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/security.h>
  19 #include <linux/in.h>
  20 #include <net/netlabel.h>
  21 #include <linux/list.h>
  22 #include <linux/rculist.h>
  23 #include <linux/lsm_audit.h>
  24
  25 /*
  26  * Smack labels were limited to 23 characters for a long time.
  27  */
  28 #define SMK_LABELLEN    24
  29 #define SMK_LONGLABEL   256
  30
  31 /*
  32  * This is the repository for labels seen so that it is
  33  * not necessary to keep allocating tiny chuncks of memory
  34  * and so that they can be shared.
  35  *
  36  * Labels are never modified in place. Anytime a label
  37  * is imported (e.g. xattrset on a file) the list is checked
  38  * for it and it is added if it doesn't exist. The address
  39  * is passed out in either case. Entries are added, but
  40  * never deleted.
  41  *
  42  * Since labels are hanging around anyway it doesn't
  43  * hurt to maintain a secid for those awkward situations
  44  * where kernel components that ought to use LSM independent
  45  * interfaces don't. The secid should go away when all of
  46  * these components have been repaired.
  47  *
  48  * The cipso value associated with the label gets stored here, too.
  49  *
  50  * Keep the access rules for this subject label here so that
  51  * the entire set of rules does not need to be examined every
  52  * time.
  53  */
  54 struct smack_known {
  55         struct list_head                list;
  56         struct hlist_node               smk_hashed;
  57         char                            *smk_known;
  58         u32                             smk_secid;
  59         struct netlbl_lsm_secattr       smk_netlabel;   /* on wire labels */
  60         struct list_head                smk_rules;      /* access rules */
  61         struct mutex                    smk_rules_lock; /* lock for rules */
  62 };
  63
  64 /*
  65  * Maximum number of bytes for the levels in a CIPSO IP option.
  66  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  67  * bigger than can be used, and 24 is the next lower multiple
  68  * of 8, and there are too many issues if there isn't space set
  69  * aside for the terminating null byte.
  70  */
  71 #define SMK_CIPSOLEN    24
  72
  73 struct superblock_smack {
  74         struct smack_known      *smk_root;
  75         struct smack_known      *smk_floor;
  76         struct smack_known      *smk_hat;
  77         struct smack_known      *smk_default;
  78         int                     smk_initialized;
  79 };
  80
  81 struct socket_smack {
  82         struct smack_known      *smk_out;       /* outbound label */
  83         struct smack_known      *smk_in;        /* inbound label */
  84         struct smack_known      *smk_packet;    /* TCP peer label */
  85 };
  86
  87 /*
  88  * Inode smack data
  89  */
  90 struct inode_smack {
  91         struct smack_known      *smk_inode;     /* label of the fso */
  92         struct smack_known      *smk_task;      /* label of the task */
  93         struct smack_known      *smk_mmap;      /* label of the mmap domain */
  94         struct mutex            smk_lock;       /* initialization lock */
  95         int                     smk_flags;      /* smack inode flags */
  96 };
  97
  98 struct task_smack {
  99         struct smack_known      *smk_task;      /* label for access control */
 100         struct smack_known      *smk_forked;    /* label when forked */
 101         struct list_head        smk_rules;      /* per task access rules */
 102         struct mutex            smk_rules_lock; /* lock for the rules */
 103 };
 104
 105 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 106 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 107 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 108 #define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */
 109
 110 /*
 111  * A label access rule.
 112  */
 113 struct smack_rule {
 114         struct list_head        list;
 115         struct smack_known      *smk_subject;
 116         struct smack_known      *smk_object;
 117         int                     smk_access;
 118 };
 119
 120 /*
 121  * An entry in the table identifying hosts.
 122  */
 123 struct smk_netlbladdr {
 124         struct list_head        list;
 125         struct sockaddr_in      smk_host;       /* network address */
 126         struct in_addr          smk_mask;       /* network mask */
 127         struct smack_known      *smk_label;     /* label */
 128 };
 129
 130 /*
 131  * An entry in the table identifying ports.
