Message-ID: <55454B6D.4080806@schaufler-ca.com>
Date: Sat, 02 May 2015 15:10:53 -0700
From: Casey Schaufler <casey@schaufler-ca.com>
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To: James Morris <jmorris@namei.org>, James Morris <james.l.morris@oracle.com>,
        LSM <linux-security-module@vger.kernel.org>,
        LKLM <linux-kernel@vger.kernel.org>
CC: Paul Moore <pmoore@redhat.com>,
        John Johansen <john.johansen@canonical.com>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Stephen Smalley <sds@tycho.nsa.gov>, Eric Paris <eparis@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Casey Schaufler <casey@schaufler-ca.com>
Subject: [PATCH 2/7 v22] LSM: Add the comment to lsm_hooks.h
References: <55454539.9020204@schaufler-ca.com>
In-Reply-To: <55454539.9020204@schaufler-ca.com>
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Subject: [PATCH 2/7 v22] LSM: Add the comment to lsm_hooks.h

Add the large comment describing the content of the
security_operations structure to lsm_hooks.h. This
wasn't done in the previous (1/7) patch because it
would have exceeded the mail list size limits.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

---

 include/linux/lsm_hooks.h | 1279 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1279 insertions(+)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index b2f447e..b798c07 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -31,6 +31,1285 @@
 
 #ifdef CONFIG_SECURITY
 
+/**
+ * struct security_operations - main security structure
+ *
+ * Security module identifier.
+ *
+ * @name:
+ *	A string that acts as a unique identifier for the LSM with max number
+ *	of characters = SECURITY_NAME_MAX.
+ *
+ * Security hooks for program execution operations.
+ *
+ * @bprm_set_creds:
+ *	Save security information in the bprm->security field, typically based
+ *	on information about the bprm->file, for later use by the apply_creds
+ *	hook.  This hook may also optionally check permissions (e.g. for
+ *	transitions between security domains).
+ *	This hook may be called multiple times during a single execve, e.g. for
+ *	interpreters.  The hook can tell whether it has already been called by
+ *	checking to see if @bprm->security is non-NULL.  If so, then the hook
+ *	may decide either to retain the security information saved earlier or
+ *	to replace it.
+ *	@bprm contains the linux_binprm structure.
+ *	Return 0 if the hook is successful and permission is granted.
+ * @bprm_check_security:
+ *	This hook mediates the point when a search for a binary handler will
+ *	begin.  It allows a check the @bprm->security value which is set in the
+ *	preceding set_creds call.  The primary difference from set_creds is
+ *	that the argv list and envp list are reliably available in @bprm.  This
+ *	hook may be called multiple times during a single execve; and in each
+ *	pass set_creds is called first.
+ *	@bprm contains the linux_binprm structure.
+ *	Return 0 if the hook is successful and permission is granted.
+ * @bprm_committing_creds:
+ *	Prepare to install the new security attributes of a process being
+ *	transformed by an execve operation, based on the old credentials
+ *	pointed to by @current->cred and the information set in @bprm->cred by
+ *	the bprm_set_creds hook.  @bprm points to the linux_binprm structure.
+ *	This hook is a good place to perform state changes on the process such
+ *	as closing open file descriptors to which access will no longer be
+ *	granted when the attributes are changed.  This is called immediately
+ *	before commit_creds().
+ * @bprm_committed_creds:
+ *	Tidy up after the installation of the new security attributes of a
+ *	process being transformed by an execve operation.  The new credentials
+ *	have, by this point, been set to @current->cred.  @bprm points to the
+ *	linux_binprm structure.  This hook is a good place to perform state
+ *	changes on the process such as clearing out non-inheritable signal
+ *	state.  This is called immediately after commit_creds().
+ * @bprm_secureexec:
+ *	Return a boolean value (0 or 1) indicating whether a "secure exec"
+ *	is required.  The flag is passed in the auxiliary table
+ *	on the initial stack to the ELF interpreter to indicate whether libc
+ *	should enable secure mode.
+ *	@bprm contains the linux_binprm structure.
+ *
+ * Security hooks for filesystem operations.
+ *
+ * @sb_alloc_security:
+ *	Allocate and attach a security structure to the sb->s_security field.
+ *	The s_security field is initialized to NULL when the structure is
+ *	allocated.
+ *	@sb contains the super_block structure to be modified.
+ *	Return 0 if operation was successful.
+ * @sb_free_security:
+ *	Deallocate and clear the sb->s_security field.
+ *	@sb contains the super_block structure to be modified.
+ * @sb_statfs:
+ *	Check permission before obtaining filesystem statistics for the @mnt
+ *	mountpoint.
+ *	@dentry is a handle on the superblock for the filesystem.
+ *	Return 0 if permission is granted.
+ * @sb_mount:
+ *	Check permission before an object specified by @dev_name is mounted on
+ *	the mount point named by @nd.  For an ordinary mount, @dev_name
+ *	identifies a device if the file system type requires a device.  For a
+ *	remount (@flags & MS_REMOUNT), @dev_name is irrelevant.  For a
+ *	loopback/bind mount (@flags & MS_BIND), @dev_name identifies the
+ *	pathname of the object being mounted.
+ *	@dev_name contains the name for object being mounted.
+ *	@path contains the path for mount point object.
+ *	@type contains the filesystem type.
+ *	@flags contains the mount flags.
+ *	@data contains the filesystem-specific data.
+ *	Return 0 if permission is granted.
+ * @sb_copy_data:
+ *	Allow mount option data to be copied prior to parsing by the filesystem,
+ *	so that the security module can extract security-specific mount
+ *	options cleanly (a filesystem may modify the data e.g. with strsep()).
+ *	This also allows the original mount data to be stripped of security-
+ *	specific options to avoid having to make filesystems aware of them.
+ *	@type the type of filesystem being mounted.
+ *	@orig the original mount data copied from userspace.
+ *	@copy copied data which will be passed to the security module.
+ *	Returns 0 if the copy was successful.
+ * @sb_remount:
+ *	Extracts security system specific mount options and verifies no changes
+ *	are being made to those options.
+ *	@sb superblock being remounted
+ *	@data contains the filesystem-specific data.
+ *	Return 0 if permission is granted.
+ * @sb_umount:
+ *	Check permission before the @mnt file system is unmounted.
+ *	@mnt contains the mounted file system.
+ *	@flags contains the unmount flags, e.g. MNT_FORCE.
+ *	Return 0 if permission is granted.
+ * @sb_pivotroot:
+ *	Check permission before pivoting the root filesystem.
+ *	@old_path contains the path for the new location of the
+ *	current root (put_old).
+ *	@new_path contains the path for the new root (new_root).
+ *	Return 0 if permission is granted.
+ * @sb_set_mnt_opts:
+ *	Set the security relevant mount options used for a superblock
+ *	@sb the superblock to set security mount options for
+ *	@opts binary data structure containing all lsm mount data
+ * @sb_clone_mnt_opts:
+ *	Copy all security options from a given superblock to another
+ *	@oldsb old superblock which contain information to clone
+ *	@newsb new superblock which needs filled in
+ * @sb_parse_opts_str:
+ *	Parse a string of security data filling in the opts structure
+ *	@options string containing all mount options known by the LSM
+ *	@opts binary data structure usable by the LSM
+ * @dentry_init_security:
+ *	Compute a context for a dentry as the inode is not yet available
+ *	since NFSv4 has no label backed by an EA anyway.
+ *	@dentry dentry to use in calculating the context.
+ *	@mode mode used to determine resource type.
