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 #include <linux/msg.h>
  28
  29 /*
  30  * Use IPv6 port labeling if IPv6 is enabled and secmarks
  31  * are not being used.
  32  */
  33 #if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
  34 #define SMACK_IPV6_PORT_LABELING 1
  35 #endif
  36
  37 #if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
  38 #define SMACK_IPV6_SECMARK_LABELING 1
  39 #endif
  40
  41 /*
  42  * Smack labels were limited to 23 characters for a long time.
  43  */
  44 #define SMK_LABELLEN    24
  45 #define SMK_LONGLABEL   256
  46
  47 /*
  48  * This is the repository for labels seen so that it is
  49  * not necessary to keep allocating tiny chuncks of memory
  50  * and so that they can be shared.
  51  *
  52  * Labels are never modified in place. Anytime a label
  53  * is imported (e.g. xattrset on a file) the list is checked
  54  * for it and it is added if it doesn't exist. The address
  55  * is passed out in either case. Entries are added, but
  56  * never deleted.
  57  *
  58  * Since labels are hanging around anyway it doesn't
  59  * hurt to maintain a secid for those awkward situations
  60  * where kernel components that ought to use LSM independent
  61  * interfaces don't. The secid should go away when all of
  62  * these components have been repaired.
  63  *
  64  * The cipso value associated with the label gets stored here, too.
  65  *
  66  * Keep the access rules for this subject label here so that
  67  * the entire set of rules does not need to be examined every
  68  * time.
  69  */
  70 struct smack_known {
  71         struct list_head                list;
  72         struct hlist_node               smk_hashed;
  73         char                            *smk_known;
  74         u32                             smk_secid;
  75         struct netlbl_lsm_secattr       smk_netlabel;   /* on wire labels */
  76         struct list_head                smk_rules;      /* access rules */
  77         struct mutex                    smk_rules_lock; /* lock for rules */
  78 };
  79
  80 /*
  81  * Maximum number of bytes for the levels in a CIPSO IP option.
  82  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  83  * bigger than can be used, and 24 is the next lower multiple
  84  * of 8, and there are too many issues if there isn't space set
  85  * aside for the terminating null byte.
  86  */
  87 #define SMK_CIPSOLEN    24
  88
  89 struct superblock_smack {
  90         struct smack_known      *smk_root;
  91         struct smack_known      *smk_floor;
  92         struct smack_known      *smk_hat;
  93         struct smack_known      *smk_default;
  94         int                     smk_flags;
  95 };
  96
  97 /*
  98  * Superblock flags
  99  */
 100 #define SMK_SB_INITIALIZED      0x01
 101 #define SMK_SB_UNTRUSTED        0x02
 102
 103 struct socket_smack {
 104         struct smack_known      *smk_out;       /* outbound label */
 105         struct smack_known      *smk_in;        /* inbound label */
 106         struct smack_known      *smk_packet;    /* TCP peer label */
 107 };
 108
 109 /*
 110  * Inode smack data
 111  */
 112 struct inode_smack {
 113         struct smack_known      *smk_inode;     /* label of the fso */
 114         struct smack_known      *smk_task;      /* label of the task */
 115         struct smack_known      *smk_mmap;      /* label of the mmap domain */
 116         struct mutex            smk_lock;       /* initialization lock */
 117         int                     smk_flags;      /* smack inode flags */
 118         struct rcu_head         smk_rcu;        /* for freeing inode_smack */
 119 };
 120
 121 struct task_smack {
 122         struct smack_known      *smk_task;      /* label for access control */
 123         struct smack_known      *smk_forked;    /* label when forked */
 124         struct list_head        smk_rules;      /* per task access rules */
 125         struct mutex            smk_rules_lock; /* lock for the rules */
 126         struct list_head        smk_relabel;    /* transit allowed labels */
 127 };
 128
 129 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 130 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 131 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 132 #define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */
 133
 134 /*
 135  * A label access rule.
 136  */
 137 struct smack_rule {
 138         struct list_head        list;
 139         struct smack_known      *smk_subject;
 140         struct smack_known      *smk_object;
 141         int                     smk_access;
 142 };
 143
 144 /*
 145  * An entry in the table identifying IPv4 hosts.
 146  */
 147 struct smk_net4addr {
 148         struct list_head        list;
 149         struct in_addr          smk_host;       /* network address */
 150         struct in_addr          smk_mask;       /* network mask */
 151         int                     smk_masks;      /* mask size */
 152         struct smack_known      *smk_label;     /* label */
 153 };
 154
 155 #if IS_ENABLED(CONFIG_IPV6)
 156 /*
 157  * An entry in the table identifying IPv6 hosts.
 158  */
 159 struct smk_net6addr {
 160         struct list_head        list;
 161         struct in6_addr         smk_host;       /* network address */
 162         struct in6_addr         smk_mask;       /* network mask */
 163         int                     smk_masks;      /* mask size */
 164         struct smack_known      *smk_label;     /* label */
 165 };
 166 #endif /* CONFIG_IPV6 */
 167
 168 #ifdef SMACK_IPV6_PORT_LABELING
 169 /*
 170  * An entry in the table identifying ports.
