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

[Konstantin Meskhidze <konstantin.meskhidze@huawei.com>]

4/1/2022 7:47 PM, Mickaël Salaün пишет:
> 
> 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.
> 
   Sure. I will rebase it on your latest updates. Thanks.
> 
>>
>> 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
>>
> .