+ *	@name name of the last path component used to create file
+ *	@ctx pointer to place the pointer to the resulting context in.
+ *	@ctxlen point to place the length of the resulting context.
+ *
+ *
+ * Security hooks for inode operations.
+ *
+ * @inode_alloc_security:
+ *	Allocate and attach a security structure to @inode->i_security.  The
+ *	i_security field is initialized to NULL when the inode structure is
+ *	allocated.
+ *	@inode contains the inode structure.
+ *	Return 0 if operation was successful.
+ * @inode_free_security:
+ *	@inode contains the inode structure.
+ *	Deallocate the inode security structure and set @inode->i_security to
+ *	NULL.
+ * @inode_init_security:
+ *	Obtain the security attribute name suffix and value to set on a newly
+ *	created inode and set up the incore security field for the new inode.
+ *	This hook is called by the fs code as part of the inode creation
+ *	transaction and provides for atomic labeling of the inode, unlike
+ *	the post_create/mkdir/... hooks called by the VFS.  The hook function
+ *	is expected to allocate the name and value via kmalloc, with the caller
+ *	being responsible for calling kfree after using them.
+ *	If the security module does not use security attributes or does
+ *	not wish to put a security attribute on this particular inode,
+ *	then it should return -EOPNOTSUPP to skip this processing.
+ *	@inode contains the inode structure of the newly created inode.
+ *	@dir contains the inode structure of the parent directory.
+ *	@qstr contains the last path component of the new object
+ *	@name will be set to the allocated name suffix (e.g. selinux).
+ *	@value will be set to the allocated attribute value.
+ *	@len will be set to the length of the value.
+ *	Returns 0 if @name and @value have been successfully set,
+ *		-EOPNOTSUPP if no security attribute is needed, or
+ *		-ENOMEM on memory allocation failure.
+ * @inode_create:
+ *	Check permission to create a regular file.
+ *	@dir contains inode structure of the parent of the new file.
+ *	@dentry contains the dentry structure for the file to be created.
+ *	@mode contains the file mode of the file to be created.
+ *	Return 0 if permission is granted.
+ * @inode_link:
+ *	Check permission before creating a new hard link to a file.
+ *	@old_dentry contains the dentry structure for an existing
+ *	link to the file.
+ *	@dir contains the inode structure of the parent directory
+ *	of the new link.
+ *	@new_dentry contains the dentry structure for the new link.
+ *	Return 0 if permission is granted.
+ * @path_link:
+ *	Check permission before creating a new hard link to a file.
+ *	@old_dentry contains the dentry structure for an existing link
+ *	to the file.
+ *	@new_dir contains the path structure of the parent directory of
+ *	the new link.
+ *	@new_dentry contains the dentry structure for the new link.
+ *	Return 0 if permission is granted.
+ * @inode_unlink:
+ *	Check the permission to remove a hard link to a file.
+ *	@dir contains the inode structure of parent directory of the file.
+ *	@dentry contains the dentry structure for file to be unlinked.
+ *	Return 0 if permission is granted.
+ * @path_unlink:
+ *	Check the permission to remove a hard link to a file.
+ *	@dir contains the path structure of parent directory of the file.
+ *	@dentry contains the dentry structure for file to be unlinked.
+ *	Return 0 if permission is granted.
+ * @inode_symlink:
+ *	Check the permission to create a symbolic link to a file.
+ *	@dir contains the inode structure of parent directory of
+ *	the symbolic link.
+ *	@dentry contains the dentry structure of the symbolic link.
+ *	@old_name contains the pathname of file.
+ *	Return 0 if permission is granted.
+ * @path_symlink:
+ *	Check the permission to create a symbolic link to a file.
+ *	@dir contains the path structure of parent directory of
+ *	the symbolic link.
+ *	@dentry contains the dentry structure of the symbolic link.
+ *	@old_name contains the pathname of file.
+ *	Return 0 if permission is granted.
+ * @inode_mkdir:
+ *	Check permissions to create a new directory in the existing directory
+ *	associated with inode structure @dir.
+ *	@dir contains the inode structure of parent of the directory
+ *	to be created.
+ *	@dentry contains the dentry structure of new directory.
+ *	@mode contains the mode of new directory.
+ *	Return 0 if permission is granted.
+ * @path_mkdir:
+ *	Check permissions to create a new directory in the existing directory
+ *	associated with path structure @path.
+ *	@dir contains the path structure of parent of the directory
+ *	to be created.
+ *	@dentry contains the dentry structure of new directory.
+ *	@mode contains the mode of new directory.
+ *	Return 0 if permission is granted.
+ * @inode_rmdir:
+ *	Check the permission to remove a directory.
+ *	@dir contains the inode structure of parent of the directory
+ *	to be removed.
+ *	@dentry contains the dentry structure of directory to be removed.
+ *	Return 0 if permission is granted.
+ * @path_rmdir:
+ *	Check the permission to remove a directory.
+ *	@dir contains the path structure of parent of the directory to be
+ *	removed.
+ *	@dentry contains the dentry structure of directory to be removed.
+ *	Return 0 if permission is granted.
+ * @inode_mknod:
+ *	Check permissions when creating a special file (or a socket or a fifo
+ *	file created via the mknod system call).  Note that if mknod operation
+ *	is being done for a regular file, then the create hook will be called
+ *	and not this hook.
+ *	@dir contains the inode structure of parent of the new file.
+ *	@dentry contains the dentry structure of the new file.
+ *	@mode contains the mode of the new file.
+ *	@dev contains the device number.
+ *	Return 0 if permission is granted.
+ * @path_mknod:
+ *	Check permissions when creating a file. Note that this hook is called
+ *	even if mknod operation is being done for a regular file.
+ *	@dir contains the path structure of parent of the new file.
+ *	@dentry contains the dentry structure of the new file.
+ *	@mode contains the mode of the new file.
+ *	@dev contains the undecoded device number. Use new_decode_dev() to get
+ *	the decoded device number.
+ *	Return 0 if permission is granted.
+ * @inode_rename:
+ *	Check for permission to rename a file or directory.
+ *	@old_dir contains the inode structure for parent of the old link.
+ *	@old_dentry contains the dentry structure of the old link.
+ *	@new_dir contains the inode structure for parent of the new link.
+ *	@new_dentry contains the dentry structure of the new link.
+ *	Return 0 if permission is granted.
+ * @path_rename:
+ *	Check for permission to rename a file or directory.
+ *	@old_dir contains the path structure for parent of the old link.
+ *	@old_dentry contains the dentry structure of the old link.
+ *	@new_dir contains the path structure for parent of the new link.
+ *	@new_dentry contains the dentry structure of the new link.
+ *	Return 0 if permission is granted.
+ * @path_chmod:
+ *	Check for permission to change DAC's permission of a file or directory.
+ *	@dentry contains the dentry structure.
+ *	@mnt contains the vfsmnt structure.
+ *	@mode contains DAC's mode.
+ *	Return 0 if permission is granted.
+ * @path_chown:
+ *	Check for permission to change owner/group of a file or directory.
+ *	@path contains the path structure.
+ *	@uid contains new owner's ID.
+ *	@gid contains new group's ID.
+ *	Return 0 if permission is granted.
+ * @path_chroot:
+ *	Check for permission to change root directory.
+ *	@path contains the path structure.
+ *	Return 0 if permission is granted.
+ * @inode_readlink:
+ *	Check the permission to read the symbolic link.
+ *	@dentry contains the dentry structure for the file link.
+ *	Return 0 if permission is granted.