 132  */
 133 struct smk_port_label {
 134         struct list_head        list;
 135         struct sock             *smk_sock;      /* socket initialized on */
 136         unsigned short          smk_port;       /* the port number */
 137         struct smack_known      *smk_in;        /* inbound label */
 138         struct smack_known      *smk_out;       /* outgoing label */
 139 };
 140
 141 /*
 142  * Mount options
 143  */
 144 #define SMK_FSDEFAULT   "smackfsdef="
 145 #define SMK_FSFLOOR     "smackfsfloor="
 146 #define SMK_FSHAT       "smackfshat="
 147 #define SMK_FSROOT      "smackfsroot="
 148 #define SMK_FSTRANS     "smackfstransmute="
 149
 150 #define SMACK_CIPSO_OPTION      "-CIPSO"
 151
 152 /*
 153  * How communications on this socket are treated.
 154  * Usually it's determined by the underlying netlabel code
 155  * but there are certain cases, including single label hosts
 156  * and potentially single label interfaces for which the
 157  * treatment can not be known in advance.
 158  *
 159  * The possibility of additional labeling schemes being
 160  * introduced in the future exists as well.
 161  */
 162 #define SMACK_UNLABELED_SOCKET  0
 163 #define SMACK_CIPSO_SOCKET      1
 164
 165 /*
 166  * CIPSO defaults.
 167  */
 168 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 169 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 170 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 171 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 172 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 173 /*
 174  * CIPSO 2.2 standard is 239, but Smack wants to use the
 175  * categories in a structured way that limits the value to
 176  * the bits in 23 bytes, hence the unusual number.
 177  */
 178 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 179
 180 /*
 181  * Ptrace rules
 182  */
 183 #define SMACK_PTRACE_DEFAULT    0
 184 #define SMACK_PTRACE_EXACT      1
 185 #define SMACK_PTRACE_DRACONIAN  2
 186 #define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN
 187
 188 /*
 189  * Flags for untraditional access modes.
 190  * It shouldn't be necessary to avoid conflicts with definitions
 191  * in fs.h, but do so anyway.
 192  */
 193 #define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
 194 #define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
 195 #define MAY_BRINGUP     0x00004000      /* Report use of this rule */
 196
 197 #define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
 198 #define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
 199 #define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */
 200
 201 /*
 202  * Just to make the common cases easier to deal with
 203  */
 204 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 205 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 206 #define MAY_NOT         0
 207
 208 /*
 209  * Number of access types used by Smack (rwxatlb)
 210  */
 211 #define SMK_NUM_ACCESS_TYPE 7
 212
 213 /* SMACK data */
 214 struct smack_audit_data {
 215         const char *function;
 216         char *subject;
 217         char *object;
 218         char *request;
 219         int result;
 220 };
 221
 222 /*
 223  * Smack audit data; is empty if CONFIG_AUDIT not set
 224  * to save some stack
 225  */
 226 struct smk_audit_info {
 227 #ifdef CONFIG_AUDIT
 228         struct common_audit_data a;
 229         struct smack_audit_data sad;
 230 #endif
 231 };
 232 /*
 233  * These functions are in smack_lsm.c
 234  */
 235 struct inode_smack *new_inode_smack(struct smack_known *);
 236
 237 /*
 238  * These functions are in smack_access.c
 239  */
 240 int smk_access_entry(char *, char *, struct list_head *);
 241 int smk_access(struct smack_known *, struct smack_known *,
 242                int, struct smk_audit_info *);
 243 int smk_tskacc(struct task_smack *, struct smack_known *,
 244                u32, struct smk_audit_info *);
 245 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 246 struct smack_known *smack_from_secid(const u32);
 247 char *smk_parse_smack(const char *string, int len);
 248 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 249 struct smack_known *smk_import_entry(const char *, int);
 250 void smk_insert_entry(struct smack_known *skp);
 251 struct smack_known *smk_find_entry(const char *);
 252
 253 /*
 254  * Shared data.
 255  */
 256 extern int smack_enabled;
 257 extern int smack_cipso_direct;
 258 extern int smack_cipso_mapped;
 259 extern struct smack_known *smack_net_ambient;
 260 extern struct smack_known *smack_onlycap;
 261 extern struct smack_known *smack_syslog_label;
 262 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 263 extern struct smack_known *smack_unconfined;
 264 #endif
 265 extern struct smack_known smack_cipso_option;
 266 extern int smack_ptrace_rule;
 267
 268 extern struct smack_known smack_known_floor;
 269 extern struct smack_known smack_known_hat;
 270 extern struct smack_known smack_known_huh;
 271 extern struct smack_known smack_known_invalid;
 272 extern struct smack_known smack_known_star;
 273 extern struct smack_known smack_known_web;
 274
 275 extern struct mutex     smack_known_lock;
 276 extern struct list_head smack_known_list;
 277 extern struct list_head smk_netlbladdr_list;
 278
 279 extern struct security_operations smack_ops;
 280
 281 #define SMACK_HASH_SLOTS 16
 282 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 283
 284 /*
 285  * Is the directory transmuting?
