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 };
 118
 119 struct task_smack {
 120         struct smack_known      *smk_task;      /* label for access control */
 121         struct smack_known      *smk_forked;    /* label when forked */
 122         struct list_head        smk_rules;      /* per task access rules */
 123         struct mutex            smk_rules_lock; /* lock for the rules */
 124         struct list_head        smk_relabel;    /* transit allowed labels */
 125 };
 126
 127 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 128 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 129 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 130 #define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */
 131
 132 /*
 133  * A label access rule.
 134  */
 135 struct smack_rule {
 136         struct list_head        list;
 137         struct smack_known      *smk_subject;
 138         struct smack_known      *smk_object;
 139         int                     smk_access;
 140 };
 141
 142 /*
 143  * An entry in the table identifying IPv4 hosts.
 144  */
 145 struct smk_net4addr {
 146         struct list_head        list;
 147         struct in_addr          smk_host;       /* network address */
 148         struct in_addr          smk_mask;       /* network mask */
 149         int                     smk_masks;      /* mask size */
 150         struct smack_known      *smk_label;     /* label */
 151 };
 152
 153 #if IS_ENABLED(CONFIG_IPV6)
 154 /*
 155  * An entry in the table identifying IPv6 hosts.
 156  */
 157 struct smk_net6addr {
 158         struct list_head        list;
 159         struct in6_addr         smk_host;       /* network address */
 160         struct in6_addr         smk_mask;       /* network mask */
 161         int                     smk_masks;      /* mask size */
 162         struct smack_known      *smk_label;     /* label */
 163 };
 164 #endif /* CONFIG_IPV6 */
 165
 166 #ifdef SMACK_IPV6_PORT_LABELING
 167 /*
 168  * An entry in the table identifying ports.
 169  */
 170 struct smk_port_label {
 171         struct list_head        list;
 172         struct sock             *smk_sock;      /* socket initialized on */
 173         unsigned short          smk_port;       /* the port number */
 174         struct smack_known      *smk_in;        /* inbound label */
 175         struct smack_known      *smk_out;       /* outgoing label */
 176         short                   smk_sock_type;  /* Socket type */
 177 };
 178 #endif /* SMACK_IPV6_PORT_LABELING */
 179
 180 struct smack_known_list_elem {
 181         struct list_head        list;
 182         struct smack_known      *smk_label;
 183 };
 184
 185 /* Super block security struct flags for mount options */
 186 #define FSDEFAULT_MNT   0x01
 187 #define FSFLOOR_MNT     0x02
 188 #define FSHAT_MNT       0x04
 189 #define FSROOT_MNT      0x08
 190 #define FSTRANS_MNT     0x10
 191
 192 #define NUM_SMK_MNT_OPTS        5
 193
 194 enum {
 195         Opt_error = -1,
 196         Opt_fsdefault = 1,
 197         Opt_fsfloor = 2,
 198         Opt_fshat = 3,
 199         Opt_fsroot = 4,
 200         Opt_fstransmute = 5,
 201 };
 202
 203 /*
 204  * Mount options
 205  */
 206 #define SMK_FSDEFAULT   "smackfsdef="
 207 #define SMK_FSFLOOR     "smackfsfloor="
 208 #define SMK_FSHAT       "smackfshat="
 209 #define SMK_FSROOT      "smackfsroot="
 210 #define SMK_FSTRANS     "smackfstransmute="
 211
 212 #define SMACK_DELETE_OPTION     "-DELETE"
 213 #define SMACK_CIPSO_OPTION      "-CIPSO"
 214
 215 /*
 216  * How communications on this socket are treated.
 217  * Usually it's determined by the underlying netlabel code
 218  * but there are certain cases, including single label hosts
 219  * and potentially single label interfaces for which the
 220  * treatment can not be known in advance.
 221  *
 222  * The possibility of additional labeling schemes being
 223  * introduced in the future exists as well.
