security/apparmor/include/file.h

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor file mediation function definitions.
   5  *
   6  * Copyright (C) 1998-2008 Novell/SUSE
   7  * Copyright 2009-2010 Canonical Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation, version 2 of the
  12  * License.
  13  */
  14
  15 #ifndef __AA_FILE_H
  16 #define __AA_FILE_H
  17
  18 #include <linux/path.h>
  19
  20 #include "domain.h"
  21 #include "match.h"
  22
  23 struct aa_profile;
  24
  25 /*
  26  * We use MAY_EXEC, MAY_WRITE, MAY_READ, MAY_APPEND and the following flags
  27  * for profile permissions
  28  */
  29 #define AA_MAY_CREATE                  0x0010
  30 #define AA_MAY_DELETE                  0x0020
  31 #define AA_MAY_META_WRITE              0x0040
  32 #define AA_MAY_META_READ               0x0080
  33
  34 #define AA_MAY_CHMOD                   0x0100
  35 #define AA_MAY_CHOWN                   0x0200
  36 #define AA_MAY_LOCK                    0x0400
  37 #define AA_EXEC_MMAP                   0x0800
  38
  39 #define AA_MAY_LINK                     0x1000
  40 #define AA_LINK_SUBSET                  AA_MAY_LOCK     /* overlaid */
  41 #define AA_MAY_ONEXEC                   0x40000000      /* exec allows onexec */
  42 #define AA_MAY_CHANGE_PROFILE           0x80000000
  43 #define AA_MAY_CHANGEHAT                0x80000000      /* ctrl auditing only */
  44
  45 #define AA_AUDIT_FILE_MASK      (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
  46                                  AA_MAY_CREATE | AA_MAY_DELETE |        \
  47                                  AA_MAY_META_READ | AA_MAY_META_WRITE | \
  48                                  AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
  49                                  AA_EXEC_MMAP | AA_MAY_LINK)
  50
  51 /*
  52  * The xindex is broken into 3 parts
  53  * - index - an index into either the exec name table or the variable table
  54  * - exec type - which determines how the executable name and index are used
  55  * - flags - which modify how the destination name is applied
  56  */
  57 #define AA_X_INDEX_MASK         0x03ff
  58
  59 #define AA_X_TYPE_MASK          0x0c00
  60 #define AA_X_TYPE_SHIFT         10
  61 #define AA_X_NONE               0x0000
  62 #define AA_X_NAME               0x0400  /* use executable name px */
  63 #define AA_X_TABLE              0x0800  /* use a specified name ->n# */
  64
  65 #define AA_X_UNSAFE             0x1000
  66 #define AA_X_CHILD              0x2000  /* make >AA_X_NONE apply to children */
  67 #define AA_X_INHERIT            0x4000
  68 #define AA_X_UNCONFINED         0x8000
  69
  70 /* AA_SECURE_X_NEEDED - is passed in the bprm->unsafe field */
  71 #define AA_SECURE_X_NEEDED      0x8000
  72
  73 /* need to make conditional which ones are being set */
  74 struct path_cond {
  75         uid_t uid;
  76         umode_t mode;
  77 };
  78
  79 /* struct file_perms - file permission
  80  * @allow: mask of permissions that are allowed
  81  * @audit: mask of permissions to force an audit message for
  82  * @quiet: mask of permissions to quiet audit messages for
  83  * @kill: mask of permissions that when matched will kill the task
  84  * @xindex: exec transition index if @allow contains MAY_EXEC
  85  *
  86  * The @audit and @queit mask should be mutually exclusive.
  87  */
  88 struct file_perms {
  89         u32 allow;
  90         u32 audit;
  91         u32 quiet;
  92         u32 kill;
  93         u16 xindex;
  94 };
  95
  96 extern struct file_perms nullperms;
  97
  98 #define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)
  99
 100 /* FIXME: split perms from dfa and match this to description
 101  *        also add delegation info.
