root/security/apparmor/include/path.h

INCLUDED FROM

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * AppArmor security module
   4  *
   5  * This file contains AppArmor basic path manipulation function definitions.
   6  *
   7  * Copyright (C) 1998-2008 Novell/SUSE
   8  * Copyright 2009-2010 Canonical Ltd.
   9  */
  10 
  11 #ifndef __AA_PATH_H
  12 #define __AA_PATH_H
  13 
  14 
  15 enum path_flags {
  16         PATH_IS_DIR = 0x1,              /* path is a directory */
  17         PATH_CONNECT_PATH = 0x4,        /* connect disconnected paths to / */
  18         PATH_CHROOT_REL = 0x8,          /* do path lookup relative to chroot */
  19         PATH_CHROOT_NSCONNECT = 0x10,   /* connect paths that are at ns root */
  20 
  21         PATH_DELEGATE_DELETED = 0x08000, /* delegate deleted files */
  22         PATH_MEDIATE_DELETED = 0x10000,  /* mediate deleted paths */
  23 };
  24 
  25 int aa_path_name(const struct path *path, int flags, char *buffer,
  26                  const char **name, const char **info,
  27                  const char *disconnected);
  28 
  29 #define MAX_PATH_BUFFERS 2
  30 
  31 /* Per cpu buffers used during mediation */
  32 /* preallocated buffers to use during path lookups */
  33 struct aa_buffers {
  34         char *buf[MAX_PATH_BUFFERS];
  35 };
  36 
  37 #include <linux/percpu.h>
  38 #include <linux/preempt.h>
  39 
  40 DECLARE_PER_CPU(struct aa_buffers, aa_buffers);
  41 
  42 #define ASSIGN(FN, A, X, N) ((X) = FN(A, N))
  43 #define EVAL1(FN, A, X) ASSIGN(FN, A, X, 0) /*X = FN(0)*/
  44 #define EVAL2(FN, A, X, Y...)   \
  45         do { ASSIGN(FN, A, X, 1);  EVAL1(FN, A, Y); } while (0)
  46 #define EVAL(FN, A, X...) CONCATENATE(EVAL, COUNT_ARGS(X))(FN, A, X)
  47 
  48 #define for_each_cpu_buffer(I) for ((I) = 0; (I) < MAX_PATH_BUFFERS; (I)++)
  49 
  50 #ifdef CONFIG_DEBUG_PREEMPT
  51 #define AA_BUG_PREEMPT_ENABLED(X) AA_BUG(preempt_count() <= 0, X)
  52 #else
  53 #define AA_BUG_PREEMPT_ENABLED(X) /* nop */
  54 #endif
  55 
  56 #define __get_buffer(C, N) ({                                           \
  57         AA_BUG_PREEMPT_ENABLED("__get_buffer without preempt disabled");  \
  58         (C)->buf[(N)]; })
  59 
  60 #define __get_buffers(C, X...)    EVAL(__get_buffer, C, X)
  61 
  62 #define __put_buffers(X, Y...) ((void)&(X))
  63 
  64 #define get_buffers(X...)                                               \
  65 do {                                                                    \
  66         struct aa_buffers *__cpu_var = get_cpu_ptr(&aa_buffers);        \
  67         __get_buffers(__cpu_var, X);                                    \
  68 } while (0)
  69 
  70 #define put_buffers(X, Y...)            \
  71 do {                                    \
  72         __put_buffers(X, Y);            \
  73         put_cpu_ptr(&aa_buffers);       \
  74 } while (0)
  75 
  76 #endif /* __AA_PATH_H */