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 enum label_flags {
  81         FLAG_HAT = 1,                   /* profile is a hat */
  82         FLAG_UNCONFINED = 2,            /* label unconfined only if all */
  83         FLAG_NULL = 4,                  /* profile is null learning profile */
  84         FLAG_IX_ON_NAME_ERROR = 8,      /* fallback to ix on name lookup fail */
  85         FLAG_IMMUTIBLE = 0x10,          /* don't allow changes/replacement */
  86         FLAG_USER_DEFINED = 0x20,       /* user based profile - lower privs */
  87         FLAG_NO_LIST_REF = 0x40,        /* list doesn't keep profile ref */
  88         FLAG_NS_COUNT = 0x80,           /* carries NS ref count */
  89         FLAG_IN_TREE = 0x100,           /* label is in tree */
  90         FLAG_PROFILE = 0x200,           /* label is a profile */
  91         FLAG_EXPLICIT = 0x400,          /* explicit static label */
  92         FLAG_STALE = 0x800,             /* replaced/removed */
  93         FLAG_RENAMED = 0x1000,          /* label has renaming in it */
  94         FLAG_REVOKED = 0x2000,          /* label has revocation in it */
  95         FLAG_DEBUG1 = 0x4000,
  96         FLAG_DEBUG2 = 0x8000,
  97
  98         /* These flags must correspond with PATH_flags */
  99         /* TODO: add new path flags */
 100 };
 101
 102 struct aa_label;
 103 struct aa_proxy {
 104         struct kref count;
 105         struct aa_label __rcu *label;
 106 };
 107
 108 struct label_it {
 109         int i, j;
 110 };
 111
 112 /* struct aa_label - lazy labeling struct
 113  * @count: ref count of active users
 114  * @node: rbtree position
 115  * @rcu: rcu callback struct
 116  * @proxy: is set to the label that replaced this label
 117  * @hname: text representation of the label (MAYBE_NULL)
 118  * @flags: stale and other flags - values may change under label set lock
 119  * @secid: secid that references this label
 120  * @size: number of entries in @ent[]
 121  * @ent: set of profiles for label, actual size determined by @size
 122  */
 123 struct aa_label {
 124         struct kref count;
 125         struct rb_node node;
 126         struct rcu_head rcu;
 127         struct aa_proxy *proxy;
 128         __counted char *hname;
 129         long flags;
 130         u32 secid;
 131         int size;
 132         struct aa_profile *vec[];
 133 };
 134
 135 #define last_error(E, FN)                               \
 136 do {                                                    \
 137         int __subE = (FN);                              \
 138         if (__subE)                                     \
 139                 (E) = __subE;                           \
 140 } while (0)
 141
 142 #define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
 143 #define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
 144 #define unconfined(X) label_unconfined(X)
 145 #define label_is_stale(X) ((X)->flags & FLAG_STALE)
 146 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
 147 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
 148 #define labels_set(X) (&labels_ns(X)->labels)
 149 #define labels_view(X) labels_ns(X)
 150 #define labels_profile(X) ((X)->vec[(X)->size - 1])
 151
 152
 153 int aa_label_next_confined(struct aa_label *l, int i);
 154
 155 /* for each profile in a label */
 156 #define label_for_each(I, L, P)                                         \
 157         for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
 158
 159 /* assumes break/goto ended label_for_each */
 160 #define label_for_each_cont(I, L, P)                                    \
 161         for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
 162
 163
 164
 165 /* for each profile that is enforcing confinement in a label */
 166 #define label_for_each_confined(I, L, P)                                \
 167         for ((I).i = aa_label_next_confined((L), 0);                    \
 168              ((P) = (L)->vec[(I).i]);                                   \
 169              (I).i = aa_label_next_confined((L), (I).i + 1))
 170
 171 #define label_for_each_in_merge(I, A, B, P)                             \
 172         for ((I).i = (I).j = 0;                                         \
 173              ((P) = aa_label_next_in_merge(&(I), (A), (B)));            \
 174              )
 175
 176 #define label_for_each_not_in_set(I, SET, SUB, P)                       \
 177         for ((I).i = (I).j = 0;                                         \
 178              ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));    \
 179              )
 180
 181 #define next_in_ns(i, NS, L)                                            \
 182 ({                                                                      \
 183         typeof(i) ___i = (i);                                           \
 184         while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))            \
 185                 (___i)++;                                               \
 186         (___i);                                                         \
 187 })
 188
 189 #define label_for_each_in_ns(I, NS, L, P)                               \
 190         for ((I).i = next_in_ns(0, (NS), (L));                          \