+ * @inode_follow_link:
+ *	Check permission to follow a symbolic link when looking up a pathname.
+ *	@dentry contains the dentry structure for the link.
+ *	@nd contains the nameidata structure for the parent directory.
+ *	Return 0 if permission is granted.
+ * @inode_permission:
+ *	Check permission before accessing an inode.  This hook is called by the
+ *	existing Linux permission function, so a security module can use it to
+ *	provide additional checking for existing Linux permission checks.
+ *	Notice that this hook is called when a file is opened (as well as many
+ *	other operations), whereas the file_security_ops permission hook is
+ *	called when the actual read/write operations are performed.
+ *	@inode contains the inode structure to check.
+ *	@mask contains the permission mask.
+ *	Return 0 if permission is granted.
+ * @inode_setattr:
+ *	Check permission before setting file attributes.  Note that the kernel
+ *	call to notify_change is performed from several locations, whenever
+ *	file attributes change (such as when a file is truncated, chown/chmod
+ *	operations, transferring disk quotas, etc).
+ *	@dentry contains the dentry structure for the file.
+ *	@attr is the iattr structure containing the new file attributes.
+ *	Return 0 if permission is granted.
+ * @path_truncate:
+ *	Check permission before truncating a file.
+ *	@path contains the path structure for the file.
+ *	Return 0 if permission is granted.
+ * @inode_getattr:
+ *	Check permission before obtaining file attributes.
+ *	@mnt is the vfsmount where the dentry was looked up
+ *	@dentry contains the dentry structure for the file.
+ *	Return 0 if permission is granted.
+ * @inode_setxattr:
+ *	Check permission before setting the extended attributes
+ *	@value identified by @name for @dentry.
+ *	Return 0 if permission is granted.
+ * @inode_post_setxattr:
+ *	Update inode security field after successful setxattr operation.
+ *	@value identified by @name for @dentry.
+ * @inode_getxattr:
+ *	Check permission before obtaining the extended attributes
+ *	identified by @name for @dentry.
+ *	Return 0 if permission is granted.
+ * @inode_listxattr:
+ *	Check permission before obtaining the list of extended attribute
+ *	names for @dentry.
+ *	Return 0 if permission is granted.
+ * @inode_removexattr:
+ *	Check permission before removing the extended attribute
+ *	identified by @name for @dentry.
+ *	Return 0 if permission is granted.
+ * @inode_getsecurity:
+ *	Retrieve a copy of the extended attribute representation of the
+ *	security label associated with @name for @inode via @buffer.  Note that
+ *	@name is the remainder of the attribute name after the security prefix
+ *	has been removed. @alloc is used to specify of the call should return a
+ *	value via the buffer or just the value length Return size of buffer on
+ *	success.
+ * @inode_setsecurity:
+ *	Set the security label associated with @name for @inode from the
+ *	extended attribute value @value.  @size indicates the size of the
+ *	@value in bytes.  @flags may be XATTR_CREATE, XATTR_REPLACE, or 0.
+ *	Note that @name is the remainder of the attribute name after the
+ *	security. prefix has been removed.
+ *	Return 0 on success.
+ * @inode_listsecurity:
+ *	Copy the extended attribute names for the security labels
+ *	associated with @inode into @buffer.  The maximum size of @buffer
+ *	is specified by @buffer_size.  @buffer may be NULL to request
+ *	the size of the buffer required.
+ *	Returns number of bytes used/required on success.
+ * @inode_need_killpriv:
+ *	Called when an inode has been changed.
+ *	@dentry is the dentry being changed.
+ *	Return <0 on error to abort the inode change operation.
+ *	Return 0 if inode_killpriv does not need to be called.
+ *	Return >0 if inode_killpriv does need to be called.
+ * @inode_killpriv:
+ *	The setuid bit is being removed.  Remove similar security labels.
+ *	Called with the dentry->d_inode->i_mutex held.
+ *	@dentry is the dentry being changed.
+ *	Return 0 on success.  If error is returned, then the operation
+ *	causing setuid bit removal is failed.
+ * @inode_getsecid:
+ *	Get the secid associated with the node.
+ *	@inode contains a pointer to the inode.
+ *	@secid contains a pointer to the location where result will be saved.
+ *	In case of failure, @secid will be set to zero.
+ *
+ * Security hooks for file operations
+ *
+ * @file_permission:
+ *	Check file permissions before accessing an open file.  This hook is
+ *	called by various operations that read or write files.  A security
+ *	module can use this hook to perform additional checking on these
+ *	operations, e.g.  to revalidate permissions on use to support privilege
+ *	bracketing or policy changes.  Notice that this hook is used when the
+ *	actual read/write operations are performed, whereas the
+ *	inode_security_ops hook is called when a file is opened (as well as
+ *	many other operations).
+ *	Caveat:  Although this hook can be used to revalidate permissions for
+ *	various system call operations that read or write files, it does not
+ *	address the revalidation of permissions for memory-mapped files.
+ *	Security modules must handle this separately if they need such
+ *	revalidation.
+ *	@file contains the file structure being accessed.
+ *	@mask contains the requested permissions.
+ *	Return 0 if permission is granted.
+ * @file_alloc_security:
+ *	Allocate and attach a security structure to the file->f_security field.
+ *	The security field is initialized to NULL when the structure is first
+ *	created.
+ *	@file contains the file structure to secure.
+ *	Return 0 if the hook is successful and permission is granted.
+ * @file_free_security:
+ *	Deallocate and free any security structures stored in file->f_security.
+ *	@file contains the file structure being modified.
+ * @file_ioctl:
+ *	@file contains the file structure.
+ *	@cmd contains the operation to perform.
+ *	@arg contains the operational arguments.
+ *	Check permission for an ioctl operation on @file.  Note that @arg
+ *	sometimes represents a user space pointer; in other cases, it may be a
+ *	simple integer value.  When @arg represents a user space pointer, it
+ *	should never be used by the security module.
+ *	Return 0 if permission is granted.
+ * @mmap_addr :
+ *	Check permissions for a mmap operation at @addr.
+ *	@addr contains virtual address that will be used for the operation.
+ *	Return 0 if permission is granted.
+ * @mmap_file :
+ *	Check permissions for a mmap operation.  The @file may be NULL, e.g.
+ *	if mapping anonymous memory.
+ *	@file contains the file structure for file to map (may be NULL).
+ *	@reqprot contains the protection requested by the application.
+ *	@prot contains the protection that will be applied by the kernel.
+ *	@flags contains the operational flags.
+ *	Return 0 if permission is granted.
+ * @file_mprotect:
+ *	Check permissions before changing memory access permissions.
+ *	@vma contains the memory region to modify.
+ *	@reqprot contains the protection requested by the application.
+ *	@prot contains the protection that will be applied by the kernel.
+ *	Return 0 if permission is granted.
+ * @file_lock:
+ *	Check permission before performing file locking operations.
+ *	Note: this hook mediates both flock and fcntl style locks.
+ *	@file contains the file structure.
+ *	@cmd contains the posix-translated lock operation to perform
+ *	(e.g. F_RDLCK, F_WRLCK).
+ *	Return 0 if permission is granted.
+ * @file_fcntl:
+ *	Check permission before allowing the file operation specified by @cmd
+ *	from being performed on the file @file.  Note that @arg sometimes
+ *	represents a user space pointer; in other cases, it may be a simple
+ *	integer value.  When @arg represents a user space pointer, it should
+ *	never be used by the security module.
+ *	@file contains the file structure.
