security/apparmor/include/label.h

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor label definitions
   5  *
   6  * Copyright 2017 Canonical Ltd.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation, version 2 of the
  11  * License.
  12  */
  13
  14 #ifndef __AA_LABEL_H
  15 #define __AA_LABEL_H
  16
  17 #include <linux/atomic.h>
  18 #include <linux/audit.h>
  19 #include <linux/rbtree.h>
  20 #include <linux/rcupdate.h>
  21
  22 #include "apparmor.h"
  23 #include "lib.h"
  24
  25 struct aa_ns;
  26
  27 #define LOCAL_VEC_ENTRIES 8
  28 #define DEFINE_VEC(T, V)                                                \
  29         struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES];      \
  30         struct aa_ ## T **(V)
  31
  32 #define vec_setup(T, V, N, GFP)                                         \
  33 ({                                                                      \
  34         if ((N) <= LOCAL_VEC_ENTRIES) {                                 \
  35                 typeof(N) i;                                            \
  36                 (V) = (_ ## V ## _localtmp);                            \
  37                 for (i = 0; i < (N); i++)                               \
  38                         (V)[i] = NULL;                                  \
  39         } else                                                          \
  40                 (V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP));  \
  41         (V) ? 0 : -ENOMEM;                                              \
  42 })
  43
  44 #define vec_cleanup(T, V, N)                                            \
  45 do {                                                                    \
  46         int i;                                                          \
  47         for (i = 0; i < (N); i++) {                                     \
  48                 if (!IS_ERR_OR_NULL((V)[i]))                            \
  49                         aa_put_ ## T((V)[i]);                           \
  50         }                                                               \
  51         if ((V) != _ ## V ## _localtmp)                                 \
  52                 kfree(V);                                               \
  53 } while (0)
  54
  55 #define vec_last(VEC, SIZE) ((VEC)[(SIZE) - 1])
  56 #define vec_ns(VEC, SIZE) (vec_last((VEC), (SIZE))->ns)
  57 #define vec_labelset(VEC, SIZE) (&vec_ns((VEC), (SIZE))->labels)
  58 #define cleanup_domain_vec(V, L) cleanup_label_vec((V), (L)->size)
  59
  60 struct aa_profile;
  61 #define VEC_FLAG_TERMINATE 1
  62 int aa_vec_unique(struct aa_profile **vec, int n, int flags);
  63 struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,
  64                                              gfp_t gfp);
  65 #define aa_sort_and_merge_vec(N, V) \
  66         aa_sort_and_merge_profiles((N), (struct aa_profile **)(V))
  67
  68
  69 /* struct aa_labelset - set of labels for a namespace
  70  *
  71  * Labels are reference counted; aa_labelset does not contribute to label
  72  * reference counts. Once a label's last refcount is put it is removed from
  73  * the set.
  74  */
  75 struct aa_labelset {
  76         rwlock_t lock;
  77
  78         struct rb_root root;
  79 };
  80
  81 #define __labelset_for_each(LS, N) \
  82         for ((N) = rb_first(&(LS)->root); (N); (N) = rb_next(N))
  83
  84 void aa_labelset_destroy(struct aa_labelset *ls);
  85 void aa_labelset_init(struct aa_labelset *ls);
  86
  87
  88 enum label_flags {
  89         FLAG_HAT = 1,                   /* profile is a hat */
  90         FLAG_UNCONFINED = 2,            /* label unconfined only if all */
  91         FLAG_NULL = 4,                  /* profile is null learning profile */
  92         FLAG_IX_ON_NAME_ERROR = 8,      /* fallback to ix on name lookup fail */
  93         FLAG_IMMUTIBLE = 0x10,          /* don't allow changes/replacement */
  94         FLAG_USER_DEFINED = 0x20,       /* user based profile - lower privs */
  95         FLAG_NO_LIST_REF = 0x40,        /* list doesn't keep profile ref */
  96         FLAG_NS_COUNT = 0x80,           /* carries NS ref count */
  97         FLAG_IN_TREE = 0x100,           /* label is in tree */
  98         FLAG_PROFILE = 0x200,           /* label is a profile */
  99         FLAG_EXPLICIT = 0x400,          /* explicit static label */
 100         FLAG_STALE = 0x800,             /* replaced/removed */
 101         FLAG_RENAMED = 0x1000,          /* label has renaming in it */
 102         FLAG_REVOKED = 0x2000,          /* label has revocation in it */
 103
 104         /* These flags must correspond with PATH_flags */
 105         /* TODO: add new path flags */
 106 };
 107
 108 struct aa_label;
 109 struct aa_proxy {
 110         struct kref count;
 111         struct aa_label __rcu *label;
 112 };
 113
 114 struct label_it {
 115         int i, j;
 116 };
 117
 118 /* struct aa_label - lazy labeling struct
 119  * @count: ref count of active users
 120  * @node: rbtree position
 121  * @rcu: rcu callback struct
 122  * @proxy: is set to the label that replaced this label
