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 #include <linux/lsm_audit.h>
  24
  25 /*
  26  * Smack labels were limited to 23 characters for a long time.
  27  */
  28 #define SMK_LABELLEN    24
  29 #define SMK_LONGLABEL   256
  30
  31 /*
  32  * This is the repository for labels seen so that it is
  33  * not necessary to keep allocating tiny chuncks of memory
  34  * and so that they can be shared.
  35  *
  36  * Labels are never modified in place. Anytime a label
  37  * is imported (e.g. xattrset on a file) the list is checked
  38  * for it and it is added if it doesn't exist. The address
  39  * is passed out in either case. Entries are added, but
  40  * never deleted.
  41  *
  42  * Since labels are hanging around anyway it doesn't
  43  * hurt to maintain a secid for those awkward situations
  44  * where kernel components that ought to use LSM independent
  45  * interfaces don't. The secid should go away when all of
  46  * these components have been repaired.
  47  *
  48  * The cipso value associated with the label gets stored here, too.
  49  *
  50  * Keep the access rules for this subject label here so that
  51  * the entire set of rules does not need to be examined every
  52  * time.
  53  */
  54 struct smack_known {
  55         struct list_head                list;
  56         char                            *smk_known;
  57         u32                             smk_secid;
  58         struct netlbl_lsm_secattr       smk_netlabel;   /* on wire labels */
  59         struct list_head                smk_rules;      /* access rules */
  60         struct mutex                    smk_rules_lock; /* lock for rules */
  61 };
  62
  63 /*
  64  * Maximum number of bytes for the levels in a CIPSO IP option.
  65  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
  66  * bigger than can be used, and 24 is the next lower multiple
  67  * of 8, and there are too many issues if there isn't space set
  68  * aside for the terminating null byte.
  69  */
  70 #define SMK_CIPSOLEN    24
  71
  72 struct superblock_smack {
  73         char            *smk_root;
  74         char            *smk_floor;
  75         char            *smk_hat;
  76         char            *smk_default;
  77         int             smk_initialized;
  78 };
  79
  80 struct socket_smack {
  81         struct smack_known      *smk_out;       /* outbound label */
  82         char                    *smk_in;        /* inbound label */
  83         char                    *smk_packet;    /* TCP peer label */
  84 };
  85
  86 /*
  87  * Inode smack data
  88  */
  89 struct inode_smack {
  90         char                    *smk_inode;     /* label of the fso */
  91         struct smack_known      *smk_task;      /* label of the task */
  92         struct smack_known      *smk_mmap;      /* label of the mmap domain */
  93         struct mutex            smk_lock;       /* initialization lock */
  94         int                     smk_flags;      /* smack inode flags */
  95 };
  96
  97 struct task_smack {
  98         struct smack_known      *smk_task;      /* label for access control */
  99         struct smack_known      *smk_forked;    /* label when forked */
 100         struct list_head        smk_rules;      /* per task access rules */
 101         struct mutex            smk_rules_lock; /* lock for the rules */
 102 };
 103
 104 #define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
 105 #define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
 106 #define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
 107
 108 /*
 109  * A label access rule.
 110  */
 111 struct smack_rule {
 112         struct list_head        list;
 113         struct smack_known      *smk_subject;
 114         char                    *smk_object;
 115         int                     smk_access;
 116 };
 117
 118 /*
 119  * An entry in the table identifying hosts.
 120  */
 121 struct smk_netlbladdr {
 122         struct list_head        list;
 123         struct sockaddr_in      smk_host;       /* network address */
 124         struct in_addr          smk_mask;       /* network mask */
 125         char                    *smk_label;     /* label */
 126 };
 127
 128 /*
 129  * An entry in the table identifying ports.
 130  */
 131 struct smk_port_label {
 132         struct list_head        list;
 133         struct sock             *smk_sock;      /* socket initialized on */
 134         unsigned short          smk_port;       /* the port number */
 135         char                    *smk_in;        /* incoming label */
 136         struct smack_known      *smk_out;       /* outgoing label */
 137 };
 138
 139 /*
 140  * Mount options
 141  */
 142 #define SMK_FSDEFAULT   "smackfsdef="
 143 #define SMK_FSFLOOR     "smackfsfloor="
 144 #define SMK_FSHAT       "smackfshat="
 145 #define SMK_FSROOT      "smackfsroot="
 146 #define SMK_FSTRANS     "smackfstransmute="
 147
 148 #define SMACK_CIPSO_OPTION      "-CIPSO"
 149
 150 /*
 151  * How communications on this socket are treated.
 152  * Usually it's determined by the underlying netlabel code
 153  * but there are certain cases, including single label hosts
 154  * and potentially single label interfaces for which the
 155  * treatment can not be known in advance.
 156  *
 157  * The possibility of additional labeling schemes being
 158  * introduced in the future exists as well.
 159  */
 160 #define SMACK_UNLABELED_SOCKET  0
 161 #define SMACK_CIPSO_SOCKET      1
 162
 163 /*
 164  * CIPSO defaults.
