linux/security/apparmor/apparmorfs.c
<<
>>
Prefs
   1/*
   2 * AppArmor security module
   3 *
   4 * This file contains AppArmor /sys/kernel/security/apparmor interface functions
   5 *
   6 * Copyright (C) 1998-2008 Novell/SUSE
   7 * Copyright 2009-2010 Canonical Ltd.
   8 *
   9 * This program is free software; you can redistribute it and/or
  10 * modify it under the terms of the GNU General Public License as
  11 * published by the Free Software Foundation, version 2 of the
  12 * License.
  13 */
  14
  15#include <linux/security.h>
  16#include <linux/vmalloc.h>
  17#include <linux/module.h>
  18#include <linux/seq_file.h>
  19#include <linux/uaccess.h>
  20#include <linux/namei.h>
  21#include <linux/capability.h>
  22
  23#include "include/apparmor.h"
  24#include "include/apparmorfs.h"
  25#include "include/audit.h"
  26#include "include/context.h"
  27#include "include/policy.h"
  28#include "include/resource.h"
  29
  30/**
  31 * aa_simple_write_to_buffer - common routine for getting policy from user
  32 * @op: operation doing the user buffer copy
  33 * @userbuf: user buffer to copy data from  (NOT NULL)
  34 * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size)
  35 * @copy_size: size of data to copy from user buffer
  36 * @pos: position write is at in the file (NOT NULL)
  37 *
  38 * Returns: kernel buffer containing copy of user buffer data or an
  39 *          ERR_PTR on failure.
  40 */
  41static char *aa_simple_write_to_buffer(int op, const char __user *userbuf,
  42                                       size_t alloc_size, size_t copy_size,
  43                                       loff_t *pos)
  44{
  45        char *data;
  46
  47        BUG_ON(copy_size > alloc_size);
  48
  49        if (*pos != 0)
  50                /* only writes from pos 0, that is complete writes */
  51                return ERR_PTR(-ESPIPE);
  52
  53        /*
  54         * Don't allow profile load/replace/remove from profiles that don't
  55         * have CAP_MAC_ADMIN
  56         */
  57        if (!aa_may_manage_policy(op))
  58                return ERR_PTR(-EACCES);
  59
  60        /* freed by caller to simple_write_to_buffer */
  61        data = kvmalloc(alloc_size);
  62        if (data == NULL)
  63                return ERR_PTR(-ENOMEM);
  64
  65        if (copy_from_user(data, userbuf, copy_size)) {
  66                kvfree(data);
  67                return ERR_PTR(-EFAULT);
  68        }
  69
  70        return data;
  71}
  72
  73
  74/* .load file hook fn to load policy */
  75static ssize_t profile_load(struct file *f, const char __user *buf, size_t size,
  76                            loff_t *pos)
  77{
  78        char *data;
  79        ssize_t error;
  80
  81        data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos);
  82
  83        error = PTR_ERR(data);
  84        if (!IS_ERR(data)) {
  85                error = aa_replace_profiles(data, size, PROF_ADD);
  86                kvfree(data);
  87        }
  88
  89        return error;
  90}
  91
  92static const struct file_operations aa_fs_profile_load = {
  93        .write = profile_load,
  94        .llseek = default_llseek,
  95};
  96
  97/* .replace file hook fn to load and/or replace policy */
  98static ssize_t profile_replace(struct file *f, const char __user *buf,
  99                               size_t size, loff_t *pos)
 100{
 101        char *data;
 102        ssize_t error;
 103
 104        data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos);
 105        error = PTR_ERR(data);
 106        if (!IS_ERR(data)) {
 107                error = aa_replace_profiles(data, size, PROF_REPLACE);
 108                kvfree(data);
 109        }
 110
 111        return error;
 112}
 113
 114static const struct file_operations aa_fs_profile_replace = {
 115        .write = profile_replace,
 116        .llseek = default_llseek,
 117};
 118
 119/* .remove file hook fn to remove loaded policy */
 120static ssize_t profile_remove(struct file *f, const char __user *buf,
 121                              size_t size, loff_t *pos)
 122{
 123        char *data;
 124        ssize_t error;
 125
 126        /*
 127         * aa_remove_profile needs a null terminated string so 1 extra
 128         * byte is allocated and the copied data is null terminated.