 171  */
 172 struct smk_port_label {
 173         struct list_head        list;
 174         struct sock             *smk_sock;      /* socket initialized on */
 175         unsigned short          smk_port;       /* the port number */
 176         struct smack_known      *smk_in;        /* inbound label */
 177         struct smack_known      *smk_out;       /* outgoing label */
 178         short                   smk_sock_type;  /* Socket type */
 179         short                   smk_can_reuse;
 180 };
 181 #endif /* SMACK_IPV6_PORT_LABELING */
 182
 183 struct smack_known_list_elem {
 184         struct list_head        list;
 185         struct smack_known      *smk_label;
 186 };
 187
 188 /* Super block security struct flags for mount options */
 189 #define FSDEFAULT_MNT   0x01
 190 #define FSFLOOR_MNT     0x02
 191 #define FSHAT_MNT       0x04
 192 #define FSROOT_MNT      0x08
 193 #define FSTRANS_MNT     0x10
 194
 195 #define NUM_SMK_MNT_OPTS        5
 196
 197 enum {
 198         Opt_error = -1,
 199         Opt_fsdefault = 1,
 200         Opt_fsfloor = 2,
 201         Opt_fshat = 3,
 202         Opt_fsroot = 4,
 203         Opt_fstransmute = 5,
 204 };
 205
 206 /*
 207  * Mount options
 208  */
 209 #define SMK_FSDEFAULT   "smackfsdef="
 210 #define SMK_FSFLOOR     "smackfsfloor="
 211 #define SMK_FSHAT       "smackfshat="
 212 #define SMK_FSROOT      "smackfsroot="
 213 #define SMK_FSTRANS     "smackfstransmute="
 214
 215 #define SMACK_DELETE_OPTION     "-DELETE"
 216 #define SMACK_CIPSO_OPTION      "-CIPSO"
 217
 218 /*
 219  * How communications on this socket are treated.
 220  * Usually it's determined by the underlying netlabel code
 221  * but there are certain cases, including single label hosts
 222  * and potentially single label interfaces for which the
 223  * treatment can not be known in advance.
 224  *
 225  * The possibility of additional labeling schemes being
 226  * introduced in the future exists as well.
 227  */
 228 #define SMACK_UNLABELED_SOCKET  0
 229 #define SMACK_CIPSO_SOCKET      1
 230
 231 /*
 232  * CIPSO defaults.
 233  */
 234 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 235 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 236 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 237 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 238 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 239 /*
 240  * CIPSO 2.2 standard is 239, but Smack wants to use the
 241  * categories in a structured way that limits the value to
 242  * the bits in 23 bytes, hence the unusual number.
 243  */
 244 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 245
 246 /*
 247  * Ptrace rules
 248  */
 249 #define SMACK_PTRACE_DEFAULT    0
 250 #define SMACK_PTRACE_EXACT      1
 251 #define SMACK_PTRACE_DRACONIAN  2
 252 #define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN
 253
 254 /*
 255  * Flags for untraditional access modes.
 256  * It shouldn't be necessary to avoid conflicts with definitions
 257  * in fs.h, but do so anyway.
 258  */
 259 #define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
 260 #define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
 261 #define MAY_BRINGUP     0x00004000      /* Report use of this rule */
 262
 263 /*
 264  * The policy for delivering signals is configurable.
 265  * It is usually "write", but can be "append".
 266  */
 267 #ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
 268 #define MAY_DELIVER     MAY_APPEND      /* Signal delivery requires append */
 269 #else
 270 #define MAY_DELIVER     MAY_WRITE       /* Signal delivery requires write */
 271 #endif
 272
 273 #define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
 274 #define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
 275 #define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */
 276
 277 /*
 278  * Just to make the common cases easier to deal with
 279  */
 280 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 281 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 282 #define MAY_NOT         0
 283
 284 /*
 285  * Number of access types used by Smack (rwxatlb)
 286  */
 287 #define SMK_NUM_ACCESS_TYPE 7
 288
 289 /* SMACK data */
 290 struct smack_audit_data {
 291         const char *function;
 292         char *subject;
 293         char *object;
 294         char *request;
 295         int result;
 296 };
 297
 298 /*
 299  * Smack audit data; is empty if CONFIG_AUDIT not set
 300  * to save some stack
 301  */
 302 struct smk_audit_info {
 303 #ifdef CONFIG_AUDIT
 304         struct common_audit_data a;
 305         struct smack_audit_data sad;
 306 #endif
 307 };
 308
 309 /*
 310  * These functions are in smack_access.c
 311  */
 312 int smk_access_entry(char *, char *, struct list_head *);
 313 int smk_access(struct smack_known *, struct smack_known *,
 314                int, struct smk_audit_info *);
 315 int smk_tskacc(struct task_smack *, struct smack_known *,
 316                u32, struct smk_audit_info *);
 317 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 318 struct smack_known *smack_from_secid(const u32);
 319 char *smk_parse_smack(const char *string, int len);
 320 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 321 struct smack_known *smk_import_entry(const char *, int);
 322 void smk_insert_entry(struct smack_known *skp);
 323 struct smack_known *smk_find_entry(const char *);
 324 bool smack_privileged(int cap);
 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 extern struct lsm_blob_sizes smack_blob_sizes;
 340
 341 extern struct smack_known smack_known_floor;
 342 extern struct smack_known smack_known_hat;
