security/apparmor/include/policy.h

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor policy 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_POLICY_H
  16 #define __AA_POLICY_H
  17
  18 #include <linux/capability.h>
  19 #include <linux/cred.h>
  20 #include <linux/kref.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <linux/socket.h>
  24
  25 #include "apparmor.h"
  26 #include "audit.h"
  27 #include "capability.h"
  28 #include "domain.h"
  29 #include "file.h"
  30 #include "lib.h"
  31 #include "resource.h"
  32
  33 extern const char *const aa_profile_mode_names[];
  34 #define APPARMOR_MODE_NAMES_MAX_INDEX 4
  35
  36 #define PROFILE_MODE(_profile, _mode)           \
  37         ((aa_g_profile_mode == (_mode)) ||      \
  38          ((_profile)->mode == (_mode)))
  39
  40 #define COMPLAIN_MODE(_profile) PROFILE_MODE((_profile), APPARMOR_COMPLAIN)
  41
  42 #define KILL_MODE(_profile) PROFILE_MODE((_profile), APPARMOR_KILL)
  43
  44 #define PROFILE_IS_HAT(_profile) ((_profile)->flags & PFLAG_HAT)
  45
  46 #define PROFILE_INVALID(_profile) ((_profile)->flags & PFLAG_INVALID)
  47
  48 #define on_list_rcu(X) (!list_empty(X) && (X)->prev != LIST_POISON2)
  49
  50 /*
  51  * FIXME: currently need a clean way to replace and remove profiles as a
  52  * set.  It should be done at the namespace level.
  53  * Either, with a set of profiles loaded at the namespace level or via
  54  * a mark and remove marked interface.
  55  */
  56 enum profile_mode {
  57         APPARMOR_ENFORCE,       /* enforce access rules */
  58         APPARMOR_COMPLAIN,      /* allow and log access violations */
  59         APPARMOR_KILL,          /* kill task on access violation */
  60         APPARMOR_UNCONFINED,    /* profile set to unconfined */
  61 };
  62
  63 enum profile_flags {
  64         PFLAG_HAT = 1,                  /* profile is a hat */
  65         PFLAG_NULL = 4,                 /* profile is null learning profile */
  66         PFLAG_IX_ON_NAME_ERROR = 8,     /* fallback to ix on name lookup fail */
  67         PFLAG_IMMUTABLE = 0x10,         /* don't allow changes/replacement */
  68         PFLAG_USER_DEFINED = 0x20,      /* user based profile - lower privs */
  69         PFLAG_NO_LIST_REF = 0x40,       /* list doesn't keep profile ref */
  70         PFLAG_OLD_NULL_TRANS = 0x100,   /* use // as the null transition */
  71         PFLAG_INVALID = 0x200,          /* profile replaced/removed */
  72         PFLAG_NS_COUNT = 0x400,         /* carries NS ref count */
  73
  74         /* These flags must correspond with PATH_flags */
  75         PFLAG_MEDIATE_DELETED = 0x10000, /* mediate instead delegate deleted */
  76 };
  77
  78 struct aa_profile;
  79
  80 /* struct aa_ns_acct - accounting of profiles in namespace
  81  * @max_size: maximum space allowed for all profiles in namespace
  82  * @max_count: maximum number of profiles that can be in this namespace
  83  * @size: current size of profiles
  84  * @count: current count of profiles (includes null profiles)
  85  */
  86 struct aa_ns_acct {
  87         int max_size;
  88         int max_count;
  89         int size;
  90         int count;
  91 };
  92
  93 /* struct aa_namespace - namespace for a set of profiles
  94  * @base: common policy
  95  * @parent: parent of namespace
  96  * @lock: lock for modifying the object
  97  * @acct: accounting for the namespace
  98  * @unconfined: special unconfined profile for the namespace
  99  * @sub_ns: list of namespaces under the current namespace.
 100  * @uniq_null: uniq value used for null learning profiles
 101  * @uniq_id: a unique id count for the profiles in the namespace
 102  * @dents: dentries for the namespaces file entries in apparmorfs
 103  *
 104  * An aa_namespace defines the set profiles that are searched to determine
 105  * which profile to attach to a task.  Profiles can not be shared between
 106  * aa_namespaces and profile names within a namespace are guaranteed to be
 107  * unique.  When profiles in separate namespaces have the same name they
 108  * are NOT considered to be equivalent.
 109  *
 110  * Namespaces are hierarchical and only namespaces and profiles below the
 111  * current namespace are visible.
 112  *
 113  * Namespace names must be unique and can not contain the characters :/\0
 114  *
 115  * FIXME TODO: add vserver support of namespaces (can it all be done in
 116  *             userspace?)
