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_initialized;
  94 };
  95
  96 struct socket_smack {
  97         struct smack_known      *smk_out;       /* outbound label */
  98         struct smack_known      *smk_in;        /* inbound label */
  99         struct smack_known      *smk_packet;    /* TCP peer label */
 100 };
 101
 102 /*
 103  * Inode smack data
 104  */
 105 struct inode_smack {
 106         struct smack_known      *smk_inode;     /* label of the fso */
 107         struct smack_known      *smk_task;      /* label of the task */
 108         struct smack_known      *smk_mmap;      /* label of the mmap domain */
 109         struct mutex            smk_lock;       /* initialization lock */
 110         int                     smk_flags;      /* smack inode flags */
 111 };
 112
 113 struct task_smack {
 114         struct smack_known      *smk_task;      /* label for access control */
 115         struct smack_known      *smk_forked;    /* label when forked */
 116         struct list_head        smk_rules;      /* per task access rules */
 117         struct mutex            smk_rules_lock; /* lock for the rules */
 118         struct list_head        smk_relabel;    /* transit allowed labels */
 119 };
 120
 121 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 122 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 123 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 124 #define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */
 125
 126 /*
 127  * A label access rule.
 128  */
 129 struct smack_rule {
 130         struct list_head        list;
 131         struct smack_known      *smk_subject;
 132         struct smack_known      *smk_object;
 133         int                     smk_access;
 134 };
 135
 136 /*
 137  * An entry in the table identifying IPv4 hosts.
 138  */
 139 struct smk_net4addr {
 140         struct list_head        list;
 141         struct in_addr          smk_host;       /* network address */
 142         struct in_addr          smk_mask;       /* network mask */
 143         int                     smk_masks;      /* mask size */
 144         struct smack_known      *smk_label;     /* label */
 145 };
 146
 147 #if IS_ENABLED(CONFIG_IPV6)
 148 /*
 149  * An entry in the table identifying IPv6 hosts.
 150  */
 151 struct smk_net6addr {
 152         struct list_head        list;
 153         struct in6_addr         smk_host;       /* network address */
 154         struct in6_addr         smk_mask;       /* network mask */
 155         int                     smk_masks;      /* mask size */
 156         struct smack_known      *smk_label;     /* label */
 157 };
 158 #endif /* CONFIG_IPV6 */
 159
 160 #ifdef SMACK_IPV6_PORT_LABELING
 161 /*
 162  * An entry in the table identifying ports.
 163  */
 164 struct smk_port_label {
 165         struct list_head        list;
 166         struct sock             *smk_sock;      /* socket initialized on */
 167         unsigned short          smk_port;       /* the port number */
 168         struct smack_known      *smk_in;        /* inbound label */
 169         struct smack_known      *smk_out;       /* outgoing label */
 170 };
 171 #endif /* SMACK_IPV6_PORT_LABELING */
 172
 173 struct smack_known_list_elem {
 174         struct list_head        list;
 175         struct smack_known      *smk_label;
 176 };
 177
 178 /* Super block security struct flags for mount options */
 179 #define FSDEFAULT_MNT   0x01
 180 #define FSFLOOR_MNT     0x02
 181 #define FSHAT_MNT       0x04
 182 #define FSROOT_MNT      0x08
 183 #define FSTRANS_MNT     0x10
 184
 185 #define NUM_SMK_MNT_OPTS        5
 186
 187 enum {
 188         Opt_error = -1,
 189         Opt_fsdefault = 1,
 190         Opt_fsfloor = 2,
 191         Opt_fshat = 3,
 192         Opt_fsroot = 4,
 193         Opt_fstransmute = 5,
 194 };
 195
 196 /*
 197  * Mount options
 198  */
 199 #define SMK_FSDEFAULT   "smackfsdef="
 200 #define SMK_FSFLOOR     "smackfsfloor="
 201 #define SMK_FSHAT       "smackfshat="
 202 #define SMK_FSROOT      "smackfsroot="
 203 #define SMK_FSTRANS     "smackfstransmute="
 204
 205 #define SMACK_DELETE_OPTION     "-DELETE"
 206 #define SMACK_CIPSO_OPTION      "-CIPSO"
 207
 208 /*
 209  * How communications on this socket are treated.
