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