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Message-ID: <8e279be2-5092-ad34-2f8d-ca77ee5a10fd@huawei.com>
Date: Mon, 11 Apr 2022 16:44:35 +0300
From: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
To: Mickaël Salaün <mic@...ikod.net>
CC: <willemdebruijn.kernel@...il.com>,
<linux-security-module@...r.kernel.org>, <netdev@...r.kernel.org>,
<netfilter-devel@...r.kernel.org>, <yusongping@...wei.com>,
<artem.kuzin@...wei.com>, <anton.sirazetdinov@...wei.com>
Subject: Re: [RFC PATCH v4 08/15] landlock: add support network rules
4/8/2022 7:30 PM, Mickaël Salaün пишет:
>
> On 09/03/2022 14:44, Konstantin Meskhidze wrote:
>> This modification adds network rules support
>> in internal landlock functions (presented in ruleset.c)
>> and landlock_create_ruleset syscall.
>>
>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
>> ---
>>
>> Changes since v3:
>> * Split commit.
>> * Add network rule support for internal landlock functions.
>> * Add set_masks and get_masks for network.
>> * Add rb_root root_net_port.
>>
>> ---
>> security/landlock/fs.c | 2 +-
>> security/landlock/limits.h | 6 +++
>> security/landlock/ruleset.c | 88 +++++++++++++++++++++++++++++++++---
>> security/landlock/ruleset.h | 14 +++++-
>> security/landlock/syscalls.c | 10 +++-
>> 5 files changed, 109 insertions(+), 11 deletions(-)
>>
>> diff --git a/security/landlock/fs.c b/security/landlock/fs.c
>> index 75ebdce5cd16..5cd339061cdb 100644
>> --- a/security/landlock/fs.c
>> +++ b/security/landlock/fs.c
>> @@ -231,7 +231,7 @@ static int check_access_path(const struct
>> landlock_ruleset *const domain,
>>
>> inode = d_backing_inode(walker_path.dentry);
>> object_ptr = landlock_inode(inode)->object;
>> - layer_mask = landlock_unmask_layers(domain, object_ptr,
>> + layer_mask = landlock_unmask_layers(domain, object_ptr, 0,
>> access_request, layer_mask,
>> LANDLOCK_RULE_PATH_BENEATH);
>> if (layer_mask == 0) {
>> diff --git a/security/landlock/limits.h b/security/landlock/limits.h
>> index 2a0a1095ee27..fdbef85e4de0 100644
>> --- a/security/landlock/limits.h
>> +++ b/security/landlock/limits.h
>> @@ -18,4 +18,10 @@
>> #define LANDLOCK_LAST_ACCESS_FS LANDLOCK_ACCESS_FS_MAKE_SYM
>> #define LANDLOCK_MASK_ACCESS_FS ((LANDLOCK_LAST_ACCESS_FS <<
>> 1) - 1)
>>
>> +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP
>> +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1)
>> - 1)
>> +#define LANDLOCK_MASK_SHIFT_NET 16
>> +
>> +#define LANDLOCK_RULE_TYPE_NUM LANDLOCK_RULE_NET_SERVICE
>> +
>> #endif /* _SECURITY_LANDLOCK_LIMITS_H */
>> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
>> index 7179b10f3538..1cecca59a942 100644
>> --- a/security/landlock/ruleset.c
>> +++ b/security/landlock/ruleset.c
>> @@ -35,6 +35,7 @@ static struct landlock_ruleset *create_ruleset(const
>> u32 num_layers)
>> refcount_set(&new_ruleset->usage, 1);
>> mutex_init(&new_ruleset->lock);
>> new_ruleset->root_inode = RB_ROOT;
>> + new_ruleset->root_net_port = RB_ROOT;
>> new_ruleset->num_layers = num_layers;
>> /*
>> * hierarchy = NULL
>> @@ -58,16 +59,32 @@ u32 landlock_get_fs_access_mask(const struct
>> landlock_ruleset *ruleset, u16 mask
>> return ruleset->access_masks[mask_level];
>> }
>>
>> +/* A helper function to set a network mask */
>> +void landlock_set_net_access_mask(struct landlock_ruleset *ruleset,
>> + const struct landlock_access_mask *access_mask_set,
>> + u16 mask_level)
>> +{
>> + ruleset->access_masks[mask_level] |= (access_mask_set->net <<
>> LANDLOCK_MASK_SHIFT_NET);
>> +}
>> +
>> +/* A helper function to get a network mask */
>> +u32 landlock_get_net_access_mask(const struct landlock_ruleset
>> *ruleset, u16 mask_level)
>> +{
>> + return (ruleset->access_masks[mask_level] >>
>> LANDLOCK_MASK_SHIFT_NET);
>> +}
>
> Both these helpers should be "static inline" and moved in net.h
I got it. Ok.
