apparmor/include/label.h

0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  * AppArmor security module
0004  *
0005  * This file contains AppArmor label definitions
0006  *
0007  * Copyright 2017 Canonical Ltd.
0008  */
0009
0010 #ifndef __AA_LABEL_H
0011 #define __AA_LABEL_H
0012
0013 #include <linux/atomic.h>
0014 #include <linux/audit.h>
0015 #include <linux/rbtree.h>
0016 #include <linux/rcupdate.h>
0017
0018 #include "apparmor.h"
0019 #include "lib.h"
0020
0021 struct aa_ns;
0022
0023 #define LOCAL_VEC_ENTRIES 8
0024 #define DEFINE_VEC(T, V)                        \
0025     struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES];  \
0026     struct aa_ ## T **(V)
0027
0028 #define vec_setup(T, V, N, GFP)                     \
0029 ({                                  \
0030     if ((N) <= LOCAL_VEC_ENTRIES) {                 \
0031         typeof(N) i;                        \
0032         (V) = (_ ## V ## _localtmp);                \
0033         for (i = 0; i < (N); i++)               \
0034             (V)[i] = NULL;                  \
0035     } else                              \
0036         (V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP));  \
0037     (V) ? 0 : -ENOMEM;                      \
0038 })
0039
0040 #define vec_cleanup(T, V, N)                        \
0041 do {                                    \
0042     int i;                              \
0043     for (i = 0; i < (N); i++) {                 \
0044         if (!IS_ERR_OR_NULL((V)[i]))                \
0045             aa_put_ ## T((V)[i]);               \
0046     }                               \
0047     if ((V) != _ ## V ## _localtmp)                 \
0048         kfree(V);                       \
0049 } while (0)
0050
0051 #define vec_last(VEC, SIZE) ((VEC)[(SIZE) - 1])
0052 #define vec_ns(VEC, SIZE) (vec_last((VEC), (SIZE))->ns)
0053 #define vec_labelset(VEC, SIZE) (&vec_ns((VEC), (SIZE))->labels)
0054 #define cleanup_domain_vec(V, L) cleanup_label_vec((V), (L)->size)
0055
0056 struct aa_profile;
0057 #define VEC_FLAG_TERMINATE 1
0058 int aa_vec_unique(struct aa_profile **vec, int n, int flags);
0059 struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,
0060                          gfp_t gfp);
0061 #define aa_sort_and_merge_vec(N, V) \
0062     aa_sort_and_merge_profiles((N), (struct aa_profile **)(V))
0063
0064
0065 /* struct aa_labelset - set of labels for a namespace
0066  *
0067  * Labels are reference counted; aa_labelset does not contribute to label
0068  * reference counts. Once a label's last refcount is put it is removed from
0069  * the set.
0070  */
0071 struct aa_labelset {
0072     rwlock_t lock;
0073
0074     struct rb_root root;
0075 };
0076
0077 #define __labelset_for_each(LS, N) \
0078     for ((N) = rb_first(&(LS)->root); (N); (N) = rb_next(N))
0079
0080 enum label_flags {
0081     FLAG_HAT = 1,           /* profile is a hat */
0082     FLAG_UNCONFINED = 2,        /* label unconfined only if all */
0083     FLAG_NULL = 4,          /* profile is null learning profile */
0084     FLAG_IX_ON_NAME_ERROR = 8,  /* fallback to ix on name lookup fail */
0085     FLAG_IMMUTIBLE = 0x10,      /* don't allow changes/replacement */
0086     FLAG_USER_DEFINED = 0x20,   /* user based profile - lower privs */
0087     FLAG_NO_LIST_REF = 0x40,    /* list doesn't keep profile ref */
0088     FLAG_NS_COUNT = 0x80,       /* carries NS ref count */
0089     FLAG_IN_TREE = 0x100,       /* label is in tree */
0090     FLAG_PROFILE = 0x200,       /* label is a profile */
0091     FLAG_EXPLICIT = 0x400,      /* explicit static label */
0092     FLAG_STALE = 0x800,     /* replaced/removed */
0093     FLAG_RENAMED = 0x1000,      /* label has renaming in it */
0094     FLAG_REVOKED = 0x2000,      /* label has revocation in it */
0095     FLAG_DEBUG1 = 0x4000,
0096     FLAG_DEBUG2 = 0x8000,
0097
0098     /* These flags must correspond with PATH_flags */
0099     /* TODO: add new path flags */
0100 };
0101
0102 struct aa_label;
0103 struct aa_proxy {
0104     struct kref count;
0105     struct aa_label __rcu *label;
0106 };
0107
0108 struct label_it {
0109     int i, j;
0110 };
0111
0112 /* struct aa_label - lazy labeling struct
0113  * @count: ref count of active users
0114  * @node: rbtree position
0115  * @rcu: rcu callback struct
0116  * @proxy: is set to the label that replaced this label
