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         char            *smk_root;
  75         char            *smk_floor;
  76         char            *smk_hat;
  77         char            *smk_default;
  78         int             smk_initialized;
  79 };
  80
  81 struct socket_smack {
  82         struct smack_known      *smk_out;       /* outbound label */
  83         char                    *smk_in;        /* inbound label */
  84         char                    *smk_packet;    /* TCP peer label */
  85 };
  86
  87 /*
  88  * Inode smack data
  89  */
  90 struct inode_smack {
  91         char                    *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
 109 /*
 110  * A label access rule.
 111  */
 112 struct smack_rule {
 113         struct list_head        list;
 114         struct smack_known      *smk_subject;
 115         char                    *smk_object;
 116         int                     smk_access;
 117 };
 118
 119 /*
 120  * An entry in the table identifying hosts.
 121  */
 122 struct smk_netlbladdr {
 123         struct list_head        list;
 124         struct sockaddr_in      smk_host;       /* network address */
 125         struct in_addr          smk_mask;       /* network mask */
 126         char                    *smk_label;     /* label */
 127 };
 128
 129 /*
 130  * An entry in the table identifying ports.
 131  */
 132 struct smk_port_label {
 133         struct list_head        list;
 134         struct sock             *smk_sock;      /* socket initialized on */
 135         unsigned short          smk_port;       /* the port number */
 136         char                    *smk_in;        /* incoming label */
 137         struct smack_known      *smk_out;       /* outgoing label */
 138 };
 139
 140 /*
 141  * Mount options
 142  */
 143 #define SMK_FSDEFAULT   "smackfsdef="
 144 #define SMK_FSFLOOR     "smackfsfloor="
 145 #define SMK_FSHAT       "smackfshat="
 146 #define SMK_FSROOT      "smackfsroot="
 147 #define SMK_FSTRANS     "smackfstransmute="
 148
 149 #define SMACK_CIPSO_OPTION      "-CIPSO"
 150
 151 /*
 152  * How communications on this socket are treated.
 153  * Usually it's determined by the underlying netlabel code
 154  * but there are certain cases, including single label hosts
 155  * and potentially single label interfaces for which the
 156  * treatment can not be known in advance.
 157  *
 158  * The possibility of additional labeling schemes being
 159  * introduced in the future exists as well.
 160  */
 161 #define SMACK_UNLABELED_SOCKET  0
 162 #define SMACK_CIPSO_SOCKET      1
 163
 164 /*
 165  * CIPSO defaults.
 166  */
 167 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 168 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 169 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 170 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 171 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 172 /*
 173  * CIPSO 2.2 standard is 239, but Smack wants to use the
 174  * categories in a structured way that limits the value to
 175  * the bits in 23 bytes, hence the unusual number.
 176  */
 177 #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
 178
 179 /*
 180  * Flag for transmute access
 181  */
 182 #define MAY_TRANSMUTE   64
 183 /*
 184  * Just to make the common cases easier to deal with
 185  */
 186 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 187 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 188 #define MAY_NOT         0
 189
 190 /*
 191  * Number of access types used by Smack (rwxat)
 192  */
 193 #define SMK_NUM_ACCESS_TYPE 5
 194
 195 /* SMACK data */
 196 struct smack_audit_data {
 197         const char *function;
 198         char *subject;
 199         char *object;
 200         char *request;
 201         int result;
 202 };
 203
 204 /*
 205  * Smack audit data; is empty if CONFIG_AUDIT not set
 206  * to save some stack
 207  */
 208 struct smk_audit_info {
 209 #ifdef CONFIG_AUDIT
 210         struct common_audit_data a;
 211         struct smack_audit_data sad;
 212 #endif
 213 };
 214 /*
 215  * These functions are in smack_lsm.c
 216  */
 217 struct inode_smack *new_inode_smack(char *);
 218
 219 /*
 220  * These functions are in smack_access.c
 221  */
 222 int smk_access_entry(char *, char *, struct list_head *);
 223 int smk_access(struct smack_known *, char *, int, struct smk_audit_info *);
 224 int smk_curacc(char *, u32, struct smk_audit_info *);
 225 struct smack_known *smack_from_secid(const u32);
 226 char *smk_parse_smack(const char *string, int len);
 227 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 228 char *smk_import(const char *, int);
 229 struct smack_known *smk_import_entry(const char *, int);
 230 void smk_insert_entry(struct smack_known *skp);
 231 struct smack_known *smk_find_entry(const char *);
 232 u32 smack_to_secid(const char *);
 233
 234 /*
 235  * Shared data.
