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