security/smack/smack.h

   1 /*
   2  * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
   3  *
   4  *      This program is free software; you can redistribute it and/or modify
   5  *      it under the terms of the GNU General Public License as published by
   6  *      the Free Software Foundation, version 2.
   7  *
   8  * Author:
   9  *      Casey Schaufler <casey@schaufler-ca.com>
  10  *
  11  */
  12
  13 #ifndef _SECURITY_SMACK_H
  14 #define _SECURITY_SMACK_H
  15
  16 #include <linux/capability.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/lsm_hooks.h>
  19 #include <linux/in.h>
  20 #if IS_ENABLED(CONFIG_IPV6)
  21 #include <linux/in6.h>
  22 #endif /* CONFIG_IPV6 */
  23 #include <net/netlabel.h>
  24 #include <linux/list.h>
  25 #include <linux/rculist.h>
  26 #include <linux/lsm_audit.h>
  27
  28 /*
  29  * Use IPv6 port labeling if IPv6 is enabled and secmarks
  30  * are not being used.
  31  */
  32 #if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
  33 #define SMACK_IPV6_PORT_LABELING 1
  34 #endif
  35
  36 #if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
  37 #define SMACK_IPV6_SECMARK_LABELING 1
  38 #endif
  39
  40 /*
  41  * Smack labels were limited to 23 characters for a long time.
  42  */
  43 #define SMK_LABELLEN    24
  44 #define SMK_LONGLABEL   256
  45
  46 /*
  47  * This is the repository for labels seen so that it is
  48  * not necessary to keep allocating tiny chuncks of memory
  49  * and so that they can be shared.
  50  *
  51  * Labels are never modified in place. Anytime a label
  52  * is imported (e.g. xattrset on a file) the list is checked
  53  * for it and it is added if it doesn't exist. The address
  54  * is passed out in either case. Entries are added, but
  55  * never deleted.
  56  *
  57  * Since labels are hanging around anyway it doesn't
  58  * hurt to maintain a secid for those awkward situations
  59  * where kernel components that ought to use LSM independent
  60  * interfaces don't. The secid should go away when all of
  61  * these components have been repaired.
  62  *
  63  * The cipso value associated with the label gets stored here, too.
  64  *
  65  * Keep the access rules for this subject label here so that
  66  * the entire set of rules does not need to be examined every
  67  * time.
  68  */
  69 struct smack_known {
  70         struct list_head                list;
  71         struct hlist_node               smk_hashed;
  72         char                            *smk_known;
  73         u32                             smk_secid;
  74         struct netlbl_lsm_secattr       smk_netlabel;   /* on wire labels */
  75         struct list_head                smk_rules;      /* access rules */
  76         struct mutex                    smk_rules_lock; /* lock for rules */
  77 };
  78
  79 /*
  80  * Maximum number of bytes for the levels in a CIPSO IP option.
  81  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  82  * bigger than can be used, and 24 is the next lower multiple
  83  * of 8, and there are too many issues if there isn't space set
  84  * aside for the terminating null byte.
  85  */
  86 #define SMK_CIPSOLEN    24
  87
  88 struct superblock_smack {
  89         struct smack_known      *smk_root;
  90         struct smack_known      *smk_floor;
  91         struct smack_known      *smk_hat;
  92         struct smack_known      *smk_default;
  93         int                     smk_flags;
  94 };
  95
  96 /*
  97  * Superblock flags
  98  */
  99 #define SMK_SB_INITIALIZED      0x01
 100 #define SMK_SB_UNTRUSTED        0x02
 101
 102 struct socket_smack {
 103         struct smack_known      *smk_out;       /* outbound label */
 104         struct smack_known      *smk_in;        /* inbound label */
 105         struct smack_known      *smk_packet;    /* TCP peer label */
 106 };
 107
 108 /*
 109  * Inode smack data
 110  */
 111 struct inode_smack {
 112         struct smack_known      *smk_inode;     /* label of the fso */
 113         struct smack_known      *smk_task;      /* label of the task */
 114         struct smack_known      *smk_mmap;      /* label of the mmap domain */
 115         struct mutex            smk_lock;       /* initialization lock */
 116         int                     smk_flags;      /* smack inode flags */
 117         struct rcu_head         smk_rcu;        /* for freeing inode_smack */
 118 };
 119
 120 struct task_smack {
 121         struct smack_known      *smk_task;      /* label for access control */
 122         struct smack_known      *smk_forked;    /* label when forked */
 123         struct list_head        smk_rules;      /* per task access rules */
 124         struct mutex            smk_rules_lock; /* lock for the rules */
 125         struct list_head        smk_relabel;    /* transit allowed labels */
 126 };
 127
 128 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 129 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 130 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 131 #define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */
 132
 133 /*
 134  * A label access rule.
