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 "resource.h"
  31
  32 extern const char *const aa_profile_mode_names[];
  33 #define APPARMOR_MODE_NAMES_MAX_INDEX 4
  34
  35 #define PROFILE_MODE(_profile, _mode)           \
  36         ((aa_g_profile_mode == (_mode)) ||      \
  37          ((_profile)->mode == (_mode)))
  38
  39 #define COMPLAIN_MODE(_profile) PROFILE_MODE((_profile), APPARMOR_COMPLAIN)
  40
  41 #define KILL_MODE(_profile) PROFILE_MODE((_profile), APPARMOR_KILL)
  42
  43 #define PROFILE_IS_HAT(_profile) ((_profile)->flags & PFLAG_HAT)
  44
  45 #define PROFILE_INVALID(_profile) ((_profile)->flags & PFLAG_INVALID)
  46
  47 #define on_list_rcu(X) (!list_empty(X) && (X)->prev != LIST_POISON2)
  48
  49 /*
  50  * FIXME: currently need a clean way to replace and remove profiles as a
  51  * set.  It should be done at the namespace level.
  52  * Either, with a set of profiles loaded at the namespace level or via
  53  * a mark and remove marked interface.
  54  */
  55 enum profile_mode {
  56         APPARMOR_ENFORCE,       /* enforce access rules */
  57         APPARMOR_COMPLAIN,      /* allow and log access violations */
  58         APPARMOR_KILL,          /* kill task on access violation */
  59         APPARMOR_UNCONFINED,    /* profile set to unconfined */
  60 };
  61
  62 enum profile_flags {
  63         PFLAG_HAT = 1,                  /* profile is a hat */
  64         PFLAG_NULL = 4,                 /* profile is null learning profile */
  65         PFLAG_IX_ON_NAME_ERROR = 8,     /* fallback to ix on name lookup fail */
  66         PFLAG_IMMUTABLE = 0x10,         /* don't allow changes/replacement */
  67         PFLAG_USER_DEFINED = 0x20,      /* user based profile - lower privs */
  68         PFLAG_NO_LIST_REF = 0x40,       /* list doesn't keep profile ref */
  69         PFLAG_OLD_NULL_TRANS = 0x100,   /* use // as the null transition */
  70         PFLAG_INVALID = 0x200,          /* profile replaced/removed */
  71         PFLAG_NS_COUNT = 0x400,         /* carries NS ref count */
  72
  73         /* These flags must correspond with PATH_flags */
  74         PFLAG_MEDIATE_DELETED = 0x10000, /* mediate instead delegate deleted */
  75 };
  76
  77 struct aa_profile;
  78
  79 /* struct aa_policy - common part of both namespaces and profiles
  80  * @name: name of the object
  81  * @hname - The hierarchical name
  82  * @list: list policy object is on
  83  * @profiles: head of the profiles list contained in the object
  84  */
  85 struct aa_policy {
  86         char *name;
  87         char *hname;
  88         struct list_head list;
  89         struct list_head profiles;
  90 };
  91
  92 /* struct aa_ns_acct - accounting of profiles in namespace
  93  * @max_size: maximum space allowed for all profiles in namespace
  94  * @max_count: maximum number of profiles that can be in this namespace
  95  * @size: current size of profiles
  96  * @count: current count of profiles (includes null profiles)
  97  */
  98 struct aa_ns_acct {
  99         int max_size;
 100         int max_count;
 101         int size;
 102         int count;
 103 };
 104
 105 /* struct aa_namespace - namespace for a set of profiles
 106  * @base: common policy
 107  * @parent: parent of namespace
 108  * @lock: lock for modifying the object
 109  * @acct: accounting for the namespace
 110  * @unconfined: special unconfined profile for the namespace
 111  * @sub_ns: list of namespaces under the current namespace.
 112  * @uniq_null: uniq value used for null learning profiles
 113  * @uniq_id: a unique id count for the profiles in the namespace
 114  * @dents: dentries for the namespaces file entries in apparmorfs
 115  *
 116  * An aa_namespace defines the set profiles that are searched to determine
 117  * which profile to attach to a task.  Profiles can not be shared between
 118  * aa_namespaces and profile names within a namespace are guaranteed to be
 119  * unique.  When profiles in separate namespaces have the same name they
 120  * are NOT considered to be equivalent.
 121  *
 122  * Namespaces are hierarchical and only namespaces and profiles below the
 123  * current namespace are visible.
 124  *
 125  * Namespace names must be unique and can not contain the characters :/\0
 126  *
 127  * FIXME TODO: add vserver support of namespaces (can it all be done in
 128  *             userspace?)
