On Fri, Feb 09, 2024 at 06:06:05PM +0100, Günther Noack wrote:
> Introduces the LANDLOCK_ACCESS_FS_IOCTL access right
> and increments the Landlock ABI version to 5.
>
> Like the truncate right, these rights are associated with a file
> descriptor at the time of open(2), and get respected even when the
> file descriptor is used outside of the thread which it was originally
> opened in.
>
> A newly enabled Landlock policy therefore does not apply to file
> descriptors which are already open.
>
> If the LANDLOCK_ACCESS_FS_IOCTL right is handled, only a small number
> of safe IOCTL commands will be permitted on newly opened files. The
> permitted IOCTLs can be configured through the ruleset in limited ways
> now. (See documentation for details.)
>
> Specifically, when LANDLOCK_ACCESS_FS_IOCTL is handled, granting this
> right on a file or directory will *not* permit to do all IOCTL
> commands, but only influence the IOCTL commands which are not already
> handled through other access rights. The intent is to keep the groups
> of IOCTL commands more fine-grained.
>
> Noteworthy scenarios which require special attention:
>
> TTY devices are often passed into a process from the parent process,
> and so a newly enabled Landlock policy does not retroactively apply to
> them automatically. In the past, TTY devices have often supported
> IOCTL commands like TIOCSTI and some TIOCLINUX subcommands, which were
> letting callers control the TTY input buffer (and simulate
> keypresses). This should be restricted to CAP_SYS_ADMIN programs on
> modern kernels though.
>
> Some legitimate file system features, like setting up fscrypt, are
> exposed as IOCTL commands on regular files and directories -- users of
> Landlock are advised to double check that the sandboxed process does
> not need to invoke these IOCTLs.
>
> Known limitations:
>
> The LANDLOCK_ACCESS_FS_IOCTL access right is a coarse-grained control
> over IOCTL commands. Future work will enable a more fine-grained
> access control for IOCTLs.
>
> In the meantime, Landlock users may use path-based restrictions in
> combination with their knowledge about the file system layout to
> control what IOCTLs can be done. Mounting file systems with the nodev
> option can help to distinguish regular files and devices, and give
> guarantees about the affected files, which Landlock alone can not give
> yet.
>
> Signed-off-by: Günther Noack <gnoack@xxxxxxxxxx>
> ---
> include/uapi/linux/landlock.h | 55 ++++-
> security/landlock/fs.c | 227 ++++++++++++++++++-
> security/landlock/fs.h | 3 +
> security/landlock/limits.h | 11 +-
> security/landlock/ruleset.h | 2 +-
> security/landlock/syscalls.c | 19 +-
> tools/testing/selftests/landlock/base_test.c | 2 +-
> tools/testing/selftests/landlock/fs_test.c | 5 +-
> 8 files changed, 302 insertions(+), 22 deletions(-)
>
> diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h
> index 25c8d7677539..16d7d72804f8 100644
> --- a/include/uapi/linux/landlock.h
> +++ b/include/uapi/linux/landlock.h
> @@ -128,7 +128,7 @@ struct landlock_net_port_attr {
> * files and directories. Files or directories opened before the sandboxing
> * are not subject to these restrictions.
> *
> - * A file can only receive these access rights:
> + * The following access rights apply only to files:
> *
> * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file.
> * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. Note that
> @@ -138,12 +138,13 @@ struct landlock_net_port_attr {
> * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access.
> * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`,
> * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with
> - * ``O_TRUNC``. Whether an opened file can be truncated with
> - * :manpage:`ftruncate(2)` is determined during :manpage:`open(2)`, in the
> - * same way as read and write permissions are checked during
> - * :manpage:`open(2)` using %LANDLOCK_ACCESS_FS_READ_FILE and
> - * %LANDLOCK_ACCESS_FS_WRITE_FILE. This access right is available since the
> - * third version of the Landlock ABI.
> + * ``O_TRUNC``. This access right is available since the third version of the
> + * Landlock ABI.
