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  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  27  * bigger than can be used, and 24 is the next lower multiple
  28  * of 8, and there are too many issues if there isn't space set
  29  * aside for the terminating null byte.
  30  */
  31 #define SMK_MAXLEN      23
  32 #define SMK_LABELLEN    (SMK_MAXLEN+1)
  33
  34 struct superblock_smack {
  35         char            *smk_root;
  36         char            *smk_floor;
  37         char            *smk_hat;
  38         char            *smk_default;
  39         int             smk_initialized;
  40         spinlock_t      smk_sblock;     /* for initialization */
  41 };
  42
  43 struct socket_smack {
  44         char            *smk_out;       /* outbound label */
  45         char            *smk_in;        /* inbound label */
  46         char            *smk_packet;    /* TCP peer label */
  47 };
  48
  49 /*
  50  * Inode smack data
  51  */
  52 struct inode_smack {
  53         char            *smk_inode;     /* label of the fso */
  54         char            *smk_task;      /* label of the task */
  55         char            *smk_mmap;      /* label of the mmap domain */
  56         struct mutex    smk_lock;       /* initialization lock */
  57         int             smk_flags;      /* smack inode flags */
  58 };
  59
  60 struct task_smack {
  61         char                    *smk_task;      /* label for access control */
  62         char                    *smk_forked;    /* label when forked */
  63         struct list_head        smk_rules;      /* per task access rules */
  64         struct mutex            smk_rules_lock; /* lock for the rules */
  65 };
  66
  67 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
  68 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
  69
  70 /*
  71  * A label access rule.
  72  */
  73 struct smack_rule {
  74         struct list_head        list;
  75         char                    *smk_subject;
  76         char                    *smk_object;
  77         int                     smk_access;
  78 };
  79
  80 /*
  81  * An entry in the table mapping smack values to
  82  * CIPSO level/category-set values.
  83  */
  84 struct smack_cipso {
  85         int     smk_level;
  86         char    smk_catset[SMK_LABELLEN];
  87 };
  88
  89 /*
  90  * An entry in the table identifying hosts.
  91  */
  92 struct smk_netlbladdr {
  93         struct list_head        list;
  94         struct sockaddr_in      smk_host;       /* network address */
  95         struct in_addr          smk_mask;       /* network mask */
  96         char                    *smk_label;     /* label */
  97 };
  98
  99 /*
 100  * This is the repository for labels seen so that it is
 101  * not necessary to keep allocating tiny chuncks of memory
 102  * and so that they can be shared.
 103  *
 104  * Labels are never modified in place. Anytime a label
 105  * is imported (e.g. xattrset on a file) the list is checked
 106  * for it and it is added if it doesn't exist. The address
 107  * is passed out in either case. Entries are added, but
 108  * never deleted.
 109  *
 110  * Since labels are hanging around anyway it doesn't
 111  * hurt to maintain a secid for those awkward situations
 112  * where kernel components that ought to use LSM independent
 113  * interfaces don't. The secid should go away when all of
 114  * these components have been repaired.
 115  *
 116  * If there is a cipso value associated with the label it
 117  * gets stored here, too. This will most likely be rare as
 118  * the cipso direct mapping in used internally.
 119  *
 120  * Keep the access rules for this subject label here so that
 121  * the entire set of rules does not need to be examined every
 122  * time.
 123  */
 124 struct smack_known {
 125         struct list_head        list;
 126         char                    smk_known[SMK_LABELLEN];
 127         u32                     smk_secid;
 128         struct smack_cipso      *smk_cipso;
 129         spinlock_t              smk_cipsolock;  /* for changing cipso map */
 130         struct list_head        smk_rules;      /* access rules */
 131         struct mutex            smk_rules_lock; /* lock for the rules */
 132 };
 133
 134 /*
 135  * Mount options
 136  */
 137 #define SMK_FSDEFAULT   "smackfsdef="
 138 #define SMK_FSFLOOR     "smackfsfloor="
 139 #define SMK_FSHAT       "smackfshat="
 140 #define SMK_FSROOT      "smackfsroot="
 141
 142 #define SMACK_CIPSO_OPTION      "-CIPSO"
 143
 144 /*
 145  * How communications on this socket are treated.
 146  * Usually it's determined by the underlying netlabel code
 147  * but there are certain cases, including single label hosts
 148  * and potentially single label interfaces for which the
 149  * treatment can not be known in advance.
 150  *
 151  * The possibility of additional labeling schemes being
 152  * introduced in the future exists as well.
 153  */
 154 #define SMACK_UNLABELED_SOCKET  0
 155 #define SMACK_CIPSO_SOCKET      1
 156
 157 /*
 158  * smackfs magic number
 159  */
 160 #define SMACK_MAGIC     0x43415d53 /* "SMAC" */
 161
 162 /*
 163  * CIPSO defaults.