 117  */
 118 struct aa_namespace {
 119         struct aa_policy base;
 120         struct aa_namespace *parent;
 121         struct mutex lock;
 122         struct aa_ns_acct acct;
 123         struct aa_profile *unconfined;
 124         struct list_head sub_ns;
 125         atomic_t uniq_null;
 126         long uniq_id;
 127
 128         struct dentry *dents[AAFS_NS_SIZEOF];
 129 };
 130
 131 /* struct aa_policydb - match engine for a policy
 132  * dfa: dfa pattern match
 133  * start: set of start states for the different classes of data
 134  */
 135 struct aa_policydb {
 136         /* Generic policy DFA specific rule types will be subsections of it */
 137         struct aa_dfa *dfa;
 138         unsigned int start[AA_CLASS_LAST + 1];
 139
 140 };
 141
 142 struct aa_replacedby {
 143         struct kref count;
 144         struct aa_profile __rcu *profile;
 145 };
 146
 147
 148 /* struct aa_profile - basic confinement data
 149  * @base - base components of the profile (name, refcount, lists, lock ...)
 150  * @count: reference count of the obj
 151  * @rcu: rcu head used when removing from @list
 152  * @parent: parent of profile
 153  * @ns: namespace the profile is in
 154  * @replacedby: is set to the profile that replaced this profile
 155  * @rename: optional profile name that this profile renamed
 156  * @attach: human readable attachment string
 157  * @xmatch: optional extended matching for unconfined executables names
 158  * @xmatch_len: xmatch prefix len, used to determine xmatch priority
 159  * @audit: the auditing mode of the profile
 160  * @mode: the enforcement mode of the profile
 161  * @flags: flags controlling profile behavior
 162  * @path_flags: flags controlling path generation behavior
 163  * @size: the memory consumed by this profiles rules
 164  * @policy: general match rules governing policy
 165  * @file: The set of rules governing basic file access and domain transitions
 166  * @caps: capabilities for the profile
 167  * @rlimits: rlimits for the profile
 168  *
 169  * @dents: dentries for the profiles file entries in apparmorfs
 170  * @dirname: name of the profile dir in apparmorfs
 171  *
 172  * The AppArmor profile contains the basic confinement data.  Each profile
 173  * has a name, and exists in a namespace.  The @name and @exec_match are
 174  * used to determine profile attachment against unconfined tasks.  All other
 175  * attachments are determined by profile X transition rules.
 176  *
 177  * The @replacedby struct is write protected by the profile lock.
 178  *
 179  * Profiles have a hierarchy where hats and children profiles keep
 180  * a reference to their parent.
 181  *
 182  * Profile names can not begin with a : and can not contain the \0
 183  * character.  If a profile name begins with / it will be considered when
 184  * determining profile attachment on "unconfined" tasks.
 185  */
 186 struct aa_profile {
 187         struct aa_policy base;
 188         struct kref count;
 189         struct rcu_head rcu;
 190         struct aa_profile __rcu *parent;
 191
 192         struct aa_namespace *ns;
 193         struct aa_replacedby *replacedby;
 194         const char *rename;
 195
 196         const char *attach;
 197         struct aa_dfa *xmatch;
 198         int xmatch_len;
 199         enum audit_mode audit;
 200         long mode;
 201         long flags;
 202         u32 path_flags;
 203         int size;
 204
 205         struct aa_policydb policy;
 206         struct aa_file_rules file;
 207         struct aa_caps caps;
 208         struct aa_rlimit rlimits;
 209
 210         unsigned char *hash;
 211         char *dirname;
 212         struct dentry *dents[AAFS_PROF_SIZEOF];
 213 };
 214
 215 extern struct aa_namespace *root_ns;
 216 extern enum profile_mode aa_g_profile_mode;
 217
 218 void aa_add_profile(struct aa_policy *common, struct aa_profile *profile);
 219
 220 bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view);
 221 const char *aa_ns_name(struct aa_namespace *parent, struct aa_namespace *child);
 222 int aa_alloc_root_ns(void);
 223 void aa_free_root_ns(void);
 224 void aa_free_namespace_kref(struct kref *kref);
 225
 226 struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
 227                                        const char *name);
 228
 229
 230 void aa_free_replacedby_kref(struct kref *kref);
 231 struct aa_profile *aa_alloc_profile(const char *name);
 232 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat);
 233 void aa_free_profile(struct aa_profile *profile);
 234 void aa_free_profile_kref(struct kref *kref);
 235 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name);
 236 struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *name);
 237 struct aa_profile *aa_match_profile(struct aa_namespace *ns, const char *name);
 238
 239 ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace);
 240 ssize_t aa_remove_profiles(char *name, size_t size);
 241
 242 #define PROF_ADD 1
 243 #define PROF_REPLACE 0
 244
 245 #define unconfined(X) ((X)->mode == APPARMOR_UNCONFINED)
 246
 247
 248 static inline struct aa_profile *aa_deref_parent(struct aa_profile *p)
 249 {
 250         return rcu_dereference_protected(p->parent,
 251                                          mutex_is_locked(&p->ns->lock));
 252 }
 253
 254 /**
 255  * aa_get_profile - increment refcount on profile @p
 256  * @p: profile  (MAYBE NULL)
 257  *
 258  * Returns: pointer to @p if @p is NULL will return NULL
 259  * Requires: @p must be held with valid refcount when called
 260  */
 261 static inline struct aa_profile *aa_get_profile(struct aa_profile *p)
 262 {
 263         if (p)
 264                 kref_get(&(p->count));
 265
 266         return p;
 267 }
 268
 269 /**
 270  * aa_get_profile_not0 - increment refcount on profile @p found via lookup
 271  * @p: profile  (MAYBE NULL)
 272  *
 273  * Returns: pointer to @p if @p is NULL will return NULL
 274  * Requires: @p must be held with valid refcount when called
 275  */
 276 static inline struct aa_profile *aa_get_profile_not0(struct aa_profile *p)
 277 {
 278         if (p && kref_get_not0(&p->count))
 279                 return p;
 280
 281         return NULL;
 282 }
 283
 284 /**
 285  * aa_get_profile_rcu - increment a refcount profile that can be replaced
 286  * @p: pointer to profile that can be replaced (NOT NULL)
 287  *
 288  * Returns: pointer to a refcounted profile.
