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