John Hubbard has a series of fixes to the MM selftesting code.
 
 - ZhangPeng continues the folio conversion campaign.
 
 - Hugh Dickins has been working on the pagetable handling code, mainly
   with a view to reducing the load on the mmap_lock.
 
 - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from
   128 to 8.
 
 - Domenico Cerasuolo has improved the zswap reclaim mechanism by
   reorganizing the LRU management.
 
 - Matthew Wilcox provides some fixups to make gfs2 work better with the
   buffer_head code.
 
 - Vishal Moola also has done some folio conversion work.
 
 - Matthew Wilcox has removed the remnants of the pagevec code - their
   functionality is migrated over to struct folio_batch.
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Merge tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull mm updates from Andrew Morton:

 - Yosry Ahmed brought back some cgroup v1 stats in OOM logs

 - Yosry has also eliminated cgroup's atomic rstat flushing

 - Nhat Pham adds the new cachestat() syscall. It provides userspace
   with the ability to query pagecache status - a similar concept to
   mincore() but more powerful and with improved usability

 - Mel Gorman provides more optimizations for compaction, reducing the
   prevalence of page rescanning

 - Lorenzo Stoakes has done some maintanance work on the
   get_user_pages() interface

 - Liam Howlett continues with cleanups and maintenance work to the
   maple tree code. Peng Zhang also does some work on maple tree

 - Johannes Weiner has done some cleanup work on the compaction code

 - David Hildenbrand has contributed additional selftests for
   get_user_pages()

 - Thomas Gleixner has contributed some maintenance and optimization
   work for the vmalloc code

 - Baolin Wang has provided some compaction cleanups,

 - SeongJae Park continues maintenance work on the DAMON code

 - Huang Ying has done some maintenance on the swap code's usage of
   device refcounting

 - Christoph Hellwig has some cleanups for the filemap/directio code

 - Ryan Roberts provides two patch series which yield some
   rationalization of the kernel's access to pte entries - use the
   provided APIs rather than open-coding accesses

 - Lorenzo Stoakes has some fixes to the interaction between pagecache
   and directio access to file mappings

 - John Hubbard has a series of fixes to the MM selftesting code

 - ZhangPeng continues the folio conversion campaign

 - Hugh Dickins has been working on the pagetable handling code, mainly
   with a view to reducing the load on the mmap_lock

 - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment
   from 128 to 8

 - Domenico Cerasuolo has improved the zswap reclaim mechanism by
   reorganizing the LRU management

 - Matthew Wilcox provides some fixups to make gfs2 work better with the
   buffer_head code

 - Vishal Moola also has done some folio conversion work

 - Matthew Wilcox has removed the remnants of the pagevec code - their
   functionality is migrated over to struct folio_batch

* tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits)
  mm/hugetlb: remove hugetlb_set_page_subpool()
  mm: nommu: correct the range of mmap_sem_read_lock in task_mem()
  hugetlb: revert use of page_cache_next_miss()
  Revert "page cache: fix page_cache_next/prev_miss off by one"
  mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
  mm: memcg: rename and document global_reclaim()
  mm: kill [add|del]_page_to_lru_list()
  mm: compaction: convert to use a folio in isolate_migratepages_block()
  mm: zswap: fix double invalidate with exclusive loads
  mm: remove unnecessary pagevec includes
  mm: remove references to pagevec
  mm: rename invalidate_mapping_pagevec to mapping_try_invalidate
  mm: remove struct pagevec
  net: convert sunrpc from pagevec to folio_batch
  i915: convert i915_gpu_error to use a folio_batch
  pagevec: rename fbatch_count()
  mm: remove check_move_unevictable_pages()
  drm: convert drm_gem_put_pages() to use a folio_batch
  i915: convert shmem_sg_free_table() to use a folio_batch
  scatterlist: add sg_set_folio()
  ...
2023-06-28 10:28:11 -07:00
Sohil Mehta
4dd595c34c syscalls: Remove file path comments from headers
Source file locations for syscall definitions can change over a period
of time. File paths in comments get stale and are hard to maintain long
term. Also, their usefulness is questionable since it would be easier to
locate a syscall definition using the SYSCALL_DEFINEx() macro.

