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_policy - common part of both namespaces and profiles
  81  * @name: name of the object
  82  * @hname - The hierarchical name
  83  * @list: list policy object is on
  84  * @profiles: head of the profiles list contained in the object
  85  */
  86 struct aa_policy {
  87         char *name;
  88         char *hname;
  89         struct list_head list;
  90         struct list_head profiles;
  91 };
  92
  93 /* struct aa_ns_acct - accounting of profiles in namespace
  94  * @max_size: maximum space allowed for all profiles in namespace
  95  * @max_count: maximum number of profiles that can be in this namespace
  96  * @size: current size of profiles
  97  * @count: current count of profiles (includes null profiles)
  98  */
  99 struct aa_ns_acct {
 100         int max_size;
 101         int max_count;
 102         int size;
 103         int count;
 104 };
 105
 106 /* struct aa_namespace - namespace for a set of profiles
 107  * @base: common policy
 108  * @parent: parent of namespace
 109  * @lock: lock for modifying the object
 110  * @acct: accounting for the namespace
 111  * @unconfined: special unconfined profile for the namespace
 112  * @sub_ns: list of namespaces under the current namespace.
 113  * @uniq_null: uniq value used for null learning profiles
 114  * @uniq_id: a unique id count for the profiles in the namespace
 115  * @dents: dentries for the namespaces file entries in apparmorfs
 116  *
 117  * An aa_namespace defines the set profiles that are searched to determine
 118  * which profile to attach to a task.  Profiles can not be shared between
 119  * aa_namespaces and profile names within a namespace are guaranteed to be
 120  * unique.  When profiles in separate namespaces have the same name they
 121  * are NOT considered to be equivalent.
 122  *
 123  * Namespaces are hierarchical and only namespaces and profiles below the
 124  * current namespace are visible.
 125  *
 126  * Namespace names must be unique and can not contain the characters :/\0
 127  *
 128  * FIXME TODO: add vserver support of namespaces (can it all be done in
 129  *             userspace?)
 130  */
 131 struct aa_namespace {
 132         struct aa_policy base;
 133         struct aa_namespace *parent;
 134         struct mutex lock;
 135         struct aa_ns_acct acct;
 136         struct aa_profile *unconfined;
 137         struct list_head sub_ns;
 138         atomic_t uniq_null;
 139         long uniq_id;
 140
 141         struct dentry *dents[AAFS_NS_SIZEOF];
 142 };
 143
 144 /* struct aa_policydb - match engine for a policy
 145  * dfa: dfa pattern match
 146  * start: set of start states for the different classes of data
 147  */
 148 struct aa_policydb {
 149         /* Generic policy DFA specific rule types will be subsections of it */
 150         struct aa_dfa *dfa;
 151         unsigned int start[AA_CLASS_LAST + 1];
 152
 153 };
 154
 155 struct aa_replacedby {
 156         struct kref count;
 157         struct aa_profile __rcu *profile;
 158 };
 159
 160
 161 /* struct aa_profile - basic confinement data
 162  * @base - base components of the profile (name, refcount, lists, lock ...)
 163  * @count: reference count of the obj
 164  * @rcu: rcu head used when removing from @list
 165  * @parent: parent of profile
 166  * @ns: namespace the profile is in
 167  * @replacedby: is set to the profile that replaced this profile
 168  * @rename: optional profile name that this profile renamed
 169  * @attach: human readable attachment string
 170  * @xmatch: optional extended matching for unconfined executables names
 171  * @xmatch_len: xmatch prefix len, used to determine xmatch priority
 172  * @audit: the auditing mode of the profile
 173  * @mode: the enforcement mode of the profile
 174  * @flags: flags controlling profile behavior
 175  * @path_flags: flags controlling path generation behavior
 176  * @size: the memory consumed by this profiles rules
 177  * @policy: general match rules governing policy
 178  * @file: The set of rules governing basic file access and domain transitions
 179  * @caps: capabilities for the profile
 180  * @rlimits: rlimits for the profile
 181  *
 182  * @dents: dentries for the profiles file entries in apparmorfs
 183  * @dirname: name of the profile dir in apparmorfs
 184  *
 185  * The AppArmor profile contains the basic confinement data.  Each profile
 186  * has a name, and exists in a namespace.  The @name and @exec_match are
 187  * used to determine profile attachment against unconfined tasks.  All other
 188  * attachments are determined by profile X transition rules.
