security/smack/smack.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
   4  *
   5  * Author:
   6  *      Casey Schaufler <casey@schaufler-ca.com>
   7  */
   8
   9 #ifndef _SECURITY_SMACK_H
  10 #define _SECURITY_SMACK_H
  11
  12 #include <linux/capability.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/lsm_hooks.h>
  15 #include <linux/in.h>
  16 #if IS_ENABLED(CONFIG_IPV6)
  17 #include <linux/in6.h>
  18 #endif /* CONFIG_IPV6 */
  19 #include <net/netlabel.h>
  20 #include <linux/list.h>
  21 #include <linux/rculist.h>
  22 #include <linux/lsm_audit.h>
  23 #include <linux/msg.h>
  24
  25 /*
  26  * Use IPv6 port labeling if IPv6 is enabled and secmarks
  27  * are not being used.
  28  */
  29 #if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
  30 #define SMACK_IPV6_PORT_LABELING 1
  31 #endif
  32
  33 #if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
  34 #define SMACK_IPV6_SECMARK_LABELING 1
  35 #endif
  36
  37 /*
  38  * Smack labels were limited to 23 characters for a long time.
  39  */
  40 #define SMK_LABELLEN    24
  41 #define SMK_LONGLABEL   256
  42
  43 /*
  44  * This is the repository for labels seen so that it is
  45  * not necessary to keep allocating tiny chuncks of memory
  46  * and so that they can be shared.
  47  *
  48  * Labels are never modified in place. Anytime a label
  49  * is imported (e.g. xattrset on a file) the list is checked
  50  * for it and it is added if it doesn't exist. The address
  51  * is passed out in either case. Entries are added, but
  52  * never deleted.
  53  *
  54  * Since labels are hanging around anyway it doesn't
  55  * hurt to maintain a secid for those awkward situations
  56  * where kernel components that ought to use LSM independent
  57  * interfaces don't. The secid should go away when all of
  58  * these components have been repaired.
  59  *
  60  * The cipso value associated with the label gets stored here, too.
  61  *
  62  * Keep the access rules for this subject label here so that
  63  * the entire set of rules does not need to be examined every
  64  * time.
  65  */
  66 struct smack_known {
  67         struct list_head                list;
  68         struct hlist_node               smk_hashed;
  69         char                            *smk_known;
  70         u32                             smk_secid;
  71         struct netlbl_lsm_secattr       smk_netlabel;   /* on wire labels */
  72         struct list_head                smk_rules;      /* access rules */
  73         struct mutex                    smk_rules_lock; /* lock for rules */
  74 };
  75
  76 /*
  77  * Maximum number of bytes for the levels in a CIPSO IP option.
  78  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  79  * bigger than can be used, and 24 is the next lower multiple
  80  * of 8, and there are too many issues if there isn't space set
  81  * aside for the terminating null byte.
  82  */
  83 #define SMK_CIPSOLEN    24
  84
  85 struct superblock_smack {
  86         struct smack_known      *smk_root;
  87         struct smack_known      *smk_floor;
  88         struct smack_known      *smk_hat;
  89         struct smack_known      *smk_default;
  90         int                     smk_flags;
  91 };
  92
  93 /*
  94  * Superblock flags
  95  */
  96 #define SMK_SB_INITIALIZED      0x01
  97 #define SMK_SB_UNTRUSTED        0x02
  98
  99 struct socket_smack {
 100         struct smack_known      *smk_out;       /* outbound label */
 101         struct smack_known      *smk_in;        /* inbound label */
 102         struct smack_known      *smk_packet;    /* TCP peer label */
 103 };
 104
 105 /*
 106  * Inode smack data
 107  */
 108 struct inode_smack {
 109         struct smack_known      *smk_inode;     /* label of the fso */
 110         struct smack_known      *smk_task;      /* label of the task */
 111         struct smack_known      *smk_mmap;      /* label of the mmap domain */
 112         struct mutex            smk_lock;       /* initialization lock */
 113         int                     smk_flags;      /* smack inode flags */
 114         struct rcu_head         smk_rcu;        /* for freeing inode_smack */
 115 };
 116
 117 struct task_smack {
 118         struct smack_known      *smk_task;      /* label for access control */
 119         struct smack_known      *smk_forked;    /* label when forked */
 120         struct list_head        smk_rules;      /* per task access rules */
 121         struct mutex            smk_rules_lock; /* lock for the rules */
 122         struct list_head        smk_relabel;    /* transit allowed labels */
 123 };
 124
 125 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 126 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 127 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 128 #define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */
 129
 130 /*
 131  * A label access rule.
