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         struct mutex    smk_lock;       /* initialization lock */
  56         int             smk_flags;      /* smack inode flags */
  57 };
  58
  59 struct task_smack {
  60         char            *smk_task;      /* label used for access control */
  61         char            *smk_forked;    /* label when forked */
  62 };
  63
  64 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
  65 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
  66
  67 /*
  68  * A label access rule.
  69  */
  70 struct smack_rule {
  71         struct list_head        list;
  72         char                    *smk_subject;
  73         char                    *smk_object;
  74         int                     smk_access;
  75 };
  76
  77 /*
  78  * An entry in the table mapping smack values to
  79  * CIPSO level/category-set values.
  80  */
  81 struct smack_cipso {
  82         int     smk_level;
  83         char    smk_catset[SMK_LABELLEN];
  84 };
  85
  86 /*
  87  * An entry in the table identifying hosts.
  88  */
  89 struct smk_netlbladdr {
  90         struct list_head        list;
  91         struct sockaddr_in      smk_host;       /* network address */
  92         struct in_addr          smk_mask;       /* network mask */
  93         char                    *smk_label;     /* label */
  94 };
  95
  96 /*
  97  * This is the repository for labels seen so that it is
  98  * not necessary to keep allocating tiny chuncks of memory
  99  * and so that they can be shared.
 100  *
 101  * Labels are never modified in place. Anytime a label
 102  * is imported (e.g. xattrset on a file) the list is checked
 103  * for it and it is added if it doesn't exist. The address
 104  * is passed out in either case. Entries are added, but
 105  * never deleted.
 106  *
 107  * Since labels are hanging around anyway it doesn't
 108  * hurt to maintain a secid for those awkward situations
 109  * where kernel components that ought to use LSM independent
 110  * interfaces don't. The secid should go away when all of
 111  * these components have been repaired.
 112  *
 113  * If there is a cipso value associated with the label it
 114  * gets stored here, too. This will most likely be rare as
 115  * the cipso direct mapping in used internally.
 116  */
 117 struct smack_known {
 118         struct list_head        list;
 119         char                    smk_known[SMK_LABELLEN];
 120         u32                     smk_secid;
 121         struct smack_cipso      *smk_cipso;
 122         spinlock_t              smk_cipsolock; /* for changing cipso map */
 123 };
 124
 125 /*
 126  * Mount options
 127  */
 128 #define SMK_FSDEFAULT   "smackfsdef="
 129 #define SMK_FSFLOOR     "smackfsfloor="
 130 #define SMK_FSHAT       "smackfshat="
 131 #define SMK_FSROOT      "smackfsroot="
 132
 133 #define SMACK_CIPSO_OPTION      "-CIPSO"
 134
 135 /*
 136  * How communications on this socket are treated.
 137  * Usually it's determined by the underlying netlabel code
 138  * but there are certain cases, including single label hosts
 139  * and potentially single label interfaces for which the
 140  * treatment can not be known in advance.
 141  *
 142  * The possibility of additional labeling schemes being
 143  * introduced in the future exists as well.
 144  */
 145 #define SMACK_UNLABELED_SOCKET  0
 146 #define SMACK_CIPSO_SOCKET      1
 147
 148 /*
 149  * smackfs magic number
 150  * smackfs macic number
 151  */
 152 #define SMACK_MAGIC     0x43415d53 /* "SMAC" */
 153
 154 /*
 155  * A limit on the number of entries in the lists
 156  * makes some of the list administration easier.
 157  */
 158 #define SMACK_LIST_MAX  10000
 159
 160 /*
 161  * CIPSO defaults.
 162  */
 163 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 164 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 165 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 166 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 167 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 168 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 169
 170 /*
 171  * Flag for transmute access
 172  */
 173 #define MAY_TRANSMUTE   64
 174 /*
 175  * Just to make the common cases easier to deal with
 176  */
 177 #define MAY_ANY         (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 178 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 179 #define MAY_ANYWRITE    (MAY_WRITE | MAY_APPEND)
 180 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 181 #define MAY_NOT         0
 182
 183 /*
 184  * Number of access types used by Smack (rwxa)
 185  */
 186 #define SMK_NUM_ACCESS_TYPE 4
 187
 188 /*
 189  * Smack audit data; is empty if CONFIG_AUDIT not set
 190  * to save some stack
 191  */
 192 struct smk_audit_info {
 193 #ifdef CONFIG_AUDIT
 194         struct common_audit_data a;
 195 #endif
 196 };
 197 /*
 198  * These functions are in smack_lsm.c
 199  */
 200 struct inode_smack *new_inode_smack(char *);
 201
 202 /*
 203  * These functions are in smack_access.c
 204  */
 205 int smk_access_entry(char *, char *);
 206 int smk_access(char *, char *, int, struct smk_audit_info *);
 207 int smk_curacc(char *, u32, struct smk_audit_info *);
 208 int smack_to_cipso(const char *, struct smack_cipso *);
 209 void smack_from_cipso(u32, char *, char *);
 210 char *smack_from_secid(const u32);
 211 char *smk_import(const char *, int);
 212 struct smack_known *smk_import_entry(const char *, int);
 213 u32 smack_to_secid(const char *);
 214
 215 /*
 216  * Shared data.
