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/spinlock.h>
  19
  20 #include "domain.h"
  21 #include "match.h"
  22 #include "label.h"
  23 #include "perms.h"
  24
  25 struct aa_profile;
  26 struct path;
  27
  28 #define mask_mode_t(X) (X & (MAY_EXEC | MAY_WRITE | MAY_READ | MAY_APPEND))
  29
  30 #define AA_AUDIT_FILE_MASK      (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
  31                                  AA_MAY_CREATE | AA_MAY_DELETE |        \
  32                                  AA_MAY_GETATTR | AA_MAY_SETATTR | \
  33                                  AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
  34                                  AA_EXEC_MMAP | AA_MAY_LINK)
  35
  36 #define file_ctx(X) ((struct aa_file_ctx *)(X)->f_security)
  37
  38 /* struct aa_file_ctx - the AppArmor context the file was opened in
  39  * @lock: lock to update the ctx
  40  * @label: label currently cached on the ctx
  41  * @perms: the permission the file was opened with
  42  */
  43 struct aa_file_ctx {
  44         spinlock_t lock;
  45         struct aa_label __rcu *label;
  46         u32 allow;
  47 };
  48
  49 /**
  50  * aa_alloc_file_ctx - allocate file_ctx
  51  * @label: initial label of task creating the file
  52  * @gfp: gfp flags for allocation
  53  *
  54  * Returns: file_ctx or NULL on failure
  55  */
  56 static inline struct aa_file_ctx *aa_alloc_file_ctx(struct aa_label *label, gfp_t gfp)
  57 {
  58         struct aa_file_ctx *ctx;
  59
  60         ctx = kzalloc(sizeof(struct aa_file_ctx), gfp);
  61         if (ctx) {
  62                 spin_lock_init(&ctx->lock);
  63                 rcu_assign_pointer(ctx->label, aa_get_label(label));
  64         }
  65         return ctx;
  66 }
  67
  68 /**
  69  * aa_free_file_ctx - free a file_ctx
  70  * @ctx: file_ctx to free  (MAYBE_NULL)
  71  */
  72 static inline void aa_free_file_ctx(struct aa_file_ctx *ctx)
  73 {
  74         if (ctx) {
  75                 aa_put_label(rcu_access_pointer(ctx->label));
  76                 kzfree(ctx);
  77         }
  78 }
  79
  80 static inline struct aa_label *aa_get_file_label(struct aa_file_ctx *ctx)
  81 {
  82         return aa_get_label_rcu(&ctx->label);
  83 }
  84
  85 #define inode_ctx(X) (X)->i_security
  86
  87 /*
  88  * The xindex is broken into 3 parts
  89  * - index - an index into either the exec name table or the variable table
  90  * - exec type - which determines how the executable name and index are used
  91  * - flags - which modify how the destination name is applied
  92  */
  93 #define AA_X_INDEX_MASK         0x03ff
  94
  95 #define AA_X_TYPE_MASK          0x0c00
  96 #define AA_X_TYPE_SHIFT         10
  97 #define AA_X_NONE               0x0000
  98 #define AA_X_NAME               0x0400  /* use executable name px */
  99 #define AA_X_TABLE              0x0800  /* use a specified name ->n# */
 100
 101 #define AA_X_UNSAFE             0x1000
 102 #define AA_X_CHILD              0x2000  /* make >AA_X_NONE apply to children */
 103 #define AA_X_INHERIT            0x4000
 104 #define AA_X_UNCONFINED         0x8000
 105
 106 /* AA_SECURE_X_NEEDED - is passed in the bprm->unsafe field */
 107 #define AA_SECURE_X_NEEDED      0x8000
 108
 109 /* need to make conditional which ones are being set */
 110 struct path_cond {
 111         kuid_t uid;
 112         umode_t mode;
 113 };
 114
 115 #define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)
 116
 117 /* FIXME: split perms from dfa and match this to description
 118  *        also add delegation info.