> + *
> + * Whether an opened file can be truncated with :manpage:`ftruncate(2)` or used
> + * with `ioctl(2)` is determined during :manpage:`open(2)`, in the same way as
> + * read and write permissions are checked during :manpage:`open(2)` using
> + * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE.
> *
> * A directory can receive access rights related to files or directories. The
> * following access right is applied to the directory itself, and the
> @@ -198,13 +199,50 @@ struct landlock_net_port_attr {
> * If multiple requirements are not met, the ``EACCES`` error code takes
> * precedence over ``EXDEV``.
> *
> + * The following access right applies both to files and directories:
> + *
> + * - %LANDLOCK_ACCESS_FS_IOCTL: Invoke :manpage:`ioctl(2)` commands on an opened
> + * file or directory.
> + *
> + * This access right applies to all :manpage:`ioctl(2)` commands, except of
> + * ``FIOCLEX``, ``FIONCLEX``, ``FIONBIO`` and ``FIOASYNC``. These commands
> + * continue to be invokable independent of the %LANDLOCK_ACCESS_FS_IOCTL
> + * access right.
> + *
> + * When certain other access rights are handled in the ruleset, in addition to
> + * %LANDLOCK_ACCESS_FS_IOCTL, granting these access rights will unlock access
> + * to additional groups of IOCTL commands, on the affected files:
> + *
> + * * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE unlock
> + * access to ``FIOQSIZE``, ``FIONREAD``, ``FIGETBSZ``, ``FS_IOC_FIEMAP``,
> + * ``FIBMAP``, ``FIDEDUPERANGE``, ``FICLONE``, ``FICLONERANGE``,
> + * ``FS_IOC_RESVSP``, ``FS_IOC_RESVSP64``, ``FS_IOC_UNRESVSP``,
> + * ``FS_IOC_UNRESVSP64``, ``FS_IOC_ZERO_RANGE``.
> + *
> + * * %LANDLOCK_ACCESS_FS_READ_DIR unlocks access to ``FIOQSIZE``,
> + * ``FIONREAD``, ``FIGETBSZ``.
> + *
> + * When these access rights are handled in the ruleset, the availability of
> + * the affected IOCTL commands is not governed by %LANDLOCK_ACCESS_FS_IOCTL
> + * any more, but by the respective access right.
> + *
> + * All other IOCTL commands are not handled specially, and are governed by
> + * %LANDLOCK_ACCESS_FS_IOCTL. This includes %FS_IOC_GETFLAGS and
> + * %FS_IOC_SETFLAGS for manipulating inode flags (:manpage:`ioctl_iflags(2)`),
> + * %FS_IOC_FSFETXATTR and %FS_IOC_FSSETXATTR for manipulating extended
> + * attributes, as well as %FIFREEZE and %FITHAW for freezing and thawing file
> + * systems.
> + *
> + * This access right is available since the fifth version of the Landlock
> + * ABI.
> + *
> * .. warning::
> *
> * It is currently not possible to restrict some file-related actions
> * accessible through these syscall families: :manpage:`chdir(2)`,
> * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`,
> * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`,
> - * :manpage:`ioctl(2)`, :manpage:`fcntl(2)`, :manpage:`access(2)`.
> + * :manpage:`fcntl(2)`, :manpage:`access(2)`.
> * Future Landlock evolutions will enable to restrict them.