>
>
>> +
>> struct landlock_ruleset *landlock_create_ruleset(const struct
>> landlock_access_mask *access_mask_set)
>> {
>> struct landlock_ruleset *new_ruleset;
>>
>> /* Informs about useless ruleset. */
>> - if (!access_mask_set->fs)
>> + if (!access_mask_set->fs && !access_mask_set->net)
>> return ERR_PTR(-ENOMSG);
>> new_ruleset = create_ruleset(1);
>> - if (!IS_ERR(new_ruleset))
>
> This is better:
>
> if (IS_ERR(new_ruleset))
> return new_ruleset;
> if (access_mask_set->fs)
> ...
I dont get this condition. Do you mean that we return new_ruleset
anyway no matter what the masks's values are? So its possible to have 0
masks values, is't it?
>
>
>> + if (!IS_ERR(new_ruleset) && access_mask_set->fs)
>> landlock_set_fs_access_mask(new_ruleset, access_mask_set, 0);
>> + if (!IS_ERR(new_ruleset) && access_mask_set->net)
>> + landlock_set_net_access_mask(new_ruleset, access_mask_set, 0);
>> return new_ruleset;
>> }
>>
>> @@ -111,6 +128,9 @@ static struct landlock_rule *create_rule(
>> landlock_get_object(object_ptr);
>> new_rule->object.ptr = object_ptr;
>> break;
>> + case LANDLOCK_RULE_NET_SERVICE:
>> + new_rule->object.data = object_data;
>> + break;
>> default:
>> return ERR_PTR(-EINVAL);
>> }
>> @@ -145,10 +165,12 @@ static void build_check_ruleset(void)
>> .num_layers = ~0,
>> };
>> typeof(ruleset.access_masks[0]) fs_access_mask = ~0;
>> + typeof(ruleset.access_masks[0]) net_access_mask = ~0;
>>
>> BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES);
>> BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS);
>> BUILD_BUG_ON(fs_access_mask < LANDLOCK_MASK_ACCESS_FS);
>> + BUILD_BUG_ON(net_access_mask < LANDLOCK_MASK_ACCESS_NET);
>> }
>>
>> /**
>> @@ -191,6 +213,12 @@ static int insert_rule(struct landlock_ruleset
>> *const ruleset,
>
> Already reviewed.
>
> [...]
>
>
>> @@ -319,6 +363,9 @@ static int tree_merge(struct landlock_ruleset
>> *const src,
>> case LANDLOCK_RULE_PATH_BENEATH:
>> src_root = &src->root_inode;
>> break;
>> + case LANDLOCK_RULE_NET_SERVICE:
>> + src_root = &src->root_net_port;
>> + break;
>> default:
>> return -EINVAL;
>> }
>> @@ -338,11 +385,14 @@ static int tree_merge(struct landlock_ruleset
>> *const src,
>> return err;
>> }
>> layers[0].access = walker_rule->layers[0].access;
>> -
>
> nit: Please keep this empty line.
>
>
>> switch (rule_type) {
>> case LANDLOCK_RULE_PATH_BENEATH:
>> err = insert_rule(dst, walker_rule->object.ptr, 0, &layers,
>> - ARRAY_SIZE(layers), rule_type);
>> + ARRAY_SIZE(layers), rule_type);
>
> Please don't insert this kind of formatting in unrelated patches.