Remove all source file path comments from the syscall headers. Also,
equalize the uneven line spacing (some of which is introduced due to the
deletions).

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2023-06-22 17:10:09 +02:00
Arnd Bergmann
892f439ea1 posix-timers: Add sys_ni_posix_timers() prototype
The sys_ni_posix_timers() definition causes a warning when the declaration
is missing, so this needs to be added along with the normal syscalls,
outside of the #ifdef.

kernel/time/posix-stubs.c:26:17: error: no previous prototype for 'sys_ni_posix_timers' [-Werror=missing-prototypes]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230607142925.3126422-1-arnd@kernel.org
2023-06-18 22:41:53 +02:00
Nhat Pham
cf264e1329 cachestat: implement cachestat syscall
There is currently no good way to query the page cache state of large file
sets and directory trees.  There is mincore(), but it scales poorly: the
kernel writes out a lot of bitmap data that userspace has to aggregate,
when the user really doesn not care about per-page information in that
case.  The user also needs to mmap and unmap each file as it goes along,
which can be quite slow as well.

Some use cases where this information could come in handy:
  * Allowing database to decide whether to perform an index scan or
    direct table queries based on the in-memory cache state of the
    index.
  * Visibility into the writeback algorithm, for performance issues
    diagnostic.
  * Workload-aware writeback pacing: estimating IO fulfilled by page
    cache (and IO to be done) within a range of a file, allowing for
    more frequent syncing when and where there is IO capacity, and
    batching when there is not.
  * Computing memory usage of large files/directory trees, analogous to
    the du tool for disk usage.

More information about these use cases could be found in the following
thread:

https://lore.kernel.org/lkml/20230315170934.GA97793@cmpxchg.org/

This patch implements a new syscall that queries cache state of a file and
summarizes the number of cached pages, number of dirty pages, number of
pages marked for writeback, number of (recently) evicted pages, etc.  in a
given range.  Currently, the syscall is only wired in for x86
architecture.

NAME
    cachestat - query the page cache statistics of a file.

SYNOPSIS
    #include <sys/mman.h>

    struct cachestat_range {
        __u64 off;
        __u64 len;
    };

    struct cachestat {
        __u64 nr_cache;
        __u64 nr_dirty;
        __u64 nr_writeback;
        __u64 nr_evicted;
        __u64 nr_recently_evicted;
    };

    int cachestat(unsigned int fd, struct cachestat_range *cstat_range,
        struct cachestat *cstat, unsigned int flags);

DESCRIPTION
    cachestat() queries the number of cached pages, number of dirty
    pages, number of pages marked for writeback, number of evicted
    pages, number of recently evicted pages, in the bytes range given by
    `off` and `len`.

    An evicted page is a page that is previously in the page cache but
    has been evicted since. A page is recently evicted if its last
    eviction was recent enough that its reentry to the cache would
    indicate that it is actively being used by the system, and that
    there is memory pressure on the system.

    These values are returned in a cachestat struct, whose address is
    given by the `cstat` argument.

    The `off` and `len` arguments must be non-negative integers. If
    `len` > 0, the queried range is [`off`, `off` + `len`]. If `len` ==
    0, we will query in the range from `off` to the end of the file.

    The `flags` argument is unused for now, but is included for future
    extensibility. User should pass 0 (i.e no flag specified).

    Currently, hugetlbfs is not supported.

    Because the status of a page can change after cachestat() checks it
    but before it returns to the application, the returned values may
    contain stale information.

RETURN VALUE
    On success, cachestat returns 0. On error, -1 is returned, and errno
    is set to indicate the error.

ERRORS
    EFAULT cstat or cstat_args points to an invalid address.

    EINVAL invalid flags.

    EBADF  invalid file descriptor.