 289  *     else NULL if no profile
 290  */
 291 static inline struct aa_profile *aa_get_profile_rcu(struct aa_profile __rcu **p)
 292 {
 293         struct aa_profile *c;
 294
 295         rcu_read_lock();
 296         do {
 297                 c = rcu_dereference(*p);
 298         } while (c && !kref_get_not0(&c->count));
 299         rcu_read_unlock();
 300
 301         return c;
 302 }
 303
 304 /**
 305  * aa_get_newest_profile - find the newest version of @profile
 306  * @profile: the profile to check for newer versions of
 307  *
 308  * Returns: refcounted newest version of @profile taking into account
 309  *          replacement, renames and removals
 310  *          return @profile.
 311  */
 312 static inline struct aa_profile *aa_get_newest_profile(struct aa_profile *p)
 313 {
 314         if (!p)
 315                 return NULL;
 316
 317         if (PROFILE_INVALID(p))
 318                 return aa_get_profile_rcu(&p->replacedby->profile);
 319
 320         return aa_get_profile(p);
 321 }
 322
 323 /**
 324  * aa_put_profile - decrement refcount on profile @p
 325  * @p: profile  (MAYBE NULL)
 326  */
 327 static inline void aa_put_profile(struct aa_profile *p)
 328 {
 329         if (p)
 330                 kref_put(&p->count, aa_free_profile_kref);
 331 }
 332
 333 static inline struct aa_replacedby *aa_get_replacedby(struct aa_replacedby *p)
 334 {
 335         if (p)
 336                 kref_get(&(p->count));
 337
 338         return p;
 339 }
 340
 341 static inline void aa_put_replacedby(struct aa_replacedby *p)
 342 {
 343         if (p)
 344                 kref_put(&p->count, aa_free_replacedby_kref);
 345 }
 346
 347 /* requires profile list write lock held */
 348 static inline void __aa_update_replacedby(struct aa_profile *orig,
 349                                           struct aa_profile *new)
 350 {
 351         struct aa_profile *tmp;
 352         tmp = rcu_dereference_protected(orig->replacedby->profile,
 353                                         mutex_is_locked(&orig->ns->lock));
 354         rcu_assign_pointer(orig->replacedby->profile, aa_get_profile(new));
 355         orig->flags |= PFLAG_INVALID;
 356         aa_put_profile(tmp);
 357 }
 358
 359 /**
 360  * aa_get_namespace - increment references count on @ns
 361  * @ns: namespace to increment reference count of (MAYBE NULL)
 362  *
 363  * Returns: pointer to @ns, if @ns is NULL returns NULL
 364  * Requires: @ns must be held with valid refcount when called
 365  */
 366 static inline struct aa_namespace *aa_get_namespace(struct aa_namespace *ns)
 367 {
 368         if (ns)
 369                 aa_get_profile(ns->unconfined);
 370
 371         return ns;
 372 }
 373
 374 /**
 375  * aa_put_namespace - decrement refcount on @ns
 376  * @ns: namespace to put reference of
 377  *
 378  * Decrement reference count of @ns and if no longer in use free it
 379  */
 380 static inline void aa_put_namespace(struct aa_namespace *ns)
 381 {
 382         if (ns)
 383                 aa_put_profile(ns->unconfined);
 384 }
 385
 386 static inline int AUDIT_MODE(struct aa_profile *profile)
 387 {
 388         if (aa_g_audit != AUDIT_NORMAL)
 389                 return aa_g_audit;
 390
 391         return profile->audit;
 392 }
 393
 394 bool policy_view_capable(void);
 395 bool policy_admin_capable(void);
 396 bool aa_may_manage_policy(int op);
 397
 398 #endif /* __AA_POLICY_H */