Re: [RFC PATCH v2 05/14] landlock: Move access types

[Francis Laniel <flaniel@linux.microsoft.com>]

Le mardi 22 octobre 2024, 18:10:00 CEST Mickaël Salaün a écrit :
> Move ACCESS_FS_OPTIONAL, access_mask_t, struct access_mask, and struct
> access_masks_all to a dedicated access.h file.
> 
> This file will be extended with a following commit, and it will help to
> avoid dependency loops.
> 
> Cc: Günther Noack <gnoack@google.com>
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
> Link: https://lore.kernel.org/r/20241022161009.982584-6-mic@digikod.net
> ---
> 
> Changes since v1:
> * New patch
> ---
>  security/landlock/access.h  | 53 +++++++++++++++++++++++++++++++++++++
>  security/landlock/fs.c      |  1 +
>  security/landlock/fs.h      |  1 +
>  security/landlock/ruleset.h | 31 +---------------------
>  4 files changed, 56 insertions(+), 30 deletions(-)
>  create mode 100644 security/landlock/access.h
> 
> diff --git a/security/landlock/access.h b/security/landlock/access.h
> new file mode 100644
> index 000000000000..2659fd9b4aaf
> --- /dev/null
> +++ b/security/landlock/access.h
> @@ -0,0 +1,53 @@
> +/* 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 Microsoft Corporation
> + */
> +
> +#ifndef _SECURITY_LANDLOCK_ACCESS_H
> +#define _SECURITY_LANDLOCK_ACCESS_H
> +
> +#include <uapi/linux/landlock.h>
> +
> +#include "limits.h"
> +
> +/* clang-format off */
> +#define ACCESS_FS_OPTIONAL ( \
> +	LANDLOCK_ACCESS_FS_TRUNCATE | \
> +	LANDLOCK_ACCESS_FS_IOCTL_DEV)

Nit: The patch message indicates this is moved from somewhere but I cannot find 
deletion for it.

> +/* 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(((union access_masks_all *)NULL)->masks) ==
> +	      sizeof(((union access_masks_all *)NULL)->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);
> +
> +#endif /* _SECURITY_LANDLOCK_ACCESS_H */
> diff --git a/security/landlock/fs.c b/security/landlock/fs.c
> index 698a623a8184..e0e5775b75ae 100644
> --- a/security/landlock/fs.c
> +++ b/security/landlock/fs.c
> @@ -36,6 +36,7 @@
>  #include <uapi/linux/fiemap.h>
>  #include <uapi/linux/landlock.h>
> 
> +#include "access.h"
>  #include "common.h"
>  #include "cred.h"
>  #include "fs.h"
> diff --git a/security/landlock/fs.h b/security/landlock/fs.h
> index 1487e1f023a1..d445f411c26a 100644
> --- a/security/landlock/fs.h
> +++ b/security/landlock/fs.h
> @@ -13,6 +13,7 @@
>  #include <linux/init.h>
>  #include <linux/rcupdate.h>
> 
> +#include "access.h"
>  #include "ruleset.h"
>  #include "setup.h"
> 
> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
> index e00edcb38c5b..7921bbe01344 100644
> --- a/security/landlock/ruleset.h
> +++ b/security/landlock/ruleset.h
> @@ -17,6 +17,7 @@
>  #include <linux/workqueue.h>
>  #include <uapi/linux/landlock.h>
> 
> +#include "access.h"
>  #include "limits.h"
>  #include "object.h"
> 
> @@ -30,36 +31,6 @@
>  	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(((union access_masks_all *)NULL)->masks) ==
> -	      sizeof(((union access_masks_all *)NULL)->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);
> -
>  /**
>   * struct landlock_layer - Access rights for a given layer
>   */