    EOPNOTSUPP file descriptor is of a hugetlbfs file

[nphamcs@gmail.com: replace rounddown logic with the existing helper]
  Link: https://lkml.kernel.org/r/20230504022044.3675469-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20230503013608.2431726-3-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-09 16:25:16 -07:00
Brian Gerst
24e6dc35cc x86/signal/32: Merge native and compat 32-bit signal code
There are significant differences between signal handling on 32-bit vs.
64-bit, like different structure layouts and legacy syscalls.  Instead
of duplicating that code for native and compat, merge both versions
into one file.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/r/20220606203802.158958-8-brgerst@gmail.com
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-10-19 09:58:49 +02:00
Arnd Bergmann
967747bbc0 uaccess: remove CONFIG_SET_FS
There are no remaining callers of set_fs(), so CONFIG_SET_FS
can be removed globally, along with the thread_info field and
any references to it.

This turns access_ok() into a cheaper check against TASK_SIZE_MAX.

As CONFIG_SET_FS is now gone, drop all remaining references to
set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel().

Acked-by: Sam Ravnborg <sam@ravnborg.org> # for sparc32 changes
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> # for arc changes
Acked-by: Stafford Horne <shorne@gmail.com> # [openrisc, asm-generic]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25 09:36:06 +01:00
Aneesh Kumar K.V
21b084fdf2 mm/mempolicy: wire up syscall set_mempolicy_home_node
Link: https://lkml.kernel.org/r/20211202123810.267175-4-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Ben Widawsky <ben.widawsky@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-15 16:30:30 +02:00
André Almeida
bf69bad38c futex: Implement sys_futex_waitv()
Add support to wait on multiple futexes. This is the interface
implemented by this syscall:

futex_waitv(struct futex_waitv *waiters, unsigned int nr_futexes,
	    unsigned int flags, struct timespec *timeout, clockid_t clockid)

struct futex_waitv {
	__u64 val;
	__u64 uaddr;
	__u32 flags;
	__u32 __reserved;
};

Given an array of struct futex_waitv, wait on each uaddr. The thread
wakes if a futex_wake() is performed at any uaddr. The syscall returns
immediately if any waiter has *uaddr != val. *timeout is an optional
absolute timeout value for the operation. This syscall supports only
64bit sized timeout structs. The flags argument of the syscall should be
empty, but it can be used for future extensions. Flags for shared
futexes, sizes, etc. should be used on the individual flags of each
waiter.

__reserved is used for explicit padding and should be 0, but it might be
used for future extensions. If the userspace uses 32-bit pointers, it
should make sure to explicitly cast it when assigning to waitv::uaddr.

Returns the array index of one of the woken futexes. There’s no given
information of how many were woken, or any particular attribute of it
(if it’s the first woken, if it is of the smaller index...).

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210923171111.300673-17-andrealmeid@collabora.com
2021-10-07 13:51:11 +02:00
Peter Zijlstra
af8cc9600b futex: Split out syscalls
Put the syscalls in their own little file.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@collabora.com>
Link: https://lore.kernel.org/r/20210923171111.300673-3-andrealmeid@collabora.com
2021-10-07 13:51:07 +02:00
Linus Torvalds
35776f1051 ARM development updates for 5.15:
- Rename "mod_init" and "mod_exit" so that initcall debug output is
   actually useful (Randy Dunlap)
 - Update maintainers entries for linux-arm-kernel to indicate it is
   moderated for non-subscribers (Randy Dunlap)
 - Move install rules to arch/arm/Makefile (Masahiro Yamada)
 - Drop unnecessary ARCH_NR_GPIOS definition (Linus Walleij)
 - Don't warn about atags_to_fdt() stack size (David Heidelberg)
 - Speed up unaligned copy_{from,to}_kernel_nofault (Arnd Bergmann)
 - Get rid of set_fs() usage (Arnd Bergmann)
 - Remove checks for GCC prior to v4.6 (Geert Uytterhoeven)
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Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM development updates from Russell King:

 - Rename "mod_init" and "mod_exit" so that initcall debug output is
   actually useful (Randy Dunlap)

 - Update maintainers entries for linux-arm-kernel to indicate it is
   moderated for non-subscribers (Randy Dunlap)

 - Move install rules to arch/arm/Makefile (Masahiro Yamada)

 - Drop unnecessary ARCH_NR_GPIOS definition (Linus Walleij)

 - Don't warn about atags_to_fdt() stack size (David Heidelberg)

 - Speed up unaligned copy_{from,to}_kernel_nofault (Arnd Bergmann)

