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 /*
  30  * How many kinds of access are there?
  31  * Here's your answer.
  32  */
  33 #define SMK_ACCESSDASH  '-'
  34 #define SMK_ACCESSLOW   "rwxa"
  35 #define SMK_ACCESSKINDS (sizeof(SMK_ACCESSLOW) - 1)
  36
  37 struct superblock_smack {
  38         char            *smk_root;
  39         char            *smk_floor;
  40         char            *smk_hat;
  41         char            *smk_default;
  42         int             smk_initialized;
  43         spinlock_t      smk_sblock;     /* for initialization */
  44 };
  45
  46 struct socket_smack {
  47         char            *smk_out;                       /* outbound label */
  48         char            *smk_in;                        /* inbound label */
  49         char            smk_packet[SMK_LABELLEN];       /* TCP peer label */
  50 };
  51
  52 /*
  53  * Inode smack data
  54  */
  55 struct inode_smack {
  56         char            *smk_inode;     /* label of the fso */
  57         struct mutex    smk_lock;       /* initialization lock */
  58         int             smk_flags;      /* smack inode flags */
  59 };
  60
  61 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
  62
  63 /*
  64  * A label access rule.
  65  */
  66 struct smack_rule {
  67         char    *smk_subject;
  68         char    *smk_object;
  69         int     smk_access;
  70 };
  71
  72 /*
  73  * An entry in the table of permitted label accesses.
  74  */
  75 struct smk_list_entry {
  76         struct smk_list_entry   *smk_next;
  77         struct smack_rule       smk_rule;
  78 };
  79
  80 /*
  81  * An entry in the table mapping smack values to
  82  * CIPSO level/category-set values.
  83  */
  84 struct smack_cipso {
  85         int     smk_level;
  86         char    smk_catset[SMK_LABELLEN];
  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 smack_known      *smk_next;
 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 /*
 127  * xattr names
 128  */
 129 #define XATTR_SMACK_SUFFIX      "SMACK64"
 130 #define XATTR_SMACK_IPIN        "SMACK64IPIN"
 131 #define XATTR_SMACK_IPOUT       "SMACK64IPOUT"
 132 #define XATTR_NAME_SMACK        XATTR_SECURITY_PREFIX XATTR_SMACK_SUFFIX
 133 #define XATTR_NAME_SMACKIPIN    XATTR_SECURITY_PREFIX XATTR_SMACK_IPIN
 134 #define XATTR_NAME_SMACKIPOUT   XATTR_SECURITY_PREFIX XATTR_SMACK_IPOUT
 135
 136 /*
 137  * smackfs macic number
 138  */
 139 #define SMACK_MAGIC     0x43415d53 /* "SMAC" */
 140
 141 /*
 142  * A limit on the number of entries in the lists
 143  * makes some of the list administration easier.
 144  */
 145 #define SMACK_LIST_MAX  10000
 146
 147 /*
 148  * CIPSO defaults.
 149  */
 150 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 151 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 152 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 153 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 154 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 155
 156 /*
 157  * Just to make the common cases easier to deal with
 158  */
 159 #define MAY_ANY         (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 160 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 161 #define MAY_ANYWRITE    (MAY_WRITE | MAY_APPEND)
 162 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 163 #define MAY_NOT         0
 164
 165 /*
 166  * These functions are in smack_lsm.c
 167  */
 168 struct inode_smack *new_inode_smack(char *);
 169
 170 /*
 171  * These functions are in smack_access.c
 172  */
 173 int smk_access(char *, char *, int);
 174 int smk_curacc(char *, u32);
 175 int smack_to_cipso(const char *, struct smack_cipso *);
 176 void smack_from_cipso(u32, char *, char *);
 177 char *smack_from_secid(const u32);
 178 char *smk_import(const char *, int);
 179 struct smack_known *smk_import_entry(const char *, int);
 180 u32 smack_to_secid(const char *);
 181
 182 /*
 183  * Shared data.
 184  */
 185 extern int smack_cipso_direct;
 186 extern int smack_net_nltype;
 187 extern char *smack_net_ambient;
 188
 189 extern struct smack_known *smack_known;
 190 extern struct smack_known smack_known_floor;
 191 extern struct smack_known smack_known_hat;
 192 extern struct smack_known smack_known_huh;
 193 extern struct smack_known smack_known_invalid;
 194 extern struct smack_known smack_known_star;
 195 extern struct smack_known smack_known_unset;
 196
 197 extern struct smk_list_entry *smack_list;
 198
 199 /*
 200  * Stricly for CIPSO level manipulation.
 201  * Set the category bit number in a smack label sized buffer.
 202  */
 203 static inline void smack_catset_bit(int cat, char *catsetp)
 204 {
 205         if (cat > SMK_LABELLEN * 8)
 206                 return;
 207
 208         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 209 }
 210
 211 /*
 212  * Present a pointer to the smack label in an inode blob.
 213  */
 214 static inline char *smk_of_inode(const struct inode *isp)
 215 {
 216         struct inode_smack *sip = isp->i_security;
 217         return sip->smk_inode;
 218 }
 219
 220 #endif  /* _SECURITY_SMACK_H */