security/landlock/fs.h

Source file repositories/reference/linux-study-clean/security/landlock/fs.h

File Facts

System
Linux kernel
Corpus path
security/landlock/fs.h
Extension
.h
Size
5049 bytes
Lines
157
Domain
Core OS
Bucket
Security And Isolation
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct landlock_inode_security {
	/**
	 * @object: Weak pointer to an allocated object.  All assignments of a
	 * new object are protected by the underlying inode->i_lock.  However,
	 * atomically disassociating @object from the inode is only protected
	 * by @object->lock, from the time @object's usage refcount drops to
	 * zero to the time this pointer is nulled out (cf. release_inode() and
	 * hook_sb_delete()).  Indeed, such disassociation doesn't require
	 * inode->i_lock thanks to the careful rcu_access_pointer() check
	 * performed by get_inode_object().
	 */
	struct landlock_object __rcu *object;
};

/**
 * struct landlock_file_security - File security blob
 *
 * This information is populated when opening a file in hook_file_open, and
 * tracks the relevant Landlock access rights that were available at the time
 * of opening the file. Other LSM hooks use these rights in order to authorize
 * operations on already opened files.
 */
struct landlock_file_security {
	/**
	 * @allowed_access: Access rights that were available at the time of
	 * opening the file. This is not necessarily the full set of access
	 * rights available at that time, but it's the necessary subset as
	 * needed to authorize later operations on the open file.
	 */
	access_mask_t allowed_access;

#ifdef CONFIG_AUDIT
	/**
	 * @deny_masks: Domain layer levels that deny an optional access (see
	 * _LANDLOCK_ACCESS_FS_OPTIONAL).
	 */
	deny_masks_t deny_masks;
	/**
	 * @quiet_optional_accesses: Stores which optional accesses are covered
	 * by quiet rules within the layer referred to in deny_masks, one access
	 * per bit.  Does not take into account whether the quiet access bits
	 * are actually set in the layer's corresponding landlock_hierarchy.
	 */
	optional_access_t quiet_optional_accesses;
	/**
	 * @fown_layer: Layer level of @fown_subject->domain with
	 * LANDLOCK_SCOPE_SIGNAL.
	 */
	u8 fown_layer;
#endif /* CONFIG_AUDIT */

	/**
	 * @fown_subject: Landlock credential of the task that set the PID that
	 * may receive a signal e.g., SIGURG when writing MSG_OOB to the
	 * related socket.  This pointer is protected by the related
	 * file->f_owner->lock, as for fown_struct's members: pid, uid, and
	 * euid.
	 */
	struct landlock_cred_security fown_subject;
	/**
	 * @fown_tg: Thread group of the task that set the file owner, pinned
	 * while @fown_subject holds a domain.  It lets
	 * hook_file_send_sigiotask() always allow a SIGIO delivered to the
	 * owner's own process -- e.g. the thread-group leader reached through a
	 * process-group owner -- matching the same-process exemption of
	 * hook_task_kill().  NULL when no domain is recorded.  Protected by
	 * file->f_owner->lock, like @fown_subject.
	 */
	struct pid *fown_tg;
};

#ifdef CONFIG_AUDIT

/* Makes sure all layers can be identified. */
/* clang-format off */
static_assert((typeof_member(struct landlock_file_security, fown_layer))~0 >=
	      LANDLOCK_MAX_NUM_LAYERS);
/* clang-format on */

/*
 * Make sure quiet_optional_accesses has enough bits to cover all optional
 * accesses.
 */
static_assert(BITS_PER_TYPE(typeof_member(struct landlock_file_security,
					  quiet_optional_accesses)) >=
	      HWEIGHT(_LANDLOCK_ACCESS_FS_OPTIONAL));

#endif /* CONFIG_AUDIT */

/**

Annotation

Implementation Notes