>
>
>> + break;
>> + case LANDLOCK_RULE_NET_SERVICE:
>> + err = insert_rule(dst, NULL, walker_rule->object.data,
>> &layers,
>> + ARRAY_SIZE(layers), rule_type);
>> break;
>> }
>> if (err)
>> @@ -379,6 +429,10 @@ static int merge_ruleset(struct landlock_ruleset
>> *const dst,
>> err = tree_merge(src, dst, LANDLOCK_RULE_PATH_BENEATH);
>> if (err)
>> goto out_unlock;
>> + /* Merges the @src network tree. */
>> + err = tree_merge(src, dst, LANDLOCK_RULE_NET_SERVICE);
>> + if (err)
>> + goto out_unlock;
>>
>> out_unlock:
>> mutex_unlock(&src->lock);
>> @@ -398,6 +452,9 @@ static int tree_copy(struct landlock_ruleset
>> *const parent,
>> case LANDLOCK_RULE_PATH_BENEATH:
>> parent_root = &parent->root_inode;
>> break;
>> + case LANDLOCK_RULE_NET_SERVICE:
>> + parent_root = &parent->root_net_port;
>> + break;
>> default:
>> return -EINVAL;
>> }
>> @@ -410,6 +467,11 @@ static int tree_copy(struct landlock_ruleset
>> *const parent,
>> &walker_rule->layers, walker_rule->num_layers,
>> rule_type);
>> break;
>> + case LANDLOCK_RULE_NET_SERVICE:
>> + err = insert_rule(child, NULL, walker_rule->object.data,
>> + &walker_rule->layers, walker_rule->num_layers,
>> + rule_type);
>> + break;
>> }
>> if (err)
>> return err;
>> @@ -432,6 +494,10 @@ static int inherit_ruleset(struct
>> landlock_ruleset *const parent,
>>
>> /* Copies the @parent inode tree. */
>> err = tree_copy(parent, child, LANDLOCK_RULE_PATH_BENEATH);
>> + if (err)
>> + goto out_unlock;
>> + /* Copies the @parent inode tree. */
>> + err = tree_copy(parent, child, LANDLOCK_RULE_NET_SERVICE);
>> if (err)
>> goto out_unlock;
>>
>> @@ -464,6 +530,9 @@ static void free_ruleset(struct landlock_ruleset
>> *const ruleset)
>> rbtree_postorder_for_each_entry_safe(freeme, next,
>> &ruleset->root_inode,
>> node)
>> free_rule(freeme, LANDLOCK_RULE_PATH_BENEATH);
>> + rbtree_postorder_for_each_entry_safe(freeme, next,
>> &ruleset->root_net_port,
>> + node)
>> + free_rule(freeme, LANDLOCK_RULE_NET_SERVICE);
>> put_hierarchy(ruleset->hierarchy);
>> kfree(ruleset);
>> }
>> @@ -565,6 +634,9 @@ const struct landlock_rule *landlock_find_rule(
>> case LANDLOCK_RULE_PATH_BENEATH:
>> node = ruleset->root_inode.rb_node;
>> break;
>> + case LANDLOCK_RULE_NET_SERVICE:
>> + node = ruleset->root_net_port.rb_node;
>> + break;
>> default:
>> return ERR_PTR(-EINVAL);
>> }
>> @@ -586,8 +658,8 @@ const struct landlock_rule *landlock_find_rule(
>> /* Access-control management */
>> u64 landlock_unmask_layers(const struct landlock_ruleset *const domain,
>> const struct landlock_object *object_ptr,
>> - const u32 access_request, u64 layer_mask,
>> - const u16 rule_type)
>> + const u16 port, const u32 access_request,
>> + u64 layer_mask, const u16 rule_type)
>> {
>> const struct landlock_rule *rule;
>> size_t i;
>> @@ -600,6 +672,10 @@ u64 landlock_unmask_layers(const struct
>> landlock_ruleset *const domain,
>> LANDLOCK_RULE_PATH_BENEATH);
>> rcu_read_unlock();
>> break;
>> + case LANDLOCK_RULE_NET_SERVICE:
>> + rule = landlock_find_rule(domain, (uintptr_t)port,
>
> Type casting should not be required.
Ok. I got it.
>
> [...]
> .
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