 129         */
 130        data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos);
 131
 132        error = PTR_ERR(data);
 133        if (!IS_ERR(data)) {
 134                data[size] = 0;
 135                error = aa_remove_profiles(data, size);
 136                kvfree(data);
 137        }
 138
 139        return error;
 140}
 141
 142static const struct file_operations aa_fs_profile_remove = {
 143        .write = profile_remove,
 144        .llseek = default_llseek,
 145};
 146
 147static int aa_fs_seq_show(struct seq_file *seq, void *v)
 148{
 149        struct aa_fs_entry *fs_file = seq->private;
 150
 151        if (!fs_file)
 152                return 0;
 153
 154        switch (fs_file->v_type) {
 155        case AA_FS_TYPE_BOOLEAN:
 156                seq_printf(seq, "%s\n", fs_file->v.boolean ? "yes" : "no");
 157                break;
 158        case AA_FS_TYPE_STRING:
 159                seq_printf(seq, "%s\n", fs_file->v.string);
 160                break;
 161        case AA_FS_TYPE_U64:
 162                seq_printf(seq, "%#08lx\n", fs_file->v.u64);
 163                break;
 164        default:
 165                /* Ignore unpritable entry types. */
 166                break;
 167        }
 168
 169        return 0;
 170}
 171
 172static int aa_fs_seq_open(struct inode *inode, struct file *file)
 173{
 174        return single_open(file, aa_fs_seq_show, inode->i_private);
 175}
 176
 177const struct file_operations aa_fs_seq_file_ops = {
 178        .owner          = THIS_MODULE,
 179        .open           = aa_fs_seq_open,
 180        .read           = seq_read,
 181        .llseek         = seq_lseek,
 182        .release        = single_release,
 183};
 184
 185/** Base file system setup **/
 186
 187static struct aa_fs_entry aa_fs_entry_file[] = {
 188        AA_FS_FILE_STRING("mask", "create read write exec append mmap_exec " \
 189                                  "link lock"),
 190        { }
 191};
 192
 193static struct aa_fs_entry aa_fs_entry_domain[] = {
 194        AA_FS_FILE_BOOLEAN("change_hat",        1),
 195        AA_FS_FILE_BOOLEAN("change_hatv",       1),
 196        AA_FS_FILE_BOOLEAN("change_onexec",     1),
 197        AA_FS_FILE_BOOLEAN("change_profile",    1),
 198        { }
 199};
 200
 201static struct aa_fs_entry aa_fs_entry_features[] = {
 202        AA_FS_DIR("domain",                     aa_fs_entry_domain),
 203        AA_FS_DIR("file",                       aa_fs_entry_file),
 204        AA_FS_FILE_U64("capability",            VFS_CAP_FLAGS_MASK),
 205        AA_FS_DIR("rlimit",                     aa_fs_entry_rlimit),
 206        { }
 207};
 208
 209static struct aa_fs_entry aa_fs_entry_apparmor[] = {
 210        AA_FS_FILE_FOPS(".load", 0640, &aa_fs_profile_load),
 211        AA_FS_FILE_FOPS(".replace", 0640, &aa_fs_profile_replace),
 212        AA_FS_FILE_FOPS(".remove", 0640, &aa_fs_profile_remove),
 213        AA_FS_DIR("features", aa_fs_entry_features),
 214        { }
 215};
 216
 217static struct aa_fs_entry aa_fs_entry =
 218        AA_FS_DIR("apparmor", aa_fs_entry_apparmor);
 219
 220/**
 221 * aafs_create_file - create a file entry in the apparmor securityfs
 222 * @fs_file: aa_fs_entry to build an entry for (NOT NULL)
 223 * @parent: the parent dentry in the securityfs
 224 *
 225 * Use aafs_remove_file to remove entries created with this fn.