 - Get rid of set_fs() usage (Arnd Bergmann)

 - Remove checks for GCC prior to v4.6 (Geert Uytterhoeven)

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 9118/1: div64: Remove always-true __div64_const32_is_OK() duplicate
  ARM: 9117/1: asm-generic: div64: Remove always-true __div64_const32_is_OK()
  ARM: 9116/1: unified: Remove check for gcc < 4
  ARM: 9110/1: oabi-compat: fix oabi epoll sparse warning
  ARM: 9113/1: uaccess: remove set_fs() implementation
  ARM: 9112/1: uaccess: add __{get,put}_kernel_nofault
  ARM: 9111/1: oabi-compat: rework fcntl64() emulation
  ARM: 9114/1: oabi-compat: rework sys_semtimedop emulation
  ARM: 9108/1: oabi-compat: rework epoll_wait/epoll_pwait emulation
  ARM: 9107/1: syscall: always store thread_info->abi_syscall
  ARM: 9109/1: oabi-compat: add epoll_pwait handler
  ARM: 9106/1: traps: use get_kernel_nofault instead of set_fs()
  ARM: 9115/1: mm/maccess: fix unaligned copy_{from,to}_kernel_nofault
  ARM: 9105/1: atags_to_fdt: don't warn about stack size
  ARM: 9103/1: Drop ARCH_NR_GPIOS definition
  ARM: 9102/1: move theinstall rules to arch/arm/Makefile
  ARM: 9100/1: MAINTAINERS: mark all linux-arm-kernel@infradead list as moderated
  ARM: 9099/1: crypto: rename 'mod_init' & 'mod_exit' functions to be module-specific
2021-09-09 13:25:49 -07:00
Linus Torvalds
14726903c8 Merge branch 'akpm' (patches from Andrew)
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
  ...
2021-09-03 10:08:28 -07:00
Suren Baghdasaryan
dce4910396 mm: wire up syscall process_mrelease
Split off from prev patch in the series that implements the syscall.

Link: https://lkml.kernel.org/r/20210809185259.405936-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jan Engelhardt <jengelh@inai.de>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tim Murray <timmurray@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-03 09:58:17 -07:00
Arnd Bergmann
bdec014528 ARM: 9114/1: oabi-compat: rework sys_semtimedop emulation
sys_oabi_semtimedop() is one of the last users of set_fs() on Arm. To
remove this one, expose the internal code of the actual implementation
that operates on a kernel pointer and call it directly after copying.

There should be no measurable impact on the normal execution of this
function, and it makes the overly long function a little shorter, which
may help readability.

While reworking the oabi version, make it behave a little more like
the native one, using kvmalloc_array() and restructure the code
flow in a similar way.

The naming of __do_semtimedop() is not very good, I hope someone can
come up with a better name.

One regression was spotted by kernel test robot <rong.a.chen@intel.com>
and fixed before the first mailing list submission.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2021-08-20 11:39:26 +01:00
Eric W. Biederman
b48c7236b1 exit/bdflush: Remove the deprecated bdflush system call
The bdflush system call has been deprecated for a very long time.
Recently Michael Schmitz tested[1] and found that the last known
caller of of the bdflush system call is unaffected by it's removal.

Since the code is not needed delete it.

[1] https://lkml.kernel.org/r/36123b5d-daa0-6c2b-f2d4-a942f069fd54@gmail.com
Link: https://lkml.kernel.org/r/87sg10quue.fsf_-_@disp2133
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-07-12 15:17:47 -05:00
Mike Rapoport
7bb7f2ac24 arch, mm: wire up memfd_secret system call where relevant
Wire up memfd_secret system call on architectures that define
ARCH_HAS_SET_DIRECT_MAP, namely arm64, risc-v and x86.

