security/apparmor/include/label.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * AppArmor security module
   4  *
   5  * This file contains AppArmor label definitions
   6  *
   7  * Copyright 2017 Canonical Ltd.
   8  */
   9
  10 #ifndef __AA_LABEL_H
  11 #define __AA_LABEL_H
  12
  13 #include <linux/atomic.h>
  14 #include <linux/audit.h>
  15 #include <linux/rbtree.h>
  16 #include <linux/rcupdate.h>
  17
  18 #include "apparmor.h"
  19 #include "lib.h"
  20
  21 struct aa_ns;
  22
  23 #define LOCAL_VEC_ENTRIES 8
  24 #define DEFINE_VEC(T, V)                                                \
  25         struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES];      \
  26         struct aa_ ## T **(V)
  27
  28 #define vec_setup(T, V, N, GFP)                                         \
  29 ({                                                                      \
  30         if ((N) <= LOCAL_VEC_ENTRIES) {                                 \
  31                 typeof(N) i;                                            \
  32                 (V) = (_ ## V ## _localtmp);                            \
  33                 for (i = 0; i < (N); i++)                               \
  34                         (V)[i] = NULL;                                  \
  35         } else                                                          \
  36                 (V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP));  \
  37         (V) ? 0 : -ENOMEM;                                              \
  38 })
  39
  40 #define vec_cleanup(T, V, N)                                            \
  41 do {                                                                    \
  42         int i;                                                          \
  43         for (i = 0; i < (N); i++) {                                     \
  44                 if (!IS_ERR_OR_NULL((V)[i]))                            \
  45                         aa_put_ ## T((V)[i]);                           \
  46         }                                                               \
  47         if ((V) != _ ## V ## _localtmp)                                 \
  48                 kfree(V);                                               \
  49 } while (0)
  50
  51 #define vec_last(VEC, SIZE) ((VEC)[(SIZE) - 1])
  52 #define vec_ns(VEC, SIZE) (vec_last((VEC), (SIZE))->ns)
  53 #define vec_labelset(VEC, SIZE) (&vec_ns((VEC), (SIZE))->labels)
  54 #define cleanup_domain_vec(V, L) cleanup_label_vec((V), (L)->size)
  55
  56 struct aa_profile;
  57 #define VEC_FLAG_TERMINATE 1
  58 int aa_vec_unique(struct aa_profile **vec, int n, int flags);
  59 struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,
  60                                              gfp_t gfp);
  61 #define aa_sort_and_merge_vec(N, V) \
  62         aa_sort_and_merge_profiles((N), (struct aa_profile **)(V))
  63
  64
  65 /* struct aa_labelset - set of labels for a namespace
  66  *
  67  * Labels are reference counted; aa_labelset does not contribute to label
  68  * reference counts. Once a label's last refcount is put it is removed from
  69  * the set.
  70  */
  71 struct aa_labelset {
  72         rwlock_t lock;
  73
  74         struct rb_root root;
  75 };
  76
  77 #define __labelset_for_each(LS, N) \
  78         for ((N) = rb_first(&(LS)->root); (N); (N) = rb_next(N))
  79
  80 void aa_labelset_destroy(struct aa_labelset *ls);
  81 void aa_labelset_init(struct aa_labelset *ls);
  82
  83
  84 enum label_flags {
  85         FLAG_HAT = 1,                   /* profile is a hat */
  86         FLAG_UNCONFINED = 2,            /* label unconfined only if all */
  87         FLAG_NULL = 4,                  /* profile is null learning profile */
  88         FLAG_IX_ON_NAME_ERROR = 8,      /* fallback to ix on name lookup fail */
  89         FLAG_IMMUTIBLE = 0x10,          /* don't allow changes/replacement */
  90         FLAG_USER_DEFINED = 0x20,       /* user based profile - lower privs */
  91         FLAG_NO_LIST_REF = 0x40,        /* list doesn't keep profile ref */
  92         FLAG_NS_COUNT = 0x80,           /* carries NS ref count */
  93         FLAG_IN_TREE = 0x100,           /* label is in tree */
  94         FLAG_PROFILE = 0x200,           /* label is a profile */
  95         FLAG_EXPLICIT = 0x400,          /* explicit static label */
  96         FLAG_STALE = 0x800,             /* replaced/removed */
  97         FLAG_RENAMED = 0x1000,          /* label has renaming in it */
  98         FLAG_REVOKED = 0x2000,          /* label has revocation in it */
  99
 100         /* These flags must correspond with PATH_flags */
 101         /* TODO: add new path flags */
 102 };
 103
 104 struct aa_label;
 105 struct aa_proxy {
 106         struct kref count;
 107         struct aa_label __rcu *label;
 108 };
 109
 110 struct label_it {
 111         int i, j;
 112 };
 113
 114 /* struct aa_label - lazy labeling struct
 115  * @count: ref count of active users
 116  * @node: rbtree position
 117  * @rcu: rcu callback struct
 118  * @proxy: is set to the label that replaced this label
 119  * @hname: text representation of the label (MAYBE_NULL)