 123  * @hname: text representation of the label (MAYBE_NULL)
 124  * @flags: stale and other flags - values may change under label set lock
 125  * @secid: secid that references this label
 126  * @size: number of entries in @ent[]
 127  * @ent: set of profiles for label, actual size determined by @size
 128  */
 129 struct aa_label {
 130         struct kref count;
 131         struct rb_node node;
 132         struct rcu_head rcu;
 133         struct aa_proxy *proxy;
 134         __counted char *hname;
 135         long flags;
 136         u32 secid;
 137         int size;
 138         struct aa_profile *vec[];
 139 };
 140
 141 #define last_error(E, FN)                               \
 142 do {                                                    \
 143         int __subE = (FN);                              \
 144         if (__subE)                                     \
 145                 (E) = __subE;                           \
 146 } while (0)
 147
 148 #define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
 149 #define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
 150 #define unconfined(X) label_unconfined(X)
 151 #define label_is_stale(X) ((X)->flags & FLAG_STALE)
 152 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
 153 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
 154 #define labels_set(X) (&labels_ns(X)->labels)
 155 #define labels_profile(X) ((X)->vec[(X)->size - 1])
 156
 157
 158 int aa_label_next_confined(struct aa_label *l, int i);
 159
 160 /* for each profile in a label */
 161 #define label_for_each(I, L, P)                                         \
 162         for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
 163
 164 /* assumes break/goto ended label_for_each */
 165 #define label_for_each_cont(I, L, P)                                    \
 166         for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
 167
 168 #define next_comb(I, L1, L2)                                            \
 169 do {                                                                    \
 170         (I).j++;                                                        \
 171         if ((I).j >= (L2)->size) {                                      \
 172                 (I).i++;                                                \
 173                 (I).j = 0;                                              \
 174         }                                                               \
 175 } while (0)
 176
 177
 178 /* for each combination of P1 in L1, and P2 in L2 */
 179 #define label_for_each_comb(I, L1, L2, P1, P2)                          \
 180 for ((I).i = (I).j = 0;                                                 \
 181         ((P1) = (L1)->vec[(I).i]) && ((P2) = (L2)->vec[(I).j]);         \
 182         (I) = next_comb(I, L1, L2))
 183
 184 #define fn_for_each_comb(L1, L2, P1, P2, FN)                            \
 185 ({                                                                      \
 186         struct label_it i;                                              \
 187         int __E = 0;                                                    \
 188         label_for_each_comb(i, (L1), (L2), (P1), (P2)) {                \
 189                 last_error(__E, (FN));                                  \
 190         }                                                               \
 191         __E;                                                            \
 192 })
 193
 194 /* for each profile that is enforcing confinement in a label */
 195 #define label_for_each_confined(I, L, P)                                \
 196         for ((I).i = aa_label_next_confined((L), 0);                    \
 197              ((P) = (L)->vec[(I).i]);                                   \
 198              (I).i = aa_label_next_confined((L), (I).i + 1))
 199
 200 #define label_for_each_in_merge(I, A, B, P)                             \
 201         for ((I).i = (I).j = 0;                                         \
 202              ((P) = aa_label_next_in_merge(&(I), (A), (B)));            \
 203              )
 204
 205 #define label_for_each_not_in_set(I, SET, SUB, P)                       \
 206         for ((I).i = (I).j = 0;                                         \
 207              ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));    \
 208              )
 209
 210 #define next_in_ns(i, NS, L)                                            \
 211 ({                                                                      \
 212         typeof(i) ___i = (i);                                           \
 213         while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))            \
 214                 (___i)++;                                               \
 215         (___i);                                                         \
 216 })
 217
 218 #define label_for_each_in_ns(I, NS, L, P)                               \
 219         for ((I).i = next_in_ns(0, (NS), (L));                          \
 220              ((P) = (L)->vec[(I).i]);                                   \
 221              (I).i = next_in_ns((I).i + 1, (NS), (L)))
 222
