/*
   * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
   *
   *      This program is free software; you can redistribute it and/or modify
   *      it under the terms of the GNU General Public License as published by
   *      the Free Software Foundation, version 2.
   *
   * Author:
   *      Casey Schaufler <casey@schaufler-ca.com>
   *
   */
  
  #ifndef _SECURITY_SMACK_H
  #define _SECURITY_SMACK_H
  
  #include <linux/capability.h>
  #include <linux/spinlock.h>
  #include <linux/security.h>
  #include <linux/in.h>
  #include <net/netlabel.h>
  #include <linux/list.h>
  #include <linux/rculist.h>
  #include <linux/lsm_audit.h>
  
  /*
   * Smack labels were limited to 23 characters for a long time.
   */
  #define SMK_LABELLEN	24
  #define SMK_LONGLABEL	256
  
  /*
   * This is the repository for labels seen so that it is
   * not necessary to keep allocating tiny chuncks of memory
   * and so that they can be shared.
   *
   * Labels are never modified in place. Anytime a label
   * is imported (e.g. xattrset on a file) the list is checked
   * for it and it is added if it doesn't exist. The address
   * is passed out in either case. Entries are added, but
   * never deleted.
   *
   * Since labels are hanging around anyway it doesn't
   * hurt to maintain a secid for those awkward situations
   * where kernel components that ought to use LSM independent
   * interfaces don't. The secid should go away when all of
   * these components have been repaired.
   *
   * The cipso value associated with the label gets stored here, too.
   *
   * Keep the access rules for this subject label here so that
   * the entire set of rules does not need to be examined every
   * time.
   */
  struct smack_known {
  	struct list_head		list;
  	struct hlist_node		smk_hashed;
  	char				*smk_known;
  	u32				smk_secid;
  	struct netlbl_lsm_secattr	smk_netlabel;	/* on wire labels */
  	struct list_head		smk_rules;	/* access rules */
  	struct mutex			smk_rules_lock;	/* lock for rules */
  };
  
  /*
   * Maximum number of bytes for the levels in a CIPSO IP option.
   * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
   * bigger than can be used, and 24 is the next lower multiple
   * of 8, and there are too many issues if there isn't space set
   * aside for the terminating null byte.
   */
  #define SMK_CIPSOLEN	24
  
  struct superblock_smack {
  	char		*smk_root;
  	char		*smk_floor;
  	char		*smk_hat;
  	char		*smk_default;
  	int		smk_initialized;
  };
  
  struct socket_smack {
  	struct smack_known	*smk_out;	/* outbound label */
  	char			*smk_in;	/* inbound label */
  	char			*smk_packet;	/* TCP peer label */
  };
  
  /*
   * Inode smack data
   */
  struct inode_smack {
  	char			*smk_inode;	/* label of the fso */
  	struct smack_known	*smk_task;	/* label of the task */
  	struct smack_known	*smk_mmap;	/* label of the mmap domain */
  	struct mutex		smk_lock;	/* initialization lock */
  	int			smk_flags;	/* smack inode flags */
  };
  
  struct task_smack {
  	struct smack_known	*smk_task;	/* label for access control */
  	struct smack_known	*smk_forked;	/* label when forked */
  	struct list_head	smk_rules;	/* per task access rules */
  	struct mutex		smk_rules_lock;	/* lock for the rules */
  };
  
  #define	SMK_INODE_INSTANT	0x01	/* inode is instantiated */
  #define	SMK_INODE_TRANSMUTE	0x02	/* directory is transmuting */
  #define	SMK_INODE_CHANGED	0x04	/* smack was transmuted */
  
  /*
   * A label access rule.
   */
  struct smack_rule {
  	struct list_head	list;
  	struct smack_known	*smk_subject;
  	char			*smk_object;
  	int			smk_access;
  };
  