 135  */
 136 struct smack_rule {
 137         struct list_head        list;
 138         struct smack_known      *smk_subject;
 139         struct smack_known      *smk_object;
 140         int                     smk_access;
 141 };
 142
 143 /*
 144  * An entry in the table identifying IPv4 hosts.
 145  */
 146 struct smk_net4addr {
 147         struct list_head        list;
 148         struct in_addr          smk_host;       /* network address */
 149         struct in_addr          smk_mask;       /* network mask */
 150         int                     smk_masks;      /* mask size */
 151         struct smack_known      *smk_label;     /* label */
 152 };
 153
 154 #if IS_ENABLED(CONFIG_IPV6)
 155 /*
 156  * An entry in the table identifying IPv6 hosts.
 157  */
 158 struct smk_net6addr {
 159         struct list_head        list;
 160         struct in6_addr         smk_host;       /* network address */
 161         struct in6_addr         smk_mask;       /* network mask */
 162         int                     smk_masks;      /* mask size */
 163         struct smack_known      *smk_label;     /* label */
 164 };
 165 #endif /* CONFIG_IPV6 */
 166
 167 #ifdef SMACK_IPV6_PORT_LABELING
 168 /*
 169  * An entry in the table identifying ports.
 170  */
 171 struct smk_port_label {
 172         struct list_head        list;
 173         struct sock             *smk_sock;      /* socket initialized on */
 174         unsigned short          smk_port;       /* the port number */
 175         struct smack_known      *smk_in;        /* inbound label */
 176         struct smack_known      *smk_out;       /* outgoing label */
 177         short                   smk_sock_type;  /* Socket type */
 178         short                   smk_can_reuse;
 179 };
 180 #endif /* SMACK_IPV6_PORT_LABELING */
 181
 182 struct smack_known_list_elem {
 183         struct list_head        list;
 184         struct smack_known      *smk_label;
 185 };
 186
 187 /* Super block security struct flags for mount options */
 188 #define FSDEFAULT_MNT   0x01
 189 #define FSFLOOR_MNT     0x02
 190 #define FSHAT_MNT       0x04
 191 #define FSROOT_MNT      0x08
 192 #define FSTRANS_MNT     0x10
 193
 194 #define NUM_SMK_MNT_OPTS        5
 195
 196 enum {
 197         Opt_error = -1,
 198         Opt_fsdefault = 1,
 199         Opt_fsfloor = 2,
 200         Opt_fshat = 3,
 201         Opt_fsroot = 4,
 202         Opt_fstransmute = 5,
 203 };
 204
 205 /*
 206  * Mount options
 207  */
 208 #define SMK_FSDEFAULT   "smackfsdef="
 209 #define SMK_FSFLOOR     "smackfsfloor="
 210 #define SMK_FSHAT       "smackfshat="
 211 #define SMK_FSROOT      "smackfsroot="
 212 #define SMK_FSTRANS     "smackfstransmute="
 213
 214 #define SMACK_DELETE_OPTION     "-DELETE"
 215 #define SMACK_CIPSO_OPTION      "-CIPSO"
 216
 217 /*
 218  * How communications on this socket are treated.
 219  * Usually it's determined by the underlying netlabel code
 220  * but there are certain cases, including single label hosts
 221  * and potentially single label interfaces for which the
 222  * treatment can not be known in advance.