 236  */
 237 extern int smack_cipso_direct;
 238 extern int smack_cipso_mapped;
 239 extern struct smack_known *smack_net_ambient;
 240 extern char *smack_onlycap;
 241 extern const char *smack_cipso_option;
 242
 243 extern struct smack_known smack_known_floor;
 244 extern struct smack_known smack_known_hat;
 245 extern struct smack_known smack_known_huh;
 246 extern struct smack_known smack_known_invalid;
 247 extern struct smack_known smack_known_star;
 248 extern struct smack_known smack_known_web;
 249
 250 extern struct mutex     smack_known_lock;
 251 extern struct list_head smack_known_list;
 252 extern struct list_head smk_netlbladdr_list;
 253
 254 extern struct security_operations smack_ops;
 255
 256 #define SMACK_HASH_SLOTS 16
 257 extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 258
 259 /*
 260  * Is the directory transmuting?
 261  */
 262 static inline int smk_inode_transmutable(const struct inode *isp)
 263 {
 264         struct inode_smack *sip = isp->i_security;
 265         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 266 }
 267
 268 /*
 269  * Present a pointer to the smack label in an inode blob.
 270  */
 271 static inline char *smk_of_inode(const struct inode *isp)
 272 {
 273         struct inode_smack *sip = isp->i_security;
 274         return sip->smk_inode;
 275 }
 276
 277 /*
 278  * Present a pointer to the smack label entry in an task blob.
 279  */
 280 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 281 {
 282         return tsp->smk_task;
 283 }
 284
 285 /*
 286  * Present a pointer to the forked smack label entry in an task blob.
 287  */
 288 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 289 {
 290         return tsp->smk_forked;
 291 }
 292
 293 /*
 294  * Present a pointer to the smack label in the current task blob.
 295  */
 296 static inline struct smack_known *smk_of_current(void)
 297 {
 298         return smk_of_task(current_security());
 299 }
 300
 301 /*
 302  * Is the task privileged and allowed to be privileged
 303  * by the onlycap rule.
 304  */
 305 static inline int smack_privileged(int cap)
 306 {
 307         struct smack_known *skp = smk_of_current();
 308
 309         if (!capable(cap))
 310                 return 0;
 311         if (smack_onlycap == NULL || smack_onlycap == skp->smk_known)
 312                 return 1;
 313         return 0;
 314 }
 315
 316 /*
 317  * logging functions
 318  */
 319 #define SMACK_AUDIT_DENIED 0x1
 320 #define SMACK_AUDIT_ACCEPT 0x2
 321 extern int log_policy;
 322
 323 void smack_log(char *subject_label, char *object_label,
 324                 int request,
 325                 int result, struct smk_audit_info *auditdata);
 326
 327 #ifdef CONFIG_AUDIT
 328
 329 /*
 330  * some inline functions to set up audit data
 331  * they do nothing if CONFIG_AUDIT is not set
 332  *
 333  */
 334 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 335                                char type)
 336 {
 337         memset(&a->sad, 0, sizeof(a->sad));
 338         a->a.type = type;
 339         a->a.smack_audit_data = &a->sad;
 340         a->a.smack_audit_data->function = func;
 341 }
 342
 343 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 344                                    char type, struct lsm_network_audit *net)
 345 {
 346         smk_ad_init(a, func, type);
 347         memset(net, 0, sizeof(*net));
 348         a->a.u.net = net;
 349 }
 350
 351 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 352                                          struct task_struct *t)
 353 {
 354         a->a.u.tsk = t;
 355 }
 356 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 357                                                     struct dentry *d)
 358 {
 359         a->a.u.dentry = d;
 360 }
 361 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 362                                               struct inode *i)
 363 {
 364         a->a.u.inode = i;
 365 }
 366 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 367                                              struct path p)
 368 {
 369         a->a.u.path = p;
 370 }
 371 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 372                                             struct sock *sk)
 373 {
 374         a->a.u.net->sk = sk;
 375 }
 376
 377 #else /* no AUDIT */
 378
 379 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 380                                char type)
 381 {
 382 }
 383 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 384                                          struct task_struct *t)
 385 {
 386 }
 387 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 388                                                     struct dentry *d)
 389 {
 390 }
 391 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 392                                                  struct vfsmount *m)
 393 {
 394 }
 395 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 396                                               struct inode *i)
 397 {
 398 }
 399 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 400                                              struct path p)
 401 {
 402 }
 403 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 404                                             struct sock *sk)
 405 {
 406 }
 407 #endif
 408
 409 #endif  /* _SECURITY_SMACK_H */