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