 224  */
 225 #define SMACK_UNLABELED_SOCKET  0
 226 #define SMACK_CIPSO_SOCKET      1
 227
 228 /*
 229  * CIPSO defaults.
 230  */
 231 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 232 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 233 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 234 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 235 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 236 /*
 237  * CIPSO 2.2 standard is 239, but Smack wants to use the
 238  * categories in a structured way that limits the value to
 239  * the bits in 23 bytes, hence the unusual number.
 240  */
 241 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 242
 243 /*
 244  * Ptrace rules
 245  */
 246 #define SMACK_PTRACE_DEFAULT    0
 247 #define SMACK_PTRACE_EXACT      1
 248 #define SMACK_PTRACE_DRACONIAN  2
 249 #define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN
 250
 251 /*
 252  * Flags for untraditional access modes.
 253  * It shouldn't be necessary to avoid conflicts with definitions
 254  * in fs.h, but do so anyway.
 255  */
 256 #define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
 257 #define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
 258 #define MAY_BRINGUP     0x00004000      /* Report use of this rule */
 259
 260 /*
 261  * The policy for delivering signals is configurable.
 262  * It is usually "write", but can be "append".
 263  */
 264 #ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
 265 #define MAY_DELIVER     MAY_APPEND      /* Signal delivery requires append */
 266 #else
 267 #define MAY_DELIVER     MAY_WRITE       /* Signal delivery requires write */
 268 #endif
 269
 270 #define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
 271 #define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
 272 #define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */
 273
 274 /*
 275  * Just to make the common cases easier to deal with
 276  */
 277 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 278 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 279 #define MAY_NOT         0
 280
 281 /*
 282  * Number of access types used by Smack (rwxatlb)
 283  */
 284 #define SMK_NUM_ACCESS_TYPE 7
 285
 286 /* SMACK data */
 287 struct smack_audit_data {
 288         const char *function;
 289         char *subject;
 290         char *object;
 291         char *request;
 292         int result;
 293 };
 294
 295 /*
 296  * Smack audit data; is empty if CONFIG_AUDIT not set
 297  * to save some stack
 298  */
 299 struct smk_audit_info {
 300 #ifdef CONFIG_AUDIT
 301         struct common_audit_data a;
 302         struct smack_audit_data sad;
 303 #endif
 304 };
 305
 306 /*
 307  * These functions are in smack_access.c
 308  */
 309 int smk_access_entry(char *, char *, struct list_head *);
 310 int smk_access(struct smack_known *, struct smack_known *,
 311                int, struct smk_audit_info *);
 312 int smk_tskacc(struct task_smack *, struct smack_known *,
 313                u32, struct smk_audit_info *);
 314 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 315 struct smack_known *smack_from_secid(const u32);
 316 char *smk_parse_smack(const char *string, int len);
 317 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 318 struct smack_known *smk_import_entry(const char *, int);
 319 void smk_insert_entry(struct smack_known *skp);
 320 struct smack_known *smk_find_entry(const char *);
 321 int smack_privileged(int cap);
 322 void smk_destroy_label_list(struct list_head *list);
 323
 324 /*
 325  * Shared data.
 326  */
 327 extern int smack_enabled;
 328 extern int smack_cipso_direct;
 329 extern int smack_cipso_mapped;
 330 extern struct smack_known *smack_net_ambient;
 331 extern struct smack_known *smack_syslog_label;
 332 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 333 extern struct smack_known *smack_unconfined;
 334 #endif
 335 extern int smack_ptrace_rule;
 336
 337 extern struct smack_known smack_known_floor;
 338 extern struct smack_known smack_known_hat;
 339 extern struct smack_known smack_known_huh;
 340 extern struct smack_known smack_known_star;
 341 extern struct smack_known smack_known_web;
 342
 343 extern struct mutex     smack_known_lock;
 344 extern struct list_head smack_known_list;
 345 extern struct list_head smk_net4addr_list;
 346 #if IS_ENABLED(CONFIG_IPV6)
 347 extern struct list_head smk_net6addr_list;
 348 #endif /* CONFIG_IPV6 */
 349
 350 extern struct mutex     smack_onlycap_lock;
 351 extern struct list_head smack_onlycap_list;
 352
 353 #define SMACK_HASH_SLOTS 16
 354 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 355
 356 /*
 357  * Is the directory transmuting?
