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
  22 /*
  23  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  24  * bigger than can be used, and 24 is the next lower multiple
  25  * of 8, and there are too many issues if there isn't space set
  26  * aside for the terminating null byte.
  27  */
  28 #define SMK_MAXLEN      23
  29 #define SMK_LABELLEN    (SMK_MAXLEN+1)
  30
  31 struct superblock_smack {
  32         char            *smk_root;
  33         char            *smk_floor;
  34         char            *smk_hat;
  35         char            *smk_default;
  36         int             smk_initialized;
  37         spinlock_t      smk_sblock;     /* for initialization */
  38 };
  39
  40 struct socket_smack {
  41         char            *smk_out;                       /* outbound label */
  42         char            *smk_in;                        /* inbound label */
  43         int             smk_labeled;                    /* label scheme */
  44         char            smk_packet[SMK_LABELLEN];       /* TCP peer label */
  45 };
  46
  47 /*
  48  * Inode smack data
  49  */
  50 struct inode_smack {
  51         char            *smk_inode;     /* label of the fso */
  52         struct mutex    smk_lock;       /* initialization lock */
  53         int             smk_flags;      /* smack inode flags */
  54 };
  55
  56 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
  57
  58 /*
  59  * A label access rule.
  60  */
  61 struct smack_rule {
  62         char    *smk_subject;
  63         char    *smk_object;
  64         int     smk_access;
  65 };
  66
  67 /*
  68  * An entry in the table of permitted label accesses.
  69  */
  70 struct smk_list_entry {
  71         struct smk_list_entry   *smk_next;
  72         struct smack_rule       smk_rule;
  73 };
  74
  75 /*
  76  * An entry in the table mapping smack values to
  77  * CIPSO level/category-set values.
  78  */
  79 struct smack_cipso {
  80         int     smk_level;
  81         char    smk_catset[SMK_LABELLEN];
  82 };
  83
  84 /*
  85  * An entry in the table identifying hosts.
  86  */
  87 struct smk_netlbladdr {
  88         struct smk_netlbladdr   *smk_next;
  89         struct sockaddr_in      smk_host;       /* network address */
  90         struct in_addr          smk_mask;       /* network mask */
  91         char                    *smk_label;     /* label */
  92 };
  93
  94 /*
  95  * This is the repository for labels seen so that it is
  96  * not necessary to keep allocating tiny chuncks of memory
  97  * and so that they can be shared.
  98  *
  99  * Labels are never modified in place. Anytime a label
 100  * is imported (e.g. xattrset on a file) the list is checked
 101  * for it and it is added if it doesn't exist. The address
 102  * is passed out in either case. Entries are added, but
 103  * never deleted.
 104  *
 105  * Since labels are hanging around anyway it doesn't
 106  * hurt to maintain a secid for those awkward situations
 107  * where kernel components that ought to use LSM independent
 108  * interfaces don't. The secid should go away when all of
 109  * these components have been repaired.
 110  *
 111  * If there is a cipso value associated with the label it
 112  * gets stored here, too. This will most likely be rare as
 113  * the cipso direct mapping in used internally.
 114  */
 115 struct smack_known {
 116         struct smack_known      *smk_next;
 117         char                    smk_known[SMK_LABELLEN];
 118         u32                     smk_secid;
 119         struct smack_cipso      *smk_cipso;
 120         spinlock_t              smk_cipsolock; /* for changing cipso map */
 121 };
 122
 123 /*
 124  * Mount options
 125  */
 126 #define SMK_FSDEFAULT   "smackfsdef="
 127 #define SMK_FSFLOOR     "smackfsfloor="
 128 #define SMK_FSHAT       "smackfshat="
 129 #define SMK_FSROOT      "smackfsroot="
 130
 131 /*
 132  * xattr names
 133  */
 134 #define XATTR_SMACK_SUFFIX      "SMACK64"
 135 #define XATTR_SMACK_IPIN        "SMACK64IPIN"
 136 #define XATTR_SMACK_IPOUT       "SMACK64IPOUT"
 137 #define XATTR_NAME_SMACK        XATTR_SECURITY_PREFIX XATTR_SMACK_SUFFIX
 138 #define XATTR_NAME_SMACKIPIN    XATTR_SECURITY_PREFIX XATTR_SMACK_IPIN
 139 #define XATTR_NAME_SMACKIPOUT   XATTR_SECURITY_PREFIX XATTR_SMACK_IPOUT
 140
 141 /*
 142  * How communications on this socket are treated.
 143  * Usually it's determined by the underlying netlabel code
 144  * but there are certain cases, including single label hosts
 145  * and potentially single label interfaces for which the
 146  * treatment can not be known in advance.
 147  *
 148  * The possibility of additional labeling schemes being
 149  * introduced in the future exists as well.
 150  */
 151 #define SMACK_UNLABELED_SOCKET  0
 152 #define SMACK_CIPSO_SOCKET      1
 153
 154 /*
 155  * smackfs magic number
 156  * smackfs macic number
 157  */
 158 #define SMACK_MAGIC     0x43415d53 /* "SMAC" */
 159
 160 /*
 161  * A limit on the number of entries in the lists
 162  * makes some of the list administration easier.
 163  */
 164 #define SMACK_LIST_MAX  10000
 165
 166 /*
 167  * CIPSO defaults.
 168  */
 169 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 170 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 171 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 172 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 173 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 174 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 175
 176 /*
 177  * Just to make the common cases easier to deal with
 178  */
 179 #define MAY_ANY         (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 180 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 181 #define MAY_ANYWRITE    (MAY_WRITE | MAY_APPEND)
 182 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 183 #define MAY_NOT         0
 184
 185 /*
 186  * These functions are in smack_lsm.c
 187  */
 188 struct inode_smack *new_inode_smack(char *);
 189
 190 /*
 191  * These functions are in smack_access.c
 192  */
 193 int smk_access(char *, char *, int);
 194 int smk_curacc(char *, u32);
 195 int smack_to_cipso(const char *, struct smack_cipso *);
 196 void smack_from_cipso(u32, char *, char *);
 197 char *smack_from_secid(const u32);
 198 char *smk_import(const char *, int);
 199 struct smack_known *smk_import_entry(const char *, int);
 200 u32 smack_to_secid(const char *);
 201
 202 /*
 203  * Shared data.
 204  */
 205 extern int smack_cipso_direct;
 206 extern char *smack_net_ambient;
 207 extern char *smack_onlycap;
 208
 209 extern struct smack_known *smack_known;
 210 extern struct smack_known smack_known_floor;
 211 extern struct smack_known smack_known_hat;
 212 extern struct smack_known smack_known_huh;
 213 extern struct smack_known smack_known_invalid;
 214 extern struct smack_known smack_known_star;
 215 extern struct smack_known smack_known_web;
 216
 217 extern struct smk_list_entry *smack_list;
 218 extern struct smk_netlbladdr *smack_netlbladdrs;
 219 extern struct security_operations smack_ops;
 220
 221 /*
 222  * Stricly for CIPSO level manipulation.
 223  * Set the category bit number in a smack label sized buffer.
 224  */
 225 static inline void smack_catset_bit(int cat, char *catsetp)
 226 {
 227         if (cat > SMK_LABELLEN * 8)
 228                 return;
 229
 230         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 231 }
 232
 233 /*
 234  * Present a pointer to the smack label in an inode blob.
 235  */
 236 static inline char *smk_of_inode(const struct inode *isp)
 237 {
 238         struct inode_smack *sip = isp->i_security;
 239         return sip->smk_inode;
 240 }
 241
 242 #endif  /* _SECURITY_SMACK_H */