 132  */
 133 struct smack_rule {
 134         struct list_head        list;
 135         struct smack_known      *smk_subject;
 136         struct smack_known      *smk_object;
 137         int                     smk_access;
 138 };
 139
 140 /*
 141  * An entry in the table identifying IPv4 hosts.
 142  */
 143 struct smk_net4addr {
 144         struct list_head        list;
 145         struct in_addr          smk_host;       /* network address */
 146         struct in_addr          smk_mask;       /* network mask */
 147         int                     smk_masks;      /* mask size */
 148         struct smack_known      *smk_label;     /* label */
 149 };
 150
 151 #if IS_ENABLED(CONFIG_IPV6)
 152 /*
 153  * An entry in the table identifying IPv6 hosts.
 154  */
 155 struct smk_net6addr {
 156         struct list_head        list;
 157         struct in6_addr         smk_host;       /* network address */
 158         struct in6_addr         smk_mask;       /* network mask */
 159         int                     smk_masks;      /* mask size */
 160         struct smack_known      *smk_label;     /* label */
 161 };
 162 #endif /* CONFIG_IPV6 */
 163
 164 #ifdef SMACK_IPV6_PORT_LABELING
 165 /*
 166  * An entry in the table identifying ports.
 167  */
 168 struct smk_port_label {
 169         struct list_head        list;
 170         struct sock             *smk_sock;      /* socket initialized on */
 171         unsigned short          smk_port;       /* the port number */
 172         struct smack_known      *smk_in;        /* inbound label */
 173         struct smack_known      *smk_out;       /* outgoing label */
 174         short                   smk_sock_type;  /* Socket type */
 175         short                   smk_can_reuse;
 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 = 0,
 196         Opt_fsfloor = 1,
 197         Opt_fshat = 2,
 198         Opt_fsroot = 3,
 199         Opt_fstransmute = 4,
 200 };
 201
 202 #define SMACK_DELETE_OPTION     "-DELETE"
 203 #define SMACK_CIPSO_OPTION      "-CIPSO"
 204
 205 /*
 206  * How communications on this socket are treated.
 207  * Usually it's determined by the underlying netlabel code
 208  * but there are certain cases, including single label hosts
 209  * and potentially single label interfaces for which the
 210  * treatment can not be known in advance.
 211  *
 212  * The possibility of additional labeling schemes being
 213  * introduced in the future exists as well.
 214  */
 215 #define SMACK_UNLABELED_SOCKET  0
 216 #define SMACK_CIPSO_SOCKET      1
 217
 218 /*
 219  * CIPSO defaults.
 220  */
 221 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 222 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 223 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 224 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 225 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 226 /*
 227  * CIPSO 2.2 standard is 239, but Smack wants to use the
 228  * categories in a structured way that limits the value to
 229  * the bits in 23 bytes, hence the unusual number.
 230  */
 231 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 232
 233 /*
 234  * Ptrace rules
 235  */
 236 #define SMACK_PTRACE_DEFAULT    0
 237 #define SMACK_PTRACE_EXACT      1
 238 #define SMACK_PTRACE_DRACONIAN  2
 239 #define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN
 240
 241 /*
 242  * Flags for untraditional access modes.
 243  * It shouldn't be necessary to avoid conflicts with definitions
 244  * in fs.h, but do so anyway.
 245  */
 246 #define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
 247 #define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
 248 #define MAY_BRINGUP     0x00004000      /* Report use of this rule */
 249
 250 /*
 251  * The policy for delivering signals is configurable.
 252  * It is usually "write", but can be "append".
