linux_dsm_epyc7002/security/apparmor/include/path.h
John Johansen 4227c333f6 apparmor: Move path lookup to using preallocated buffers
Dynamically allocating buffers is problematic and is an extra layer
that is a potntial point of failure and can slow down mediation.
Change path lookup to use the preallocated per cpu buffers.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2017-06-08 11:29:34 -07:00

87 lines
2.4 KiB
C

/*
* AppArmor security module
*
* This file contains AppArmor basic path manipulation function definitions.
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* 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, version 2 of the
* License.
*/
#ifndef __AA_PATH_H
#define __AA_PATH_H
enum path_flags {
PATH_IS_DIR = 0x1, /* path is a directory */
PATH_CONNECT_PATH = 0x4, /* connect disconnected paths to / */
PATH_CHROOT_REL = 0x8, /* do path lookup relative to chroot */
PATH_CHROOT_NSCONNECT = 0x10, /* connect paths that are at ns root */
PATH_DELEGATE_DELETED = 0x08000, /* delegate deleted files */
PATH_MEDIATE_DELETED = 0x10000, /* mediate deleted paths */
};
int aa_path_name(const struct path *path, int flags, char *buffer,
const char **name, const char **info,
const char *disconnected);
#define MAX_PATH_BUFFERS 2
/* Per cpu buffers used during mediation */
/* preallocated buffers to use during path lookups */
struct aa_buffers {
char *buf[MAX_PATH_BUFFERS];
};
#include <linux/percpu.h>
#include <linux/preempt.h>
DECLARE_PER_CPU(struct aa_buffers, aa_buffers);
#define COUNT_ARGS(X...) COUNT_ARGS_HELPER(, ##X, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
#define COUNT_ARGS_HELPER(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, n, X...) n
#define CONCAT(X, Y) X ## Y
#define CONCAT_AFTER(X, Y) CONCAT(X, Y)
#define ASSIGN(FN, X, N) ((X) = FN(N))
#define EVAL1(FN, X) ASSIGN(FN, X, 0) /*X = FN(0)*/
#define EVAL2(FN, X, Y...) do { ASSIGN(FN, X, 1); EVAL1(FN, Y); } while (0)
#define EVAL(FN, X...) CONCAT_AFTER(EVAL, COUNT_ARGS(X))(FN, X)
#define for_each_cpu_buffer(I) for ((I) = 0; (I) < MAX_PATH_BUFFERS; (I)++)
#ifdef CONFIG_DEBUG_PREEMPT
#define AA_BUG_PREEMPT_ENABLED(X) AA_BUG(preempt_count() <= 0, X)
#else
#define AA_BUG_PREEMPT_ENABLED(X) /* nop */
#endif
#define __get_buffer(N) ({ \
struct aa_buffers *__cpu_var; \
AA_BUG_PREEMPT_ENABLED("__get_buffer without preempt disabled"); \
__cpu_var = this_cpu_ptr(&aa_buffers); \
__cpu_var->buf[(N)]; })
#define __get_buffers(X...) EVAL(__get_buffer, X)
#define __put_buffers(X, Y...) ((void)&(X))
#define get_buffers(X...) \
do { \
preempt_disable(); \
__get_buffers(X); \
} while (0)
#define put_buffers(X, Y...) \
do { \
__put_buffers(X, Y); \
preempt_enable(); \
} while (0)
#endif /* __AA_PATH_H */