 189  *
 190  * The @replacedby struct is write protected by the profile lock.
 191  *
 192  * Profiles have a hierarchy where hats and children profiles keep
 193  * a reference to their parent.
 194  *
 195  * Profile names can not begin with a : and can not contain the \0
 196  * character.  If a profile name begins with / it will be considered when
 197  * determining profile attachment on "unconfined" tasks.
 198  */
 199 struct aa_profile {
 200         struct aa_policy base;
 201         struct kref count;
 202         struct rcu_head rcu;
 203         struct aa_profile __rcu *parent;
 204
 205         struct aa_namespace *ns;
 206         struct aa_replacedby *replacedby;
 207         const char *rename;
 208
 209         const char *attach;
 210         struct aa_dfa *xmatch;
 211         int xmatch_len;
 212         enum audit_mode audit;
 213         long mode;
 214         long flags;
 215         u32 path_flags;
 216         int size;
 217
 218         struct aa_policydb policy;
 219         struct aa_file_rules file;
 220         struct aa_caps caps;
 221         struct aa_rlimit rlimits;
 222
 223         unsigned char *hash;
 224         char *dirname;
 225         struct dentry *dents[AAFS_PROF_SIZEOF];
 226 };
 227
 228 extern struct aa_namespace *root_ns;
 229 extern enum profile_mode aa_g_profile_mode;
 230
 231 void aa_add_profile(struct aa_policy *common, struct aa_profile *profile);
 232
 233 bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view);
 234 const char *aa_ns_name(struct aa_namespace *parent, struct aa_namespace *child);
 235 int aa_alloc_root_ns(void);
 236 void aa_free_root_ns(void);
 237 void aa_free_namespace_kref(struct kref *kref);
 238
 239 struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
 240                                        const char *name);
 241
 242
 243 void aa_free_replacedby_kref(struct kref *kref);
 244 struct aa_profile *aa_alloc_profile(const char *name);
 245 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat);
 246 void aa_free_profile(struct aa_profile *profile);
 247 void aa_free_profile_kref(struct kref *kref);
 248 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name);
 249 struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *name);
 250 struct aa_profile *aa_match_profile(struct aa_namespace *ns, const char *name);
 251
 252 ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace);
 253 ssize_t aa_remove_profiles(char *name, size_t size);
 254
 255 #define PROF_ADD 1
 256 #define PROF_REPLACE 0
 257
 258 #define unconfined(X) ((X)->mode == APPARMOR_UNCONFINED)
 259
 260
 261 static inline struct aa_profile *aa_deref_parent(struct aa_profile *p)
 262 {
 263         return rcu_dereference_protected(p->parent,
 264                                          mutex_is_locked(&p->ns->lock));
 265 }
 266
 267 /**
 268  * aa_get_profile - increment refcount on profile @p
 269  * @p: profile  (MAYBE NULL)
 270  *
 271  * Returns: pointer to @p if @p is NULL will return NULL
 272  * Requires: @p must be held with valid refcount when called
 273  */
 274 static inline struct aa_profile *aa_get_profile(struct aa_profile *p)
 275 {
 276         if (p)
 277                 kref_get(&(p->count));
 278
 279         return p;
 280 }
 281
 282 /**
 283  * aa_get_profile_not0 - increment refcount on profile @p found via lookup
 284  * @p: profile  (MAYBE NULL)
 285  *
 286  * Returns: pointer to @p if @p is NULL will return NULL
 287  * Requires: @p must be held with valid refcount when called
 288  */
 289 static inline struct aa_profile *aa_get_profile_not0(struct aa_profile *p)
 290 {
 291         if (p && kref_get_not0(&p->count))
 292                 return p;
 293
 294         return NULL;
 295 }
 296
 297 /**
 298  * aa_get_profile_rcu - increment a refcount profile that can be replaced
 299  * @p: pointer to profile that can be replaced (NOT NULL)
 300  *
 301  * Returns: pointer to a refcounted profile.