 226 */
 227static int __init aafs_create_file(struct aa_fs_entry *fs_file,
 228                                   struct dentry *parent)
 229{
 230        int error = 0;
 231
 232        fs_file->dentry = securityfs_create_file(fs_file->name,
 233                                                 S_IFREG | fs_file->mode,
 234                                                 parent, fs_file,
 235                                                 fs_file->file_ops);
 236        if (IS_ERR(fs_file->dentry)) {
 237                error = PTR_ERR(fs_file->dentry);
 238                fs_file->dentry = NULL;
 239        }
 240        return error;
 241}
 242
 243/**
 244 * aafs_create_dir - recursively create a directory entry in the securityfs
 245 * @fs_dir: aa_fs_entry (and all child entries) to build (NOT NULL)
 246 * @parent: the parent dentry in the securityfs
 247 *
 248 * Use aafs_remove_dir to remove entries created with this fn.
 249 */
 250static int __init aafs_create_dir(struct aa_fs_entry *fs_dir,
 251                                  struct dentry *parent)
 252{
 253        int error;
 254        struct aa_fs_entry *fs_file;
 255
 256        fs_dir->dentry = securityfs_create_dir(fs_dir->name, parent);
 257        if (IS_ERR(fs_dir->dentry)) {
 258                error = PTR_ERR(fs_dir->dentry);
 259                fs_dir->dentry = NULL;
 260                goto failed;
 261        }
 262
 263        for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) {
 264                if (fs_file->v_type == AA_FS_TYPE_DIR)
 265                        error = aafs_create_dir(fs_file, fs_dir->dentry);
 266                else
 267                        error = aafs_create_file(fs_file, fs_dir->dentry);
 268                if (error)
 269                        goto failed;
 270        }
 271
 272        return 0;
 273
 274failed:
 275        return error;
 276}
 277
 278/**
 279 * aafs_remove_file - drop a single file entry in the apparmor securityfs
 280 * @fs_file: aa_fs_entry to detach from the securityfs (NOT NULL)
 281 */
 282static void __init aafs_remove_file(struct aa_fs_entry *fs_file)
 283{
 284        if (!fs_file->dentry)
 285                return;
 286
 287        securityfs_remove(fs_file->dentry);
 288        fs_file->dentry = NULL;
 289}
 290
 291/**
 292 * aafs_remove_dir - recursively drop a directory entry from the securityfs
 293 * @fs_dir: aa_fs_entry (and all child entries) to detach (NOT NULL)
 294 */
 295static void __init aafs_remove_dir(struct aa_fs_entry *fs_dir)
 296{
 297        struct aa_fs_entry *fs_file;
 298
 299        for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) {
 300                if (fs_file->v_type == AA_FS_TYPE_DIR)
 301                        aafs_remove_dir(fs_file);
 302                else
 303                        aafs_remove_file(fs_file);
 304        }
 305
 306        aafs_remove_file(fs_dir);
 307}
 308
 309/**
 310 * aa_destroy_aafs - cleanup and free aafs
 311 *
 312 * releases dentries allocated by aa_create_aafs
 313 */
 314void __init aa_destroy_aafs(void)
 315{
 316        aafs_remove_dir(&aa_fs_entry);
 317}
 318
 319/**
 320 * aa_create_aafs - create the apparmor security filesystem
 321 *
 322 * dentries created here are released by aa_destroy_aafs
 323 *
 324 * Returns: error on failure
 325 */
 326static int __init aa_create_aafs(void)
 327{
 328        int error;
 329
 330        if (!apparmor_initialized)
 331                return 0;
 332
 333        if (aa_fs_entry.dentry) {
 334                AA_ERROR("%s: AppArmor securityfs already exists\n", __func__);
 335                return -EEXIST;
 336        }
 337
 338        /* Populate fs tree. */
 339        error = aafs_create_dir(&aa_fs_entry, NULL);
 340        if (error)
 341                goto error;
 342
 343        /* TODO: add support for apparmorfs_null and apparmorfs_mnt */
 344
 345        /* Report that AppArmor fs is enabled */
 346        aa_info_message("AppArmor Filesystem Enabled");
 347        return 0;
 348
 349error:
 350        aa_destroy_aafs();
 351        AA_ERROR("Error creating AppArmor securityfs\n");
 352        return error;
 353}
 354
 355fs_initcall(aa_create_aafs);
 356
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.