 120  * @flags: stale and other flags - values may change under label set lock
 121  * @secid: secid that references this label
 122  * @size: number of entries in @ent[]
 123  * @ent: set of profiles for label, actual size determined by @size
 124  */
 125 struct aa_label {
 126         struct kref count;
 127         struct rb_node node;
 128         struct rcu_head rcu;
 129         struct aa_proxy *proxy;
 130         __counted char *hname;
 131         long flags;
 132         u32 secid;
 133         int size;
 134         struct aa_profile *vec[];
 135 };
 136
 137 #define last_error(E, FN)                               \
 138 do {                                                    \
 139         int __subE = (FN);                              \
 140         if (__subE)                                     \
 141                 (E) = __subE;                           \
 142 } while (0)
 143
 144 #define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
 145 #define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
 146 #define unconfined(X) label_unconfined(X)
 147 #define label_is_stale(X) ((X)->flags & FLAG_STALE)
 148 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
 149 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
 150 #define labels_set(X) (&labels_ns(X)->labels)
 151 #define labels_profile(X) ((X)->vec[(X)->size - 1])
 152
 153
 154 int aa_label_next_confined(struct aa_label *l, int i);
 155
 156 /* for each profile in a label */
 157 #define label_for_each(I, L, P)                                         \
 158         for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
 159
 160 /* assumes break/goto ended label_for_each */
 161 #define label_for_each_cont(I, L, P)                                    \
 162         for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
 163
 164 #define next_comb(I, L1, L2)                                            \
 165 do {                                                                    \
 166         (I).j++;                                                        \
 167         if ((I).j >= (L2)->size) {                                      \
 168                 (I).i++;                                                \
 169                 (I).j = 0;                                              \
 170         }                                                               \
 171 } while (0)
 172
 173
 174 /* for each combination of P1 in L1, and P2 in L2 */
 175 #define label_for_each_comb(I, L1, L2, P1, P2)                          \
 176 for ((I).i = (I).j = 0;                                                 \
 177         ((P1) = (L1)->vec[(I).i]) && ((P2) = (L2)->vec[(I).j]);         \
 178         (I) = next_comb(I, L1, L2))
 179
 180 #define fn_for_each_comb(L1, L2, P1, P2, FN)                            \
 181 ({                                                                      \
 182         struct label_it i;                                              \
 183         int __E = 0;                                                    \
 184         label_for_each_comb(i, (L1), (L2), (P1), (P2)) {                \
 185                 last_error(__E, (FN));                                  \
 186         }                                                               \
 187         __E;                                                            \
 188 })
 189
 190 /* for each profile that is enforcing confinement in a label */
 191 #define label_for_each_confined(I, L, P)                                \
 192         for ((I).i = aa_label_next_confined((L), 0);                    \
 193              ((P) = (L)->vec[(I).i]);                                   \
 194              (I).i = aa_label_next_confined((L), (I).i + 1))
 195
 196 #define label_for_each_in_merge(I, A, B, P)                             \
 197         for ((I).i = (I).j = 0;                                         \
 198              ((P) = aa_label_next_in_merge(&(I), (A), (B)));            \
 199              )
 200
 201 #define label_for_each_not_in_set(I, SET, SUB, P)                       \
 202         for ((I).i = (I).j = 0;                                         \
 203              ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));    \
 204              )
 205
 206 #define next_in_ns(i, NS, L)                                            \
 207 ({                                                                      \
 208         typeof(i) ___i = (i);                                           \
 209         while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))            \
 210                 (___i)++;                                               \
 211         (___i);                                                         \
 212 })
 213
 214 #define label_for_each_in_ns(I, NS, L, P)                               \
 215         for ((I).i = next_in_ns(0, (NS), (L));                          \
 216              ((P) = (L)->vec[(I).i]);                                   \
 217              (I).i = next_in_ns((I).i + 1, (NS), (L)))
 218
 219 #define fn_for_each_in_ns(L, P, FN)                                     \