 129  */
 130 struct aa_namespace {
 131         struct aa_policy base;
 132         struct aa_namespace *parent;
 133         struct mutex lock;
 134         struct aa_ns_acct acct;
 135         struct aa_profile *unconfined;
 136         struct list_head sub_ns;
 137         atomic_t uniq_null;
 138         long uniq_id;
 139
 140         struct dentry *dents[AAFS_NS_SIZEOF];
 141 };
 142
 143 /* struct aa_policydb - match engine for a policy
 144  * dfa: dfa pattern match
 145  * start: set of start states for the different classes of data
 146  */
 147 struct aa_policydb {
 148         /* Generic policy DFA specific rule types will be subsections of it */
 149         struct aa_dfa *dfa;
 150         unsigned int start[AA_CLASS_LAST + 1];
 151
 152 };
 153
 154 struct aa_replacedby {
 155         struct kref count;
 156         struct aa_profile __rcu *profile;
 157 };
 158
 159
 160 /* struct aa_profile - basic confinement data
 161  * @base - base components of the profile (name, refcount, lists, lock ...)
 162  * @count: reference count of the obj
 163  * @rcu: rcu head used when removing from @list
 164  * @parent: parent of profile
 165  * @ns: namespace the profile is in
 166  * @replacedby: is set to the profile that replaced this profile
 167  * @rename: optional profile name that this profile renamed
 168  * @attach: human readable attachment string
 169  * @xmatch: optional extended matching for unconfined executables names
 170  * @xmatch_len: xmatch prefix len, used to determine xmatch priority
 171  * @audit: the auditing mode of the profile
 172  * @mode: the enforcement mode of the profile
 173  * @flags: flags controlling profile behavior
 174  * @path_flags: flags controlling path generation behavior
 175  * @size: the memory consumed by this profiles rules
 176  * @policy: general match rules governing policy
 177  * @file: The set of rules governing basic file access and domain transitions
 178  * @caps: capabilities for the profile
 179  * @rlimits: rlimits for the profile
 180  *
 181  * @dents: dentries for the profiles file entries in apparmorfs
 182  * @dirname: name of the profile dir in apparmorfs
 183  *
 184  * The AppArmor profile contains the basic confinement data.  Each profile
 185  * has a name, and exists in a namespace.  The @name and @exec_match are
 186  * used to determine profile attachment against unconfined tasks.  All other
 187  * attachments are determined by profile X transition rules.
 188  *
 189  * The @replacedby struct is write protected by the profile lock.
 190  *
 191  * Profiles have a hierarchy where hats and children profiles keep
 192  * a reference to their parent.
 193  *
 194  * Profile names can not begin with a : and can not contain the \0
 195  * character.  If a profile name begins with / it will be considered when
 196  * determining profile attachment on "unconfined" tasks.
 197  */
 198 struct aa_profile {
 199         struct aa_policy base;
 200         struct kref count;
 201         struct rcu_head rcu;
 202         struct aa_profile __rcu *parent;
 203
 204         struct aa_namespace *ns;
 205         struct aa_replacedby *replacedby;
 206         const char *rename;
 207
 208         const char *attach;
 209         struct aa_dfa *xmatch;
 210         int xmatch_len;
 211         enum audit_mode audit;
 212         long mode;
 213         long flags;
 214         u32 path_flags;
 215         int size;
 216
 217         struct aa_policydb policy;
 218         struct aa_file_rules file;
 219         struct aa_caps caps;
 220         struct aa_rlimit rlimits;
 221
 222         unsigned char *hash;
 223         char *dirname;
 224         struct dentry *dents[AAFS_PROF_SIZEOF];
 225 };
 226
 227 extern struct aa_namespace *root_ns;
 228 extern enum profile_mode aa_g_profile_mode;
 229
 230 void aa_add_profile(struct aa_policy *common, struct aa_profile *profile);
 231
 232 bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view);
 233 const char *aa_ns_name(struct aa_namespace *parent, struct aa_namespace *child);
 234 int aa_alloc_root_ns(void);
 235 void aa_free_root_ns(void);
 236 void aa_free_namespace_kref(struct kref *kref);
 237
 238 struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
 239                                        const char *name);
 240
 241
 242 void aa_free_replacedby_kref(struct kref *kref);
 243 struct aa_profile *aa_alloc_profile(const char *name);
 244 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat);
 245 void aa_free_profile(struct aa_profile *profile);
 246 void aa_free_profile_kref(struct kref *kref);
 247 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name);
 248 struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *name);
 249 struct aa_profile *aa_match_profile(struct aa_namespace *ns, const char *name);
 250
 251 ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace);
 252 ssize_t aa_remove_profiles(char *name, size_t size);
 253
 254 #define PROF_ADD 1
 255 #define PROF_REPLACE 0
 256
 257 #define unconfined(X) ((X)->mode == APPARMOR_UNCONFINED)
 258
 259
 260 static inline struct aa_profile *aa_deref_parent(struct aa_profile *p)
 261 {
 262         return rcu_dereference_protected(p->parent,
 263                                          mutex_is_locked(&p->ns->lock));
 264 }
 265
 266 /**
 267  * aa_get_profile - increment refcount on profile @p
 268  * @p: profile  (MAYBE NULL)
 269  *
 270  * Returns: pointer to @p if @p is NULL will return NULL
 271  * Requires: @p must be held with valid refcount when called
 272  */
 273 static inline struct aa_profile *aa_get_profile(struct aa_profile *p)
 274 {
 275         if (p)
 276                 kref_get(&(p->count));
 277
 278         return p;
 279 }
 280
 281 /**
 282  * aa_get_profile_not0 - increment refcount on profile @p found via lookup
 283  * @p: profile  (MAYBE NULL)
 284  *
 285  * Returns: pointer to @p if @p is NULL will return NULL
 286  * Requires: @p must be held with valid refcount when called
 287  */
 288 static inline struct aa_profile *aa_get_profile_not0(struct aa_profile *p)
 289 {
 290         if (p && kref_get_not0(&p->count))
 291                 return p;
 292
 293         return NULL;
 294 }
 295
 296 /**
 297  * aa_get_profile_rcu - increment a refcount profile that can be replaced
 298  * @p: pointer to profile that can be replaced (NOT NULL)
 299  *
 300  * Returns: pointer to a refcounted profile.