0117  * @hname: text representation of the label (MAYBE_NULL)
0118  * @flags: stale and other flags - values may change under label set lock
0119  * @secid: secid that references this label
0120  * @size: number of entries in @ent[]
0121  * @ent: set of profiles for label, actual size determined by @size
0122  */
0123 struct aa_label {
0124     struct kref count;
0125     struct rb_node node;
0126     struct rcu_head rcu;
0127     struct aa_proxy *proxy;
0128     __counted char *hname;
0129     long flags;
0130     u32 secid;
0131     int size;
0132     struct aa_profile *vec[];
0133 };
0134
0135 #define last_error(E, FN)               \
0136 do {                            \
0137     int __subE = (FN);              \
0138     if (__subE)                 \
0139         (E) = __subE;               \
0140 } while (0)
0141
0142 #define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
0143 #define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
0144 #define unconfined(X) label_unconfined(X)
0145 #define label_is_stale(X) ((X)->flags & FLAG_STALE)
0146 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
0147 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
0148 #define labels_set(X) (&labels_ns(X)->labels)
0149 #define labels_view(X) labels_ns(X)
0150 #define labels_profile(X) ((X)->vec[(X)->size - 1])
0151
0152
0153 int aa_label_next_confined(struct aa_label *l, int i);
0154
0155 /* for each profile in a label */
0156 #define label_for_each(I, L, P)                     \
0157     for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
0158
0159 /* assumes break/goto ended label_for_each */
0160 #define label_for_each_cont(I, L, P)                    \
0161     for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
0162
0163 #define next_comb(I, L1, L2)                        \
0164 do {                                    \
0165     (I).j++;                            \
0166     if ((I).j >= (L2)->size) {                  \
0167         (I).i++;                        \
0168         (I).j = 0;                      \
0169     }                               \
0170 } while (0)
0171
0172
0173 /* for each combination of P1 in L1, and P2 in L2 */
0174 #define label_for_each_comb(I, L1, L2, P1, P2)              \
0175 for ((I).i = (I).j = 0;                         \
0176     ((P1) = (L1)->vec[(I).i]) && ((P2) = (L2)->vec[(I).j]);     \
0177     (I) = next_comb(I, L1, L2))
0178
0179 #define fn_for_each_comb(L1, L2, P1, P2, FN)                \
0180 ({                                  \
0181     struct label_it i;                      \
0182     int __E = 0;                            \
0183     label_for_each_comb(i, (L1), (L2), (P1), (P2)) {        \
0184         last_error(__E, (FN));                  \
0185     }                               \
0186     __E;                                \
0187 })
0188
0189 /* for each profile that is enforcing confinement in a label */
0190 #define label_for_each_confined(I, L, P)                \
0191     for ((I).i = aa_label_next_confined((L), 0);            \
0192          ((P) = (L)->vec[(I).i]);                   \
0193          (I).i = aa_label_next_confined((L), (I).i + 1))
0194
0195 #define label_for_each_in_merge(I, A, B, P)             \
0196     for ((I).i = (I).j = 0;                     \
0197          ((P) = aa_label_next_in_merge(&(I), (A), (B)));        \
0198          )
0199
0200 #define label_for_each_not_in_set(I, SET, SUB, P)           \
0201     for ((I).i = (I).j = 0;                     \
0202          ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));    \
0203          )
0204
0205 #define next_in_ns(i, NS, L)                        \
0206 ({                                  \
0207     typeof(i) ___i = (i);                       \
0208     while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))        \
0209         (___i)++;                       \
0210     (___i);                             \
0211 })
0212
0213 #define label_for_each_in_ns(I, NS, L, P)               \
0214     for ((I).i = next_in_ns(0, (NS), (L));              \
0215          ((P) = (L)->vec[(I).i]);                   \
0216          (I).i = next_in_ns((I).i + 1, (NS), (L)))
0217
0218 #define fn_for_each_in_ns(L, P, FN)                 \
0219 ({                                  \
0220     struct label_it __i;                        \
0221     struct aa_ns *__ns = labels_ns(L);              \
