landlock_add_rule(2) System Calls Manual landlock_add_rule(2)
NAME
landlock_add_rule - add a new Landlock rule to a ruleset
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <linux/landlock.h> /* Definition of LANDLOCK_* constants */
#include <sys/syscall.h> /* Definition of SYS_* constants */
int syscall(SYS_landlock_add_rule, int ruleset_fd,
enum landlock_rule_type rule_type,
const void *rule_attr, uint32_t flags);
DESCRIPTION
A Landlock rule describes an action on an object. An object is cur-
rently a file hierarchy, and the related filesystem actions are defined
with a set of access rights. This landlock_add_rule() system call en-
ables adding a new Landlock rule to an existing ruleset created with
landlock_create_ruleset(2). See landlock(7) for a global overview.
ruleset_fd is a Landlock ruleset file descriptor obtained with land-
lock_create_ruleset(2).
rule_type identifies the structure type pointed to by rule_attr. Cur-
rently, Linux supports the following rule_type value:
LANDLOCK_RULE_PATH_BENEATH
This defines the object type as a file hierarchy. In this case,
rule_attr points to the following structure:
struct landlock_path_beneath_attr {
__u64 allowed_access;
__s32 parent_fd;
} __attribute__((packed));
allowed_access contains a bitmask of allowed filesystem actions
for this file hierarchy (see Filesystem actions in landlock(7)).
parent_fd is an opened file descriptor, preferably with the
O_PATH flag, which identifies the parent directory of the file
hierarchy or just a file.
flags must be 0.
RETURN VALUE
On success, landlock_add_rule() returns 0.
ERRORS
landlock_add_rule() can failed for the following reasons:
EOPNOTSUPP
Landlock is supported by the kernel but disabled at boot time.
EINVAL flags is not 0, or the rule accesses are inconsistent (i.e.,
rule_attr->allowed_access is not a subset of the ruleset handled
accesses).
ENOMSG Empty accesses (i.e., rule_attr->allowed_access is 0).
EBADF ruleset_fd is not a file descriptor for the current thread, or a
member of rule_attr is not a file descriptor as expected.
EBADFD ruleset_fd is not a ruleset file descriptor, or a member of
rule_attr is not the expected file descriptor type.
EPERM ruleset_fd has no write access to the underlying ruleset.
EFAULT rule_attr was not a valid address.
VERSIONS
Landlock was added in Linux 5.13.
STANDARDS
This system call is Linux-specific.
EXAMPLES
See landlock(7).
SEE ALSO
landlock_create_ruleset(2), landlock_restrict_self(2), landlock(7)
Linux man-pages 6.03 2023-02-10 landlock_add_rule(2)
Generated by dwww version 1.15 on Sat Aug 30 08:48:51 CEST 2025.