> */
> /* clang-format off */
> @@ -223,6 +261,7 @@ struct landlock_net_port_attr {
> #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12)
> #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13)
> #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14)
> +#define LANDLOCK_ACCESS_FS_IOCTL (1ULL << 15)
> /* clang-format on */
>
> /**
> diff --git a/security/landlock/fs.c b/security/landlock/fs.c
> index 73997e63734f..84efea3f7c0f 100644
> --- a/security/landlock/fs.c
> +++ b/security/landlock/fs.c
> @@ -7,6 +7,7 @@
> * Copyright © 2021-2022 Microsoft Corporation
> */
>
> +#include <asm/ioctls.h>
> #include <kunit/test.h>
> #include <linux/atomic.h>
> #include <linux/bitops.h>
> @@ -14,6 +15,7 @@
> #include <linux/compiler_types.h>
> #include <linux/dcache.h>
> #include <linux/err.h>
> +#include <linux/falloc.h>
> #include <linux/fs.h>
> #include <linux/init.h>
> #include <linux/kernel.h>
> @@ -29,6 +31,7 @@
> #include <linux/types.h>
> #include <linux/wait_bit.h>
> #include <linux/workqueue.h>
> +#include <uapi/linux/fiemap.h>
> #include <uapi/linux/landlock.h>
>
> #include "common.h"
> @@ -84,6 +87,186 @@ static const struct landlock_object_underops landlock_fs_underops = {
> .release = release_inode
> };
>
> +/* IOCTL helpers */
> +
> +/*
> + * These are synthetic access rights, which are only used within the kernel, but
> + * not exposed to callers in userspace. The mapping between these access rights
> + * and IOCTL commands is defined in the get_required_ioctl_access() helper function.
> + */
> +#define LANDLOCK_ACCESS_FS_IOCTL_RW (LANDLOCK_LAST_PUBLIC_ACCESS_FS << 1)
> +#define LANDLOCK_ACCESS_FS_IOCTL_RW_FILE (LANDLOCK_LAST_PUBLIC_ACCESS_FS << 2)
> +
> +/* ioctl_groups - all synthetic access rights for IOCTL command groups */
> +/* clang-format off */
> +#define IOCTL_GROUPS ( \
> + LANDLOCK_ACCESS_FS_IOCTL_RW | \
> + LANDLOCK_ACCESS_FS_IOCTL_RW_FILE)
> +/* clang-format on */
> +
> +static_assert((IOCTL_GROUPS & LANDLOCK_MASK_ACCESS_FS) == IOCTL_GROUPS);
> +
> +/**
> + * get_required_ioctl_access(): Determine required IOCTL access rights.
> + *
> + * @cmd: The IOCTL command that is supposed to be run.
> + *
> + * Any new IOCTL commands that are implemented in fs/ioctl.c's do_vfs_ioctl()
> + * should be considered for inclusion here.
It might be a good idea to add a similar comment in
fs/ioctl.c:do_vfs_ioctl(), just before the "default" case, to make sure
nobody forget to Cc us if a new command is added.
> + *
> + * Returns: The access rights that must be granted on an opened file in order to
> + * use the given @cmd.
> + */
> +static __attribute_const__ access_mask_t
> +get_required_ioctl_access(const unsigned int cmd)
> +{
> + switch (cmd) {
> + case FIOCLEX:
> + case FIONCLEX:
> + case FIONBIO:
> + case FIOASYNC:
> + /*
> + * FIOCLEX, FIONCLEX, FIONBIO and FIOASYNC manipulate the FD's
> + * close-on-exec and the file's buffered-IO and async flags.
> + * These operations are also available through fcntl(2), and are
> + * unconditionally permitted in Landlock.
> + */
> + return 0;
> + case FIONREAD:
> + case FIOQSIZE:
> + case FIGETBSZ:
> + /*
> + * FIONREAD returns the number of bytes available for reading.
> + * FIONREAD returns the number of immediately readable bytes for
> + * a file.
> + *
> + * FIOQSIZE queries the size of a file or directory.
> + *
> + * FIGETBSZ queries the file system's block size for a file or
> + * directory.
> + *
> + * These IOCTL commands are permitted for files which are opened
> + * with LANDLOCK_ACCESS_FS_READ_DIR,
> + * LANDLOCK_ACCESS_FS_READ_FILE, or
> + * LANDLOCK_ACCESS_FS_WRITE_FILE.
