Name
landlock_add_rule - add a new Landlock rule to a rulesetLibrary
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 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.
Return Value
On success, landlock_add_rule() returns 0.Errors
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.