+ *	@cmd contains the operation to be performed.
+ *	@arg contains the operational arguments.
+ *	Return 0 if permission is granted.
+ * @file_set_fowner:
+ *	Save owner security information (typically from current->security) in
+ *	file->f_security for later use by the send_sigiotask hook.
+ *	@file contains the file structure to update.
+ *	Return 0 on success.
+ * @file_send_sigiotask:
+ *	Check permission for the file owner @fown to send SIGIO or SIGURG to the
+ *	process @tsk.  Note that this hook is sometimes called from interrupt.
+ *	Note that the fown_struct, @fown, is never outside the context of a
+ *	struct file, so the file structure (and associated security information)
+ *	can always be obtained:
+ *		container_of(fown, struct file, f_owner)
+ *	@tsk contains the structure of task receiving signal.
+ *	@fown contains the file owner information.
+ *	@sig is the signal that will be sent.  When 0, kernel sends SIGIO.
+ *	Return 0 if permission is granted.
+ * @file_receive:
+ *	This hook allows security modules to control the ability of a process
+ *	to receive an open file descriptor via socket IPC.
+ *	@file contains the file structure being received.
+ *	Return 0 if permission is granted.
+ * @file_open
+ *	Save open-time permission checking state for later use upon
+ *	file_permission, and recheck access if anything has changed
+ *	since inode_permission.
+ *
+ * Security hooks for task operations.
+ *
+ * @task_create:
+ *	Check permission before creating a child process.  See the clone(2)
+ *	manual page for definitions of the @clone_flags.
+ *	@clone_flags contains the flags indicating what should be shared.
+ *	Return 0 if permission is granted.
+ * @task_free:
+ *	@task task being freed
+ *	Handle release of task-related resources. (Note that this can be called
+ *	from interrupt context.)
+ * @cred_alloc_blank:
+ *	@cred points to the credentials.
+ *	@gfp indicates the atomicity of any memory allocations.
+ *	Only allocate sufficient memory and attach to @cred such that
+ *	cred_transfer() will not get ENOMEM.
+ * @cred_free:
+ *	@cred points to the credentials.
+ *	Deallocate and clear the cred->security field in a set of credentials.
+ * @cred_prepare:
+ *	@new points to the new credentials.
+ *	@old points to the original credentials.
+ *	@gfp indicates the atomicity of any memory allocations.
+ *	Prepare a new set of credentials by copying the data from the old set.
+ * @cred_transfer:
+ *	@new points to the new credentials.
+ *	@old points to the original credentials.
+ *	Transfer data from original creds to new creds
+ * @kernel_act_as:
+ *	Set the credentials for a kernel service to act as (subjective context).
+ *	@new points to the credentials to be modified.
+ *	@secid specifies the security ID to be set
+ *	The current task must be the one that nominated @secid.
+ *	Return 0 if successful.
+ * @kernel_create_files_as:
+ *	Set the file creation context in a set of credentials to be the same as
+ *	the objective context of the specified inode.
+ *	@new points to the credentials to be modified.
+ *	@inode points to the inode to use as a reference.
+ *	The current task must be the one that nominated @inode.
+ *	Return 0 if successful.
+ * @kernel_fw_from_file:
+ *	Load firmware from userspace (not called for built-in firmware).
+ *	@file contains the file structure pointing to the file containing
+ *	the firmware to load. This argument will be NULL if the firmware
+ *	was loaded via the uevent-triggered blob-based interface exposed
+ *	by CONFIG_FW_LOADER_USER_HELPER.
+ *	@buf pointer to buffer containing firmware contents.
+ *	@size length of the firmware contents.
+ *	Return 0 if permission is granted.
+ * @kernel_module_request:
+ *	Ability to trigger the kernel to automatically upcall to userspace for
+ *	userspace to load a kernel module with the given name.
+ *	@kmod_name name of the module requested by the kernel
+ *	Return 0 if successful.
+ * @kernel_module_from_file:
+ *	Load a kernel module from userspace.
+ *	@file contains the file structure pointing to the file containing
+ *	the kernel module to load. If the module is being loaded from a blob,
+ *	this argument will be NULL.
+ *	Return 0 if permission is granted.
+ * @task_fix_setuid:
+ *	Update the module's state after setting one or more of the user
+ *	identity attributes of the current process.  The @flags parameter
+ *	indicates which of the set*uid system calls invoked this hook.  If
+ *	@new is the set of credentials that will be installed.  Modifications
+ *	should be made to this rather than to @current->cred.
+ *	@old is the set of credentials that are being replaces
+ *	@flags contains one of the LSM_SETID_* values.
+ *	Return 0 on success.
+ * @task_setpgid:
+ *	Check permission before setting the process group identifier of the
+ *	process @p to @pgid.
+ *	@p contains the task_struct for process being modified.
+ *	@pgid contains the new pgid.
+ *	Return 0 if permission is granted.
+ * @task_getpgid:
+ *	Check permission before getting the process group identifier of the
+ *	process @p.
+ *	@p contains the task_struct for the process.
+ *	Return 0 if permission is granted.
+ * @task_getsid:
+ *	Check permission before getting the session identifier of the process
+ *	@p.
+ *	@p contains the task_struct for the process.
+ *	Return 0 if permission is granted.
+ * @task_getsecid:
+ *	Retrieve the security identifier of the process @p.
+ *	@p contains the task_struct for the process and place is into @secid.
+ *	In case of failure, @secid will be set to zero.
+ *
+ * @task_setnice:
+ *	Check permission before setting the nice value of @p to @nice.
+ *	@p contains the task_struct of process.
+ *	@nice contains the new nice value.
+ *	Return 0 if permission is granted.
+ * @task_setioprio
+ *	Check permission before setting the ioprio value of @p to @ioprio.
+ *	@p contains the task_struct of process.
+ *	@ioprio contains the new ioprio value
+ *	Return 0 if permission is granted.
+ * @task_getioprio
+ *	Check permission before getting the ioprio value of @p.
+ *	@p contains the task_struct of process.
+ *	Return 0 if permission is granted.
+ * @task_setrlimit:
+ *	Check permission before setting the resource limits of the current
+ *	process for @resource to @new_rlim.  The old resource limit values can
+ *	be examined by dereferencing (current->signal->rlim + resource).
+ *	@resource contains the resource whose limit is being set.
+ *	@new_rlim contains the new limits for @resource.
+ *	Return 0 if permission is granted.
+ * @task_setscheduler:
+ *	Check permission before setting scheduling policy and/or parameters of
+ *	process @p based on @policy and @lp.
+ *	@p contains the task_struct for process.
+ *	@policy contains the scheduling policy.
+ *	@lp contains the scheduling parameters.
+ *	Return 0 if permission is granted.
+ * @task_getscheduler:
+ *	Check permission before obtaining scheduling information for process
+ *	@p.
+ *	@p contains the task_struct for process.
+ *	Return 0 if permission is granted.
+ * @task_movememory
+ *	Check permission before moving memory owned by process @p.
+ *	@p contains the task_struct for process.
+ *	Return 0 if permission is granted.
+ * @task_kill:
+ *	Check permission before sending signal @sig to @p.  @info can be NULL,
+ *	the constant 1, or a pointer to a siginfo structure.  If @info is 1 or
+ *	SI_FROMKERNEL(info) is true, then the signal should be viewed as coming
+ *	from the kernel and should typically be permitted.
+ *	SIGIO signals are handled separately by the send_sigiotask hook in
+ *	file_security_ops.
+ *	@p contains the task_struct for process.
+ *	@info contains the signal information.
