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 <net/netlabel.h>
  19
  20 /*
  21  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  22  * bigger than can be used, and 24 is the next lower multiple
  23  * of 8, and there are too many issues if there isn't space set
  24  * aside for the terminating null byte.
  25  */
  26 #define SMK_MAXLEN      23
  27 #define SMK_LABELLEN    (SMK_MAXLEN+1)
  28
  29 struct superblock_smack {
  30         char            *smk_root;
  31         char            *smk_floor;
  32         char            *smk_hat;
  33         char            *smk_default;
  34         int             smk_initialized;
  35         spinlock_t      smk_sblock;     /* for initialization */
  36 };
  37
  38 struct socket_smack {
  39         char            *smk_out;                       /* outbound label */
  40         char            *smk_in;                        /* inbound label */
  41         char            smk_packet[SMK_LABELLEN];       /* TCP peer label */
  42 };
  43
  44 /*
  45  * Inode smack data
  46  */
  47 struct inode_smack {
  48         char            *smk_inode;     /* label of the fso */
  49         struct mutex    smk_lock;       /* initialization lock */
  50         int             smk_flags;      /* smack inode flags */
  51 };
  52
  53 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
  54
  55 /*
  56  * A label access rule.
  57  */
  58 struct smack_rule {
  59         char    *smk_subject;
  60         char    *smk_object;
  61         int     smk_access;
  62 };
  63
  64 /*
  65  * An entry in the table of permitted label accesses.
  66  */
  67 struct smk_list_entry {
  68         struct smk_list_entry   *smk_next;
  69         struct smack_rule       smk_rule;
  70 };
  71
  72 /*
  73  * An entry in the table mapping smack values to
  74  * CIPSO level/category-set values.
  75  */
  76 struct smack_cipso {
  77         int     smk_level;
  78         char    smk_catset[SMK_LABELLEN];
  79 };
  80
  81 /*
  82  * This is the repository for labels seen so that it is
  83  * not necessary to keep allocating tiny chuncks of memory
  84  * and so that they can be shared.
  85  *
  86  * Labels are never modified in place. Anytime a label
  87  * is imported (e.g. xattrset on a file) the list is checked
  88  * for it and it is added if it doesn't exist. The address
  89  * is passed out in either case. Entries are added, but
  90  * never deleted.
  91  *
  92  * Since labels are hanging around anyway it doesn't
  93  * hurt to maintain a secid for those awkward situations
  94  * where kernel components that ought to use LSM independent
  95  * interfaces don't. The secid should go away when all of
  96  * these components have been repaired.
  97  *
  98  * If there is a cipso value associated with the label it
  99  * gets stored here, too. This will most likely be rare as
 100  * the cipso direct mapping in used internally.
 101  */
 102 struct smack_known {
 103         struct smack_known      *smk_next;
 104         char                    smk_known[SMK_LABELLEN];
 105         u32                     smk_secid;
 106         struct smack_cipso      *smk_cipso;
 107         spinlock_t              smk_cipsolock; /* for changing cipso map */
 108 };
 109
 110 /*
 111  * Mount options
 112  */
 113 #define SMK_FSDEFAULT   "smackfsdef="
 114 #define SMK_FSFLOOR     "smackfsfloor="
 115 #define SMK_FSHAT       "smackfshat="
 116 #define SMK_FSROOT      "smackfsroot="
 117
 118 /*
 119  * xattr names
 120  */
 121 #define XATTR_SMACK_SUFFIX      "SMACK64"
 122 #define XATTR_SMACK_IPIN        "SMACK64IPIN"
 123 #define XATTR_SMACK_IPOUT       "SMACK64IPOUT"
 124 #define XATTR_NAME_SMACK        XATTR_SECURITY_PREFIX XATTR_SMACK_SUFFIX
 125 #define XATTR_NAME_SMACKIPIN    XATTR_SECURITY_PREFIX XATTR_SMACK_IPIN
 126 #define XATTR_NAME_SMACKIPOUT   XATTR_SECURITY_PREFIX XATTR_SMACK_IPOUT
 127
 128 /*
 129  * smackfs macic number
 130  */
 131 #define SMACK_MAGIC     0x43415d53 /* "SMAC" */
 132
 133 /*
 134  * A limit on the number of entries in the lists
 135  * makes some of the list administration easier.
 136  */
 137 #define SMACK_LIST_MAX  10000
 138
 139 /*
 140  * CIPSO defaults.
 141  */
 142 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 143 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 144 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 145 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 146 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 147
 148 /*
 149  * Just to make the common cases easier to deal with
 150  */
 151 #define MAY_ANY         (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 152 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 153 #define MAY_ANYWRITE    (MAY_WRITE | MAY_APPEND)
 154 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 155 #define MAY_NOT         0
 156
 157 /*
 158  * These functions are in smack_lsm.c
 159  */
 160 struct inode_smack *new_inode_smack(char *);
 161
 162 /*
 163  * These functions are in smack_access.c
 164  */
 165 int smk_access(char *, char *, int);
 166 int smk_curacc(char *, u32);
 167 int smack_to_cipso(const char *, struct smack_cipso *);
 168 void smack_from_cipso(u32, char *, char *);
 169 char *smack_from_secid(const u32);
 170 char *smk_import(const char *, int);
 171 struct smack_known *smk_import_entry(const char *, int);
 172 u32 smack_to_secid(const char *);
 173
 174 /*
 175  * Shared data.
 176  */
 177 extern int smack_cipso_direct;
 178 extern int smack_net_nltype;
 179 extern char *smack_net_ambient;
 180
 181 extern struct smack_known *smack_known;
 182 extern struct smack_known smack_known_floor;
 183 extern struct smack_known smack_known_hat;
 184 extern struct smack_known smack_known_huh;
 185 extern struct smack_known smack_known_invalid;
 186 extern struct smack_known smack_known_star;
 187 extern struct smack_known smack_known_unset;
 188
 189 extern struct smk_list_entry *smack_list;
 190
 191 /*
 192  * Stricly for CIPSO level manipulation.
 193  * Set the category bit number in a smack label sized buffer.
 194  */
 195 static inline void smack_catset_bit(int cat, char *catsetp)
 196 {
 197         if (cat > SMK_LABELLEN * 8)
 198                 return;
 199
 200         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 201 }
 202
 203 /*
 204  * Present a pointer to the smack label in an inode blob.
 205  */
 206 static inline char *smk_of_inode(const struct inode *isp)
 207 {
 208         struct inode_smack *sip = isp->i_security;
 209         return sip->smk_inode;
 210 }
 211
 212 #endif  /* _SECURITY_SMACK_H */