> + */
> + return LANDLOCK_ACCESS_FS_IOCTL_RW;
> + case FS_IOC_FIEMAP:
> + case FIBMAP:
> + /*
> + * FS_IOC_FIEMAP and FIBMAP query information about the
> + * allocation of blocks within a file. They are permitted for
> + * files which are opened with LANDLOCK_ACCESS_FS_READ_FILE or
> + * LANDLOCK_ACCESS_FS_WRITE_FILE.
> + */
> + fallthrough;
> + case FIDEDUPERANGE:
> + case FICLONE:
> + case FICLONERANGE:
> + /*
> + * FIDEDUPERANGE, FICLONE and FICLONERANGE make files share
> + * their underlying storage ("reflink") between source and
> + * destination FDs, on file systems which support that.
> + *
> + * The underlying implementations are already checking whether
> + * the involved files are opened with the appropriate read/write
> + * modes. We rely on this being implemented correctly.
> + *
> + * These IOCTLs are permitted for files which are opened with
> + * LANDLOCK_ACCESS_FS_READ_FILE or
> + * LANDLOCK_ACCESS_FS_WRITE_FILE.
> + */
> + fallthrough;
> + case FS_IOC_RESVSP:
> + case FS_IOC_RESVSP64:
> + case FS_IOC_UNRESVSP:
> + case FS_IOC_UNRESVSP64:
> + case FS_IOC_ZERO_RANGE:
> + /*
> + * These IOCTLs reserve space, or create holes like
> + * fallocate(2). We rely on the implementations checking the
> + * files' read/write modes.
> + *
> + * These IOCTLs are permitted for files which are opened with
> + * LANDLOCK_ACCESS_FS_READ_FILE or
> + * LANDLOCK_ACCESS_FS_WRITE_FILE.
> + */
> + return LANDLOCK_ACCESS_FS_IOCTL_RW_FILE;
> + default:
> + /*
> + * Other commands are guarded by the catch-all access right.
> + */
> + return LANDLOCK_ACCESS_FS_IOCTL;
> + }
Good documentation and better grouping!
> +}
> +
> +/**
> + * expand_ioctl() - Return the dst flags from either the src flag or the
> + * %LANDLOCK_ACCESS_FS_IOCTL flag, depending on whether the
> + * %LANDLOCK_ACCESS_FS_IOCTL and src access rights are handled or not.
> + *
> + * @handled: Handled access rights.
> + * @access: The access mask to copy values from.
> + * @src: A single access right to copy from in @access.
> + * @dst: One or more access rights to copy to.
> + *
> + * Returns: @dst, or 0.
> + */
> +static __attribute_const__ access_mask_t
> +expand_ioctl(const access_mask_t handled, const access_mask_t access,
> + const access_mask_t src, const access_mask_t dst)
> +{
> + access_mask_t copy_from;
> +
> + if (!(handled & LANDLOCK_ACCESS_FS_IOCTL))
> + return 0;
> +
> + copy_from = (handled & src) ? src : LANDLOCK_ACCESS_FS_IOCTL;
> + if (access & copy_from)
> + return dst;
> +
> + return 0;
> +}
> +
> +/**
> + * landlock_expand_access_fs() - Returns @access with the synthetic IOCTL group
> + * flags enabled if necessary.
> + *
> + * @handled: Handled FS access rights.
> + * @access: FS access rights to expand.
> + *
> + * Returns: @access expanded by the necessary flags for the synthetic IOCTL
> + * access rights.
> + */
> +static __attribute_const__ access_mask_t landlock_expand_access_fs(
> + const access_mask_t handled, const access_mask_t access)
> +{
> + return access |
> + expand_ioctl(handled, access, LANDLOCK_ACCESS_FS_WRITE_FILE,
> + LANDLOCK_ACCESS_FS_IOCTL_RW |
> + LANDLOCK_ACCESS_FS_IOCTL_RW_FILE) |
> + expand_ioctl(handled, access, LANDLOCK_ACCESS_FS_READ_FILE,
> + LANDLOCK_ACCESS_FS_IOCTL_RW |
> + LANDLOCK_ACCESS_FS_IOCTL_RW_FILE) |
> + expand_ioctl(handled, access, LANDLOCK_ACCESS_FS_READ_DIR,
> + LANDLOCK_ACCESS_FS_IOCTL_RW);
> +}
> +
> +/**
> + * landlock_expand_handled_access_fs() - add synthetic IOCTL access rights to an
> + * access mask of handled accesses.