+ *	@sig contains the signal value.
+ *	@secid contains the sid of the process where the signal originated
+ *	Return 0 if permission is granted.
+ * @task_wait:
+ *	Check permission before allowing a process to reap a child process @p
+ *	and collect its status information.
+ *	@p contains the task_struct for process.
+ *	Return 0 if permission is granted.
+ * @task_prctl:
+ *	Check permission before performing a process control operation on the
+ *	current process.
+ *	@option contains the operation.
+ *	@arg2 contains a argument.
+ *	@arg3 contains a argument.
+ *	@arg4 contains a argument.
+ *	@arg5 contains a argument.
+ *	Return -ENOSYS if no-one wanted to handle this op, any other value to
+ *	cause prctl() to return immediately with that value.
+ * @task_to_inode:
+ *	Set the security attributes for an inode based on an associated task's
+ *	security attributes, e.g. for /proc/pid inodes.
+ *	@p contains the task_struct for the task.
+ *	@inode contains the inode structure for the inode.
+ *
+ * Security hooks for Netlink messaging.
+ *
+ * @netlink_send:
+ *	Save security information for a netlink message so that permission
+ *	checking can be performed when the message is processed.  The security
+ *	information can be saved using the eff_cap field of the
+ *	netlink_skb_parms structure.  Also may be used to provide fine
+ *	grained control over message transmission.
+ *	@sk associated sock of task sending the message.
+ *	@skb contains the sk_buff structure for the netlink message.
+ *	Return 0 if the information was successfully saved and message
+ *	is allowed to be transmitted.
+ *
+ * Security hooks for Unix domain networking.
+ *
+ * @unix_stream_connect:
+ *	Check permissions before establishing a Unix domain stream connection
+ *	between @sock and @other.
+ *	@sock contains the sock structure.
+ *	@other contains the peer sock structure.
+ *	@newsk contains the new sock structure.
+ *	Return 0 if permission is granted.
+ * @unix_may_send:
+ *	Check permissions before connecting or sending datagrams from @sock to
+ *	@other.
+ *	@sock contains the socket structure.
+ *	@other contains the peer socket structure.
+ *	Return 0 if permission is granted.
+ *
+ * The @unix_stream_connect and @unix_may_send hooks were necessary because
+ * Linux provides an alternative to the conventional file name space for Unix
+ * domain sockets.  Whereas binding and connecting to sockets in the file name
+ * space is mediated by the typical file permissions (and caught by the mknod
+ * and permission hooks in inode_security_ops), binding and connecting to
+ * sockets in the abstract name space is completely unmediated.  Sufficient
+ * control of Unix domain sockets in the abstract name space isn't possible
+ * using only the socket layer hooks, since we need to know the actual target
+ * socket, which is not looked up until we are inside the af_unix code.
+ *
+ * Security hooks for socket operations.
+ *
+ * @socket_create:
+ *	Check permissions prior to creating a new socket.
+ *	@family contains the requested protocol family.
+ *	@type contains the requested communications type.
+ *	@protocol contains the requested protocol.
+ *	@kern set to 1 if a kernel socket.
+ *	Return 0 if permission is granted.
+ * @socket_post_create:
+ *	This hook allows a module to update or allocate a per-socket security
+ *	structure. Note that the security field was not added directly to the
+ *	socket structure, but rather, the socket security information is stored
+ *	in the associated inode.  Typically, the inode alloc_security hook will
+ *	allocate and and attach security information to
+ *	sock->inode->i_security.  This hook may be used to update the
+ *	sock->inode->i_security field with additional information that wasn't
+ *	available when the inode was allocated.
+ *	@sock contains the newly created socket structure.
+ *	@family contains the requested protocol family.
+ *	@type contains the requested communications type.
+ *	@protocol contains the requested protocol.
+ *	@kern set to 1 if a kernel socket.
+ * @socket_bind:
+ *	Check permission before socket protocol layer bind operation is
+ *	performed and the socket @sock is bound to the address specified in the
+ *	@address parameter.
+ *	@sock contains the socket structure.
+ *	@address contains the address to bind to.
+ *	@addrlen contains the length of address.
+ *	Return 0 if permission is granted.
+ * @socket_connect:
+ *	Check permission before socket protocol layer connect operation
+ *	attempts to connect socket @sock to a remote address, @address.
+ *	@sock contains the socket structure.
+ *	@address contains the address of remote endpoint.
+ *	@addrlen contains the length of address.
+ *	Return 0 if permission is granted.
+ * @socket_listen:
+ *	Check permission before socket protocol layer listen operation.
+ *	@sock contains the socket structure.
+ *	@backlog contains the maximum length for the pending connection queue.
+ *	Return 0 if permission is granted.
+ * @socket_accept:
+ *	Check permission before accepting a new connection.  Note that the new
+ *	socket, @newsock, has been created and some information copied to it,
+ *	but the accept operation has not actually been performed.
+ *	@sock contains the listening socket structure.
+ *	@newsock contains the newly created server socket for connection.
+ *	Return 0 if permission is granted.
+ * @socket_sendmsg:
+ *	Check permission before transmitting a message to another socket.
+ *	@sock contains the socket structure.
+ *	@msg contains the message to be transmitted.
+ *	@size contains the size of message.
+ *	Return 0 if permission is granted.
+ * @socket_recvmsg:
+ *	Check permission before receiving a message from a socket.
+ *	@sock contains the socket structure.
+ *	@msg contains the message structure.
+ *	@size contains the size of message structure.
+ *	@flags contains the operational flags.
+ *	Return 0 if permission is granted.
+ * @socket_getsockname:
+ *	Check permission before the local address (name) of the socket object
+ *	@sock is retrieved.
+ *	@sock contains the socket structure.
+ *	Return 0 if permission is granted.
+ * @socket_getpeername:
+ *	Check permission before the remote address (name) of a socket object
+ *	@sock is retrieved.
+ *	@sock contains the socket structure.
+ *	Return 0 if permission is granted.
+ * @socket_getsockopt:
+ *	Check permissions before retrieving the options associated with socket
+ *	@sock.
+ *	@sock contains the socket structure.
+ *	@level contains the protocol level to retrieve option from.
+ *	@optname contains the name of option to retrieve.
+ *	Return 0 if permission is granted.
+ * @socket_setsockopt:
+ *	Check permissions before setting the options associated with socket
+ *	@sock.
+ *	@sock contains the socket structure.
+ *	@level contains the protocol level to set options for.
+ *	@optname contains the name of the option to set.
+ *	Return 0 if permission is granted.
+ * @socket_shutdown:
+ *	Checks permission before all or part of a connection on the socket
+ *	@sock is shut down.
+ *	@sock contains the socket structure.
+ *	@how contains the flag indicating how future sends and receives
+ *	are handled.
+ *	Return 0 if permission is granted.
+ * @socket_sock_rcv_skb:
+ *	Check permissions on incoming network packets.  This hook is distinct
+ *	from Netfilter's IP input hooks since it is the first time that the
+ *	incoming sk_buff @skb has been associated with a particular socket, @sk.
+ *	Must not sleep inside this hook because some callers hold spinlocks.
+ *	@sk contains the sock (not socket) associated with the incoming sk_buff.
+ *	@skb contains the incoming network data.
+ * @socket_getpeersec_stream:
+ *	This hook allows the security module to provide peer socket security
+ *	state for unix or connected tcp sockets to userspace via getsockopt
+ *	SO_GETPEERSEC.  For tcp sockets this can be meaningful if the
+ *	socket is associated with an ipsec SA.