0222     int __E = 0;                            \
0223     label_for_each_in_ns(__i, __ns, (L), (P)) {         \
0224         last_error(__E, (FN));                  \
0225     }                               \
0226     __E;                                \
0227 })
0228
0229
0230 #define fn_for_each_XXX(L, P, FN, ...)                  \
0231 ({                                  \
0232     struct label_it i;                      \
0233     int __E = 0;                            \
0234     label_for_each ## __VA_ARGS__(i, (L), (P)) {            \
0235         last_error(__E, (FN));                  \
0236     }                               \
0237     __E;                                \
0238 })
0239
0240 #define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
0241 #define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
0242
0243 #define fn_for_each2_XXX(L1, L2, P, FN, ...)                \
0244 ({                                  \
0245     struct label_it i;                      \
0246     int __E = 0;                            \
0247     label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {     \
0248         last_error(__E, (FN));                  \
0249     }                               \
0250     __E;                                \
0251 })
0252
0253 #define fn_for_each_in_merge(L1, L2, P, FN)             \
0254     fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
0255 #define fn_for_each_not_in_set(L1, L2, P, FN)               \
0256     fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
0257
0258 #define LABEL_MEDIATES(L, C)                        \
0259 ({                                  \
0260     struct aa_profile *profile;                 \
0261     struct label_it i;                      \
0262     int ret = 0;                            \
0263     label_for_each(i, (L), profile) {               \
0264         if (PROFILE_MEDIATES(profile, (C))) {           \
0265             ret = 1;                    \
0266             break;                      \
0267         }                           \
0268     }                               \
0269     ret;                                \
0270 })
0271
0272
0273 void aa_labelset_destroy(struct aa_labelset *ls);
0274 void aa_labelset_init(struct aa_labelset *ls);
0275 void __aa_labelset_update_subtree(struct aa_ns *ns);
0276
0277 void aa_label_destroy(struct aa_label *label);
0278 void aa_label_free(struct aa_label *label);
0279 void aa_label_kref(struct kref *kref);
0280 bool aa_label_init(struct aa_label *label, int size, gfp_t gfp);
0281 struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
0282
0283 bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
0284 bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub);
0285 struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
0286                          struct aa_label *set,
0287                          struct aa_label *sub);
0288 bool aa_label_remove(struct aa_label *label);
0289 struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
0290 bool aa_label_replace(struct aa_label *old, struct aa_label *new);
0291 bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
0292               struct aa_label *new);
0293
0294 struct aa_label *aa_label_find(struct aa_label *l);
0295
0296 struct aa_profile *aa_label_next_in_merge(struct label_it *I,
0297                       struct aa_label *a,
0298                       struct aa_label *b);
0299 struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
0300 struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
0301                 gfp_t gfp);
0302
0303
0304 bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
0305
0306 #define FLAGS_NONE 0
0307 #define FLAG_SHOW_MODE 1
0308 #define FLAG_VIEW_SUBNS 2
0309 #define FLAG_HIDDEN_UNCONFINED 4
0310 #define FLAG_ABS_ROOT 8
0311 int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
0312               struct aa_label *label, int flags);
0313 int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
0314               int flags, gfp_t gfp);
0315 int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
0316              struct aa_label *label, int flags, gfp_t gfp);
0317 void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
0318              struct aa_label *label, int flags, gfp_t gfp);
0319 void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