> + *
> + * @handled: The handled accesses of a ruleset that is being created.
> + *
> + * Returns: @handled, with the bits for the synthetic IOCTL access rights set,
> + * if %LANDLOCK_ACCESS_FS_IOCTL is handled.
> + */
> +__attribute_const__ access_mask_t
> +landlock_expand_handled_access_fs(const access_mask_t handled)
> +{
> + return landlock_expand_access_fs(handled, handled);
> +}
> +
> /* Ruleset management */
>
> static struct landlock_object *get_inode_object(struct inode *const inode)
> @@ -148,7 +331,8 @@ static struct landlock_object *get_inode_object(struct inode *const inode)
> LANDLOCK_ACCESS_FS_EXECUTE | \
> LANDLOCK_ACCESS_FS_WRITE_FILE | \
> LANDLOCK_ACCESS_FS_READ_FILE | \
> - LANDLOCK_ACCESS_FS_TRUNCATE)
> + LANDLOCK_ACCESS_FS_TRUNCATE | \
> + LANDLOCK_ACCESS_FS_IOCTL)
> /* clang-format on */
>
> /*
> @@ -158,6 +342,7 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
> const struct path *const path,
> access_mask_t access_rights)
> {
> + access_mask_t handled;
> int err;
> struct landlock_id id = {
> .type = LANDLOCK_KEY_INODE,
> @@ -170,9 +355,11 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
> if (WARN_ON_ONCE(ruleset->num_layers != 1))
> return -EINVAL;
>
> + handled = landlock_get_fs_access_mask(ruleset, 0);
> + /* Expands the synthetic IOCTL groups. */
> + access_rights |= landlock_expand_access_fs(handled, access_rights);
> /* Transforms relative access rights to absolute ones. */
> - access_rights |= LANDLOCK_MASK_ACCESS_FS &
> - ~landlock_get_fs_access_mask(ruleset, 0);
> + access_rights |= LANDLOCK_MASK_ACCESS_FS & ~handled;
> id.key.object = get_inode_object(d_backing_inode(path->dentry));
> if (IS_ERR(id.key.object))
> return PTR_ERR(id.key.object);
> @@ -1333,7 +1520,9 @@ static int hook_file_open(struct file *const file)
> {
> layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_FS] = {};
> access_mask_t open_access_request, full_access_request, allowed_access;
> - const access_mask_t optional_access = LANDLOCK_ACCESS_FS_TRUNCATE;
> + const access_mask_t optional_access = LANDLOCK_ACCESS_FS_TRUNCATE |
> + LANDLOCK_ACCESS_FS_IOCTL |
> + IOCTL_GROUPS;
> const struct landlock_ruleset *const dom = get_current_fs_domain();
>
> if (!dom)
> @@ -1375,6 +1564,16 @@ static int hook_file_open(struct file *const file)
> }
> }
>
> + /*
> + * Named pipes should be treated just like anonymous pipes.
> + * Therefore, we permit all IOCTLs on them.
> + */
> + if (S_ISFIFO(file_inode(file)->i_mode)) {
> + allowed_access |= LANDLOCK_ACCESS_FS_IOCTL |
> + LANDLOCK_ACCESS_FS_IOCTL_RW |
> + LANDLOCK_ACCESS_FS_IOCTL_RW_FILE;
> + }
This should not be required, cf. other thread.