+ *	@sock is the local socket.
+ *	@optval userspace memory where the security state is to be copied.
+ *	@optlen userspace int where the module should copy the actual length
+ *	of the security state.
+ *	@len as input is the maximum length to copy to userspace provided
+ *	by the caller.
+ *	Return 0 if all is well, otherwise, typical getsockopt return
+ *	values.
+ * @socket_getpeersec_dgram:
+ *	This hook allows the security module to provide peer socket security
+ *	state for udp sockets on a per-packet basis to userspace via
+ *	getsockopt SO_GETPEERSEC.  The application must first have indicated
+ *	the IP_PASSSEC option via getsockopt.  It can then retrieve the
+ *	security state returned by this hook for a packet via the SCM_SECURITY
+ *	ancillary message type.
+ *	@skb is the skbuff for the packet being queried
+ *	@secdata is a pointer to a buffer in which to copy the security data
+ *	@seclen is the maximum length for @secdata
+ *	Return 0 on success, error on failure.
+ * @sk_alloc_security:
+ *	Allocate and attach a security structure to the sk->sk_security field,
+ *	which is used to copy security attributes between local stream sockets.
+ * @sk_free_security:
+ *	Deallocate security structure.
+ * @sk_clone_security:
+ *	Clone/copy security structure.
+ * @sk_getsecid:
+ *	Retrieve the LSM-specific secid for the sock to enable caching
+ *	of network authorizations.
+ * @sock_graft:
+ *	Sets the socket's isec sid to the sock's sid.
+ * @inet_conn_request:
+ *	Sets the openreq's sid to socket's sid with MLS portion taken
+ *	from peer sid.
+ * @inet_csk_clone:
+ *	Sets the new child socket's sid to the openreq sid.
+ * @inet_conn_established:
+ *	Sets the connection's peersid to the secmark on skb.
+ * @secmark_relabel_packet:
+ *	check if the process should be allowed to relabel packets to
+ *	the given secid
+ * @security_secmark_refcount_inc
+ *	tells the LSM to increment the number of secmark labeling rules loaded
+ * @security_secmark_refcount_dec
+ *	tells the LSM to decrement the number of secmark labeling rules loaded
+ * @req_classify_flow:
+ *	Sets the flow's sid to the openreq sid.
+ * @tun_dev_alloc_security:
+ *	This hook allows a module to allocate a security structure for a TUN
+ *	device.
+ *	@security pointer to a security structure pointer.
+ *	Returns a zero on success, negative values on failure.
+ * @tun_dev_free_security:
+ *	This hook allows a module to free the security structure for a TUN
+ *	device.
+ *	@security pointer to the TUN device's security structure
+ * @tun_dev_create:
+ *	Check permissions prior to creating a new TUN device.
+ * @tun_dev_attach_queue:
+ *	Check permissions prior to attaching to a TUN device queue.
+ *	@security pointer to the TUN device's security structure.
+ * @tun_dev_attach:
+ *	This hook can be used by the module to update any security state
+ *	associated with the TUN device's sock structure.
+ *	@sk contains the existing sock structure.
+ *	@security pointer to the TUN device's security structure.
+ * @tun_dev_open:
+ *	This hook can be used by the module to update any security state
+ *	associated with the TUN device's security structure.
+ *	@security pointer to the TUN devices's security structure.
+ *
+ * Security hooks for XFRM operations.
+ *
+ * @xfrm_policy_alloc_security:
+ *	@ctxp is a pointer to the xfrm_sec_ctx being added to Security Policy
+ *	Database used by the XFRM system.
+ *	@sec_ctx contains the security context information being provided by
+ *	the user-level policy update program (e.g., setkey).
+ *	Allocate a security structure to the xp->security field; the security
+ *	field is initialized to NULL when the xfrm_policy is allocated.
+ *	Return 0 if operation was successful (memory to allocate, legal context)
+ *	@gfp is to specify the context for the allocation
+ * @xfrm_policy_clone_security:
+ *	@old_ctx contains an existing xfrm_sec_ctx.
+ *	@new_ctxp contains a new xfrm_sec_ctx being cloned from old.
+ *	Allocate a security structure in new_ctxp that contains the
+ *	information from the old_ctx structure.
+ *	Return 0 if operation was successful (memory to allocate).
+ * @xfrm_policy_free_security:
+ *	@ctx contains the xfrm_sec_ctx
+ *	Deallocate xp->security.
+ * @xfrm_policy_delete_security:
+ *	@ctx contains the xfrm_sec_ctx.
+ *	Authorize deletion of xp->security.
+ * @xfrm_state_alloc:
+ *	@x contains the xfrm_state being added to the Security Association
+ *	Database by the XFRM system.
+ *	@sec_ctx contains the security context information being provided by
+ *	the user-level SA generation program (e.g., setkey or racoon).
+ *	Allocate a security structure to the x->security field; the security
+ *	field is initialized to NULL when the xfrm_state is allocated. Set the
+ *	context to correspond to sec_ctx. Return 0 if operation was successful
+ *	(memory to allocate, legal context).
+ * @xfrm_state_alloc_acquire:
+ *	@x contains the xfrm_state being added to the Security Association
+ *	Database by the XFRM system.
+ *	@polsec contains the policy's security context.
+ *	@secid contains the secid from which to take the mls portion of the
+ *	context.
+ *	Allocate a security structure to the x->security field; the security
+ *	field is initialized to NULL when the xfrm_state is allocated. Set the
+ *	context to correspond to secid. Return 0 if operation was successful
+ *	(memory to allocate, legal context).
+ * @xfrm_state_free_security:
+ *	@x contains the xfrm_state.
+ *	Deallocate x->security.
+ * @xfrm_state_delete_security:
+ *	@x contains the xfrm_state.
+ *	Authorize deletion of x->security.
+ * @xfrm_policy_lookup:
+ *	@ctx contains the xfrm_sec_ctx for which the access control is being
+ *	checked.
+ *	@fl_secid contains the flow security label that is used to authorize
+ *	access to the policy xp.
+ *	@dir contains the direction of the flow (input or output).
+ *	Check permission when a flow selects a xfrm_policy for processing
+ *	XFRMs on a packet.  The hook is called when selecting either a
+ *	per-socket policy or a generic xfrm policy.
+ *	Return 0 if permission is granted, -ESRCH otherwise, or -errno
+ *	on other errors.
+ * @xfrm_state_pol_flow_match:
+ *	@x contains the state to match.
+ *	@xp contains the policy to check for a match.
+ *	@fl contains the flow to check for a match.
+ *	Return 1 if there is a match.
+ * @xfrm_decode_session:
+ *	@skb points to skb to decode.
+ *	@secid points to the flow key secid to set.
+ *	@ckall says if all xfrms used should be checked for same secid.
+ *	Return 0 if ckall is zero or all xfrms used have the same secid.
+ *
+ * Security hooks affecting all Key Management operations
+ *
+ * @key_alloc:
+ *	Permit allocation of a key and assign security data. Note that key does
+ *	not have a serial number assigned at this point.
+ *	@key points to the key.
+ *	@flags is the allocation flags
+ *	Return 0 if permission is granted, -ve error otherwise.
+ * @key_free:
+ *	Notification of destruction; free security data.
+ *	@key points to the key.
+ *	No return value.
+ * @key_permission:
+ *	See whether a specific operational right is granted to a process on a
+ *	key.
+ *	@key_ref refers to the key (key pointer + possession attribute bit).