 223 #define fn_for_each_in_ns(L, P, FN)                                     \
 224 ({                                                                      \
 225         struct label_it __i;                                            \
 226         struct aa_ns *__ns = labels_ns(L);                              \
 227         int __E = 0;                                                    \
 228         label_for_each_in_ns(__i, __ns, (L), (P)) {                     \
 229                 last_error(__E, (FN));                                  \
 230         }                                                               \
 231         __E;                                                            \
 232 })
 233
 234
 235 #define fn_for_each_XXX(L, P, FN, ...)                                  \
 236 ({                                                                      \
 237         struct label_it i;                                              \
 238         int __E = 0;                                                    \
 239         label_for_each ## __VA_ARGS__(i, (L), (P)) {                    \
 240                 last_error(__E, (FN));                                  \
 241         }                                                               \
 242         __E;                                                            \
 243 })
 244
 245 #define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
 246 #define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
 247
 248 #define fn_for_each2_XXX(L1, L2, P, FN, ...)                            \
 249 ({                                                                      \
 250         struct label_it i;                                              \
 251         int __E = 0;                                                    \
 252         label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {             \
 253                 last_error(__E, (FN));                                  \
 254         }                                                               \
 255         __E;                                                            \
 256 })
 257
 258 #define fn_for_each_in_merge(L1, L2, P, FN)                             \
 259         fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
 260 #define fn_for_each_not_in_set(L1, L2, P, FN)                           \
 261         fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
 262
 263 #define LABEL_MEDIATES(L, C)                                            \
 264 ({                                                                      \
 265         struct aa_profile *profile;                                     \
 266         struct label_it i;                                              \
 267         int ret = 0;                                                    \
 268         label_for_each(i, (L), profile) {                               \
 269                 if (PROFILE_MEDIATES(profile, (C))) {                   \
 270                         ret = 1;                                        \
 271                         break;                                          \
 272                 }                                                       \
 273         }                                                               \
 274         ret;                                                            \
 275 })
 276
 277
 278 void aa_labelset_destroy(struct aa_labelset *ls);
 279 void aa_labelset_init(struct aa_labelset *ls);
 280 void __aa_labelset_update_subtree(struct aa_ns *ns);
 281
 282 void aa_label_free(struct aa_label *label);
 283 void aa_label_kref(struct kref *kref);
 284 bool aa_label_init(struct aa_label *label, int size, gfp_t gfp);
 285 struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
 286
 287 bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
 288 struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
 289                                              struct aa_label *set,
 290                                              struct aa_label *sub);
 291 bool aa_label_remove(struct aa_label *label);
 292 struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
 293 bool aa_label_replace(struct aa_label *old, struct aa_label *new);
 294 bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
 295                           struct aa_label *new);
 296
 297 struct aa_label *aa_label_find(struct aa_label *l);
 298
 299 struct aa_profile *aa_label_next_in_merge(struct label_it *I,
 300                                           struct aa_label *a,
 301                                           struct aa_label *b);
 302 struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
 303 struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
 304                                 gfp_t gfp);
 305
 306
 307 bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
 308
 309 #define FLAGS_NONE 0
 310 #define FLAG_SHOW_MODE 1
 311 #define FLAG_VIEW_SUBNS 2
 312 #define FLAG_HIDDEN_UNCONFINED 4
 313 #define FLAG_ABS_ROOT 8
 314 int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
 315                       struct aa_label *label, int flags);