 253  */
 254 #ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
 255 #define MAY_DELIVER     MAY_APPEND      /* Signal delivery requires append */
 256 #else
 257 #define MAY_DELIVER     MAY_WRITE       /* Signal delivery requires write */
 258 #endif
 259
 260 #define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
 261 #define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
 262 #define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */
 263
 264 /*
 265  * Just to make the common cases easier to deal with
 266  */
 267 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 268 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 269 #define MAY_NOT         0
 270
 271 /*
 272  * Number of access types used by Smack (rwxatlb)
 273  */
 274 #define SMK_NUM_ACCESS_TYPE 7
 275
 276 /* SMACK data */
 277 struct smack_audit_data {
 278         const char *function;
 279         char *subject;
 280         char *object;
 281         char *request;
 282         int result;
 283 };
 284
 285 /*
 286  * Smack audit data; is empty if CONFIG_AUDIT not set
 287  * to save some stack
 288  */
 289 struct smk_audit_info {
 290 #ifdef CONFIG_AUDIT
 291         struct common_audit_data a;
 292         struct smack_audit_data sad;
 293 #endif
 294 };
 295
 296 /*
 297  * These functions are in smack_access.c
 298  */
 299 int smk_access_entry(char *, char *, struct list_head *);
 300 int smk_access(struct smack_known *, struct smack_known *,
 301                int, struct smk_audit_info *);
 302 int smk_tskacc(struct task_smack *, struct smack_known *,
 303                u32, struct smk_audit_info *);
 304 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 305 struct smack_known *smack_from_secid(const u32);
 306 char *smk_parse_smack(const char *string, int len);
 307 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 308 struct smack_known *smk_import_entry(const char *, int);
 309 void smk_insert_entry(struct smack_known *skp);
 310 struct smack_known *smk_find_entry(const char *);
 311 bool smack_privileged(int cap);
 312 bool smack_privileged_cred(int cap, const struct cred *cred);
 313 void smk_destroy_label_list(struct list_head *list);
 314
 315 /*
 316  * Shared data.
 317  */
 318 extern int smack_enabled;
 319 extern int smack_cipso_direct;
 320 extern int smack_cipso_mapped;
 321 extern struct smack_known *smack_net_ambient;
 322 extern struct smack_known *smack_syslog_label;
 323 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 324 extern struct smack_known *smack_unconfined;
 325 #endif
 326 extern int smack_ptrace_rule;
 327 extern struct lsm_blob_sizes smack_blob_sizes;
 328
 329 extern struct smack_known smack_known_floor;
 330 extern struct smack_known smack_known_hat;
 331 extern struct smack_known smack_known_huh;
 332 extern struct smack_known smack_known_star;
 333 extern struct smack_known smack_known_web;
 334
 335 extern struct mutex     smack_known_lock;
 336 extern struct list_head smack_known_list;
 337 extern struct list_head smk_net4addr_list;
 338 #if IS_ENABLED(CONFIG_IPV6)
 339 extern struct list_head smk_net6addr_list;
 340 #endif /* CONFIG_IPV6 */
 341
 342 extern struct mutex     smack_onlycap_lock;
 343 extern struct list_head smack_onlycap_list;
 344
 345 #define SMACK_HASH_SLOTS 16
 346 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 347 extern struct kmem_cache *smack_rule_cache;
 348
 349 static inline struct task_smack *smack_cred(const struct cred *cred)
 350 {
 351         return cred->security + smack_blob_sizes.lbs_cred;
 352 }
 353
 354 static inline struct smack_known **smack_file(const struct file *file)
 355 {
 356         return (struct smack_known **)(file->f_security +
 357                                        smack_blob_sizes.lbs_file);
 358 }
 359
 360 static inline struct inode_smack *smack_inode(const struct inode *inode)
 361 {
 362         return inode->i_security + smack_blob_sizes.lbs_inode;
 363 }
 364
 365 static inline struct smack_known **smack_msg_msg(const struct msg_msg *msg)
 366 {
 367         return msg->security + smack_blob_sizes.lbs_msg_msg;
 368 }
 369
 370 static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc)
 371 {
 372         return ipc->security + smack_blob_sizes.lbs_ipc;
 373 }
 374
 375 /*
 376  * Is the directory transmuting?
 377  */
 378 static inline int smk_inode_transmutable(const struct inode *isp)
 379 {
 380         struct inode_smack *sip = smack_inode(isp);
 381         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 382 }
 383
 384 /*
 385  * Present a pointer to the smack label entry in an inode blob.
 386  */
 387 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 388 {
 389         struct inode_smack *sip = smack_inode(isp);
 390         return sip->smk_inode;
 391 }
 392
 393 /*
 394  * Present a pointer to the smack label entry in an task blob.
 395  */
 396 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 397 {
 398         return tsp->smk_task;
 399 }
 400
 401 static inline struct smack_known *smk_of_task_struct(
 402                                                 const struct task_struct *t)
 403 {
 404         struct smack_known *skp;
 405         const struct cred *cred;
 406
 407         rcu_read_lock();
 408
 409         cred = __task_cred(t);
 410         skp = smk_of_task(smack_cred(cred));
 411
 412         rcu_read_unlock();
 413
 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 */