+ *	@cred points to the credentials to provide the context against which to
+ *	evaluate the security data on the key.
+ *	@perm describes the combination of permissions required of this key.
+ *	Return 0 if permission is granted, -ve error otherwise.
+ * @key_getsecurity:
+ *	Get a textual representation of the security context attached to a key
+ *	for the purposes of honouring KEYCTL_GETSECURITY.  This function
+ *	allocates the storage for the NUL-terminated string and the caller
+ *	should free it.
+ *	@key points to the key to be queried.
+ *	@_buffer points to a pointer that should be set to point to the
+ *	resulting string (if no label or an error occurs).
+ *	Return the length of the string (including terminating NUL) or -ve if
+ *	an error.
+ *	May also return 0 (and a NULL buffer pointer) if there is no label.
+ *
+ * Security hooks affecting all System V IPC operations.
+ *
+ * @ipc_permission:
+ *	Check permissions for access to IPC
+ *	@ipcp contains the kernel IPC permission structure
+ *	@flag contains the desired (requested) permission set
+ *	Return 0 if permission is granted.
+ * @ipc_getsecid:
+ *	Get the secid associated with the ipc object.
+ *	@ipcp contains the kernel IPC permission structure.
+ *	@secid contains a pointer to the location where result will be saved.
+ *	In case of failure, @secid will be set to zero.
+ *
+ * Security hooks for individual messages held in System V IPC message queues
+ * @msg_msg_alloc_security:
+ *	Allocate and attach a security structure to the msg->security field.
+ *	The security field is initialized to NULL when the structure is first
+ *	created.
+ *	@msg contains the message structure to be modified.
+ *	Return 0 if operation was successful and permission is granted.
+ * @msg_msg_free_security:
+ *	Deallocate the security structure for this message.
+ *	@msg contains the message structure to be modified.
+ *
+ * Security hooks for System V IPC Message Queues
+ *
+ * @msg_queue_alloc_security:
+ *	Allocate and attach a security structure to the
+ *	msq->q_perm.security field. The security field is initialized to
+ *	NULL when the structure is first created.
+ *	@msq contains the message queue structure to be modified.
+ *	Return 0 if operation was successful and permission is granted.
+ * @msg_queue_free_security:
+ *	Deallocate security structure for this message queue.
+ *	@msq contains the message queue structure to be modified.
+ * @msg_queue_associate:
+ *	Check permission when a message queue is requested through the
+ *	msgget system call.  This hook is only called when returning the
+ *	message queue identifier for an existing message queue, not when a
+ *	new message queue is created.
+ *	@msq contains the message queue to act upon.
+ *	@msqflg contains the operation control flags.
+ *	Return 0 if permission is granted.
+ * @msg_queue_msgctl:
+ *	Check permission when a message control operation specified by @cmd
+ *	is to be performed on the message queue @msq.
+ *	The @msq may be NULL, e.g. for IPC_INFO or MSG_INFO.
+ *	@msq contains the message queue to act upon.  May be NULL.
+ *	@cmd contains the operation to be performed.
+ *	Return 0 if permission is granted.
+ * @msg_queue_msgsnd:
+ *	Check permission before a message, @msg, is enqueued on the message
+ *	queue, @msq.
+ *	@msq contains the message queue to send message to.
+ *	@msg contains the message to be enqueued.
+ *	@msqflg contains operational flags.
+ *	Return 0 if permission is granted.
+ * @msg_queue_msgrcv:
+ *	Check permission before a message, @msg, is removed from the message
+ *	queue, @msq.  The @target task structure contains a pointer to the
+ *	process that will be receiving the message (not equal to the current
+ *	process when inline receives are being performed).
+ *	@msq contains the message queue to retrieve message from.
+ *	@msg contains the message destination.
+ *	@target contains the task structure for recipient process.
+ *	@type contains the type of message requested.
+ *	@mode contains the operational flags.
+ *	Return 0 if permission is granted.
+ *
+ * Security hooks for System V Shared Memory Segments
+ *
+ * @shm_alloc_security:
+ *	Allocate and attach a security structure to the shp->shm_perm.security
+ *	field.  The security field is initialized to NULL when the structure is
+ *	first created.
+ *	@shp contains the shared memory structure to be modified.
+ *	Return 0 if operation was successful and permission is granted.
+ * @shm_free_security:
+ *	Deallocate the security struct for this memory segment.
+ *	@shp contains the shared memory structure to be modified.
+ * @shm_associate:
+ *	Check permission when a shared memory region is requested through the
+ *	shmget system call.  This hook is only called when returning the shared
+ *	memory region identifier for an existing region, not when a new shared
+ *	memory region is created.
+ *	@shp contains the shared memory structure to be modified.
+ *	@shmflg contains the operation control flags.
+ *	Return 0 if permission is granted.
+ * @shm_shmctl:
+ *	Check permission when a shared memory control operation specified by
+ *	@cmd is to be performed on the shared memory region @shp.
+ *	The @shp may be NULL, e.g. for IPC_INFO or SHM_INFO.
+ *	@shp contains shared memory structure to be modified.
+ *	@cmd contains the operation to be performed.
+ *	Return 0 if permission is granted.
+ * @shm_shmat:
+ *	Check permissions prior to allowing the shmat system call to attach the
+ *	shared memory segment @shp to the data segment of the calling process.
+ *	The attaching address is specified by @shmaddr.
+ *	@shp contains the shared memory structure to be modified.
+ *	@shmaddr contains the address to attach memory region to.
+ *	@shmflg contains the operational flags.
+ *	Return 0 if permission is granted.
+ *
+ * Security hooks for System V Semaphores
+ *
+ * @sem_alloc_security:
+ *	Allocate and attach a security structure to the sma->sem_perm.security
+ *	field.  The security field is initialized to NULL when the structure is
+ *	first created.
+ *	@sma contains the semaphore structure
+ *	Return 0 if operation was successful and permission is granted.
+ * @sem_free_security:
+ *	deallocate security struct for this semaphore
+ *	@sma contains the semaphore structure.
+ * @sem_associate:
+ *	Check permission when a semaphore is requested through the semget
+ *	system call.  This hook is only called when returning the semaphore
+ *	identifier for an existing semaphore, not when a new one must be
+ *	created.
+ *	@sma contains the semaphore structure.
+ *	@semflg contains the operation control flags.
+ *	Return 0 if permission is granted.
+ * @sem_semctl:
+ *	Check permission when a semaphore operation specified by @cmd is to be
+ *	performed on the semaphore @sma.  The @sma may be NULL, e.g. for
+ *	IPC_INFO or SEM_INFO.
+ *	@sma contains the semaphore structure.  May be NULL.
+ *	@cmd contains the operation to be performed.
+ *	Return 0 if permission is granted.
+ * @sem_semop
+ *	Check permissions before performing operations on members of the
+ *	semaphore set @sma.  If the @alter flag is nonzero, the semaphore set
+ *	may be modified.
+ *	@sma contains the semaphore structure.
+ *	@sops contains the operations to perform.
+ *	@nsops contains the number of operations to perform.
+ *	@alter contains the flag indicating whether changes are to be made.
+ *	Return 0 if permission is granted.
+ *
+ * @binder_set_context_mgr
+ *	Check whether @mgr is allowed to be the binder context manager.
+ *	@mgr contains the task_struct for the task being registered.
+ *	Return 0 if permission is granted.
+ * @binder_transaction
+ *	Check whether @from is allowed to invoke a binder transaction call
+ *	to @to.
+ *	@from contains the task_struct for the sending task.
