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[SMK_LABELLEN];       /* 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 struct smack_known {
 121         struct list_head        list;
 122         char                    smk_known[SMK_LABELLEN];
 123         u32                     smk_secid;
 124         struct smack_cipso      *smk_cipso;
 125         spinlock_t              smk_cipsolock; /* for changing cipso map */
 126 };
 127
 128 /*
 129  * Mount options
 130  */
 131 #define SMK_FSDEFAULT   "smackfsdef="
 132 #define SMK_FSFLOOR     "smackfsfloor="
 133 #define SMK_FSHAT       "smackfshat="
 134 #define SMK_FSROOT      "smackfsroot="
 135
 136 #define SMACK_CIPSO_OPTION      "-CIPSO"
 137
 138 /*
 139  * How communications on this socket are treated.
 140  * Usually it's determined by the underlying netlabel code
 141  * but there are certain cases, including single label hosts
 142  * and potentially single label interfaces for which the
 143  * treatment can not be known in advance.
 144  *
 145  * The possibility of additional labeling schemes being
 146  * introduced in the future exists as well.
 147  */
 148 #define SMACK_UNLABELED_SOCKET  0
 149 #define SMACK_CIPSO_SOCKET      1
 150
 151 /*
 152  * smackfs magic number
 153  * smackfs macic number
 154  */
 155 #define SMACK_MAGIC     0x43415d53 /* "SMAC" */
 156
 157 /*
 158  * CIPSO defaults.
 159  */
 160 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 161 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 162 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 163 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 164 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 165 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 166
 167 /*
 168  * Flag for transmute access
 169  */
 170 #define MAY_TRANSMUTE   64
 171 /*
 172  * Just to make the common cases easier to deal with
 173  */
 174 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 175 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 176 #define MAY_NOT         0
 177
 178 /*
 179  * Number of access types used by Smack (rwxa)
 180  */
 181 #define SMK_NUM_ACCESS_TYPE 4
 182
 183 /*
 184  * Smack audit data; is empty if CONFIG_AUDIT not set
 185  * to save some stack
 186  */
 187 struct smk_audit_info {
 188 #ifdef CONFIG_AUDIT
 189         struct common_audit_data a;
 190 #endif
 191 };
 192 /*
 193  * These functions are in smack_lsm.c
 194  */
 195 struct inode_smack *new_inode_smack(char *);
 196
 197 /*
 198  * These functions are in smack_access.c
 199  */
 200 int smk_access_entry(char *, char *, struct list_head *);
 201 int smk_access(char *, char *, int, struct smk_audit_info *);
 202 int smk_curacc(char *, u32, struct smk_audit_info *);
 203 int smack_to_cipso(const char *, struct smack_cipso *);
 204 void smack_from_cipso(u32, char *, char *);
 205 char *smack_from_secid(const u32);
 206 char *smk_import(const char *, int);
 207 struct smack_known *smk_import_entry(const char *, int);
 208 u32 smack_to_secid(const char *);
 209
 210 /*
 211  * Shared data.
 212  */
 213 extern int smack_cipso_direct;
 214 extern char *smack_net_ambient;
 215 extern char *smack_onlycap;
 216 extern const char *smack_cipso_option;
 217
 218 extern struct smack_known smack_known_floor;
 219 extern struct smack_known smack_known_hat;
 220 extern struct smack_known smack_known_huh;
 221 extern struct smack_known smack_known_invalid;
 222 extern struct smack_known smack_known_star;
 223 extern struct smack_known smack_known_web;
 224
 225 extern struct list_head smack_known_list;
 226 extern struct list_head smack_rule_list;
 227 extern struct list_head smk_netlbladdr_list;
 228
 229 extern struct security_operations smack_ops;
 230
 231 /*
 232  * Stricly for CIPSO level manipulation.
 233  * Set the category bit number in a smack label sized buffer.
 234  */
 235 static inline void smack_catset_bit(int cat, char *catsetp)
 236 {
 237         if (cat > SMK_LABELLEN * 8)
 238                 return;
 239
 240         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 241 }
 242
 243 /*
 244  * Is the directory transmuting?
 245  */
 246 static inline int smk_inode_transmutable(const struct inode *isp)
 247 {
 248         struct inode_smack *sip = isp->i_security;
 249         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 250 }
 251
 252 /*
 253  * Present a pointer to the smack label in an inode blob.
 254  */
 255 static inline char *smk_of_inode(const struct inode *isp)
 256 {
 257         struct inode_smack *sip = isp->i_security;
 258         return sip->smk_inode;
 259 }
 260
 261 /*
 262  * Present a pointer to the smack label in an task blob.
 263  */
 264 static inline char *smk_of_task(const struct task_smack *tsp)
 265 {
 266         return tsp->smk_task;
 267 }
 268
 269 /*
 270  * Present a pointer to the forked smack label in an task blob.
 271  */
 272 static inline char *smk_of_forked(const struct task_smack *tsp)
 273 {
 274         return tsp->smk_forked;
 275 }
 276
 277 /*
 278  * Present a pointer to the smack label in the current task blob.
 279  */
 280 static inline char *smk_of_current(void)
 281 {
 282         return smk_of_task(current_security());
 283 }
 284
 285 /*
 286  * logging functions
 287  */
 288 #define SMACK_AUDIT_DENIED 0x1
 289 #define SMACK_AUDIT_ACCEPT 0x2
 290 extern int log_policy;
 291
 292 void smack_log(char *subject_label, char *object_label,
 293                 int request,
 294                 int result, struct smk_audit_info *auditdata);
 295
 296 #ifdef CONFIG_AUDIT
 297
 298 /*
 299  * some inline functions to set up audit data
 300  * they do nothing if CONFIG_AUDIT is not set
 301  *
 302  */
 303 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 304                                char type)
 305 {
 306         memset(a, 0, sizeof(*a));
 307         a->a.type = type;
 308         a->a.smack_audit_data.function = func;
 309 }
 310
 311 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 312                                          struct task_struct *t)
 313 {
 314         a->a.u.tsk = t;
 315 }
 316 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 317                                                     struct dentry *d)
 318 {
 319         a->a.u.dentry = d;
 320 }
 321 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 322                                               struct inode *i)
 323 {
 324         a->a.u.inode = i;
 325 }
 326 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 327                                              struct path p)
 328 {
 329         a->a.u.path = p;
 330 }
 331 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 332                                             struct sock *sk)
 333 {
 334         a->a.u.net.sk = sk;
 335 }
 336
 337 #else /* no AUDIT */
 338
 339 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 340                                char type)
 341 {
 342 }
 343 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 344                                          struct task_struct *t)
 345 {
 346 }
 347 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 348                                                     struct dentry *d)
 349 {
 350 }
 351 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 352                                                  struct vfsmount *m)
 353 {
 354 }
 355 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 356                                               struct inode *i)
 357 {
 358 }
 359 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 360                                              struct path p)
 361 {
 362 }
 363 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 364                                             struct sock *sk)
 365 {
 366 }
 367 #endif
 368
 369 #endif  /* _SECURITY_SMACK_H */