 217  */
 218 extern int smack_cipso_direct;
 219 extern char *smack_net_ambient;
 220 extern char *smack_onlycap;
 221 extern const char *smack_cipso_option;
 222
 223 extern struct smack_known smack_known_floor;
 224 extern struct smack_known smack_known_hat;
 225 extern struct smack_known smack_known_huh;
 226 extern struct smack_known smack_known_invalid;
 227 extern struct smack_known smack_known_star;
 228 extern struct smack_known smack_known_web;
 229
 230 extern struct list_head smack_known_list;
 231 extern struct list_head smack_rule_list;
 232 extern struct list_head smk_netlbladdr_list;
 233
 234 extern struct security_operations smack_ops;
 235
 236 /*
 237  * Stricly for CIPSO level manipulation.
 238  * Set the category bit number in a smack label sized buffer.
 239  */
 240 static inline void smack_catset_bit(int cat, char *catsetp)
 241 {
 242         if (cat > SMK_LABELLEN * 8)
 243                 return;
 244
 245         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 246 }
 247
 248 /*
 249  * Is the directory transmuting?
 250  */
 251 static inline int smk_inode_transmutable(const struct inode *isp)
 252 {
 253         struct inode_smack *sip = isp->i_security;
 254         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 255 }
 256
 257 /*
 258  * Present a pointer to the smack label in an inode blob.
 259  */
 260 static inline char *smk_of_inode(const struct inode *isp)
 261 {
 262         struct inode_smack *sip = isp->i_security;
 263         return sip->smk_inode;
 264 }
 265
 266 /*
 267  * Present a pointer to the smack label in an task blob.
 268  */
 269 static inline char *smk_of_task(const struct task_smack *tsp)
 270 {
 271         return tsp->smk_task;
 272 }
 273
 274 /*
 275  * Present a pointer to the forked smack label in an task blob.
 276  */
 277 static inline char *smk_of_forked(const struct task_smack *tsp)
 278 {
 279         return tsp->smk_forked;
 280 }
 281
 282 /*
 283  * Present a pointer to the smack label in the current task blob.
 284  */
 285 static inline char *smk_of_current(void)
 286 {
 287         return smk_of_task(current_security());
 288 }
 289
 290 /*
 291  * logging functions
 292  */
 293 #define SMACK_AUDIT_DENIED 0x1
 294 #define SMACK_AUDIT_ACCEPT 0x2
 295 extern int log_policy;
 296
 297 void smack_log(char *subject_label, char *object_label,
 298                 int request,
 299                 int result, struct smk_audit_info *auditdata);
 300
 301 #ifdef CONFIG_AUDIT
 302
 303 /*
 304  * some inline functions to set up audit data
 305  * they do nothing if CONFIG_AUDIT is not set
 306  *
 307  */
 308 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 309                                char type)
 310 {
 311         memset(a, 0, sizeof(*a));
 312         a->a.type = type;
 313         a->a.smack_audit_data.function = func;
 314 }
 315
 316 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 317                                          struct task_struct *t)
 318 {
 319         a->a.u.tsk = t;
 320 }
 321 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 322                                                     struct dentry *d)
 323 {
 324         a->a.u.fs.path.dentry = d;
 325 }
 326 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 327                                                  struct vfsmount *m)
 328 {
 329         a->a.u.fs.path.mnt = m;
 330 }
 331 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 332                                               struct inode *i)
 333 {
 334         a->a.u.fs.inode = i;
 335 }
 336 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 337                                              struct path p)
 338 {
 339         a->a.u.fs.path = p;
 340 }
 341 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 342                                             struct sock *sk)
 343 {
 344         a->a.u.net.sk = sk;
 345 }
 346
 347 #else /* no AUDIT */
 348
 349 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 350                                char type)
 351 {
 352 }
 353 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 354                                          struct task_struct *t)
 355 {
 356 }
 357 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 358                                                     struct dentry *d)
 359 {
 360 }
 361 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 362                                                  struct vfsmount *m)
 363 {
 364 }
 365 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 366                                               struct inode *i)
 367 {
 368 }
 369 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 370                                              struct path p)
 371 {
 372 }
 373 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 374                                             struct sock *sk)
 375 {
 376 }
 377 #endif
 378
 379 #endif  /* _SECURITY_SMACK_H */