 191              ((P) = (L)->vec[(I).i]);                                   \
 192              (I).i = next_in_ns((I).i + 1, (NS), (L)))
 193
 194 #define fn_for_each_in_ns(L, P, FN)                                     \
 195 ({                                                                      \
 196         struct label_it __i;                                            \
 197         struct aa_ns *__ns = labels_ns(L);                              \
 198         int __E = 0;                                                    \
 199         label_for_each_in_ns(__i, __ns, (L), (P)) {                     \
 200                 last_error(__E, (FN));                                  \
 201         }                                                               \
 202         __E;                                                            \
 203 })
 204
 205
 206 #define fn_for_each_XXX(L, P, FN, ...)                                  \
 207 ({                                                                      \
 208         struct label_it i;                                              \
 209         int __E = 0;                                                    \
 210         label_for_each ## __VA_ARGS__(i, (L), (P)) {                    \
 211                 last_error(__E, (FN));                                  \
 212         }                                                               \
 213         __E;                                                            \
 214 })
 215
 216 #define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
 217 #define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
 218
 219 #define fn_for_each2_XXX(L1, L2, P, FN, ...)                            \
 220 ({                                                                      \
 221         struct label_it i;                                              \
 222         int __E = 0;                                                    \
 223         label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {             \
 224                 last_error(__E, (FN));                                  \
 225         }                                                               \
 226         __E;                                                            \
 227 })
 228
 229 #define fn_for_each_in_merge(L1, L2, P, FN)                             \
 230         fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
 231 #define fn_for_each_not_in_set(L1, L2, P, FN)                           \
 232         fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
 233
 234 #define LABEL_MEDIATES(L, C)                                            \
 235 ({                                                                      \
 236         struct aa_profile *profile;                                     \
 237         struct label_it i;                                              \
 238         int ret = 0;                                                    \
 239         label_for_each(i, (L), profile) {                               \
 240                 if (RULE_MEDIATES(&profile->rules, (C))) {              \
 241                         ret = 1;                                        \
 242                         break;                                          \
 243                 }                                                       \
 244         }                                                               \
 245         ret;                                                            \
 246 })
 247
 248
 249 void aa_labelset_destroy(struct aa_labelset *ls);
 250 void aa_labelset_init(struct aa_labelset *ls);
 251 void __aa_labelset_update_subtree(struct aa_ns *ns);
 252
 253 void aa_label_destroy(struct aa_label *label);
 254 void aa_label_free(struct aa_label *label);
 255 void aa_label_kref(struct kref *kref);
 256 bool aa_label_init(struct aa_label *label, int size, gfp_t gfp);
 257 struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
 258
 259 bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
 260 bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub);
 261 struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
 262                                              struct aa_label *set,
 263                                              struct aa_label *sub);
 264 bool aa_label_remove(struct aa_label *label);
 265 struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
 266 bool aa_label_replace(struct aa_label *old, struct aa_label *new);
 267 bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
 268                           struct aa_label *new);
 269
 270 struct aa_profile *aa_label_next_in_merge(struct label_it *I,
 271                                           struct aa_label *a,
 272                                           struct aa_label *b);
 273 struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
 274 struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
 275                                 gfp_t gfp);
 276
 277
 278 bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
 279
 280 #define FLAGS_NONE 0
 281 #define FLAG_SHOW_MODE 1
 282 #define FLAG_VIEW_SUBNS 2
 283 #define FLAG_HIDDEN_UNCONFINED 4