 286  */
 287 static inline int smk_inode_transmutable(const struct inode *isp)
 288 {
 289         struct inode_smack *sip = isp->i_security;
 290         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 291 }
 292
 293 /*
 294  * Present a pointer to the smack label entry in an inode blob.
 295  */
 296 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 297 {
 298         struct inode_smack *sip = isp->i_security;
 299         return sip->smk_inode;
 300 }
 301
 302 /*
 303  * Present a pointer to the smack label entry in an task blob.
 304  */
 305 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 306 {
 307         return tsp->smk_task;
 308 }
 309
 310 static inline struct smack_known *smk_of_task_struct(const struct task_struct *t)
 311 {
 312         struct smack_known *skp;
 313
 314         rcu_read_lock();
 315         skp = smk_of_task(__task_cred(t)->security);
 316         rcu_read_unlock();
 317         return skp;
 318 }
 319
 320 /*
 321  * Present a pointer to the forked smack label entry in an task blob.
 322  */
 323 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 324 {
 325         return tsp->smk_forked;
 326 }
 327
 328 /*
 329  * Present a pointer to the smack label in the current task blob.
 330  */
 331 static inline struct smack_known *smk_of_current(void)
 332 {
 333         return smk_of_task(current_security());
 334 }
 335
 336 /*
 337  * Is the task privileged and allowed to be privileged
 338  * by the onlycap rule.
 339  */
 340 static inline int smack_privileged(int cap)
 341 {
 342         struct smack_known *skp = smk_of_current();
 343
 344         if (!capable(cap))
 345                 return 0;
 346         if (smack_onlycap == NULL || smack_onlycap == skp)
 347                 return 1;
 348         return 0;
 349 }
 350
 351 /*
 352  * logging functions
 353  */
 354 #define SMACK_AUDIT_DENIED 0x1
 355 #define SMACK_AUDIT_ACCEPT 0x2
 356 extern int log_policy;
 357
 358 void smack_log(char *subject_label, char *object_label,
 359                 int request,
 360                 int result, struct smk_audit_info *auditdata);
 361
 362 #ifdef CONFIG_AUDIT
 363
 364 /*
 365  * some inline functions to set up audit data
 366  * they do nothing if CONFIG_AUDIT is not set
 367  *
 368  */
 369 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 370                                char type)
 371 {
 372         memset(&a->sad, 0, sizeof(a->sad));
 373         a->a.type = type;
 374         a->a.smack_audit_data = &a->sad;
 375         a->a.smack_audit_data->function = func;
 376 }
 377
 378 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 379                                    char type, struct lsm_network_audit *net)
 380 {
 381         smk_ad_init(a, func, type);
 382         memset(net, 0, sizeof(*net));
 383         a->a.u.net = net;
 384 }
 385
 386 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 387                                          struct task_struct *t)
 388 {
 389         a->a.u.tsk = t;
 390 }
 391 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 392                                                     struct dentry *d)
 393 {
 394         a->a.u.dentry = d;
 395 }
 396 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 397                                               struct inode *i)
 398 {
 399         a->a.u.inode = i;
 400 }
 401 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 402                                              struct path p)
 403 {
 404         a->a.u.path = p;
 405 }
 406 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 407                                             struct sock *sk)
 408 {
 409         a->a.u.net->sk = sk;
 410 }
 411
 412 #else /* no AUDIT */
 413
 414 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 415                                char type)
 416 {
 417 }
 418 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 419                                          struct task_struct *t)
 420 {
 421 }
 422 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 423                                                     struct dentry *d)
 424 {
 425 }
 426 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 427                                                  struct vfsmount *m)
 428 {
 429 }
 430 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 431                                               struct inode *i)
 432 {
 433 }
 434 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 435                                              struct path p)
 436 {
 437 }
 438 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 439                                             struct sock *sk)
 440 {
 441 }
 442 #endif
 443
 444 #endif  /* _SECURITY_SMACK_H */