 301  *     else NULL if no profile
 302  */
 303 static inline struct aa_profile *aa_get_profile_rcu(struct aa_profile __rcu **p)
 304 {
 305         struct aa_profile *c;
 306
 307         rcu_read_lock();
 308         do {
 309                 c = rcu_dereference(*p);
 310         } while (c && !kref_get_not0(&c->count));
 311         rcu_read_unlock();
 312
 313         return c;
 314 }
 315
 316 /**
 317  * aa_get_newest_profile - find the newest version of @profile
 318  * @profile: the profile to check for newer versions of
 319  *
 320  * Returns: refcounted newest version of @profile taking into account
 321  *          replacement, renames and removals
 322  *          return @profile.
 323  */
 324 static inline struct aa_profile *aa_get_newest_profile(struct aa_profile *p)
 325 {
 326         if (!p)
 327                 return NULL;
 328
 329         if (PROFILE_INVALID(p))
 330                 return aa_get_profile_rcu(&p->replacedby->profile);
 331
 332         return aa_get_profile(p);
 333 }
 334
 335 /**
 336  * aa_put_profile - decrement refcount on profile @p
 337  * @p: profile  (MAYBE NULL)
 338  */
 339 static inline void aa_put_profile(struct aa_profile *p)
 340 {
 341         if (p)
 342                 kref_put(&p->count, aa_free_profile_kref);
 343 }
 344
 345 static inline struct aa_replacedby *aa_get_replacedby(struct aa_replacedby *p)
 346 {
 347         if (p)
 348                 kref_get(&(p->count));
 349
 350         return p;
 351 }
 352
 353 static inline void aa_put_replacedby(struct aa_replacedby *p)
 354 {
 355         if (p)
 356                 kref_put(&p->count, aa_free_replacedby_kref);
 357 }
 358
 359 /* requires profile list write lock held */
 360 static inline void __aa_update_replacedby(struct aa_profile *orig,
 361                                           struct aa_profile *new)
 362 {
 363         struct aa_profile *tmp;
 364         tmp = rcu_dereference_protected(orig->replacedby->profile,
 365                                         mutex_is_locked(&orig->ns->lock));
 366         rcu_assign_pointer(orig->replacedby->profile, aa_get_profile(new));
 367         orig->flags |= PFLAG_INVALID;
 368         aa_put_profile(tmp);
 369 }
 370
 371 /**
 372  * aa_get_namespace - increment references count on @ns
 373  * @ns: namespace to increment reference count of (MAYBE NULL)
 374  *
 375  * Returns: pointer to @ns, if @ns is NULL returns NULL
 376  * Requires: @ns must be held with valid refcount when called
 377  */
 378 static inline struct aa_namespace *aa_get_namespace(struct aa_namespace *ns)
 379 {
 380         if (ns)
 381                 aa_get_profile(ns->unconfined);
 382
 383         return ns;
 384 }
 385
 386 /**
 387  * aa_put_namespace - decrement refcount on @ns
 388  * @ns: namespace to put reference of
 389  *
 390  * Decrement reference count of @ns and if no longer in use free it
 391  */
 392 static inline void aa_put_namespace(struct aa_namespace *ns)
 393 {
 394         if (ns)
 395                 aa_put_profile(ns->unconfined);
 396 }
 397
 398 static inline int AUDIT_MODE(struct aa_profile *profile)
 399 {
 400         if (aa_g_audit != AUDIT_NORMAL)
 401                 return aa_g_audit;
 402
 403         return profile->audit;
 404 }
 405
 406 bool aa_may_manage_policy(int op);
 407
 408 #endif /* __AA_POLICY_H */