 284 #define FLAG_ABS_ROOT 8
 285 int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
 286                       struct aa_label *label, int flags);
 287 int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
 288                       int flags, gfp_t gfp);
 289 int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
 290                          struct aa_label *label, int flags, gfp_t gfp);
 291 void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
 292                      struct aa_label *label, int flags, gfp_t gfp);
 293 void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
 294                          struct aa_label *label, int flags, gfp_t gfp);
 295 void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
 296                       gfp_t gfp);
 297 void aa_label_printk(struct aa_label *label, gfp_t gfp);
 298
 299 struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
 300                                      size_t n, gfp_t gfp, bool create,
 301                                      bool force_stack);
 302 struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
 303                                 gfp_t gfp, bool create, bool force_stack);
 304
 305 static inline const char *aa_label_strn_split(const char *str, int n)
 306 {
 307         const char *pos;
 308         aa_state_t state;
 309
 310         state = aa_dfa_matchn_until(stacksplitdfa, DFA_START, str, n, &pos);
 311         if (!ACCEPT_TABLE(stacksplitdfa)[state])
 312                 return NULL;
 313
 314         return pos - 3;
 315 }
 316
 317 static inline const char *aa_label_str_split(const char *str)
 318 {
 319         const char *pos;
 320         aa_state_t state;
 321
 322         state = aa_dfa_match_until(stacksplitdfa, DFA_START, str, &pos);
 323         if (!ACCEPT_TABLE(stacksplitdfa)[state])
 324                 return NULL;
 325
 326         return pos - 3;
 327 }
 328
 329
 330
 331 struct aa_perms;
 332 struct aa_ruleset;
 333 int aa_label_match(struct aa_profile *profile, struct aa_ruleset *rules,
 334                    struct aa_label *label, aa_state_t state, bool subns,
 335                    u32 request, struct aa_perms *perms);
 336
 337
 338 /**
 339  * __aa_get_label - get a reference count to uncounted label reference
 340  * @l: reference to get a count on
 341  *
 342  * Returns: pointer to reference OR NULL if race is lost and reference is
 343  *          being repeated.
 344  * Requires: lock held, and the return code MUST be checked
 345  */
 346 static inline struct aa_label *__aa_get_label(struct aa_label *l)
 347 {
 348         if (l && kref_get_unless_zero(&l->count))
 349                 return l;
 350
 351         return NULL;
 352 }
 353
 354 static inline struct aa_label *aa_get_label(struct aa_label *l)
 355 {
 356         if (l)
 357                 kref_get(&(l->count));
 358
 359         return l;
 360 }
 361
 362
 363 /**
 364  * aa_get_label_rcu - increment refcount on a label that can be replaced
 365  * @l: pointer to label that can be replaced (NOT NULL)
 366  *
 367  * Returns: pointer to a refcounted label.
 368  *     else NULL if no label
 369  */
 370 static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
 371 {
 372         struct aa_label *c;
 373
 374         rcu_read_lock();
 375         do {
 376                 c = rcu_dereference(*l);
 377         } while (c && !kref_get_unless_zero(&c->count));
 378         rcu_read_unlock();
 379
 380         return c;
 381 }
 382
 383 /**
 384  * aa_get_newest_label - find the newest version of @l
 385  * @l: the label to check for newer versions of
 386  *
 387  * Returns: refcounted newest version of @l taking into account
 388  *          replacement, renames and removals
 389  *          return @l.
 390  */
 391 static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
 392 {
 393         if (!l)
 394                 return NULL;
 395
 396         if (label_is_stale(l)) {
 397                 struct aa_label *tmp;
 398
 399                 AA_BUG(!l->proxy);
 400                 AA_BUG(!l->proxy->label);
 401                 /* BUG: only way this can happen is @l ref count and its
 402                  * replacement count have gone to 0 and are on their way
 403                  * to destruction. ie. we have a refcounting error
 404                  */
 405                 tmp = aa_get_label_rcu(&l->proxy->label);
 406                 AA_BUG(!tmp);
 407
 408                 return tmp;
 409         }
 410
 411         return aa_get_label(l);
 412 }
 413
 414 static inline void aa_put_label(struct aa_label *l)
 415 {
 416         if (l)
 417                 kref_put(&l->count, aa_label_kref);
 418 }
 419
 420
 421 struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
 422 void aa_proxy_kref(struct kref *kref);
 423
 424 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
 425 {
 426         if (proxy)
 427                 kref_get(&(proxy->count));
 428
 429         return proxy;
 430 }
 431
 432 static inline void aa_put_proxy(struct aa_proxy *proxy)
 433 {
 434         if (proxy)
 435                 kref_put(&proxy->count, aa_proxy_kref);
 436 }
 437
 438 void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
 439
 440 #endif /* __AA_LABEL_H */