1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Landlock LSM - Access types and helpers 4 * 5 * Copyright © 2016-2020 Mickaël Salaün <mic@digikod.net> 6 * Copyright © 2018-2020 ANSSI 7 * Copyright © 2024-2025 Microsoft Corporation 8 */ 9 10 #ifndef _SECURITY_LANDLOCK_ACCESS_H 11 #define _SECURITY_LANDLOCK_ACCESS_H 12 13 #include <linux/bitops.h> 14 #include <linux/build_bug.h> 15 #include <linux/kernel.h> 16 #include <uapi/linux/landlock.h> 17 18 #include "limits.h" 19 20 /* 21 * All access rights that are denied by default whether they are handled or not 22 * by a ruleset/layer. This must be ORed with all ruleset->access_masks[] 23 * entries when we need to get the absolute handled access masks, see 24 * landlock_upgrade_handled_access_masks(). 25 */ 26 /* clang-format off */ 27 #define _LANDLOCK_ACCESS_FS_INITIALLY_DENIED ( \ 28 LANDLOCK_ACCESS_FS_REFER) 29 /* clang-format on */ 30 31 typedef u16 access_mask_t; 32 33 /* Makes sure all filesystem access rights can be stored. */ 34 static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); 35 /* Makes sure all network access rights can be stored. */ 36 static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_NET); 37 /* Makes sure all scoped rights can be stored. */ 38 static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_SCOPE); 39 /* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */ 40 static_assert(sizeof(unsigned long) >= sizeof(access_mask_t)); 41 42 /* Ruleset access masks. */ 43 struct access_masks { 44 access_mask_t fs : LANDLOCK_NUM_ACCESS_FS; 45 access_mask_t net : LANDLOCK_NUM_ACCESS_NET; 46 access_mask_t scope : LANDLOCK_NUM_SCOPE; 47 }; 48 49 union access_masks_all { 50 struct access_masks masks; 51 u32 all; 52 }; 53 54 /* Makes sure all fields are covered. */ 55 static_assert(sizeof(typeof_member(union access_masks_all, masks)) == 56 sizeof(typeof_member(union access_masks_all, all))); 57 58 typedef u16 layer_mask_t; 59 60 /* Makes sure all layers can be checked. */ 61 static_assert(BITS_PER_TYPE(layer_mask_t) >= LANDLOCK_MAX_NUM_LAYERS); 62 63 /* Upgrades with all initially denied by default access rights. */ 64 static inline struct access_masks landlock_upgrade_handled_access_masks(struct access_masks access_masks)65landlock_upgrade_handled_access_masks(struct access_masks access_masks) 66 { 67 /* 68 * All access rights that are denied by default whether they are 69 * explicitly handled or not. 70 */ 71 if (access_masks.fs) 72 access_masks.fs |= _LANDLOCK_ACCESS_FS_INITIALLY_DENIED; 73 74 return access_masks; 75 } 76 77 #endif /* _SECURITY_LANDLOCK_ACCESS_H */ 78