> +
> /*
> * For operations on already opened files (i.e. ftruncate()), it is the
> * access rights at the time of open() which decide whether the
> @@ -1406,6 +1605,25 @@ static int hook_file_truncate(struct file *const file)
> return -EACCES;
> }
>
> +static int hook_file_ioctl(struct file *file, unsigned int cmd,
> + unsigned long arg)
> +{
> + const access_mask_t required_access = get_required_ioctl_access(cmd);
> + const access_mask_t allowed_access =
> + landlock_file(file)->allowed_access;
> +
> + /*
> + * It is the access rights at the time of opening the file which
> + * determine whether IOCTL can be used on the opened file later.
> + *
> + * The access right is attached to the opened file in hook_file_open().
> + */
> + if ((allowed_access & required_access) == required_access)
> + return 0;
> +
> + return -EACCES;
> +}
> +
> static struct security_hook_list landlock_hooks[] __ro_after_init = {
> LSM_HOOK_INIT(inode_free_security, hook_inode_free_security),
>
> @@ -1428,6 +1646,7 @@ static struct security_hook_list landlock_hooks[] __ro_after_init = {
> LSM_HOOK_INIT(file_alloc_security, hook_file_alloc_security),
> LSM_HOOK_INIT(file_open, hook_file_open),
> LSM_HOOK_INIT(file_truncate, hook_file_truncate),
> + LSM_HOOK_INIT(file_ioctl, hook_file_ioctl),
> };
>
> __init void landlock_add_fs_hooks(void)
> diff --git a/security/landlock/fs.h b/security/landlock/fs.h
> index 488e4813680a..086576b8386b 100644
> --- a/security/landlock/fs.h
> +++ b/security/landlock/fs.h
> @@ -92,4 +92,7 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
> const struct path *const path,
> access_mask_t access_hierarchy);
>
> +__attribute_const__ access_mask_t
> +landlock_expand_handled_access_fs(const access_mask_t handled);
> +
> #endif /* _SECURITY_LANDLOCK_FS_H */
> diff --git a/security/landlock/limits.h b/security/landlock/limits.h
> index 93c9c6f91556..ecbdc8bbf906 100644
> --- a/security/landlock/limits.h
> +++ b/security/landlock/limits.h
> @@ -18,7 +18,16 @@
> #define LANDLOCK_MAX_NUM_LAYERS 16
> #define LANDLOCK_MAX_NUM_RULES U32_MAX
>
> -#define LANDLOCK_LAST_ACCESS_FS LANDLOCK_ACCESS_FS_TRUNCATE
> +/*
> + * For file system access rights, Landlock distinguishes between the publicly
> + * visible access rights (1 to LANDLOCK_LAST_PUBLIC_ACCESS_FS) and the private
> + * ones which are not exposed to userspace (LANDLOCK_LAST_PUBLIC_ACCESS_FS + 1
> + * to LANDLOCK_LAST_ACCESS_FS). The private access rights are defined in fs.c.
> + */
> +#define LANDLOCK_LAST_PUBLIC_ACCESS_FS LANDLOCK_ACCESS_FS_IOCTL
> +#define LANDLOCK_MASK_PUBLIC_ACCESS_FS ((LANDLOCK_LAST_PUBLIC_ACCESS_FS << 1) - 1)
> +
> +#define LANDLOCK_LAST_ACCESS_FS (LANDLOCK_LAST_PUBLIC_ACCESS_FS << 2)
> #define LANDLOCK_MASK_ACCESS_FS ((LANDLOCK_LAST_ACCESS_FS << 1) - 1)
> #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS)
> #define LANDLOCK_SHIFT_ACCESS_FS 0
> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
> index c7f1526784fd..5a28ea8e1c3d 100644
> --- a/security/landlock/ruleset.h
> +++ b/security/landlock/ruleset.h
> @@ -30,7 +30,7 @@
> LANDLOCK_ACCESS_FS_REFER)
> /* clang-format on */
>
> -typedef u16 access_mask_t;
> +typedef u32 access_mask_t;
