Re: [RFC PATCH v4 01/15] landlock: access mask renaming

["Mickaël Salaün" <mic@digikod.net>]

On 09/03/2022 14:44, Konstantin Meskhidze wrote:
> Currently Landlock supports filesystem
> restrictions. To support network type rules,
> this modification extends and renames
> ruleset's access masks.

Please use 72 columns for all commit messages.
With vim: set tw=72

The code looks good but you'll have to rebase it on top of my 
access_mask_t changes.

Next time you can rebase your changes on my landlock-wip branch at 
https://git.kernel.org/pub/scm/linux/kernel/git/mic/linux.git
I'll update this branch regularly but it should not impact much your 
changes.


> 
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
> ---
> 
> Changes since v3:
> * Split commit.
> 
> ---
>   security/landlock/fs.c       |  4 ++--
>   security/landlock/ruleset.c  | 18 +++++++++---------
>   security/landlock/ruleset.h  |  8 ++++----
>   security/landlock/syscalls.c |  6 +++---
>   4 files changed, 18 insertions(+), 18 deletions(-)
> 
> diff --git a/security/landlock/fs.c b/security/landlock/fs.c
> index 97b8e421f617..d727bdab7840 100644
> --- a/security/landlock/fs.c
> +++ b/security/landlock/fs.c
> @@ -163,7 +163,7 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
>   		return -EINVAL;
> 
>   	/* Transforms relative access rights to absolute ones. */
> -	access_rights |= LANDLOCK_MASK_ACCESS_FS & ~ruleset->fs_access_masks[0];
> +	access_rights |= LANDLOCK_MASK_ACCESS_FS & ~ruleset->access_masks[0];
>   	object = get_inode_object(d_backing_inode(path->dentry));
>   	if (IS_ERR(object))
>   		return PTR_ERR(object);
> @@ -252,7 +252,7 @@ static int check_access_path(const struct landlock_ruleset *const domain,
>   	/* Saves all layers handling a subset of requested accesses. */
>   	layer_mask = 0;
>   	for (i = 0; i < domain->num_layers; i++) {
> -		if (domain->fs_access_masks[i] & access_request)
> +		if (domain->access_masks[i] & access_request)
>   			layer_mask |= BIT_ULL(i);
>   	}
>   	/* An access request not handled by the domain is allowed. */
> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
> index ec72b9262bf3..78341a0538de 100644
> --- a/security/landlock/ruleset.c
> +++ b/security/landlock/ruleset.c
> @@ -28,7 +28,7 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers)
>   {
>   	struct landlock_ruleset *new_ruleset;
> 
> -	new_ruleset = kzalloc(struct_size(new_ruleset, fs_access_masks,
> +	new_ruleset = kzalloc(struct_size(new_ruleset, access_masks,
>   				num_layers), GFP_KERNEL_ACCOUNT);
>   	if (!new_ruleset)
>   		return ERR_PTR(-ENOMEM);
> @@ -39,21 +39,21 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers)
>   	/*
>   	 * hierarchy = NULL
>   	 * num_rules = 0
> -	 * fs_access_masks[] = 0
> +	 * access_masks[] = 0
>   	 */
>   	return new_ruleset;
>   }
> 
> -struct landlock_ruleset *landlock_create_ruleset(const u32 fs_access_mask)
> +struct landlock_ruleset *landlock_create_ruleset(const u32 access_mask)
>   {
>   	struct landlock_ruleset *new_ruleset;
> 
>   	/* Informs about useless ruleset. */
> -	if (!fs_access_mask)
> +	if (!access_mask)
>   		return ERR_PTR(-ENOMSG);
>   	new_ruleset = create_ruleset(1);
>   	if (!IS_ERR(new_ruleset))
> -		new_ruleset->fs_access_masks[0] = fs_access_mask;
> +		new_ruleset->access_masks[0] = access_mask;
>   	return new_ruleset;
>   }
> 
> @@ -116,7 +116,7 @@ static void build_check_ruleset(void)
>   		.num_rules = ~0,
>   		.num_layers = ~0,
>   	};
> -	typeof(ruleset.fs_access_masks[0]) fs_access_mask = ~0;
> +	typeof(ruleset.access_masks[0]) fs_access_mask = ~0;
> 
>   	BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES);
>   	BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS);
> @@ -279,7 +279,7 @@ static int merge_ruleset(struct landlock_ruleset *const dst,
>   		err = -EINVAL;
>   		goto out_unlock;
>   	}
> -	dst->fs_access_masks[dst->num_layers - 1] = src->fs_access_masks[0];
> +	dst->access_masks[dst->num_layers - 1] = src->access_masks[0];
> 
>   	/* Merges the @src tree. */
>   	rbtree_postorder_for_each_entry_safe(walker_rule, next_rule,
> @@ -337,8 +337,8 @@ static int inherit_ruleset(struct landlock_ruleset *const parent,
>   		goto out_unlock;
>   	}
>   	/* Copies the parent layer stack and leaves a space for the new layer. */
> -	memcpy(child->fs_access_masks, parent->fs_access_masks,
> -			flex_array_size(parent, fs_access_masks, parent->num_layers));
> +	memcpy(child->access_masks, parent->access_masks,
> +			flex_array_size(parent, access_masks, parent->num_layers));
> 
>   	if (WARN_ON_ONCE(!parent->hierarchy)) {
>   		err = -EINVAL;
> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
> index 2d3ed7ec5a0a..32d90ce72428 100644
> --- a/security/landlock/ruleset.h
> +++ b/security/landlock/ruleset.h
> @@ -97,7 +97,7 @@ struct landlock_ruleset {
>   		 * section.  This is only used by
>   		 * landlock_put_ruleset_deferred() when @usage reaches zero.
>   		 * The fields @lock, @usage, @num_rules, @num_layers and
> -		 * @fs_access_masks are then unused.
> +		 * @access_masks are then unused.
>   		 */
>   		struct work_struct work_free;
>   		struct {
> @@ -124,7 +124,7 @@ struct landlock_ruleset {
>   			 */
>   			u32 num_layers;
>   			/**
> -			 * @fs_access_masks: Contains the subset of filesystem
> +			 * @access_masks: Contains the subset of filesystem
>   			 * actions that are restricted by a ruleset.  A domain
>   			 * saves all layers of merged rulesets in a stack
>   			 * (FAM), starting from the first layer to the last
> @@ -135,12 +135,12 @@ struct landlock_ruleset {
>   			 * layers are set once and never changed for the
>   			 * lifetime of the ruleset.
>   			 */
> -			u16 fs_access_masks[];
> +			u32 access_masks[];