+ *	@to contains the task_struct for the receiving task.
+ * @binder_transfer_binder
+ *	Check whether @from is allowed to transfer a binder reference to @to.
+ *	@from contains the task_struct for the sending task.
+ *	@to contains the task_struct for the receiving task.
+ * @binder_transfer_file
+ *	Check whether @from is allowed to transfer @file to @to.
+ *	@from contains the task_struct for the sending task.
+ *	@file contains the struct file being transferred.
+ *	@to contains the task_struct for the receiving task.
+ *
+ * @ptrace_access_check:
+ *	Check permission before allowing the current process to trace the
+ *	@child process.
+ *	Security modules may also want to perform a process tracing check
+ *	during an execve in the set_security or apply_creds hooks of
+ *	tracing check during an execve in the bprm_set_creds hook of
+ *	binprm_security_ops if the process is being traced and its security
+ *	attributes would be changed by the execve.
+ *	@child contains the task_struct structure for the target process.
+ *	@mode contains the PTRACE_MODE flags indicating the form of access.
+ *	Return 0 if permission is granted.
+ * @ptrace_traceme:
+ *	Check that the @parent process has sufficient permission to trace the
+ *	current process before allowing the current process to present itself
+ *	to the @parent process for tracing.
+ *	@parent contains the task_struct structure for debugger process.
+ *	Return 0 if permission is granted.
+ * @capget:
+ *	Get the @effective, @inheritable, and @permitted capability sets for
+ *	the @target process.  The hook may also perform permission checking to
+ *	determine if the current process is allowed to see the capability sets
+ *	of the @target process.
+ *	@target contains the task_struct structure for target process.
+ *	@effective contains the effective capability set.
+ *	@inheritable contains the inheritable capability set.
+ *	@permitted contains the permitted capability set.
+ *	Return 0 if the capability sets were successfully obtained.
+ * @capset:
+ *	Set the @effective, @inheritable, and @permitted capability sets for
+ *	the current process.
+ *	@new contains the new credentials structure for target process.
+ *	@old contains the current credentials structure for target process.
+ *	@effective contains the effective capability set.
+ *	@inheritable contains the inheritable capability set.
+ *	@permitted contains the permitted capability set.
+ *	Return 0 and update @new if permission is granted.
+ * @capable:
+ *	Check whether the @tsk process has the @cap capability in the indicated
+ *	credentials.
+ *	@cred contains the credentials to use.
+ *	@ns contains the user namespace we want the capability in
+ *	@cap contains the capability <include/linux/capability.h>.
+ *	@audit: Whether to write an audit message or not
+ *	Return 0 if the capability is granted for @tsk.
+ * @syslog:
+ *	Check permission before accessing the kernel message ring or changing
+ *	logging to the console.
+ *	See the syslog(2) manual page for an explanation of the @type values.
+ *	@type contains the type of action.
+ *	@from_file indicates the context of action (if it came from /proc).
+ *	Return 0 if permission is granted.
+ * @settime:
+ *	Check permission to change the system time.
+ *	struct timespec and timezone are defined in include/linux/time.h
+ *	@ts contains new time
+ *	@tz contains new timezone
+ *	Return 0 if permission is granted.
+ * @vm_enough_memory:
+ *	Check permissions for allocating a new virtual mapping.
+ *	@mm contains the mm struct it is being added to.
+ *	@pages contains the number of pages.
+ *	Return 0 if permission is granted.
+ *
+ * @ismaclabel:
+ *	Check if the extended attribute specified by @name
+ *	represents a MAC label. Returns 1 if name is a MAC
+ *	attribute otherwise returns 0.
+ *	@name full extended attribute name to check against
+ *	LSM as a MAC label.
+ *
+ * @secid_to_secctx:
+ *	Convert secid to security context.  If secdata is NULL the length of
+ *	the result will be returned in seclen, but no secdata will be returned.
+ *	This does mean that the length could change between calls to check the
+ *	length and the next call which actually allocates and returns the
+ *	secdata.
+ *	@secid contains the security ID.
+ *	@secdata contains the pointer that stores the converted security
+ *	context.
+ *	@seclen pointer which contains the length of the data
+ * @secctx_to_secid:
+ *	Convert security context to secid.
+ *	@secid contains the pointer to the generated security ID.
+ *	@secdata contains the security context.
+ *
+ * @release_secctx:
+ *	Release the security context.
+ *	@secdata contains the security context.
+ *	@seclen contains the length of the security context.
+ *
+ * Security hooks for Audit
+ *
+ * @audit_rule_init:
+ *	Allocate and initialize an LSM audit rule structure.
+ *	@field contains the required Audit action.
+ *	Fields flags are defined in include/linux/audit.h
+ *	@op contains the operator the rule uses.
+ *	@rulestr contains the context where the rule will be applied to.
+ *	@lsmrule contains a pointer to receive the result.
+ *	Return 0 if @lsmrule has been successfully set,
+ *	-EINVAL in case of an invalid rule.
+ *
+ * @audit_rule_known:
+ *	Specifies whether given @rule contains any fields related to
+ *	current LSM.
+ *	@rule contains the audit rule of interest.
+ *	Return 1 in case of relation found, 0 otherwise.
+ *
+ * @audit_rule_match:
+ *	Determine if given @secid matches a rule previously approved
+ *	by @audit_rule_known.
+ *	@secid contains the security id in question.
+ *	@field contains the field which relates to current LSM.
+ *	@op contains the operator that will be used for matching.
+ *	@rule points to the audit rule that will be checked against.
+ *	@actx points to the audit context associated with the check.
+ *	Return 1 if secid matches the rule, 0 if it does not, -ERRNO on failure.
+ *
+ * @audit_rule_free:
+ *	Deallocate the LSM audit rule structure previously allocated by
+ *	audit_rule_init.
+ *	@rule contains the allocated rule
+ *
+ * @inode_notifysecctx:
+ *	Notify the security module of what the security context of an inode
+ *	should be.  Initializes the incore security context managed by the
+ *	security module for this inode.  Example usage:  NFS client invokes
+ *	this hook to initialize the security context in its incore inode to the
+ *	value provided by the server for the file when the server returned the
+ *	file's attributes to the client.
+ *
+ *	Must be called with inode->i_mutex locked.
+ *
+ *	@inode we wish to set the security context of.
+ *	@ctx contains the string which we wish to set in the inode.
+ *	@ctxlen contains the length of @ctx.
+ *
+ * @inode_setsecctx:
+ *	Change the security context of an inode.  Updates the
+ *	incore security context managed by the security module and invokes the
+ *	fs code as needed (via __vfs_setxattr_noperm) to update any backing
+ *	xattrs that represent the context.  Example usage:  NFS server invokes
+ *	this hook to change the security context in its incore inode and on the
+ *	backing filesystem to a value provided by the client on a SETATTR
+ *	operation.
+ *
+ *	Must be called with inode->i_mutex locked.
+ *
+ *	@dentry contains the inode we wish to set the security context of.
+ *	@ctx contains the string which we wish to set in the inode.
+ *	@ctxlen contains the length of @ctx.
+ *
+ * @inode_getsecctx:
+ *	On success, returns 0 and fills out @ctx and @ctxlen with the security
+ *	context for the given @inode.
+ *
+ *	@inode we wish to get the security context of.
+ *	@ctx is a pointer in which to place the allocated security context.
+ *	@ctxlen points to the place to put the length of @ctx.
+ * This is the main security structure.
+ */
+
 struct security_operations {
 	char name[SECURITY_NAME_MAX + 1];
 

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