 358  */
 359 static inline int smk_inode_transmutable(const struct inode *isp)
 360 {
 361         struct inode_smack *sip = isp->i_security;
 362         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 363 }
 364
 365 /*
 366  * Present a pointer to the smack label entry in an inode blob.
 367  */
 368 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 369 {
 370         struct inode_smack *sip = isp->i_security;
 371         return sip->smk_inode;
 372 }
 373
 374 /*
 375  * Present a pointer to the smack label entry in an task blob.
 376  */
 377 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 378 {
 379         return tsp->smk_task;
 380 }
 381
 382 static inline struct smack_known *smk_of_task_struct(const struct task_struct *t)
 383 {
 384         struct smack_known *skp;
 385
 386         rcu_read_lock();
 387         skp = smk_of_task(__task_cred(t)->security);
 388         rcu_read_unlock();
 389         return skp;
 390 }
 391
 392 /*
 393  * Present a pointer to the forked smack label entry in an task blob.
 394  */
 395 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 396 {
 397         return tsp->smk_forked;
 398 }
 399
 400 /*
 401  * Present a pointer to the smack label in the current task blob.
 402  */
 403 static inline struct smack_known *smk_of_current(void)
 404 {
 405         return smk_of_task(current_security());
 406 }
 407
 408 /*
 409  * logging functions
 410  */
 411 #define SMACK_AUDIT_DENIED 0x1
 412 #define SMACK_AUDIT_ACCEPT 0x2
 413 extern int log_policy;
 414
 415 void smack_log(char *subject_label, char *object_label,
 416                 int request,
 417                 int result, struct smk_audit_info *auditdata);
 418
 419 #ifdef CONFIG_AUDIT
 420
 421 /*
 422  * some inline functions to set up audit data
 423  * they do nothing if CONFIG_AUDIT is not set
 424  *
 425  */
 426 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 427                                char type)
 428 {
 429         memset(&a->sad, 0, sizeof(a->sad));
 430         a->a.type = type;
 431         a->a.smack_audit_data = &a->sad;
 432         a->a.smack_audit_data->function = func;
 433 }
 434
 435 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 436                                    char type, struct lsm_network_audit *net)
 437 {
 438         smk_ad_init(a, func, type);
 439         memset(net, 0, sizeof(*net));
 440         a->a.u.net = net;
 441 }
 442
 443 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 444                                          struct task_struct *t)
 445 {
 446         a->a.u.tsk = t;
 447 }
 448 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 449                                                     struct dentry *d)
 450 {
 451         a->a.u.dentry = d;
 452 }
 453 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 454                                               struct inode *i)
 455 {
 456         a->a.u.inode = i;
 457 }
 458 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 459                                              struct path p)
 460 {
 461         a->a.u.path = p;
 462 }
 463 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 464                                             struct sock *sk)
 465 {
 466         a->a.u.net->sk = sk;
 467 }
 468
 469 #else /* no AUDIT */
 470
 471 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 472                                char type)
 473 {
 474 }
 475 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 476                                          struct task_struct *t)
 477 {
 478 }
 479 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 480                                                     struct dentry *d)
 481 {
 482 }
 483 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 484                                                  struct vfsmount *m)
 485 {
 486 }
 487 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 488                                               struct inode *i)
 489 {
 490 }
 491 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 492                                              struct path p)
 493 {
 494 }
 495 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 496                                             struct sock *sk)
 497 {
 498 }
 499 #endif
 500
 501 #endif  /* _SECURITY_SMACK_H */