 343 extern struct smack_known smack_known_huh;
 344 extern struct smack_known smack_known_star;
 345 extern struct smack_known smack_known_web;
 346
 347 extern struct mutex     smack_known_lock;
 348 extern struct list_head smack_known_list;
 349 extern struct list_head smk_net4addr_list;
 350 #if IS_ENABLED(CONFIG_IPV6)
 351 extern struct list_head smk_net6addr_list;
 352 #endif /* CONFIG_IPV6 */
 353
 354 extern struct mutex     smack_onlycap_lock;
 355 extern struct list_head smack_onlycap_list;
 356
 357 #define SMACK_HASH_SLOTS 16
 358 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 359
 360 static inline struct task_smack *smack_cred(const struct cred *cred)
 361 {
 362 #ifdef CONFIG_SECURITY_STACKING
 363         return cred->security + smack_blob_sizes.lbs_cred;
 364 #else
 365         return cred->security;
 366 #endif
 367 }
 368
 369 static inline struct smack_known **smack_file(const struct file *file)
 370 {
 371 #ifdef CONFIG_SECURITY_STACKING
 372         return file->f_security + smack_blob_sizes.lbs_file;
 373 #else
 374         return file->f_security;
 375 #endif
 376 }
 377
 378 /*
 379  * Is the directory transmuting?
 380  */
 381 static inline int smk_inode_transmutable(const struct inode *isp)
 382 {
 383         struct inode_smack *sip = isp->i_security;
 384         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 385 }
 386
 387 /*
 388  * Present a pointer to the smack label entry in an inode blob.
 389  */
 390 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 391 {
 392         struct inode_smack *sip = isp->i_security;
 393         return sip->smk_inode;
 394 }
 395
 396 /*
 397  * Present a pointer to the smack label entry in an task blob.
 398  */
 399 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 400 {
 401         return tsp->smk_task;
 402 }
 403
 404 static inline struct smack_known *smk_of_task_struct(
 405                                                 const struct task_struct *t)
 406 {
 407         struct smack_known *skp;
 408         const struct cred *cred;
 409
 410         rcu_read_lock();
 411         cred = __task_cred(t);
 412         rcu_read_unlock();
 413         skp = smk_of_task(smack_cred(cred));
 414         return skp;
 415 }
 416
 417 /*
 418  * Present a pointer to the forked smack label entry in an task blob.
 419  */
 420 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 421 {
 422         return tsp->smk_forked;
 423 }
 424
 425 /*
 426  * Present a pointer to the smack label in the current task blob.
 427  */
 428 static inline struct smack_known *smk_of_current(void)
 429 {
 430         return smk_of_task(smack_cred(current_cred()));
 431 }
 432
 433 /*
 434  * logging functions
 435  */
 436 #define SMACK_AUDIT_DENIED 0x1
 437 #define SMACK_AUDIT_ACCEPT 0x2
 438 extern int log_policy;
 439
 440 void smack_log(char *subject_label, char *object_label,
 441                 int request,
 442                 int result, struct smk_audit_info *auditdata);
 443
 444 #ifdef CONFIG_AUDIT
 445
 446 /*
 447  * some inline functions to set up audit data
 448  * they do nothing if CONFIG_AUDIT is not set
 449  *
 450  */
 451 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 452                                char type)
 453 {
 454         memset(&a->sad, 0, sizeof(a->sad));
 455         a->a.type = type;
 456         a->a.smack_audit_data = &a->sad;
 457         a->a.smack_audit_data->function = func;
 458 }
 459
 460 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 461                                    char type, struct lsm_network_audit *net)
 462 {
 463         smk_ad_init(a, func, type);
 464         memset(net, 0, sizeof(*net));
 465         a->a.u.net = net;
 466 }
 467
 468 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 469                                          struct task_struct *t)
 470 {
 471         a->a.u.tsk = t;
 472 }
 473 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 474                                                     struct dentry *d)
 475 {
 476         a->a.u.dentry = d;
 477 }
 478 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 479                                               struct inode *i)
 480 {
 481         a->a.u.inode = i;
 482 }
 483 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 484                                              struct path p)
 485 {
 486         a->a.u.path = p;
 487 }
 488 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 489                                             struct sock *sk)
 490 {
 491         a->a.u.net->sk = sk;
 492 }
 493
 494 #else /* no AUDIT */
 495
 496 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 497                                char type)
 498 {
 499 }
 500 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 501                                          struct task_struct *t)
 502 {
 503 }
 504 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 505                                                     struct dentry *d)
 506 {
 507 }
 508 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 509                                                  struct vfsmount *m)
 510 {
 511 }
 512 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 513                                               struct inode *i)
 514 {
 515 }
 516 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 517                                              struct path p)
 518 {
 519 }
 520 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 521                                             struct sock *sk)
 522 {
 523 }
 524 #endif
 525
 526 #endif  /* _SECURITY_SMACK_H */