diff options
Diffstat (limited to 'security/landlock/access.h')
| -rw-r--r-- | security/landlock/access.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/security/landlock/access.h b/security/landlock/access.h new file mode 100644 index 000000000000..74fd8f399fbd --- /dev/null +++ b/security/landlock/access.h @@ -0,0 +1,77 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Landlock LSM - Access types and helpers + * + * Copyright © 2016-2020 Mickaël Salaün <mic@digikod.net> + * Copyright © 2018-2020 ANSSI + * Copyright © 2024-2025 Microsoft Corporation + */ + +#ifndef _SECURITY_LANDLOCK_ACCESS_H +#define _SECURITY_LANDLOCK_ACCESS_H + +#include <linux/bitops.h> +#include <linux/build_bug.h> +#include <linux/kernel.h> +#include <uapi/linux/landlock.h> + +#include "limits.h" + +/* + * All access rights that are denied by default whether they are handled or not + * by a ruleset/layer. This must be ORed with all ruleset->access_masks[] + * entries when we need to get the absolute handled access masks, see + * landlock_upgrade_handled_access_masks(). + */ +/* clang-format off */ +#define _LANDLOCK_ACCESS_FS_INITIALLY_DENIED ( \ + LANDLOCK_ACCESS_FS_REFER) +/* clang-format on */ + +typedef u16 access_mask_t; + +/* Makes sure all filesystem access rights can be stored. */ +static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); +/* Makes sure all network access rights can be stored. */ +static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_NET); +/* Makes sure all scoped rights can be stored. */ +static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_SCOPE); +/* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */ +static_assert(sizeof(unsigned long) >= sizeof(access_mask_t)); + +/* Ruleset access masks. */ +struct access_masks { + access_mask_t fs : LANDLOCK_NUM_ACCESS_FS; + access_mask_t net : LANDLOCK_NUM_ACCESS_NET; + access_mask_t scope : LANDLOCK_NUM_SCOPE; +}; + +union access_masks_all { + struct access_masks masks; + u32 all; +}; + +/* Makes sure all fields are covered. */ +static_assert(sizeof(typeof_member(union access_masks_all, masks)) == + sizeof(typeof_member(union access_masks_all, all))); + +typedef u16 layer_mask_t; + +/* Makes sure all layers can be checked. */ +static_assert(BITS_PER_TYPE(layer_mask_t) >= LANDLOCK_MAX_NUM_LAYERS); + +/* Upgrades with all initially denied by default access rights. */ +static inline struct access_masks +landlock_upgrade_handled_access_masks(struct access_masks access_masks) +{ + /* + * All access rights that are denied by default whether they are + * explicitly handled or not. + */ + if (access_masks.fs) + access_masks.fs |= _LANDLOCK_ACCESS_FS_INITIALLY_DENIED; + + return access_masks; +} + +#endif /* _SECURITY_LANDLOCK_ACCESS_H */ |