  /*
   * An entry in the table identifying hosts.
   */
  struct smk_netlbladdr {
  	struct list_head	list;
  	struct sockaddr_in	smk_host;	/* network address */
  	struct in_addr		smk_mask;	/* network mask */
  	char			*smk_label;	/* label */
  };
  
  /*
   * An entry in the table identifying ports.
   */
  struct smk_port_label {
  	struct list_head	list;
  	struct sock		*smk_sock;	/* socket initialized on */
  	unsigned short		smk_port;	/* the port number */
  	char			*smk_in;	/* incoming label */
  	struct smack_known	*smk_out;	/* outgoing label */
  };
  
  /*
   * Mount options
   */
  #define SMK_FSDEFAULT	"smackfsdef="
  #define SMK_FSFLOOR	"smackfsfloor="
  #define SMK_FSHAT	"smackfshat="
  #define SMK_FSROOT	"smackfsroot="
  #define SMK_FSTRANS	"smackfstransmute="
  
  #define SMACK_CIPSO_OPTION 	"-CIPSO"
  
  /*
   * How communications on this socket are treated.
   * Usually it's determined by the underlying netlabel code
   * but there are certain cases, including single label hosts
   * and potentially single label interfaces for which the
   * treatment can not be known in advance.
   *
   * The possibility of additional labeling schemes being
   * introduced in the future exists as well.
   */
  #define SMACK_UNLABELED_SOCKET	0
  #define SMACK_CIPSO_SOCKET	1
  
  /*
   * CIPSO defaults.
   */
  #define SMACK_CIPSO_DOI_DEFAULT		3	/* Historical */
  #define SMACK_CIPSO_DOI_INVALID		-1	/* Not a DOI */
  #define SMACK_CIPSO_DIRECT_DEFAULT	250	/* Arbitrary */
  #define SMACK_CIPSO_MAPPED_DEFAULT	251	/* Also arbitrary */
  #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
  /*
   * CIPSO 2.2 standard is 239, but Smack wants to use the
   * categories in a structured way that limits the value to
   * the bits in 23 bytes, hence the unusual number.
   */
  #define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
  
  /*
   * Flags for untraditional access modes.
   * It shouldn't be necessary to avoid conflicts with definitions
   * in fs.h, but do so anyway.
   */
  #define MAY_TRANSMUTE	0x00001000	/* Controls directory labeling */
  #define MAY_LOCK	0x00002000	/* Locks should be writes, but ... */
  
  /*
   * Just to make the common cases easier to deal with
   */
  #define MAY_ANYREAD	(MAY_READ | MAY_EXEC)
  #define MAY_READWRITE	(MAY_READ | MAY_WRITE)
  #define MAY_NOT		0
  
  /*
   * Number of access types used by Smack (rwxatl)
   */
  #define SMK_NUM_ACCESS_TYPE 6
  
  /* SMACK data */
  struct smack_audit_data {
  	const char *function;
  	char *subject;
  	char *object;
  	char *request;
  	int result;
  };
  
  /*
   * Smack audit data; is empty if CONFIG_AUDIT not set
   * to save some stack
   */
  struct smk_audit_info {
  #ifdef CONFIG_AUDIT
  	struct common_audit_data a;
  	struct smack_audit_data sad;
  #endif
  };
  /*
   * These functions are in smack_lsm.c
   */
  struct inode_smack *new_inode_smack(char *);
  
  /*
   * These functions are in smack_access.c
   */
  int smk_access_entry(char *, char *, struct list_head *);
  int smk_access(struct smack_known *, char *, int, struct smk_audit_info *);
  int smk_curacc(char *, u32, struct smk_audit_info *);
  struct smack_known *smack_from_secid(const u32);
  char *smk_parse_smack(const char *string, int len);
  int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
  char *smk_import(const char *, int);
  struct smack_known *smk_import_entry(const char *, int);
  void smk_insert_entry(struct smack_known *skp);
  struct smack_known *smk_find_entry(const char *);
  u32 smack_to_secid(const char *);
  