Link: https://lkml.kernel.org/r/20210518072034.31572-7-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tycho Andersen <tycho@tycho.ws>
Cc: Will Deacon <will@kernel.org>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-08 11:48:21 -07:00
Jan Kara
64c2c2c62f quota: Change quotactl_path() systcall to an fd-based one
Some users have pointed out that path-based syscalls are problematic in
some environments and at least directory fd argument and possibly also
resolve flags are desirable for such syscalls. Rather than
reimplementing all details of pathname lookup and following where it may
eventually evolve, let's go for full file descriptor based syscall
similar to how ioctl(2) works since the beginning. Managing of quotas
isn't performance sensitive so the extra overhead of open does not
matter and we are able to consume O_PATH descriptors as well which makes
open cheap anyway. Also for frequent operations (such as retrieving
usage information for all users) we can reuse single fd and in fact get
even better performance as well as avoiding races with possible remounts
etc.

Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
2021-06-07 12:11:24 +02:00
Linus Torvalds
17ae69aba8 Add Landlock, a new LSM from Mickaël Salaün <mic@linux.microsoft.com>
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Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull Landlock LSM from James Morris:
 "Add Landlock, a new LSM from Mickaël Salaün.

  Briefly, Landlock provides for unprivileged application sandboxing.

  From Mickaël's cover letter:
    "The goal of Landlock is to enable to restrict ambient rights (e.g.
     global filesystem access) for a set of processes. Because Landlock
     is a stackable LSM [1], it makes possible to create safe security
     sandboxes as new security layers in addition to the existing
     system-wide access-controls. This kind of sandbox is expected to
     help mitigate the security impact of bugs or unexpected/malicious
     behaviors in user-space applications. Landlock empowers any
     process, including unprivileged ones, to securely restrict
     themselves.

     Landlock is inspired by seccomp-bpf but instead of filtering
     syscalls and their raw arguments, a Landlock rule can restrict the
     use of kernel objects like file hierarchies, according to the
     kernel semantic. Landlock also takes inspiration from other OS
     sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD
     Pledge/Unveil.

     In this current form, Landlock misses some access-control features.
     This enables to minimize this patch series and ease review. This
     series still addresses multiple use cases, especially with the
     combined use of seccomp-bpf: applications with built-in sandboxing,
     init systems, security sandbox tools and security-oriented APIs [2]"

  The cover letter and v34 posting is here:

      https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/

  See also:

      https://landlock.io/

  This code has had extensive design discussion and review over several
  years"

Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1]
Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2]

* tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  landlock: Enable user space to infer supported features
  landlock: Add user and kernel documentation
  samples/landlock: Add a sandbox manager example
  selftests/landlock: Add user space tests
  landlock: Add syscall implementations
  arch: Wire up Landlock syscalls
  fs,security: Add sb_delete hook
  landlock: Support filesystem access-control
  LSM: Infrastructure management of the superblock
  landlock: Add ptrace restrictions
  landlock: Set up the security framework and manage credentials
  landlock: Add ruleset and domain management
  landlock: Add object management
2021-05-01 18:50:44 -07:00
Mickaël Salaün
265885daf3 landlock: Add syscall implementations
These 3 system calls are designed to be used by unprivileged processes
to sandbox themselves:
* landlock_create_ruleset(2): Creates a ruleset and returns its file
  descriptor.
* landlock_add_rule(2): Adds a rule (e.g. file hierarchy access) to a
  ruleset, identified by the dedicated file descriptor.
* landlock_restrict_self(2): Enforces a ruleset on the calling thread
  and its future children (similar to seccomp).  This syscall has the
  same usage restrictions as seccomp(2): the caller must have the
  no_new_privs attribute set or have CAP_SYS_ADMIN in the current user
  namespace.

All these syscalls have a "flags" argument (not currently used) to
enable extensibility.

Here are the motivations for these new syscalls:
* A sandboxed process may not have access to file systems, including
  /dev, /sys or /proc, but it should still be able to add more
  restrictions to itself.
* Neither prctl(2) nor seccomp(2) (which was used in a previous version)
  fit well with the current definition of a Landlock security policy.

All passed structs (attributes) are checked at build time to ensure that
they don't contain holes and that they are aligned the same way for each
architecture.

See the user and kernel documentation for more details (provided by a
following commit):
* Documentation/userspace-api/landlock.rst
* Documentation/security/landlock.rst

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: James Morris <jmorris@namei.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Link: https://lore.kernel.org/r/20210422154123.13086-9-mic@digikod.net
Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-04-22 12:22:11 -07:00