> /* Makes sure all filesystem access rights can be stored. */
> static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS);
> /* Makes sure all network access rights can be stored. */
> diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
> index 898358f57fa0..f0bc50003b46 100644
> --- a/security/landlock/syscalls.c
> +++ b/security/landlock/syscalls.c
> @@ -137,7 +137,7 @@ static const struct file_operations ruleset_fops = {
> .write = fop_dummy_write,
> };
>
> -#define LANDLOCK_ABI_VERSION 4
> +#define LANDLOCK_ABI_VERSION 5
>
> /**
> * sys_landlock_create_ruleset - Create a new ruleset
> @@ -192,8 +192,8 @@ SYSCALL_DEFINE3(landlock_create_ruleset,
> return err;
>
> /* Checks content (and 32-bits cast). */
> - if ((ruleset_attr.handled_access_fs | LANDLOCK_MASK_ACCESS_FS) !=
> - LANDLOCK_MASK_ACCESS_FS)
> + if ((ruleset_attr.handled_access_fs | LANDLOCK_MASK_PUBLIC_ACCESS_FS) !=
> + LANDLOCK_MASK_PUBLIC_ACCESS_FS)
> return -EINVAL;
>
> /* Checks network content (and 32-bits cast). */
> @@ -201,6 +201,10 @@ SYSCALL_DEFINE3(landlock_create_ruleset,
> LANDLOCK_MASK_ACCESS_NET)
> return -EINVAL;
>
> + /* Expands synthetic IOCTL groups. */
> + ruleset_attr.handled_access_fs = landlock_expand_handled_access_fs(
> + ruleset_attr.handled_access_fs);
> +
> /* Checks arguments and transforms to kernel struct. */
> ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs,
> ruleset_attr.handled_access_net);
> @@ -309,8 +313,13 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset,
> if (!path_beneath_attr.allowed_access)
> return -ENOMSG;
>
> - /* Checks that allowed_access matches the @ruleset constraints. */
> - mask = landlock_get_raw_fs_access_mask(ruleset, 0);
> + /*
> + * Checks that allowed_access matches the @ruleset constraints and only
> + * consists of publicly visible access rights (as opposed to synthetic
> + * ones).
> + */
> + mask = landlock_get_raw_fs_access_mask(ruleset, 0) &
> + LANDLOCK_MASK_PUBLIC_ACCESS_FS;
> if ((path_beneath_attr.allowed_access | mask) != mask)
> return -EINVAL;
>
> diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c
> index 646f778dfb1e..d292b419ccba 100644
> --- a/tools/testing/selftests/landlock/base_test.c
> +++ b/tools/testing/selftests/landlock/base_test.c
> @@ -75,7 +75,7 @@ TEST(abi_version)
> const struct landlock_ruleset_attr ruleset_attr = {
> .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
> };
> - ASSERT_EQ(4, landlock_create_ruleset(NULL, 0,
> + ASSERT_EQ(5, landlock_create_ruleset(NULL, 0,
> LANDLOCK_CREATE_RULESET_VERSION));
>
> ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0,
> diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
> index 2d6d9b43d958..3203f4a5bc85 100644
> --- a/tools/testing/selftests/landlock/fs_test.c
> +++ b/tools/testing/selftests/landlock/fs_test.c
> @@ -527,9 +527,10 @@ TEST_F_FORK(layout1, inval)
> LANDLOCK_ACCESS_FS_EXECUTE | \
> LANDLOCK_ACCESS_FS_WRITE_FILE | \
> LANDLOCK_ACCESS_FS_READ_FILE | \
> - LANDLOCK_ACCESS_FS_TRUNCATE)
> + LANDLOCK_ACCESS_FS_TRUNCATE | \
> + LANDLOCK_ACCESS_FS_IOCTL)
>
> -#define ACCESS_LAST LANDLOCK_ACCESS_FS_TRUNCATE
> +#define ACCESS_LAST LANDLOCK_ACCESS_FS_IOCTL
>
> #define ACCESS_ALL ( \
> ACCESS_FILE | \
> --
> 2.43.0.687.g38aa6559b0-goog
>
>