  /*
   * Shared data.
   */
  extern int smack_cipso_direct;
  extern int smack_cipso_mapped;
  extern struct smack_known *smack_net_ambient;
  extern struct smack_known *smack_onlycap;
  extern struct smack_known *smack_syslog_label;
  extern const char *smack_cipso_option;
  
  extern struct smack_known smack_known_floor;
  extern struct smack_known smack_known_hat;
  extern struct smack_known smack_known_huh;
  extern struct smack_known smack_known_invalid;
  extern struct smack_known smack_known_star;
  extern struct smack_known smack_known_web;
  
  extern struct mutex	smack_known_lock;
  extern struct list_head smack_known_list;
  extern struct list_head smk_netlbladdr_list;
  
  extern struct security_operations smack_ops;
  
  #define SMACK_HASH_SLOTS 16
  extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
  
  /*
   * Is the directory transmuting?
   */
  static inline int smk_inode_transmutable(const struct inode *isp)
  {
  	struct inode_smack *sip = isp->i_security;
  	return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
  }
  
  /*
   * Present a pointer to the smack label in an inode blob.
   */
  static inline char *smk_of_inode(const struct inode *isp)
  {
  	struct inode_smack *sip = isp->i_security;
  	return sip->smk_inode;
  }
  
  /*
   * Present a pointer to the smack label entry in an task blob.
   */
  static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
  {
  	return tsp->smk_task;
  }
  
  /*
   * Present a pointer to the forked smack label entry in an task blob.
   */
  static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
  {
  	return tsp->smk_forked;
  }
  
  /*
   * Present a pointer to the smack label in the current task blob.
   */
  static inline struct smack_known *smk_of_current(void)
  {
  	return smk_of_task(current_security());
  }
  
  /*
   * Is the task privileged and allowed to be privileged
   * by the onlycap rule.
   */
  static inline int smack_privileged(int cap)
  {
  	struct smack_known *skp = smk_of_current();
  
  	if (!capable(cap))
  		return 0;
  	if (smack_onlycap == NULL || smack_onlycap == skp)
  		return 1;
  	return 0;
  }
  
  /*
   * logging functions
   */
  #define SMACK_AUDIT_DENIED 0x1
  #define SMACK_AUDIT_ACCEPT 0x2
  extern int log_policy;
  
  void smack_log(char *subject_label, char *object_label,
  		int request,
  		int result, struct smk_audit_info *auditdata);
  
  #ifdef CONFIG_AUDIT
  
  /*
   * some inline functions to set up audit data
   * they do nothing if CONFIG_AUDIT is not set
   *
   */
  static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
  			       char type)
  {
  	memset(&a->sad, 0, sizeof(a->sad));
  	a->a.type = type;
  	a->a.smack_audit_data = &a->sad;
  	a->a.smack_audit_data->function = func;
  }
  
  static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
  				   char type, struct lsm_network_audit *net)
  {
  	smk_ad_init(a, func, type);
  	memset(net, 0, sizeof(*net));
  	a->a.u.net = net;
  }
  
  static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
  					 struct task_struct *t)
  {
  	a->a.u.tsk = t;
  }
  static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
  						    struct dentry *d)
  {
  	a->a.u.dentry = d;
  }
  static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
  					      struct inode *i)
  {
  	a->a.u.inode = i;
  }
  static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
  					     struct path p)
  {
  	a->a.u.path = p;
  }
  static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
  					    struct sock *sk)
  {
  	a->a.u.net->sk = sk;
  }
  
  #else /* no AUDIT */
  
  static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
  			       char type)
  {
  }
  static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
  					 struct task_struct *t)
  {
  }
  static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
  						    struct dentry *d)
  {
  }
  static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
  						 struct vfsmount *m)
  {
  }
  static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
  					      struct inode *i)
  {
  }
  static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
  					     struct path p)
  {
  }
  static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
  					    struct sock *sk)
  {
  }
  #endif
  
  #endif  /* _SECURITY_SMACK_H */