 119  */
 120 static inline u16 dfa_map_xindex(u16 mask)
 121 {
 122         u16 old_index = (mask >> 10) & 0xf;
 123         u16 index = 0;
 124
 125         if (mask & 0x100)
 126                 index |= AA_X_UNSAFE;
 127         if (mask & 0x200)
 128                 index |= AA_X_INHERIT;
 129         if (mask & 0x80)
 130                 index |= AA_X_UNCONFINED;
 131
 132         if (old_index == 1) {
 133                 index |= AA_X_UNCONFINED;
 134         } else if (old_index == 2) {
 135                 index |= AA_X_NAME;
 136         } else if (old_index == 3) {
 137                 index |= AA_X_NAME | AA_X_CHILD;
 138         } else if (old_index) {
 139                 index |= AA_X_TABLE;
 140                 index |= old_index - 4;
 141         }
 142
 143         return index;
 144 }
 145
 146 /*
 147  * map old dfa inline permissions to new format
 148  */
 149 #define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
 150                                     ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
 151 #define dfa_user_audit(dfa, state) ((ACCEPT_TABLE2(dfa)[state]) & 0x7f)
 152 #define dfa_user_quiet(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 7) & 0x7f)
 153 #define dfa_user_xindex(dfa, state) \
 154         (dfa_map_xindex(ACCEPT_TABLE(dfa)[state] & 0x3fff))
 155
 156 #define dfa_other_allow(dfa, state) ((((ACCEPT_TABLE(dfa)[state]) >> 14) & \
 157                                       0x7f) |                           \
 158                                      ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
 159 #define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
 160 #define dfa_other_quiet(dfa, state) \
 161         ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
 162 #define dfa_other_xindex(dfa, state) \
 163         dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)
 164
 165 int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms,
 166                   const char *op, u32 request, const char *name, const char *target, struct aa_label *tlabel,
 167                   kuid_t ouid, const char *info, int error);
 168
 169 /**
 170  * struct aa_file_rules - components used for file rule permissions
 171  * @dfa: dfa to match path names and conditionals against
 172  * @perms: permission table indexed by the matched state accept entry of @dfa
 173  * @trans: transition table for indexed by named x transitions
 174  *
 175  * File permission are determined by matching a path against @dfa and then
 176  * then using the value of the accept entry for the matching state as
 177  * an index into @perms.  If a named exec transition is required it is
 178  * looked up in the transition table.
 179  */
 180 struct aa_file_rules {
 181         unsigned int start;
 182         struct aa_dfa *dfa;
 183         /* struct perms perms; */
 184         struct aa_domain trans;
 185         /* TODO: add delegate table */
 186 };
 187
 188 struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state,
 189                                     struct path_cond *cond);
 190 unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
 191                           const char *name, struct path_cond *cond,
 192                           struct aa_perms *perms);
 193
 194 int __aa_path_perm(const char *op, struct aa_profile *profile, const char *name,
 195                    u32 request, struct path_cond *cond, int flags,
 196                    struct aa_perms *perms);
 197 int aa_path_perm(const char *op, struct aa_label *label,
 198                  const struct path *path, int flags, u32 request,
 199                  struct path_cond *cond);
 200
 201 int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
 202                  const struct path *new_dir, struct dentry *new_dentry);
 203
 204 int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
 205                  u32 request);
 206
 207 void aa_inherit_files(const struct cred *cred, struct files_struct *files);
 208
 209 static inline void aa_free_file_rules(struct aa_file_rules *rules)
 210 {
 211         aa_put_dfa(rules->dfa);
 212         aa_free_domain_entries(&rules->trans);
 213 }
 214
 215 /**
 216  * aa_map_file_perms - map file flags to AppArmor permissions
 217  * @file: open file to map flags to AppArmor permissions
 218  *
 219  * Returns: apparmor permission set for the file
 220  */
 221 static inline u32 aa_map_file_to_perms(struct file *file)
 222 {
 223         int flags = file->f_flags;
 224         u32 perms = 0;
 225
 226         if (file->f_mode & FMODE_WRITE)
 227                 perms |= MAY_WRITE;
 228         if (file->f_mode & FMODE_READ)
 229                 perms |= MAY_READ;
 230
 231         if ((flags & O_APPEND) && (perms & MAY_WRITE))
 232                 perms = (perms & ~MAY_WRITE) | MAY_APPEND;
 233         /* trunc implies write permission */
 234         if (flags & O_TRUNC)
 235                 perms |= MAY_WRITE;
 236         if (flags & O_CREAT)
 237                 perms |= AA_MAY_CREATE;
 238
 239         return perms;
 240 }
 241
 242 #endif /* __AA_FILE_H */