 223  *
 224  * The possibility of additional labeling schemes being
 225  * introduced in the future exists as well.
 226  */
 227 #define SMACK_UNLABELED_SOCKET  0
 228 #define SMACK_CIPSO_SOCKET      1
 229
 230 /*
 231  * CIPSO defaults.
 232  */
 233 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 234 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 235 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 236 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 237 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 238 /*
 239  * CIPSO 2.2 standard is 239, but Smack wants to use the
 240  * categories in a structured way that limits the value to
 241  * the bits in 23 bytes, hence the unusual number.
 242  */
 243 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 244
 245 /*
 246  * Ptrace rules
 247  */
 248 #define SMACK_PTRACE_DEFAULT    0
 249 #define SMACK_PTRACE_EXACT      1
 250 #define SMACK_PTRACE_DRACONIAN  2
 251 #define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN
 252
 253 /*
 254  * Flags for untraditional access modes.
 255  * It shouldn't be necessary to avoid conflicts with definitions
 256  * in fs.h, but do so anyway.
 257  */
 258 #define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
 259 #define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
 260 #define MAY_BRINGUP     0x00004000      /* Report use of this rule */
 261
 262 /*
 263  * The policy for delivering signals is configurable.
 264  * It is usually "write", but can be "append".
 265  */
 266 #ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
 267 #define MAY_DELIVER     MAY_APPEND      /* Signal delivery requires append */
 268 #else
 269 #define MAY_DELIVER     MAY_WRITE       /* Signal delivery requires write */
 270 #endif
 271
 272 #define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
 273 #define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
 274 #define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */
 275
 276 /*
 277  * Just to make the common cases easier to deal with
 278  */
 279 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 280 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 281 #define MAY_NOT         0
 282
 283 /*
 284  * Number of access types used by Smack (rwxatlb)
 285  */
 286 #define SMK_NUM_ACCESS_TYPE 7
 287
 288 /* SMACK data */
 289 struct smack_audit_data {
 290         const char *function;
 291         char *subject;
 292         char *object;
 293         char *request;
 294         int result;
 295 };
 296
 297 /*
 298  * Smack audit data; is empty if CONFIG_AUDIT not set
 299  * to save some stack
 300  */
 301 struct smk_audit_info {
 302 #ifdef CONFIG_AUDIT
 303         struct common_audit_data a;
 304         struct smack_audit_data sad;
 305 #endif
 306 };
 307
 308 /*
 309  * These functions are in smack_access.c
 310  */
 311 int smk_access_entry(char *, char *, struct list_head *);
 312 int smk_access(struct smack_known *, struct smack_known *,
 313                int, struct smk_audit_info *);
 314 int smk_tskacc(struct task_smack *, struct smack_known *,
 315                u32, struct smk_audit_info *);
 316 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 317 struct smack_known *smack_from_secid(const u32);
 318 char *smk_parse_smack(const char *string, int len);
 319 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 320 struct smack_known *smk_import_entry(const char *, int);
 321 void smk_insert_entry(struct smack_known *skp);
 322 struct smack_known *smk_find_entry(const char *);
 323 bool smack_privileged(int cap);
 324 bool smack_privileged_cred(int cap, const struct cred *cred);
 325 void smk_destroy_label_list(struct list_head *list);
 326
 327 /*
 328  * Shared data.
 329  */
 330 extern int smack_enabled;
 331 extern int smack_cipso_direct;
 332 extern int smack_cipso_mapped;
 333 extern struct smack_known *smack_net_ambient;
 334 extern struct smack_known *smack_syslog_label;
 335 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 336 extern struct smack_known *smack_unconfined;
 337 #endif
 338 extern int smack_ptrace_rule;
 339
 340 extern struct smack_known smack_known_floor;
 341 extern struct smack_known smack_known_hat;
 342 extern struct smack_known smack_known_huh;
 343 extern struct smack_known smack_known_star;
 344 extern struct smack_known smack_known_web;
 345
 346 extern struct mutex     smack_known_lock;
 347 extern struct list_head smack_known_list;
 348 extern struct list_head smk_net4addr_list;
 349 #if IS_ENABLED(CONFIG_IPV6)
 350 extern struct list_head smk_net6addr_list;
 351 #endif /* CONFIG_IPV6 */
 352
 353 extern struct mutex     smack_onlycap_lock;
 354 extern struct list_head smack_onlycap_list;
 355
 356 #define SMACK_HASH_SLOTS 16
 357 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 358
 359 /*
 360  * Is the directory transmuting?