 164  */
 165 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 166 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 167 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 168 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 169 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 170 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 171
 172 /*
 173  * Flag for transmute access
 174  */
 175 #define MAY_TRANSMUTE   64
 176 /*
 177  * Just to make the common cases easier to deal with
 178  */
 179 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 180 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 181 #define MAY_NOT         0
 182
 183 /*
 184  * Number of access types used by Smack (rwxat)
 185  */
 186 #define SMK_NUM_ACCESS_TYPE 5
 187
 188 /* SMACK data */
 189 struct smack_audit_data {
 190         const char *function;
 191         char *subject;
 192         char *object;
 193         char *request;
 194         int result;
 195 };
 196
 197 /*
 198  * Smack audit data; is empty if CONFIG_AUDIT not set
 199  * to save some stack
 200  */
 201 struct smk_audit_info {
 202 #ifdef CONFIG_AUDIT
 203         struct common_audit_data a;
 204         struct smack_audit_data sad;
 205 #endif
 206 };
 207 /*
 208  * These functions are in smack_lsm.c
 209  */
 210 struct inode_smack *new_inode_smack(char *);
 211
 212 /*
 213  * These functions are in smack_access.c
 214  */
 215 int smk_access_entry(char *, char *, struct list_head *);
 216 int smk_access(char *, char *, int, struct smk_audit_info *);
 217 int smk_curacc(char *, u32, struct smk_audit_info *);
 218 int smack_to_cipso(const char *, struct smack_cipso *);
 219 char *smack_from_cipso(u32, char *);
 220 char *smack_from_secid(const u32);
 221 void smk_parse_smack(const char *string, int len, char *smack);
 222 char *smk_import(const char *, int);
 223 struct smack_known *smk_import_entry(const char *, int);
 224 struct smack_known *smk_find_entry(const char *);
 225 u32 smack_to_secid(const char *);
 226
 227 /*
 228  * Shared data.
 229  */
 230 extern int smack_cipso_direct;
 231 extern char *smack_net_ambient;
 232 extern char *smack_onlycap;
 233 extern const char *smack_cipso_option;
 234
 235 extern struct smack_known smack_known_floor;
 236 extern struct smack_known smack_known_hat;
 237 extern struct smack_known smack_known_huh;
 238 extern struct smack_known smack_known_invalid;
 239 extern struct smack_known smack_known_star;
 240 extern struct smack_known smack_known_web;
 241
 242 extern struct list_head smack_known_list;
 243 extern struct list_head smk_netlbladdr_list;
 244
 245 extern struct security_operations smack_ops;
 246
 247 /*
 248  * Stricly for CIPSO level manipulation.
 249  * Set the category bit number in a smack label sized buffer.
 250  */
 251 static inline void smack_catset_bit(int cat, char *catsetp)
 252 {
 253         if (cat > SMK_LABELLEN * 8)
 254                 return;
 255
 256         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 257 }
 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 in an task blob.
 279  */
 280 static inline char *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 in an task blob.
 287  */
 288 static inline char *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 char *smk_of_current(void)
 297 {
 298         return smk_of_task(current_security());
 299 }
 300
 301 /*
 302  * logging functions
 303  */
 304 #define SMACK_AUDIT_DENIED 0x1
 305 #define SMACK_AUDIT_ACCEPT 0x2
 306 extern int log_policy;
 307
 308 void smack_log(char *subject_label, char *object_label,
 309                 int request,
 310                 int result, struct smk_audit_info *auditdata);
 311
 312 #ifdef CONFIG_AUDIT
 313
 314 /*
 315  * some inline functions to set up audit data
 316  * they do nothing if CONFIG_AUDIT is not set
 317  *
 318  */
 319 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 320                                char type)
 321 {
 322         memset(a, 0, sizeof(*a));
 323         a->a.type = type;
 324         a->a.smack_audit_data = &a->sad;
 325         a->a.smack_audit_data->function = func;
 326 }
 327
 328 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 329                                    char type, struct lsm_network_audit *net)
 330 {
 331         smk_ad_init(a, func, type);
 332         memset(net, 0, sizeof(*net));
 333         a->a.u.net = net;
 334 }
 335
 336 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 337                                          struct task_struct *t)
 338 {
 339         a->a.u.tsk = t;
 340 }
 341 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 342                                                     struct dentry *d)
 343 {
 344         a->a.u.dentry = d;
 345 }
 346 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 347                                               struct inode *i)
 348 {
 349         a->a.u.inode = i;
 350 }
 351 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 352                                              struct path p)
 353 {
 354         a->a.u.path = p;
 355 }
 356 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 357                                             struct sock *sk)
 358 {
 359         a->a.u.net->sk = sk;
 360 }
 361
 362 #else /* no AUDIT */
 363
 364 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 365                                char type)
 366 {
 367 }
 368 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 369                                          struct task_struct *t)
 370 {
 371 }
 372 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 373                                                     struct dentry *d)
 374 {
 375 }
 376 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 377                                                  struct vfsmount *m)
 378 {
 379 }
 380 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 381                                               struct inode *i)
 382 {
 383 }
 384 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 385                                              struct path p)
 386 {
 387 }
 388 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 389                                             struct sock *sk)
 390 {
 391 }
 392 #endif
 393
 394 #endif  /* _SECURITY_SMACK_H */