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