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/*
* Linux Security Module interfaces
*
* Copyright (C) 2001 WireX Communications, Inc <chris@wirex.com>
* Copyright (C) 2001 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2001 Networks Associates Technology, Inc <ssmalley@nai.com>
* Copyright (C) 2001 James Morris <jmorris@intercode.com.au>
* Copyright (C) 2001 Silicon Graphics, Inc. (Trust Technology Group)
* Copyright (C) 2015 Intel Corporation.
* Copyright (C) 2015 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2016 Mellanox Techonologies
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Due to this file being licensed under the GPL there is controversy over
* whether this permits you to write a module that #includes this file
* without placing your module under the GPL. Please consult a lawyer for
* advice before doing this.
*
*/
#ifndef __LINUX_LSM_HOOKS_H
#define __LINUX_LSM_HOOKS_H
#include <uapi/linux/lsm.h>
#include <linux/security.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/xattr.h>
#include <linux/static_call.h>
#include <linux/unroll.h>
#include <linux/jump_label.h>
#include <linux/lsm_count.h>
union security_list_options {
#define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__);
#include "lsm_hook_defs.h"
#undef LSM_HOOK
void *lsm_func_addr;
};
/*
* @key: static call key as defined by STATIC_CALL_KEY
* @trampoline: static call trampoline as defined by STATIC_CALL_TRAMP
* @hl: The security_hook_list as initialized by the owning LSM.
* @active: Enabled when the static call has an LSM hook associated.
*/
struct lsm_static_call {
struct static_call_key *key;
void *trampoline;
struct security_hook_list *hl;
/* this needs to be true or false based on what the key defaults to */
struct static_key_false *active;
} __randomize_layout;
/*
* Table of the static calls for each LSM hook.
* Once the LSMs are initialized, their callbacks will be copied to these
* tables such that the calls are filled backwards (from last to first).
* This way, we can jump directly to the first used static call, and execute
* all of them after. This essentially makes the entry point
* dynamic to adapt the number of static calls to the number of callbacks.
*/
struct lsm_static_calls_table {
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
struct lsm_static_call NAME[MAX_LSM_COUNT];
#include <linux/lsm_hook_defs.h>
#undef LSM_HOOK
} __packed __randomize_layout;
/**
* struct lsm_id - Identify a Linux Security Module.
* @lsm: name of the LSM, must be approved by the LSM maintainers
* @id: LSM ID number from uapi/linux/lsm.h
*
* Contains the information that identifies the LSM.
*/
struct lsm_id {
const char *name;
u64 id;
};
/*
* Security module hook list structure.
* For use with generic list macros for common operations.
*
* struct security_hook_list - Contents of a cacheable, mappable object.
* @scalls: The beginning of the array of static calls assigned to this hook.
* @hook: The callback for the hook.
* @lsm: The name of the lsm that owns this hook.
*/
struct security_hook_list {
struct lsm_static_call *scalls;
union security_list_options hook;
const struct lsm_id *lsmid;
} __randomize_layout;
/*
* Security blob size or offset data.
*/
struct lsm_blob_sizes {
int lbs_cred;
int lbs_file;
int lbs_ib;
int lbs_inode;
int lbs_sock;
int lbs_superblock;
int lbs_ipc;
int lbs_key;
int lbs_msg_msg;
int lbs_perf_event;
int lbs_task;
int lbs_xattr_count; /* number of xattr slots in new_xattrs array */
int lbs_tun_dev;
int lbs_bdev;
};
/*
* LSM_RET_VOID is used as the default value in LSM_HOOK definitions for void
* LSM hooks (in include/linux/lsm_hook_defs.h).
*/
#define LSM_RET_VOID ((void) 0)
/*
* Initializing a security_hook_list structure takes
* up a lot of space in a source file. This macro takes
* care of the common case and reduces the amount of
* text involved.
*/
#define LSM_HOOK_INIT(NAME, HOOK) \
{ \
.scalls = static_calls_table.NAME, \
.hook = { .NAME = HOOK } \
}
extern void security_add_hooks(struct security_hook_list *hooks, int count,
const struct lsm_id *lsmid);
#define LSM_FLAG_LEGACY_MAJOR BIT(0)
#define LSM_FLAG_EXCLUSIVE BIT(1)
enum lsm_order {
LSM_ORDER_FIRST = -1, /* This is only for capabilities. */
LSM_ORDER_MUTABLE = 0,
LSM_ORDER_LAST = 1, /* This is only for integrity. */
};
struct lsm_info {
const char *name; /* Required. */
enum lsm_order order; /* Optional: default is LSM_ORDER_MUTABLE */
unsigned long flags; /* Optional: flags describing LSM */
int *enabled; /* Optional: controlled by CONFIG_LSM */
int (*init)(void); /* Required. */
struct lsm_blob_sizes *blobs; /* Optional: for blob sharing. */
};
#define DEFINE_LSM(lsm) \
static struct lsm_info __lsm_##lsm \
__used __section(".lsm_info.init") \
__aligned(sizeof(unsigned long))
#define DEFINE_EARLY_LSM(lsm) \
static struct lsm_info __early_lsm_##lsm \
__used __section(".early_lsm_info.init") \
__aligned(sizeof(unsigned long))
/* DO NOT tamper with these variables outside of the LSM framework */
extern char *lsm_names;
extern struct lsm_static_calls_table static_calls_table __ro_after_init;
extern struct lsm_info __start_lsm_info[], __end_lsm_info[];
extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[];
/**
* lsm_get_xattr_slot - Return the next available slot and increment the index
* @xattrs: array storing LSM-provided xattrs
* @xattr_count: number of already stored xattrs (updated)
*
* Retrieve the first available slot in the @xattrs array to fill with an xattr,
* and increment @xattr_count.
*
* Return: The slot to fill in @xattrs if non-NULL, NULL otherwise.
*/
static inline struct xattr *lsm_get_xattr_slot(struct xattr *xattrs,
int *xattr_count)
{
if (unlikely(!xattrs))
return NULL;
return &xattrs[(*xattr_count)++];
}
#endif /* ! __LINUX_LSM_HOOKS_H */
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