 220 ({                                                                      \
 221         struct label_it __i;                                            \
 222         struct aa_ns *__ns = labels_ns(L);                              \
 223         int __E = 0;                                                    \
 224         label_for_each_in_ns(__i, __ns, (L), (P)) {                     \
 225                 last_error(__E, (FN));                                  \
 226         }                                                               \
 227         __E;                                                            \
 228 })
 229
 230
 231 #define fn_for_each_XXX(L, P, FN, ...)                                  \
 232 ({                                                                      \
 233         struct label_it i;                                              \
 234         int __E = 0;                                                    \
 235         label_for_each ## __VA_ARGS__(i, (L), (P)) {                    \
 236                 last_error(__E, (FN));                                  \
 237         }                                                               \
 238         __E;                                                            \
 239 })
 240
 241 #define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
 242 #define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
 243
 244 #define fn_for_each2_XXX(L1, L2, P, FN, ...)                            \
 245 ({                                                                      \
 246         struct label_it i;                                              \
 247         int __E = 0;                                                    \
 248         label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {             \
 249                 last_error(__E, (FN));                                  \
 250         }                                                               \
 251         __E;                                                            \
 252 })
 253
 254 #define fn_for_each_in_merge(L1, L2, P, FN)                             \
 255         fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
 256 #define fn_for_each_not_in_set(L1, L2, P, FN)                           \
 257         fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
 258
 259 #define LABEL_MEDIATES(L, C)                                            \
 260 ({                                                                      \
 261         struct aa_profile *profile;                                     \
 262         struct label_it i;                                              \
 263         int ret = 0;                                                    \
 264         label_for_each(i, (L), profile) {                               \
 265                 if (PROFILE_MEDIATES(profile, (C))) {                   \
 266                         ret = 1;                                        \
 267                         break;                                          \
 268                 }                                                       \
 269         }                                                               \
 270         ret;                                                            \
 271 })
 272
 273
 274 void aa_labelset_destroy(struct aa_labelset *ls);
 275 void aa_labelset_init(struct aa_labelset *ls);
 276 void __aa_labelset_update_subtree(struct aa_ns *ns);
 277
 278 void aa_label_destroy(struct aa_label *label);
 279 void aa_label_free(struct aa_label *label);
 280 void aa_label_kref(struct kref *kref);
 281 bool aa_label_init(struct aa_label *label, int size, gfp_t gfp);
 282 struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
 283
 284 bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
 285 bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub);
 286 struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
 287                                              struct aa_label *set,
 288                                              struct aa_label *sub);
 289 bool aa_label_remove(struct aa_label *label);
 290 struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
 291 bool aa_label_replace(struct aa_label *old, struct aa_label *new);
 292 bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
 293                           struct aa_label *new);
 294
 295 struct aa_label *aa_label_find(struct aa_label *l);
 296
 297 struct aa_profile *aa_label_next_in_merge(struct label_it *I,
 298                                           struct aa_label *a,
 299                                           struct aa_label *b);
 300 struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
 301 struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
 302                                 gfp_t gfp);
 303
 304
 305 bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
 306
 307 #define FLAGS_NONE 0
 308 #define FLAG_SHOW_MODE 1
 309 #define FLAG_VIEW_SUBNS 2
 310 #define FLAG_HIDDEN_UNCONFINED 4
 311 #define FLAG_ABS_ROOT 8
 312 int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
 313                       struct aa_label *label, int flags);