 210  * Usually it's determined by the underlying netlabel code
 211  * but there are certain cases, including single label hosts
 212  * and potentially single label interfaces for which the
 213  * treatment can not be known in advance.
 214  *
 215  * The possibility of additional labeling schemes being
 216  * introduced in the future exists as well.
 217  */
 218 #define SMACK_UNLABELED_SOCKET  0
 219 #define SMACK_CIPSO_SOCKET      1
 220
 221 /*
 222  * CIPSO defaults.
 223  */
 224 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 225 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 226 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 227 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 228 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 229 /*
 230  * CIPSO 2.2 standard is 239, but Smack wants to use the
 231  * categories in a structured way that limits the value to
 232  * the bits in 23 bytes, hence the unusual number.
 233  */
 234 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 235
 236 /*
 237  * Ptrace rules
 238  */
 239 #define SMACK_PTRACE_DEFAULT    0
 240 #define SMACK_PTRACE_EXACT      1
 241 #define SMACK_PTRACE_DRACONIAN  2
 242 #define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN
 243
 244 /*
 245  * Flags for untraditional access modes.
 246  * It shouldn't be necessary to avoid conflicts with definitions
 247  * in fs.h, but do so anyway.
 248  */
 249 #define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
 250 #define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
 251 #define MAY_BRINGUP     0x00004000      /* Report use of this rule */
 252
 253 #define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
 254 #define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
 255 #define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */
 256
 257 /*
 258  * Just to make the common cases easier to deal with
 259  */
 260 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 261 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 262 #define MAY_NOT         0
 263
 264 /*
 265  * Number of access types used by Smack (rwxatlb)
 266  */
 267 #define SMK_NUM_ACCESS_TYPE 7
 268
 269 /* SMACK data */
 270 struct smack_audit_data {
 271         const char *function;
 272         char *subject;
 273         char *object;
 274         char *request;
 275         int result;
 276 };
 277
 278 /*
 279  * Smack audit data; is empty if CONFIG_AUDIT not set
 280  * to save some stack
 281  */
 282 struct smk_audit_info {
 283 #ifdef CONFIG_AUDIT
 284         struct common_audit_data a;
 285         struct smack_audit_data sad;
 286 #endif
 287 };
 288
 289 /*
 290  * These functions are in smack_access.c
 291  */
 292 int smk_access_entry(char *, char *, struct list_head *);
 293 int smk_access(struct smack_known *, struct smack_known *,
 294                int, struct smk_audit_info *);
 295 int smk_tskacc(struct task_smack *, struct smack_known *,
 296                u32, struct smk_audit_info *);
 297 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 298 struct smack_known *smack_from_secid(const u32);
 299 char *smk_parse_smack(const char *string, int len);
 300 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 301 struct smack_known *smk_import_entry(const char *, int);
 302 void smk_insert_entry(struct smack_known *skp);
 303 struct smack_known *smk_find_entry(const char *);
 304 int smack_privileged(int cap);
 305 void smk_destroy_label_list(struct list_head *list);
 306
 307 /*
 308  * Shared data.
 309  */
 310 extern int smack_enabled;
 311 extern int smack_cipso_direct;
 312 extern int smack_cipso_mapped;
 313 extern struct smack_known *smack_net_ambient;
 314 extern struct smack_known *smack_syslog_label;
 315 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 316 extern struct smack_known *smack_unconfined;
 317 #endif
 318 extern int smack_ptrace_rule;
 319
 320 extern struct smack_known smack_known_floor;
 321 extern struct smack_known smack_known_hat;
 322 extern struct smack_known smack_known_huh;
 323 extern struct smack_known smack_known_invalid;
 324 extern struct smack_known smack_known_star;
 325 extern struct smack_known smack_known_web;
 326
 327 extern struct mutex     smack_known_lock;
 328 extern struct list_head smack_known_list;
 329 extern struct list_head smk_net4addr_list;
 330 #if IS_ENABLED(CONFIG_IPV6)
 331 extern struct list_head smk_net6addr_list;
 332 #endif /* CONFIG_IPV6 */
 333
 334 extern struct mutex     smack_onlycap_lock;
 335 extern struct list_head smack_onlycap_list;
 336
 337 #define SMACK_HASH_SLOTS 16
 338 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 339
 340 /*
 341  * Is the directory transmuting?
