From: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx> This is an adaptation of https://www.kernel.org/doc/html/v5.13/userspace-api/landlock.html Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210706182217.32338-4-mic@xxxxxxxxxxx --- man2/landlock_add_rule.2 | 139 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) create mode 100644 man2/landlock_add_rule.2 diff --git a/man2/landlock_add_rule.2 b/man2/landlock_add_rule.2 new file mode 100644 index 000000000000..66da2c142a03 --- /dev/null +++ b/man2/landlock_add_rule.2 @@ -0,0 +1,139 @@ +.\" Copyright © 2017-2020 Mickaël Salaün <mic@xxxxxxxxxxx> +.\" Copyright © 2019-2020 ANSSI +.\" Copyright © 2021 Microsoft Corporation +.\" +.\" %%%LICENSE_START(VERBATIM) +.\" Permission is granted to make and distribute verbatim copies of this +.\" manual provided the copyright notice and this permission notice are +.\" preserved on all copies. +.\" +.\" Permission is granted to copy and distribute modified versions of this +.\" manual under the conditions for verbatim copying, provided that the +.\" entire resulting derived work is distributed under the terms of a +.\" permission notice identical to this one. +.\" +.\" Since the Linux kernel and libraries are constantly changing, this +.\" manual page may be incorrect or out-of-date. The author(s) assume no +.\" responsibility for errors or omissions, or for damages resulting from +.\" the use of the information contained herein. The author(s) may not +.\" have taken the same level of care in the production of this manual, +.\" which is licensed free of charge, as they might when working +.\" professionally. +.\" +.\" Formatted or processed versions of this manual, if unaccompanied by +.\" the source, must acknowledge the copyright and authors of this work. +.\" %%%LICENSE_END +.\" +.TH LANDLOCK_ADD_RULE 2 2021-06-27 Linux "Linux Programmer's Manual" +.SH NAME +landlock_add_rule \- add a new Landlock rule to a ruleset +.SH SYNOPSIS +.nf +.BR "#include <linux/landlock.h>" " /* Definition of " LANDLOCK_* " constants */" +.BR "#include <sys/syscall.h>" " /* Definition of " SYS_* " constants */" +.PP +.BI "int syscall(SYS_landlock_add_rule, int " ruleset_fd , +.BI " enum landlock_rule_type " rule_type , +.BI " const void * " rule_attr ", __u32 " flags ); +.SH 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 +.BR landlock_add_rule (2) +system call enables adding a new Landlock rule to an existing ruleset +created with +.BR landlock_create_ruleset (2) +\&. See +.BR landlock (7) +for a global overview. +.PP +.I ruleset_fd +is a Landlock ruleset file descriptor obtained with +.BR landlock_create_ruleset (2) +\&. +.PP +.I rule_type +identifies the structure type pointed to by +.I rule_attr +\&. Currently, Linux supports the following +.I rule_type +value: +.TP +.BR LANDLOCK_RULE_PATH_BENEATH +This defines the object type as a file hierarchy. +In this case, +.I rule_attr +points to the following structure: +.IP +.in +4n +.EX +struct landlock_path_beneath_attr { + __u64 allowed_access; + __s32 parent_fd; +} __attribute__((packed)); +.EE +.in +.IP +.I allowed_access +contains a bitmask of allowed filesystem actions for this file hierarchy +(see +.BR "Filesystem actions" +in +.BR landlock (7) +). +.IP +.I parent_fd +is an opened file descriptor, preferably with the +.I O_PATH +flag, which identifies the parent directory of the file hierarchy or a just +file. +.PP +.I flags +must be 0. +.SH RETURN VALUE +On success, +.BR landlock_add_rule (2) +returns 0. +.SH ERRORS +.BR landlock_add_rule (2) +can failed for the following reasons: +.TP +.BR EOPNOTSUPP +Landlock is supported by the kernel but disabled at boot time. +.TP +.BR EINVAL +.I flags +is not 0, or the rule accesses are inconsistent (i.e. +.I rule_attr->allowed_access +is not a subset of the ruleset handled accesses). +.TP +.BR ENOMSG +Empty accesses (i.e. +.I rule_attr->allowed_access +is 0). +.TP +.BR EBADF +.I ruleset_fd +is not a file descriptor for the current thread, or a member of +.I rule_attr +is not a file descriptor as expected. +.TP +.BR EBADFD +.I ruleset_fd +is not a ruleset file descriptor, or a member of +.I rule_attr +is not the expected file descriptor type. +.TP +.BR EPERM +.I ruleset_fd +has no write access to the underlying ruleset. +.TP +.BR EFAULT +.I rule_attr +was not a valid address. +.SH VERSIONS +Landlock was added in Linux 5.13. +.SH SEE ALSO +.BR landlock (7), +.BR landlock_create_ruleset (2), +.BR landlock_restrict_self (2) -- 2.32.0