 102  */
 103 static inline u16 dfa_map_xindex(u16 mask)
 104 {
 105         u16 old_index = (mask >> 10) & 0xf;
 106         u16 index = 0;
 107
 108         if (mask & 0x100)
 109                 index |= AA_X_UNSAFE;
 110         if (mask & 0x200)
 111                 index |= AA_X_INHERIT;
 112         if (mask & 0x80)
 113                 index |= AA_X_UNCONFINED;
 114
 115         if (old_index == 1) {
 116                 index |= AA_X_UNCONFINED;
 117         } else if (old_index == 2) {
 118                 index |= AA_X_NAME;
 119         } else if (old_index == 3) {
 120                 index |= AA_X_NAME | AA_X_CHILD;
 121         } else {
 122                 index |= AA_X_TABLE;
 123                 index |= old_index - 4;
 124         }
 125
 126         return index;
 127 }
 128
 129 /*
 130  * map old dfa inline permissions to new format
 131  */
 132 #define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
 133                                     ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
 134 #define dfa_user_audit(dfa, state) ((ACCEPT_TABLE2(dfa)[state]) & 0x7f)
 135 #define dfa_user_quiet(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 7) & 0x7f)
 136 #define dfa_user_xindex(dfa, state) \
 137         (dfa_map_xindex(ACCEPT_TABLE(dfa)[state] & 0x3fff))
 138
 139 #define dfa_other_allow(dfa, state) ((((ACCEPT_TABLE(dfa)[state]) >> 14) & \
 140                                       0x7f) |                           \
 141                                      ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
 142 #define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
 143 #define dfa_other_quiet(dfa, state) \
 144         ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
 145 #define dfa_other_xindex(dfa, state) \
 146         dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)
 147
 148 int aa_audit_file(struct aa_profile *profile, struct file_perms *perms,
 149                   gfp_t gfp, int op, u32 request, const char *name,
 150                   const char *target, uid_t ouid, const char *info, int error);
 151
 152 /**
 153  * struct aa_file_rules - components used for file rule permissions
 154  * @dfa: dfa to match path names and conditionals against
 155  * @perms: permission table indexed by the matched state accept entry of @dfa
 156  * @trans: transition table for indexed by named x transitions
 157  *
 158  * File permission are determined by matching a path against @dfa and then
 159  * then using the value of the accept entry for the matching state as
 160  * an index into @perms.  If a named exec transition is required it is
 161  * looked up in the transition table.
 162  */
 163 struct aa_file_rules {
 164         unsigned int start;
 165         struct aa_dfa *dfa;
 166         /* struct perms perms; */
 167         struct aa_domain trans;
 168         /* TODO: add delegate table */
 169 };
 170
 171 unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
 172                           const char *name, struct path_cond *cond,
 173                           struct file_perms *perms);
 174
 175 int aa_path_perm(int op, struct aa_profile *profile, struct path *path,
 176                  int flags, u32 request, struct path_cond *cond);
 177
 178 int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
 179                  struct path *new_dir, struct dentry *new_dentry);
 180
 181 int aa_file_perm(int op, struct aa_profile *profile, struct file *file,
 182                  u32 request);
 183
 184 static inline void aa_free_file_rules(struct aa_file_rules *rules)
 185 {
 186         aa_put_dfa(rules->dfa);
 187         aa_free_domain_entries(&rules->trans);
 188 }
 189
 190 #define ACC_FMODE(x) (("\000\004\002\006"[(x)&O_ACCMODE]) | (((x) << 1) & 0x40))
 191
 192 /* from namei.c */
 193 #define MAP_OPEN_FLAGS(x) ((((x) + 1) & O_ACCMODE) ? (x) + 1 : (x))
 194
 195 /**
 196  * aa_map_file_perms - map file flags to AppArmor permissions
 197  * @file: open file to map flags to AppArmor permissions
 198  *
 199  * Returns: apparmor permission set for the file
 200  */
 201 static inline u32 aa_map_file_to_perms(struct file *file)
 202 {
 203         int flags = MAP_OPEN_FLAGS(file->f_flags);
 204         u32 perms = ACC_FMODE(file->f_mode);
 205
 206         if ((flags & O_APPEND) && (perms & MAY_WRITE))
 207                 perms = (perms & ~MAY_WRITE) | MAY_APPEND;
 208         /* trunc implies write permission */
 209         if (flags & O_TRUNC)
 210                 perms |= MAY_WRITE;
 211         if (flags & O_CREAT)
 212                 perms |= AA_MAY_CREATE;
 213
 214         return perms;
 215 }
 216
 217 #endif /* __AA_FILE_H */