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