file.h

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/*
 * AppArmor security module
 *
 * This file contains AppArmor file mediation function definitions.
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2010 Canonical Ltd.
 *
 * 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 of the
 * License.
 */

#ifndef __AA_FILE_H
#define __AA_FILE_H

#include "domain.h"
#include "match.h"

struct aa_profile;
struct path;

/*
 * We use MAY_EXEC, MAY_WRITE, MAY_READ, MAY_APPEND and the following flags
 * for profile permissions
 */
#define AA_MAY_CREATE                  0x0010
#define AA_MAY_DELETE                  0x0020
#define AA_MAY_META_WRITE              0x0040
#define AA_MAY_META_READ               0x0080

#define AA_MAY_CHMOD                   0x0100
#define AA_MAY_CHOWN                   0x0200
#define AA_MAY_LOCK                    0x0400
#define AA_EXEC_MMAP                   0x0800

#define AA_MAY_LINK         0x1000
#define AA_LINK_SUBSET          AA_MAY_LOCK /* overlaid */
#define AA_MAY_ONEXEC           0x40000000  /* exec allows onexec */
#define AA_MAY_CHANGE_PROFILE       0x80000000
#define AA_MAY_CHANGEHAT        0x80000000  /* ctrl auditing only */

#define AA_AUDIT_FILE_MASK  (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
                 AA_MAY_CREATE | AA_MAY_DELETE |    \
                 AA_MAY_META_READ | AA_MAY_META_WRITE | \
                 AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
                 AA_EXEC_MMAP | AA_MAY_LINK)

/*
 * The xindex is broken into 3 parts
 * - index - an index into either the exec name table or the variable table
 * - exec type - which determines how the executable name and index are used
 * - flags - which modify how the destination name is applied
 */
#define AA_X_INDEX_MASK     0x03ff

#define AA_X_TYPE_MASK      0x0c00
#define AA_X_TYPE_SHIFT     10
#define AA_X_NONE       0x0000
#define AA_X_NAME       0x0400  /* use executable name px */
#define AA_X_TABLE      0x0800  /* use a specified name ->n# */

#define AA_X_UNSAFE     0x1000
#define AA_X_CHILD      0x2000  /* make >AA_X_NONE apply to children */
#define AA_X_INHERIT        0x4000
#define AA_X_UNCONFINED     0x8000

/* AA_SECURE_X_NEEDED - is passed in the bprm->unsafe field */
#define AA_SECURE_X_NEEDED  0x8000

/* need to make conditional which ones are being set */
struct path_cond {
    kuid_t uid;
    umode_t mode;
};

/* struct file_perms - file permission
 * @allow: mask of permissions that are allowed
 * @audit: mask of permissions to force an audit message for
 * @quiet: mask of permissions to quiet audit messages for
 * @kill: mask of permissions that when matched will kill the task
 * @xindex: exec transition index if @allow contains MAY_EXEC
 *
 * The @audit and @queit mask should be mutually exclusive.
 */
struct file_perms {
    u32 allow;
    u32 audit;
    u32 quiet;
    u32 kill;
    u16 xindex;
};

extern struct file_perms nullperms;

#define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)

/* FIXME: split perms from dfa and match this to description
 *        also add delegation info.
 */
static inline u16 dfa_map_xindex(u16 mask)
{
    u16 old_index = (mask >> 10) & 0xf;
    u16 index = 0;

    if (mask & 0x100)
        index |= AA_X_UNSAFE;
    if (mask & 0x200)
        index |= AA_X_INHERIT;
    if (mask & 0x80)
        index |= AA_X_UNCONFINED;

    if (old_index == 1) {
        index |= AA_X_UNCONFINED;
    } else if (old_index == 2) {
        index |= AA_X_NAME;
    } else if (old_index == 3) {
        index |= AA_X_NAME | AA_X_CHILD;
    } else if (old_index) {
        index |= AA_X_TABLE;
        index |= old_index - 4;
    }

    return index;
}

/*
 * map old dfa inline permissions to new format
 */
#define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
                    ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
#define dfa_user_audit(dfa, state) ((ACCEPT_TABLE2(dfa)[state]) & 0x7f)
#define dfa_user_quiet(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 7) & 0x7f)
#define dfa_user_xindex(dfa, state) \
    (dfa_map_xindex(ACCEPT_TABLE(dfa)[state] & 0x3fff))

#define dfa_other_allow(dfa, state) ((((ACCEPT_TABLE(dfa)[state]) >> 14) & \
                      0x7f) |               \
                     ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
#define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
#define dfa_other_quiet(dfa, state) \
    ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
#define dfa_other_xindex(dfa, state) \
    dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)

int aa_audit_file(struct aa_profile *profile, struct file_perms *perms,
          gfp_t gfp, int op, u32 request, const char *name,
          const char *target, kuid_t ouid, const char *info, int error);

struct aa_file_rules {
    unsigned int start;
    struct aa_dfa *dfa;
    /* struct perms perms; */
    struct aa_domain trans;
    /* TODO: add delegate table */
};

unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
              const char *name, struct path_cond *cond,
              struct file_perms *perms);

int aa_path_perm(int op, struct aa_profile *profile, struct path *path,
         int flags, u32 request, struct path_cond *cond);

int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
         struct path *new_dir, struct dentry *new_dentry);

int aa_file_perm(int op, struct aa_profile *profile, struct file *file,
         u32 request);

static inline void aa_free_file_rules(struct aa_file_rules *rules)
{
    aa_put_dfa(rules->dfa);
    aa_free_domain_entries(&rules->trans);
}

#define ACC_FMODE(x) (("\000\004\002\006"[(x)&O_ACCMODE]) | (((x) << 1) & 0x40))

/* from namei.c */
#define MAP_OPEN_FLAGS(x) ((((x) + 1) & O_ACCMODE) ? (x) + 1 : (x))

static inline u32 aa_map_file_to_perms(struct file *file)
{
    int flags = MAP_OPEN_FLAGS(file->f_flags);
    u32 perms = ACC_FMODE(file->f_mode);

    if ((flags & O_APPEND) && (perms & MAY_WRITE))
        perms = (perms & ~MAY_WRITE) | MAY_APPEND;
    /* trunc implies write permission */
    if (flags & O_TRUNC)
        perms |= MAY_WRITE;
    if (flags & O_CREAT)
        perms |= AA_MAY_CREATE;

    return perms;
}

#endif /* __AA_FILE_H */