diff mbox series

[RFC,v4,08/15] landlock: add support network rules

Message ID 20220309134459.6448-9-konstantin.meskhidze@huawei.com (mailing list archive)
State RFC
Headers show
Series Landlock LSM | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch, async

Commit Message

Konstantin Meskhidze (A) March 9, 2022, 1:44 p.m. UTC 
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@huawei.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(-)

--
2.25.1

Comments

Mickaël Salaün April 8, 2022, 4:30 p.m. UTC | #1 
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@huawei.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


> +
>   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)
...


> +	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.

[...]
Konstantin Meskhidze (A) April 11, 2022, 1:44 p.m. UTC | #2 
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@huawei.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.
> 
> [...]
> .
Mickaël Salaün April 11, 2022, 4:20 p.m. UTC | #3 
On 11/04/2022 15:44, Konstantin Meskhidze wrote:
> 
> 
> 4/8/2022 7:30 PM, Mickaël Salaün пишет:

[...]


>>>   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?

No, the logic is correct but it would be simpler to exit as soon as 
there is a ruleset error, you don't need to duplicate 
"IS_ERR(new_ruleset) &&":

if (IS_ERR(new_ruleset))
	return new_ruleset;
if (access_mask_set->fs)
	landlock_set_fs_access_mask(new_ruleset, access_mask_set, 0);
if (access_mask_set->net)
	landlock_set_net_access_mask(new_ruleset, access_mask_set, 0);
return new_ruleset;
Konstantin Meskhidze (A) April 12, 2022, 8:38 a.m. UTC | #4 
4/11/2022 7:20 PM, Mickaël Salaün пишет:
> 
> On 11/04/2022 15:44, Konstantin Meskhidze wrote:
>>
>>
>> 4/8/2022 7:30 PM, Mickaël Salaün пишет:
> 
> [...]
> 
> 
>>>>   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?
> 
> No, the logic is correct but it would be simpler to exit as soon as 
> there is a ruleset error, you don't need to duplicate 
> "IS_ERR(new_ruleset) &&":
> 
> if (IS_ERR(new_ruleset))
>      return new_ruleset;
> if (access_mask_set->fs)
>      landlock_set_fs_access_mask(new_ruleset, access_mask_set, 0);
> if (access_mask_set->net)
>      landlock_set_net_access_mask(new_ruleset, access_mask_set, 0);
> return new_ruleset;
> 
   Ok. I got it. Thank you.
> .
diff mbox series

Patch

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);
+}
+
 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))
+	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,
 		object = (uintptr_t)object_ptr;
 		root = &ruleset->root_inode;
 		break;
+	case LANDLOCK_RULE_NET_SERVICE:
+		if (WARN_ON_ONCE(!object_data || !layers))
+			return -ENOENT;
+		object = object_data;
+		root = &ruleset->root_net_port;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -242,6 +270,14 @@  static int insert_rule(struct landlock_ruleset *const ruleset,
 			rb_replace_node(&this->node, &new_rule->node, &ruleset->root_inode);
 			free_rule(this, rule_type);
 			break;
+		case LANDLOCK_RULE_NET_SERVICE:
+			new_rule = create_rule(NULL, object_data, &this->layers, this->num_layers,
+					       &(*layers)[0], rule_type);
+			if (IS_ERR(new_rule))
+				return PTR_ERR(new_rule);
+			rb_replace_node(&this->node, &new_rule->node, &ruleset->root_net_port);
+			free_rule(this, rule_type);
+			break;
 		}
 		return 0;
 	}
@@ -259,6 +295,14 @@  static int insert_rule(struct landlock_ruleset *const ruleset,
 		rb_insert_color(&new_rule->node, &ruleset->root_inode);
 		ruleset->num_rules++;
 		break;
+	case LANDLOCK_RULE_NET_SERVICE:
+		new_rule = create_rule(NULL, object_data, layers, num_layers, NULL, rule_type);
+		if (IS_ERR(new_rule))
+			return PTR_ERR(new_rule);
+		rb_link_node(&new_rule->node, parent_node, walker_node);
+		rb_insert_color(&new_rule->node, &ruleset->root_net_port);
+		ruleset->num_rules++;
+		break;
 	}
 	return 0;
 }
@@ -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;
-
 		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);
+			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,
+					LANDLOCK_RULE_NET_SERVICE);
+		break;
 	}

 	if (!rule)
diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
index 0a7d4b1f51fd..abf3e09a65cd 100644
--- a/security/landlock/ruleset.h
+++ b/security/landlock/ruleset.h
@@ -24,6 +24,10 @@  struct landlock_access_mask {
 	 * @fs: Filesystem access mask.
 	 */
 	u16 fs;
+	/**
+	 * @net: Network access mask.
+	 */
+	u16 net;
 };

 /**
@@ -98,6 +102,12 @@  struct landlock_ruleset {
 	 * tree is immutable until @usage reaches zero.
 	 */
 	struct rb_root root_inode;
+	/**
+	 * @root_net_port: Root of a red-black tree containing object nodes
+	 * for network port. Once a ruleset is tied to a process (i.e. as a domain),
+	 * this tree is immutable until @usage reaches zero.
+	 */
+	struct rb_root root_net_port;
 	/**
 	 * @hierarchy: Enables hierarchy identification even when a parent
 	 * domain vanishes.  This is needed for the ptrace protection.
@@ -185,7 +195,7 @@  u32 landlock_get_fs_access_mask(const struct landlock_ruleset *ruleset, u16 mask

 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);

 #endif /* _SECURITY_LANDLOCK_RULESET_H */
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index fcbce83d64ef..b91455a19356 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -160,7 +160,7 @@  SYSCALL_DEFINE3(landlock_create_ruleset,
 {
 	struct landlock_ruleset_attr ruleset_attr;
 	struct landlock_ruleset *ruleset;
-	struct landlock_access_mask access_mask_set = {.fs = 0};
+	struct landlock_access_mask access_mask_set = {.fs = 0, .net = 0};
 	int err, ruleset_fd;

 	/* Build-time checks. */
@@ -187,8 +187,14 @@  SYSCALL_DEFINE3(landlock_create_ruleset,
 	if ((ruleset_attr.handled_access_fs | LANDLOCK_MASK_ACCESS_FS) !=
 			 LANDLOCK_MASK_ACCESS_FS)
 		return -EINVAL;
-	access_mask_set.fs = ruleset_attr.handled_access_fs;

+	/* Checks network content (and 32-bits cast). */
+	if ((ruleset_attr.handled_access_net | LANDLOCK_MASK_ACCESS_NET) !=
+			LANDLOCK_MASK_ACCESS_NET)
+		return -EINVAL;
+
+	access_mask_set.fs = ruleset_attr.handled_access_fs;
+	access_mask_set.net = ruleset_attr.handled_access_net;
 	/* Checks arguments and transforms to kernel struct. */
 	ruleset = landlock_create_ruleset(&access_mask_set);
 	if (IS_ERR(ruleset))