0320              struct aa_label *label, int flags, gfp_t gfp);
0321 void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
0322               gfp_t gfp);
0323 void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp);
0324 void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp);
0325 void aa_label_printk(struct aa_label *label, gfp_t gfp);
0326
0327 struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
0328                      size_t n, gfp_t gfp, bool create,
0329                      bool force_stack);
0330 struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
0331                 gfp_t gfp, bool create, bool force_stack);
0332
0333 static inline const char *aa_label_strn_split(const char *str, int n)
0334 {
0335     const char *pos;
0336     unsigned int state;
0337
0338     state = aa_dfa_matchn_until(stacksplitdfa, DFA_START, str, n, &pos);
0339     if (!ACCEPT_TABLE(stacksplitdfa)[state])
0340         return NULL;
0341
0342     return pos - 3;
0343 }
0344
0345 static inline const char *aa_label_str_split(const char *str)
0346 {
0347     const char *pos;
0348     unsigned int state;
0349
0350     state = aa_dfa_match_until(stacksplitdfa, DFA_START, str, &pos);
0351     if (!ACCEPT_TABLE(stacksplitdfa)[state])
0352         return NULL;
0353
0354     return pos - 3;
0355 }
0356
0357
0358
0359 struct aa_perms;
0360 int aa_label_match(struct aa_profile *profile, struct aa_label *label,
0361            unsigned int state, bool subns, u32 request,
0362            struct aa_perms *perms);
0363
0364
0365 /**
0366  * __aa_get_label - get a reference count to uncounted label reference
0367  * @l: reference to get a count on
0368  *
0369  * Returns: pointer to reference OR NULL if race is lost and reference is
0370  *          being repeated.
0371  * Requires: lock held, and the return code MUST be checked
0372  */
0373 static inline struct aa_label *__aa_get_label(struct aa_label *l)
0374 {
0375     if (l && kref_get_unless_zero(&l->count))
0376         return l;
0377
0378     return NULL;
0379 }
0380
0381 static inline struct aa_label *aa_get_label(struct aa_label *l)
0382 {
0383     if (l)
0384         kref_get(&(l->count));
0385
0386     return l;
0387 }
0388
0389
0390 /**
0391  * aa_get_label_rcu - increment refcount on a label that can be replaced
0392  * @l: pointer to label that can be replaced (NOT NULL)
0393  *
0394  * Returns: pointer to a refcounted label.
0395  *     else NULL if no label
0396  */
0397 static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
0398 {
0399     struct aa_label *c;
0400
0401     rcu_read_lock();
0402     do {
0403         c = rcu_dereference(*l);
0404     } while (c && !kref_get_unless_zero(&c->count));
0405     rcu_read_unlock();
0406
0407     return c;
0408 }
0409
0410 /**
0411  * aa_get_newest_label - find the newest version of @l
0412  * @l: the label to check for newer versions of
0413  *
0414  * Returns: refcounted newest version of @l taking into account
0415  *          replacement, renames and removals
0416  *          return @l.
0417  */
0418 static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
0419 {
0420     if (!l)
0421         return NULL;
0422
0423     if (label_is_stale(l)) {
0424         struct aa_label *tmp;
0425
0426         AA_BUG(!l->proxy);
0427         AA_BUG(!l->proxy->label);
0428         /* BUG: only way this can happen is @l ref count and its
0429          * replacement count have gone to 0 and are on their way
0430          * to destruction. ie. we have a refcounting error
0431          */
0432         tmp = aa_get_label_rcu(&l->proxy->label);
0433         AA_BUG(!tmp);
0434
0435         return tmp;
0436     }
0437
0438     return aa_get_label(l);
0439 }
0440
0441 static inline void aa_put_label(struct aa_label *l)
0442 {
0443     if (l)
0444         kref_put(&l->count, aa_label_kref);
0445 }
0446
0447
0448 struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
0449 void aa_proxy_kref(struct kref *kref);
0450
0451 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
0452 {
0453     if (proxy)
0454         kref_get(&(proxy->count));
0455
0456     return proxy;
0457 }
0458
0459 static inline void aa_put_proxy(struct aa_proxy *proxy)
0460 {
0461     if (proxy)
0462         kref_put(&proxy->count, aa_proxy_kref);
0463 }
0464
0465 void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
0466
0467 #endif /* __AA_LABEL_H */