 316 int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
 317                       int flags, gfp_t gfp);
 318 int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
 319                          struct aa_label *label, int flags, gfp_t gfp);
 320 void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
 321                      struct aa_label *label, int flags, gfp_t gfp);
 322 void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
 323                          struct aa_label *label, int flags, gfp_t gfp);
 324 void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
 325                       gfp_t gfp);
 326 void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp);
 327 void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp);
 328 void aa_label_printk(struct aa_label *label, gfp_t gfp);
 329
 330 struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
 331                                      size_t n, gfp_t gfp, bool create,
 332                                      bool force_stack);
 333 struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
 334                                 gfp_t gfp, bool create, bool force_stack);
 335
 336 static inline const char *aa_label_strn_split(const char *str, int n)
 337 {
 338         const char *pos;
 339         unsigned int state;
 340
 341         state = aa_dfa_matchn_until(stacksplitdfa, DFA_START, str, n, &pos);
 342         if (!ACCEPT_TABLE(stacksplitdfa)[state])
 343                 return NULL;
 344
 345         return pos - 3;
 346 }
 347
 348 static inline const char *aa_label_str_split(const char *str)
 349 {
 350         const char *pos;
 351         unsigned int state;
 352
 353         state = aa_dfa_match_until(stacksplitdfa, DFA_START, str, &pos);
 354         if (!ACCEPT_TABLE(stacksplitdfa)[state])
 355                 return NULL;
 356
 357         return pos - 3;
 358 }
 359
 360
 361
 362 struct aa_perms;
 363 int aa_label_match(struct aa_profile *profile, struct aa_label *label,
 364                    unsigned int state, bool subns, u32 request,
 365                    struct aa_perms *perms);
 366
 367
 368 /**
 369  * __aa_get_label - get a reference count to uncounted label reference
 370  * @l: reference to get a count on
 371  *
 372  * Returns: pointer to reference OR NULL if race is lost and reference is
 373  *          being repeated.
 374  * Requires: lock held, and the return code MUST be checked
 375  */
 376 static inline struct aa_label *__aa_get_label(struct aa_label *l)
 377 {
 378         if (l && kref_get_unless_zero(&l->count))
 379                 return l;
 380
 381         return NULL;
 382 }
 383
 384 static inline struct aa_label *aa_get_label(struct aa_label *l)
 385 {
 386         if (l)
 387                 kref_get(&(l->count));
 388
 389         return l;
 390 }
 391
 392
 393 /**
 394  * aa_get_label_rcu - increment refcount on a label that can be replaced
 395  * @l: pointer to label that can be replaced (NOT NULL)
 396  *
 397  * Returns: pointer to a refcounted label.
 398  *     else NULL if no label
 399  */
 400 static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
 401 {
 402         struct aa_label *c;
 403
 404         rcu_read_lock();
 405         do {
 406                 c = rcu_dereference(*l);
 407         } while (c && !kref_get_unless_zero(&c->count));
 408         rcu_read_unlock();
 409
 410         return c;
 411 }
 412
 413 /**
 414  * aa_get_newest_label - find the newest version of @l
 415  * @l: the label to check for newer versions of
 416  *
 417  * Returns: refcounted newest version of @l taking into account
 418  *          replacement, renames and removals
 419  *          return @l.
 420  */
 421 static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
 422 {
 423         if (!l)
 424                 return NULL;
 425
 426         if (label_is_stale(l)) {
 427                 struct aa_label *tmp;
 428
 429                 AA_BUG(!l->proxy);
 430                 AA_BUG(!l->proxy->label);
 431                 /* BUG: only way this can happen is @l ref count and its
 432                  * replacement count have gone to 0 and are on their way
 433                  * to destruction. ie. we have a refcounting error
 434                  */
 435                 tmp = aa_get_label_rcu(&l->proxy->label);
 436                 AA_BUG(!tmp);
 437
 438                 return tmp;
 439         }
 440
 441         return aa_get_label(l);
 442 }
 443
 444 static inline void aa_put_label(struct aa_label *l)
 445 {
 446         if (l)
 447                 kref_put(&l->count, aa_label_kref);
 448 }
 449
 450
 451 struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
 452 void aa_proxy_kref(struct kref *kref);
 453
 454 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
 455 {
 456         if (proxy)
 457                 kref_get(&(proxy->count));
 458
 459         return proxy;
 460 }
 461
 462 static inline void aa_put_proxy(struct aa_proxy *proxy)
 463 {
 464         if (proxy)
 465                 kref_put(&proxy->count, aa_proxy_kref);
 466 }
 467
 468 void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
 469
 470 #endif /* __AA_LABEL_H */