 314 int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
 315                       int flags, gfp_t gfp);
 316 int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
 317                          struct aa_label *label, int flags, gfp_t gfp);
 318 void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
 319                      struct aa_label *label, int flags, gfp_t gfp);
 320 void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
 321                          struct aa_label *label, int flags, gfp_t gfp);
 322 void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
 323                       gfp_t gfp);
 324 void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp);
 325 void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp);
 326 void aa_label_printk(struct aa_label *label, gfp_t gfp);
 327
 328 struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
 329                                      size_t n, gfp_t gfp, bool create,
 330                                      bool force_stack);
 331 struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
 332                                 gfp_t gfp, bool create, bool force_stack);
 333
 334 static inline const char *aa_label_strn_split(const char *str, int n)
 335 {
 336         const char *pos;
 337         unsigned int state;
 338
 339         state = aa_dfa_matchn_until(stacksplitdfa, DFA_START, str, n, &pos);
 340         if (!ACCEPT_TABLE(stacksplitdfa)[state])
 341                 return NULL;
 342
 343         return pos - 3;
 344 }
 345
 346 static inline const char *aa_label_str_split(const char *str)
 347 {
 348         const char *pos;
 349         unsigned int state;
 350
 351         state = aa_dfa_match_until(stacksplitdfa, DFA_START, str, &pos);
 352         if (!ACCEPT_TABLE(stacksplitdfa)[state])
 353                 return NULL;
 354
 355         return pos - 3;
 356 }
 357
 358
 359
 360 struct aa_perms;
 361 int aa_label_match(struct aa_profile *profile, struct aa_label *label,
 362                    unsigned int state, bool subns, u32 request,
 363                    struct aa_perms *perms);
 364
 365
 366 /**
 367  * __aa_get_label - get a reference count to uncounted label reference
 368  * @l: reference to get a count on
 369  *
 370  * Returns: pointer to reference OR NULL if race is lost and reference is
 371  *          being repeated.
 372  * Requires: lock held, and the return code MUST be checked
 373  */
 374 static inline struct aa_label *__aa_get_label(struct aa_label *l)
 375 {
 376         if (l && kref_get_unless_zero(&l->count))
 377                 return l;
 378
 379         return NULL;
 380 }
 381
 382 static inline struct aa_label *aa_get_label(struct aa_label *l)
 383 {
 384         if (l)
 385                 kref_get(&(l->count));
 386
 387         return l;
 388 }
 389
 390
 391 /**
 392  * aa_get_label_rcu - increment refcount on a label that can be replaced
 393  * @l: pointer to label that can be replaced (NOT NULL)
 394  *
 395  * Returns: pointer to a refcounted label.
 396  *     else NULL if no label
 397  */
 398 static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
 399 {
 400         struct aa_label *c;
 401
 402         rcu_read_lock();
 403         do {
 404                 c = rcu_dereference(*l);
 405         } while (c && !kref_get_unless_zero(&c->count));
 406         rcu_read_unlock();
 407
 408         return c;
 409 }
 410
 411 /**
 412  * aa_get_newest_label - find the newest version of @l
 413  * @l: the label to check for newer versions of
 414  *
 415  * Returns: refcounted newest version of @l taking into account
 416  *          replacement, renames and removals
 417  *          return @l.
 418  */
 419 static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
 420 {
 421         if (!l)
 422                 return NULL;
 423
 424         if (label_is_stale(l)) {
 425                 struct aa_label *tmp;
 426
 427                 AA_BUG(!l->proxy);
 428                 AA_BUG(!l->proxy->label);
 429                 /* BUG: only way this can happen is @l ref count and its
 430                  * replacement count have gone to 0 and are on their way
 431                  * to destruction. ie. we have a refcounting error
 432                  */
 433                 tmp = aa_get_label_rcu(&l->proxy->label);
 434                 AA_BUG(!tmp);
 435
 436                 return tmp;
 437         }
 438
 439         return aa_get_label(l);
 440 }
 441
 442 static inline void aa_put_label(struct aa_label *l)
 443 {
 444         if (l)
 445                 kref_put(&l->count, aa_label_kref);
 446 }
 447
 448
 449 struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
 450 void aa_proxy_kref(struct kref *kref);
 451
 452 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
 453 {
 454         if (proxy)
 455                 kref_get(&(proxy->count));
 456
 457         return proxy;
 458 }
 459
 460 static inline void aa_put_proxy(struct aa_proxy *proxy)
 461 {
 462         if (proxy)
 463                 kref_put(&proxy->count, aa_proxy_kref);
 464 }
 465
 466 void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
 467
 468 #endif /* __AA_LABEL_H */