landlock_add_rule − add a new Landlock rule to a ruleset
Standard C library (libc, −lc)
#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);
A Landlock rule describes an action on an object. An object is currently a file hierarchy, and the related filesystem actions are defined with a set of access rights. This landlock_add_rule() system call enables 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 landlock_create_ruleset(2).
rule_type
identifies the structure type pointed to by
rule_attr. Currently, 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.
On success, landlock_add_rule() returns 0.
landlock_add_rule()
can fail 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. |
Linux.
Linux 5.13.
See landlock(7).
landlock_create_ruleset(2), landlock_restrict_self(2), landlock(7)