 302  *     else NULL if no profile
 303  */
 304 static inline struct aa_profile *aa_get_profile_rcu(struct aa_profile __rcu **p)
 305 {
 306         struct aa_profile *c;
 307
 308         rcu_read_lock();
 309         do {
 310                 c = rcu_dereference(*p);
 311         } while (c && !kref_get_not0(&c->count));
 312         rcu_read_unlock();
 313
 314         return c;
 315 }
 316
 317 /**
 318  * aa_get_newest_profile - find the newest version of @profile
 319  * @profile: the profile to check for newer versions of
 320  *
 321  * Returns: refcounted newest version of @profile taking into account
 322  *          replacement, renames and removals
 323  *          return @profile.
 324  */
 325 static inline struct aa_profile *aa_get_newest_profile(struct aa_profile *p)
 326 {
 327         if (!p)
 328                 return NULL;
 329
 330         if (PROFILE_INVALID(p))
 331                 return aa_get_profile_rcu(&p->replacedby->profile);
 332
 333         return aa_get_profile(p);
 334 }
 335
 336 /**
 337  * aa_put_profile - decrement refcount on profile @p
 338  * @p: profile  (MAYBE NULL)
 339  */
 340 static inline void aa_put_profile(struct aa_profile *p)
 341 {
 342         if (p)
 343                 kref_put(&p->count, aa_free_profile_kref);
 344 }
 345
 346 static inline struct aa_replacedby *aa_get_replacedby(struct aa_replacedby *p)
 347 {
 348         if (p)
 349                 kref_get(&(p->count));
 350
 351         return p;
 352 }
 353
 354 static inline void aa_put_replacedby(struct aa_replacedby *p)
 355 {
 356         if (p)
 357                 kref_put(&p->count, aa_free_replacedby_kref);
 358 }
 359
 360 /* requires profile list write lock held */
 361 static inline void __aa_update_replacedby(struct aa_profile *orig,
 362                                           struct aa_profile *new)
 363 {
 364         struct aa_profile *tmp;
 365         tmp = rcu_dereference_protected(orig->replacedby->profile,
 366                                         mutex_is_locked(&orig->ns->lock));
 367         rcu_assign_pointer(orig->replacedby->profile, aa_get_profile(new));
 368         orig->flags |= PFLAG_INVALID;
 369         aa_put_profile(tmp);
 370 }
 371
 372 /**
 373  * aa_get_namespace - increment references count on @ns
 374  * @ns: namespace to increment reference count of (MAYBE NULL)
 375  *
 376  * Returns: pointer to @ns, if @ns is NULL returns NULL
 377  * Requires: @ns must be held with valid refcount when called
 378  */
 379 static inline struct aa_namespace *aa_get_namespace(struct aa_namespace *ns)
 380 {
 381         if (ns)
 382                 aa_get_profile(ns->unconfined);
 383
 384         return ns;
 385 }
 386
 387 /**
 388  * aa_put_namespace - decrement refcount on @ns
 389  * @ns: namespace to put reference of
 390  *
 391  * Decrement reference count of @ns and if no longer in use free it
 392  */
 393 static inline void aa_put_namespace(struct aa_namespace *ns)
 394 {
 395         if (ns)
 396                 aa_put_profile(ns->unconfined);
 397 }
 398
 399 static inline int AUDIT_MODE(struct aa_profile *profile)
 400 {
 401         if (aa_g_audit != AUDIT_NORMAL)
 402                 return aa_g_audit;
 403
 404         return profile->audit;
 405 }
 406
 407 bool policy_view_capable(void);
 408 bool policy_admin_capable(void);
 409 bool aa_may_manage_policy(int op);
 410
 411 #endif /* __AA_POLICY_H */