diff options
Diffstat (limited to 'include/linux/lsm_hooks.h')
| -rw-r--r-- | include/linux/lsm_hooks.h | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h new file mode 100644 index 000000000000..b92008641242 --- /dev/null +++ b/include/linux/lsm_hooks.h @@ -0,0 +1,218 @@ +/* + * 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 { + unsigned int lbs_cred; + unsigned int lbs_file; + unsigned int lbs_ib; + unsigned int lbs_inode; + unsigned int lbs_sock; + unsigned int lbs_superblock; + unsigned int lbs_ipc; + unsigned int lbs_key; + unsigned int lbs_msg_msg; + unsigned int lbs_perf_event; + unsigned int lbs_task; + unsigned int lbs_xattr_count; /* num xattr slots in new_xattrs array */ + unsigned int lbs_tun_dev; + unsigned int lbs_bdev; + unsigned int lbs_bpf_map; + unsigned int lbs_bpf_prog; + unsigned int lbs_bpf_token; +}; + +/* + * 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 - Define an individual LSM for the LSM framework. + * @id: LSM name/ID info + * @order: ordering with respect to other LSMs, optional + * @flags: descriptive flags, optional + * @blobs: LSM blob sharing, optional + * @enabled: controlled by CONFIG_LSM, optional + * @init: LSM specific initialization routine + * @initcall_pure: LSM callback for initcall_pure() setup, optional + * @initcall_early: LSM callback for early_initcall setup, optional + * @initcall_core: LSM callback for core_initcall() setup, optional + * @initcall_subsys: LSM callback for subsys_initcall() setup, optional + * @initcall_fs: LSM callback for fs_initcall setup, optional + * @nitcall_device: LSM callback for device_initcall() setup, optional + * @initcall_late: LSM callback for late_initcall() setup, optional + */ +struct lsm_info { + const struct lsm_id *id; + enum lsm_order order; + unsigned long flags; + struct lsm_blob_sizes *blobs; + int *enabled; + int (*init)(void); + int (*initcall_pure)(void); + int (*initcall_early)(void); + int (*initcall_core)(void); + int (*initcall_subsys)(void); + int (*initcall_fs)(void); + int (*initcall_device)(void); + int (*initcall_late)(void); +}; + +#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 struct lsm_static_calls_table static_calls_table __ro_after_init; + +/** + * 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 */ |