 165  */
 166 #define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
 167 #define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
 168 #define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
 169 #define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
 170 #define SMACK_CIPSO_MAXCATVAL           63      /* Bigger gets harder */
 171 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
 172 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
 173
 174 /*
 175  * Flag for transmute access
 176  */
 177 #define MAY_TRANSMUTE   64
 178 /*
 179  * Just to make the common cases easier to deal with
 180  */
 181 #define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
 182 #define MAY_READWRITE   (MAY_READ | MAY_WRITE)
 183 #define MAY_NOT         0
 184
 185 /*
 186  * Number of access types used by Smack (rwxat)
 187  */
 188 #define SMK_NUM_ACCESS_TYPE 5
 189
 190 /* SMACK data */
 191 struct smack_audit_data {
 192         const char *function;
 193         char *subject;
 194         char *object;
 195         char *request;
 196         int result;
 197 };
 198
 199 /*
 200  * Smack audit data; is empty if CONFIG_AUDIT not set
 201  * to save some stack
 202  */
 203 struct smk_audit_info {
 204 #ifdef CONFIG_AUDIT
 205         struct common_audit_data a;
 206         struct smack_audit_data sad;
 207 #endif
 208 };
 209 /*
 210  * These functions are in smack_lsm.c
 211  */
 212 struct inode_smack *new_inode_smack(char *);
 213
 214 /*
 215  * These functions are in smack_access.c
 216  */
 217 int smk_access_entry(char *, char *, struct list_head *);
 218 int smk_access(struct smack_known *, char *, int, struct smk_audit_info *);
 219 int smk_curacc(char *, u32, struct smk_audit_info *);
 220 struct smack_known *smack_from_secid(const u32);
 221 char *smk_parse_smack(const char *string, int len);
 222 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 223 char *smk_import(const char *, int);
 224 struct smack_known *smk_import_entry(const char *, int);
 225 struct smack_known *smk_find_entry(const char *);
 226 u32 smack_to_secid(const char *);
 227
 228 /*
 229  * Shared data.
 230  */
 231 extern int smack_cipso_direct;
 232 extern int smack_cipso_mapped;
 233 extern struct smack_known *smack_net_ambient;
 234 extern char *smack_onlycap;
 235 extern const char *smack_cipso_option;
 236
 237 extern struct smack_known smack_known_floor;
 238 extern struct smack_known smack_known_hat;
 239 extern struct smack_known smack_known_huh;
 240 extern struct smack_known smack_known_invalid;
 241 extern struct smack_known smack_known_star;
 242 extern struct smack_known smack_known_web;
 243
 244 extern struct mutex     smack_known_lock;
 245 extern struct list_head smack_known_list;
 246 extern struct list_head smk_netlbladdr_list;
 247
 248 extern struct security_operations smack_ops;
 249
 250 /*
 251  * Is the directory transmuting?
 252  */
 253 static inline int smk_inode_transmutable(const struct inode *isp)
 254 {
 255         struct inode_smack *sip = isp->i_security;
 256         return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 257 }
 258
 259 /*
 260  * Present a pointer to the smack label in an inode blob.
 261  */
 262 static inline char *smk_of_inode(const struct inode *isp)
 263 {
 264         struct inode_smack *sip = isp->i_security;
 265         return sip->smk_inode;
 266 }
 267
 268 /*
 269  * Present a pointer to the smack label entry in an task blob.
 270  */
 271 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 272 {
 273         return tsp->smk_task;
 274 }
 275
 276 /*
 277  * Present a pointer to the forked smack label entry in an task blob.
 278  */
 279 static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
 280 {
 281         return tsp->smk_forked;
 282 }
 283
 284 /*
 285  * Present a pointer to the smack label in the current task blob.
 286  */
 287 static inline struct smack_known *smk_of_current(void)
 288 {
 289         return smk_of_task(current_security());
 290 }
 291
 292 /*
 293  * Is the task privileged and allowed to be privileged
 294  * by the onlycap rule.
 295  */
 296 static inline int smack_privileged(int cap)
 297 {
 298         struct smack_known *skp = smk_of_current();
 299
 300         if (!capable(cap))
 301                 return 0;
 302         if (smack_onlycap == NULL || smack_onlycap == skp->smk_known)
 303                 return 1;
 304         return 0;
 305 }
 306
 307 /*
 308  * logging functions
 309  */
 310 #define SMACK_AUDIT_DENIED 0x1
 311 #define SMACK_AUDIT_ACCEPT 0x2
 312 extern int log_policy;
 313
 314 void smack_log(char *subject_label, char *object_label,
 315                 int request,
 316                 int result, struct smk_audit_info *auditdata);
 317
 318 #ifdef CONFIG_AUDIT
 319
 320 /*
 321  * some inline functions to set up audit data
 322  * they do nothing if CONFIG_AUDIT is not set
 323  *
 324  */
 325 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 326                                char type)
 327 {
 328         memset(&a->sad, 0, sizeof(a->sad));
 329         a->a.type = type;
 330         a->a.smack_audit_data = &a->sad;
 331         a->a.smack_audit_data->function = func;
 332 }
 333
 334 static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
 335                                    char type, struct lsm_network_audit *net)
 336 {
 337         smk_ad_init(a, func, type);
 338         memset(net, 0, sizeof(*net));
 339         a->a.u.net = net;
 340 }
 341
 342 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 343                                          struct task_struct *t)
 344 {
 345         a->a.u.tsk = t;
 346 }
 347 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 348                                                     struct dentry *d)
 349 {
 350         a->a.u.dentry = d;
 351 }
 352 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 353                                               struct inode *i)
 354 {
 355         a->a.u.inode = i;
 356 }
 357 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 358                                              struct path p)
 359 {
 360         a->a.u.path = p;
 361 }
 362 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 363                                             struct sock *sk)
 364 {
 365         a->a.u.net->sk = sk;
 366 }
 367
 368 #else /* no AUDIT */
 369
 370 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 371                                char type)
 372 {
 373 }
 374 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 375                                          struct task_struct *t)
 376 {
 377 }
 378 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
 379                                                     struct dentry *d)
 380 {
 381 }
 382 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
 383                                                  struct vfsmount *m)
 384 {
 385 }
 386 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
 387                                               struct inode *i)
 388 {
 389 }
 390 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
 391                                              struct path p)
 392 {
 393 }
 394 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
 395                                             struct sock *sk)
 396 {
 397 }
 398 #endif
 399
 400 #endif  /* _SECURITY_SMACK_H */