 342  */
 343 static inline int smk_inode_transmutable(const struct inode *isp)
 344 {
 345         struct inode_smack *sip = isp->i_security;
 346         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 347 }
 348
 349 /*
 350  * Present a pointer to the smack label entry in an inode blob.
 351  */
 352 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 353 {
 354         struct inode_smack *sip = isp->i_security;
 355         return sip->smk_inode;
 356 }
 357
 358 /*
 359  * Present a pointer to the smack label entry in an task blob.
 360  */
 361 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 362 {
 363         return tsp->smk_task;
 364 }
 365
 366 static inline struct smack_known *smk_of_task_struct(const struct task_struct *t)
 367 {
 368         struct smack_known *skp;
 369
 370         rcu_read_lock();
 371         skp = smk_of_task(__task_cred(t)->security);
 372         rcu_read_unlock();
 373         return skp;
 374 }
 375
 376 /*
 377  * Present a pointer to the forked smack label entry in an task blob.
 378  */
 379 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 380 {
 381         return tsp->smk_forked;
 382 }
 383
 384 /*
 385  * Present a pointer to the smack label in the current task blob.
 386  */
 387 static inline struct smack_known *smk_of_current(void)
 388 {
 389         return smk_of_task(current_security());
 390 }
 391
 392 /*
 393  * logging functions
 394  */
 395 #define SMACK_AUDIT_DENIED 0x1
 396 #define SMACK_AUDIT_ACCEPT 0x2
 397 extern int log_policy;
 398
 399 void smack_log(char *subject_label, char *object_label,
 400                 int request,
 401                 int result, struct smk_audit_info *auditdata);
 402
 403 #ifdef CONFIG_AUDIT
 404
 405 /*
 406  * some inline functions to set up audit data
 407  * they do nothing if CONFIG_AUDIT is not set
 408  *
 409  */
 410 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 411                                char type)
 412 {
 413         memset(&a->sad, 0, sizeof(a->sad));
 414         a->a.type = type;
 415         a->a.smack_audit_data = &a->sad;
 416         a->a.smack_audit_data->function = func;
 417 }
 418
 419 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 420                                    char type, struct lsm_network_audit *net)
 421 {
 422         smk_ad_init(a, func, type);
 423         memset(net, 0, sizeof(*net));
 424         a->a.u.net = net;
 425 }
 426
 427 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 428                                          struct task_struct *t)
 429 {
 430         a->a.u.tsk = t;
 431 }
 432 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 433                                                     struct dentry *d)
 434 {
 435         a->a.u.dentry = d;
 436 }
 437 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 438                                               struct inode *i)
 439 {
 440         a->a.u.inode = i;
 441 }
 442 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 443                                              struct path p)
 444 {
 445         a->a.u.path = p;
 446 }
 447 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 448                                             struct sock *sk)
 449 {
 450         a->a.u.net->sk = sk;
 451 }
 452
 453 #else /* no AUDIT */
 454
 455 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 456                                char type)
 457 {
 458 }
 459 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 460                                          struct task_struct *t)
 461 {
 462 }
 463 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 464                                                     struct dentry *d)
 465 {
 466 }
 467 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 468                                                  struct vfsmount *m)
 469 {
 470 }
 471 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 472                                               struct inode *i)
 473 {
 474 }
 475 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 476                                              struct path p)
 477 {
 478 }
 479 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 480                                             struct sock *sk)
 481 {
 482 }
 483 #endif
 484
 485 #endif  /* _SECURITY_SMACK_H */