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 <net/netlabel.h>
  20
  21 /*
  22  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  23  * bigger than can be used, and 24 is the next lower multiple
  24  * of 8, and there are too many issues if there isn't space set
  25  * aside for the terminating null byte.
  26  */
  27 #define SMK_MAXLEN      23
  28 #define SMK_LABELLEN    (SMK_MAXLEN+1)
  29
  30 struct superblock_smack {
  31         char            *smk_root;
  32         char            *smk_floor;
  33         char            *smk_hat;
  34         char            *smk_default;
  35         int             smk_initialized;
  36         spinlock_t      smk_sblock;     /* for initialization */
  37 };
  38
  39 struct socket_smack {
  40         char            *smk_out;                       /* outbound label */
  41         char            *smk_in;                        /* inbound label */
  42         char            smk_packet[SMK_LABELLEN];       /* TCP peer label */
  43 };
  44
  45 /*
  46  * Inode smack data
  47  */
  48 struct inode_smack {
  49         char            *smk_inode;     /* label of the fso */
  50         struct mutex    smk_lock;       /* initialization lock */
  51         int             smk_flags;      /* smack inode flags */
  52 };
  53
  54 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
  55
  56 /*
  57  * A label access rule.
  58  */
  59 struct smack_rule {
  60         char    *smk_subject;
  61         char    *smk_object;
  62         int     smk_access;
  63 };
  64
  65 /*
  66  * An entry in the table of permitted label accesses.
  67  */
  68 struct smk_list_entry {
  69         struct smk_list_entry   *smk_next;
  70         struct smack_rule       smk_rule;
  71 };
  72
  73 /*
  74  * An entry in the table mapping smack values to
  75  * CIPSO level/category-set values.
  76  */
  77 struct smack_cipso {
  78         int     smk_level;
  79         char    smk_catset[SMK_LABELLEN];
  80 };
  81
  82 /*
  83  * This is the repository for labels seen so that it is
  84  * not necessary to keep allocating tiny chuncks of memory
  85  * and so that they can be shared.
  86  *
  87  * Labels are never modified in place. Anytime a label
  88  * is imported (e.g. xattrset on a file) the list is checked
  89  * for it and it is added if it doesn't exist. The address
  90  * is passed out in either case. Entries are added, but
  91  * never deleted.
  92  *
  93  * Since labels are hanging around anyway it doesn't
  94  * hurt to maintain a secid for those awkward situations
  95  * where kernel components that ought to use LSM independent
  96  * interfaces don't. The secid should go away when all of
  97  * these components have been repaired.
  98  *
  99  * If there is a cipso value associated with the label it
 100  * gets stored here, too. This will most likely be rare as
 101  * the cipso direct mapping in used internally.
 102  */
 103 struct smack_known {
 104         struct smack_known      *smk_next;
 105         char                    smk_known[SMK_LABELLEN];
 106         u32                     smk_secid;
 107         struct smack_cipso      *smk_cipso;
 108         spinlock_t              smk_cipsolock; /* for changing cipso map */
 109 };
 110
 111 /*
 112  * Mount options
 113  */
 114 #define SMK_FSDEFAULT   "smackfsdef="
 115 #define SMK_FSFLOOR     "smackfsfloor="
 116 #define SMK_FSHAT       "smackfshat="
 117 #define SMK_FSROOT      "smackfsroot="
 118
 119 /*
 120  * xattr names
 121  */
 122 #define XATTR_SMACK_SUFFIX      "SMACK64"
 123 #define XATTR_SMACK_IPIN        "SMACK64IPIN"
 124 #define XATTR_SMACK_IPOUT       "SMACK64IPOUT"
 125 #define XATTR_NAME_SMACK        XATTR_SECURITY_PREFIX XATTR_SMACK_SUFFIX
 126 #define XATTR_NAME_SMACKIPIN    XATTR_SECURITY_PREFIX XATTR_SMACK_IPIN
 127 #define XATTR_NAME_SMACKIPOUT   XATTR_SECURITY_PREFIX XATTR_SMACK_IPOUT
 128
 129 /*
 130  * smackfs macic number
 131  */
 132 #define SMACK_MAGIC     0x43415d53 /* "SMAC" */
 133
 134 /*
 135  * A limit on the number of entries in the lists
 136  * makes some of the list administration easier.
 137  */
 138 #define SMACK_LIST_MAX  10000
 139
 140 /*
 141  * CIPSO defaults.
 142  */
 143 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 144 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 145 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 146 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 147 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 148
 149 /*
 150  * Just to make the common cases easier to deal with
 151  */
 152 #define MAY_ANY         (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 153 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 154 #define MAY_ANYWRITE    (MAY_WRITE | MAY_APPEND)
 155 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 156 #define MAY_NOT         0
 157
 158 /*
 159  * These functions are in smack_lsm.c
 160  */
 161 struct inode_smack *new_inode_smack(char *);
 162
 163 /*
 164  * These functions are in smack_access.c
 165  */
 166 int smk_access(char *, char *, int);
 167 int smk_curacc(char *, u32);
 168 int smack_to_cipso(const char *, struct smack_cipso *);
 169 void smack_from_cipso(u32, char *, char *);
 170 char *smack_from_secid(const u32);
 171 char *smk_import(const char *, int);
 172 struct smack_known *smk_import_entry(const char *, int);
 173 u32 smack_to_secid(const char *);
 174
 175 /*
 176  * Shared data.
 177  */
 178 extern int smack_cipso_direct;
 179 extern int smack_net_nltype;
 180 extern char *smack_net_ambient;
 181
 182 extern struct smack_known *smack_known;
 183 extern struct smack_known smack_known_floor;
 184 extern struct smack_known smack_known_hat;
 185 extern struct smack_known smack_known_huh;
 186 extern struct smack_known smack_known_invalid;
 187 extern struct smack_known smack_known_star;
 188 extern struct smack_known smack_known_unset;
 189
 190 extern struct smk_list_entry *smack_list;
 191 extern struct security_operations smack_ops;
 192
 193 /*
 194  * Stricly for CIPSO level manipulation.
 195  * Set the category bit number in a smack label sized buffer.
 196  */
 197 static inline void smack_catset_bit(int cat, char *catsetp)
 198 {
 199         if (cat > SMK_LABELLEN * 8)
 200                 return;
 201
 202         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 203 }
 204
 205 /*
 206  * Present a pointer to the smack label in an inode blob.
 207  */
 208 static inline char *smk_of_inode(const struct inode *isp)
 209 {
 210         struct inode_smack *sip = isp->i_security;
 211         return sip->smk_inode;
 212 }
 213
 214 #endif  /* _SECURITY_SMACK_H */