linux/security/lsm_syscalls.c
Casey Schaufler ad4aff9ec2 LSM: Create lsm_list_modules system call
Create a system call to report the list of Linux Security Modules
that are active on the system. The list is provided as an array
of LSM ID numbers.

The calling application can use this list determine what LSM
specific actions it might take. That might include choosing an
output format, determining required privilege or bypassing
security module specific behavior.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12 22:54:42 -05:00

97 lines
3.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* System calls implementing the Linux Security Module API.
*
* Copyright (C) 2022 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2022 Intel Corporation
*/
#include <asm/current.h>
#include <linux/compiler_types.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/security.h>
#include <linux/stddef.h>
#include <linux/syscalls.h>
#include <linux/types.h>
#include <linux/lsm_hooks.h>
#include <uapi/linux/lsm.h>
/**
* sys_lsm_set_self_attr - Set current task's security module attribute
* @attr: which attribute to set
* @ctx: the LSM contexts
* @size: size of @ctx
* @flags: reserved for future use
*
* Sets the calling task's LSM context. On success this function
* returns 0. If the attribute specified cannot be set a negative
* value indicating the reason for the error is returned.
*/
SYSCALL_DEFINE4(lsm_set_self_attr, unsigned int, attr, struct lsm_ctx __user *,
ctx, size_t, size, u32, flags)
{
return security_setselfattr(attr, ctx, size, flags);
}
/**
* sys_lsm_get_self_attr - Return current task's security module attributes
* @attr: which attribute to return
* @ctx: the user-space destination for the information, or NULL
* @size: pointer to the size of space available to receive the data
* @flags: special handling options. LSM_FLAG_SINGLE indicates that only
* attributes associated with the LSM identified in the passed @ctx be
* reported.
*
* Returns the calling task's LSM contexts. On success this
* function returns the number of @ctx array elements. This value
* may be zero if there are no LSM contexts assigned. If @size is
* insufficient to contain the return data -E2BIG is returned and
* @size is set to the minimum required size. In all other cases
* a negative value indicating the error is returned.
*/
SYSCALL_DEFINE4(lsm_get_self_attr, unsigned int, attr, struct lsm_ctx __user *,
ctx, size_t __user *, size, u32, flags)
{
return security_getselfattr(attr, ctx, size, flags);
}
/**
* sys_lsm_list_modules - Return a list of the active security modules
* @ids: the LSM module ids
* @size: pointer to size of @ids, updated on return
* @flags: reserved for future use, must be zero
*
* Returns a list of the active LSM ids. On success this function
* returns the number of @ids array elements. This value may be zero
* if there are no LSMs active. If @size is insufficient to contain
* the return data -E2BIG is returned and @size is set to the minimum
* required size. In all other cases a negative value indicating the
* error is returned.
*/
SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, size_t __user *, size,
u32, flags)
{
size_t total_size = lsm_active_cnt * sizeof(*ids);
size_t usize;
int i;
if (flags)
return -EINVAL;
if (get_user(usize, size))
return -EFAULT;
if (put_user(total_size, size) != 0)
return -EFAULT;
if (usize < total_size)
return -E2BIG;
for (i = 0; i < lsm_active_cnt; i++)
if (put_user(lsm_idlist[i]->id, ids++))
return -EFAULT;
return lsm_active_cnt;
}