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Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull Landlock LSM from James Morris: "Add Landlock, a new LSM from Mickaël Salaün. Briefly, Landlock provides for unprivileged application sandboxing. From Mickaël's cover letter: "The goal of Landlock is to enable to restrict ambient rights (e.g. global filesystem access) for a set of processes. Because Landlock is a stackable LSM [1], it makes possible to create safe security sandboxes as new security layers in addition to the existing system-wide access-controls. This kind of sandbox is expected to help mitigate the security impact of bugs or unexpected/malicious behaviors in user-space applications. Landlock empowers any process, including unprivileged ones, to securely restrict themselves. Landlock is inspired by seccomp-bpf but instead of filtering syscalls and their raw arguments, a Landlock rule can restrict the use of kernel objects like file hierarchies, according to the kernel semantic. Landlock also takes inspiration from other OS sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD Pledge/Unveil. In this current form, Landlock misses some access-control features. This enables to minimize this patch series and ease review. This series still addresses multiple use cases, especially with the combined use of seccomp-bpf: applications with built-in sandboxing, init systems, security sandbox tools and security-oriented APIs [2]" The cover letter and v34 posting is here: https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/ See also: https://landlock.io/ This code has had extensive design discussion and review over several years" Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1] Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2] * tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: landlock: Enable user space to infer supported features landlock: Add user and kernel documentation samples/landlock: Add a sandbox manager example selftests/landlock: Add user space tests landlock: Add syscall implementations arch: Wire up Landlock syscalls fs,security: Add sb_delete hook landlock: Support filesystem access-control LSM: Infrastructure management of the superblock landlock: Add ptrace restrictions landlock: Set up the security framework and manage credentials landlock: Add ruleset and domain management landlock: Add object management

Linus Torvalds committed 5 years ago

Commit 17ae69a2 parents e6f0bf0 3532b0b72 files · +6987 −77Browse files

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include/uapi/linux/landlock.h+137−0
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1+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2+/*
3+ * Landlock - User space API
4+ *
5+ * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
6+ * Copyright © 2018-2020 ANSSI
7+ */
8+
9+#ifndef _UAPI_LINUX_LANDLOCK_H
10+#define _UAPI_LINUX_LANDLOCK_H
11+
12+#include <linux/types.h>
13+
14+/**
15+ * struct landlock_ruleset_attr - Ruleset definition
16+ *
17+ * Argument of sys_landlock_create_ruleset(). This structure can grow in
18+ * future versions.
19+ */
20+struct landlock_ruleset_attr {
21+ /**
22+ * @handled_access_fs: Bitmask of actions (cf. `Filesystem flags`_)
23+ * that is handled by this ruleset and should then be forbidden if no
24+ * rule explicitly allow them. This is needed for backward
25+ * compatibility reasons.
26+ */
27+ __u64 handled_access_fs;
28+};
29+
30+/*
31+ * sys_landlock_create_ruleset() flags:
32+ *
33+ * - %LANDLOCK_CREATE_RULESET_VERSION: Get the highest supported Landlock ABI
34+ * version.
35+ */
36+#define LANDLOCK_CREATE_RULESET_VERSION (1U << 0)
37+
38+/**
39+ * enum landlock_rule_type - Landlock rule type
40+ *
41+ * Argument of sys_landlock_add_rule().
42+ */
43+enum landlock_rule_type {
44+ /**
45+ * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct
46+ * landlock_path_beneath_attr .
47+ */
48+ LANDLOCK_RULE_PATH_BENEATH = 1,
49+};
50+
51+/**
52+ * struct landlock_path_beneath_attr - Path hierarchy definition
53+ *
54+ * Argument of sys_landlock_add_rule().
55+ */
56+struct landlock_path_beneath_attr {
57+ /**
58+ * @allowed_access: Bitmask of allowed actions for this file hierarchy
59+ * (cf. `Filesystem flags`_).
60+ */
61+ __u64 allowed_access;
62+ /**
63+ * @parent_fd: File descriptor, open with ``O_PATH``, which identifies
64+ * the parent directory of a file hierarchy, or just a file.
65+ */
66+ __s32 parent_fd;
67+ /*
68+ * This struct is packed to avoid trailing reserved members.
69+ * Cf. security/landlock/syscalls.c:build_check_abi()
70+ */
71+} __attribute__((packed));
72+
73+/**
74+ * DOC: fs_access
75+ *
76+ * A set of actions on kernel objects may be defined by an attribute (e.g.
77+ * &struct landlock_path_beneath_attr) including a bitmask of access.
78+ *
79+ * Filesystem flags
80+ * ~~~~~~~~~~~~~~~~
81+ *
82+ * These flags enable to restrict a sandboxed process to a set of actions on
83+ * files and directories. Files or directories opened before the sandboxing
84+ * are not subject to these restrictions.
85+ *
86+ * A file can only receive these access rights:
87+ *
88+ * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file.
89+ * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access.
90+ * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access.
91+ *
92+ * A directory can receive access rights related to files or directories. The
93+ * following access right is applied to the directory itself, and the
94+ * directories beneath it:
95+ *
96+ * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content.
97+ *
98+ * However, the following access rights only apply to the content of a
99+ * directory, not the directory itself:
100+ *
101+ * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one.
102+ * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file.
103+ * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character
104+ * device.
105+ * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory.
106+ * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file.
107+ * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain
108+ * socket.
109+ * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe.
110+ * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device.
111+ * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link.
112+ *
113+ * .. warning::
114+ *
115+ * It is currently not possible to restrict some file-related actions
116+ * accessible through these syscall families: :manpage:`chdir(2)`,
117+ * :manpage:`truncate(2)`, :manpage:`stat(2)`, :manpage:`flock(2)`,
118+ * :manpage:`chmod(2)`, :manpage:`chown(2)`, :manpage:`setxattr(2)`,
119+ * :manpage:`utime(2)`, :manpage:`ioctl(2)`, :manpage:`fcntl(2)`,
120+ * :manpage:`access(2)`.
121+ * Future Landlock evolutions will enable to restrict them.
122+ */
123+#define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0)
124+#define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1)
125+#define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2)
126+#define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3)
127+#define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4)
128+#define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5)
129+#define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6)
130+#define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7)
131+#define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8)
132+#define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9)
133+#define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10)
134+#define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11)
135+#define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12)
136+
137+#endif /* _UAPI_LINUX_LANDLOCK_H */