Changing from u16 to u32 is not correct for this patch, but it would not 
be visible with access_mask_t anyway.

>   		};
>   	};
>   };
> 
> -struct landlock_ruleset *landlock_create_ruleset(const u32 fs_access_mask);
> +struct landlock_ruleset *landlock_create_ruleset(const u32 access_mask);
> 
>   void landlock_put_ruleset(struct landlock_ruleset *const ruleset);
>   void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset);
> diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
> index 32396962f04d..f1d86311df7e 100644
> --- a/security/landlock/syscalls.c
> +++ b/security/landlock/syscalls.c
> @@ -341,10 +341,10 @@ SYSCALL_DEFINE4(landlock_add_rule,
>   	}
>   	/*
>   	 * Checks that allowed_access matches the @ruleset constraints
> -	 * (ruleset->fs_access_masks[0] is automatically upgraded to 64-bits).
> +	 * (ruleset->access_masks[0] is automatically upgraded to 64-bits).
>   	 */
> -	if ((path_beneath_attr.allowed_access | ruleset->fs_access_masks[0]) !=
> -			ruleset->fs_access_masks[0]) {
> +	if ((path_beneath_attr.allowed_access | ruleset->access_masks[0]) !=
> +			ruleset->access_masks[0]) {
>   		err = -EINVAL;
>   		goto out_put_ruleset;
>   	}
> --
> 2.25.1
>