 361  */
 362 static inline int smk_inode_transmutable(const struct inode *isp)
 363 {
 364         struct inode_smack *sip = isp->i_security;
 365         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 366 }
 367
 368 /*
 369  * Present a pointer to the smack label entry in an inode blob.
 370  */
 371 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 372 {
 373         struct inode_smack *sip = isp->i_security;
 374         return sip->smk_inode;
 375 }
 376
 377 /*
 378  * Present a pointer to the smack label entry in an task blob.
 379  */
 380 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 381 {
 382         return tsp->smk_task;
 383 }
 384
 385 static inline struct smack_known *smk_of_task_struct(const struct task_struct *t)
 386 {
 387         struct smack_known *skp;
 388
 389         rcu_read_lock();
 390         skp = smk_of_task(__task_cred(t)->security);
 391         rcu_read_unlock();
 392         return skp;
 393 }
 394
 395 /*
 396  * Present a pointer to the forked smack label entry in an task blob.
 397  */
 398 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 399 {
 400         return tsp->smk_forked;
 401 }
 402
 403 /*
 404  * Present a pointer to the smack label in the current task blob.
 405  */
 406 static inline struct smack_known *smk_of_current(void)
 407 {
 408         return smk_of_task(current_security());
 409 }
 410
 411 /*
 412  * logging functions
 413  */
 414 #define SMACK_AUDIT_DENIED 0x1
 415 #define SMACK_AUDIT_ACCEPT 0x2
 416 extern int log_policy;
 417
 418 void smack_log(char *subject_label, char *object_label,
 419                 int request,
 420                 int result, struct smk_audit_info *auditdata);
 421
 422 #ifdef CONFIG_AUDIT
 423
 424 /*
 425  * some inline functions to set up audit data
 426  * they do nothing if CONFIG_AUDIT is not set
 427  *
 428  */
 429 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 430                                char type)
 431 {
 432         memset(&a->sad, 0, sizeof(a->sad));
 433         a->a.type = type;
 434         a->a.smack_audit_data = &a->sad;
 435         a->a.smack_audit_data->function = func;
 436 }
 437
 438 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 439                                    char type, struct lsm_network_audit *net)
 440 {
 441         smk_ad_init(a, func, type);
 442         memset(net, 0, sizeof(*net));
 443         a->a.u.net = net;
 444 }
 445
 446 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 447                                          struct task_struct *t)
 448 {
 449         a->a.u.tsk = t;
 450 }
 451 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 452                                                     struct dentry *d)
 453 {
 454         a->a.u.dentry = d;
 455 }
 456 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 457                                               struct inode *i)
 458 {
 459         a->a.u.inode = i;
 460 }
 461 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 462                                              struct path p)
 463 {
 464         a->a.u.path = p;
 465 }
 466 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 467                                             struct sock *sk)
 468 {
 469         a->a.u.net->sk = sk;
 470 }
 471
 472 #else /* no AUDIT */
 473
 474 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 475                                char type)
 476 {
 477 }
 478 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 479                                          struct task_struct *t)
 480 {
 481 }
 482 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 483                                                     struct dentry *d)
 484 {
 485 }
 486 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 487                                                  struct vfsmount *m)
 488 {
 489 }
 490 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 491                                               struct inode *i)
 492 {
 493 }
 494 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 495                                              struct path p)
 496 {
 497 }
 498 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 499                                             struct sock *sk)
 500 {
 501 }
 502 #endif
 503
 504 #endif  /* _SECURITY_SMACK_H */