linux/security/tomoyo/securityfs_if.c
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   1/*
   2 * security/tomoyo/securityfs_if.c
   3 *
   4 * Copyright (C) 2005-2011  NTT DATA CORPORATION
   5 */
   6
   7#include <linux/security.h>
   8#include "common.h"
   9
  10/**
  11 * tomoyo_check_task_acl - Check permission for task operation.
  12 *
  13 * @r:   Pointer to "struct tomoyo_request_info".
  14 * @ptr: Pointer to "struct tomoyo_acl_info".
  15 *
  16 * Returns true if granted, false otherwise.
  17 */
  18static bool tomoyo_check_task_acl(struct tomoyo_request_info *r,
  19                                  const struct tomoyo_acl_info *ptr)
  20{
  21        const struct tomoyo_task_acl *acl = container_of(ptr, typeof(*acl),
  22                                                         head);
  23        return !tomoyo_pathcmp(r->param.task.domainname, acl->domainname);
  24}
  25
  26/**
  27 * tomoyo_write_self - write() for /sys/kernel/security/tomoyo/self_domain interface.
  28 *
  29 * @file:  Pointer to "struct file".
  30 * @buf:   Domainname to transit to.
  31 * @count: Size of @buf.
  32 * @ppos:  Unused.
  33 *
  34 * Returns @count on success, negative value otherwise.
  35 *
  36 * If domain transition was permitted but the domain transition failed, this
  37 * function returns error rather than terminating current thread with SIGKILL.
  38 */
  39static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
  40                              size_t count, loff_t *ppos)
  41{
  42        char *data;
  43        int error;
  44        if (!count || count >= TOMOYO_EXEC_TMPSIZE - 10)
  45                return -ENOMEM;
  46        data = kzalloc(count + 1, GFP_NOFS);
  47        if (!data)
  48                return -ENOMEM;
  49        if (copy_from_user(data, buf, count)) {
  50                error = -EFAULT;
  51                goto out;
  52        }
  53        tomoyo_normalize_line(data);
  54        if (tomoyo_correct_domain(data)) {
  55                const int idx = tomoyo_read_lock();
  56                struct tomoyo_path_info name;
  57                struct tomoyo_request_info r;
  58                name.name = data;
  59                tomoyo_fill_path_info(&name);
  60                /* Check "task manual_domain_transition" permission. */
  61                tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
  62                r.param_type = TOMOYO_TYPE_MANUAL_TASK_ACL;
  63                r.param.task.domainname = &name;
  64                tomoyo_check_acl(&r, tomoyo_check_task_acl);
  65                if (!r.granted)
  66                        error = -EPERM;
  67                else {
  68                        struct tomoyo_domain_info *new_domain =
  69                                tomoyo_assign_domain(data, true);
  70                        if (!new_domain) {
  71                                error = -ENOENT;
  72                        } else {
  73                                struct cred *cred = prepare_creds();
  74                                if (!cred) {
  75                                        error = -ENOMEM;
  76                                } else {
  77                                        struct tomoyo_domain_info *old_domain =
  78                                                cred->security;
  79                                        cred->security = new_domain;
  80                                        atomic_inc(&new_domain->users);
  81                                        atomic_dec(&old_domain->users);
  82                                        commit_creds(cred);
  83                                        error = 0;
  84                                }
  85                        }
  86                }
  87                tomoyo_read_unlock(idx);
  88        } else
  89                error = -EINVAL;
  90out:
  91        kfree(data);
  92        return error ? error : count;
  93}
  94
  95/**
  96 * tomoyo_read_self - read() for /sys/kernel/security/tomoyo/self_domain interface.
  97 *
  98 * @file:  Pointer to "struct file".
  99 * @buf:   Domainname which current thread belongs to.
 100 * @count: Size of @buf.
 101 * @ppos:  Bytes read by now.
 102 *
 103 * Returns read size on success, negative value otherwise.
 104 */
 105static ssize_t tomoyo_read_self(struct file *file, char __user *buf,
 106                                size_t count, loff_t *ppos)
 107{
 108        const char *domain = tomoyo_domain()->domainname->name;
 109        loff_t len = strlen(domain);
 110        loff_t pos = *ppos;
 111        if (pos >= len || !count)
 112                return 0;
 113        len -= pos;
 114        if (count < len)
 115                len = count;
 116        if (copy_to_user(buf, domain + pos, len))
 117                return -EFAULT;
 118        *ppos += len;
 119        return len;
 120}
 121
 122/* Operations for /sys/kernel/security/tomoyo/self_domain interface. */
 123static const struct file_operations tomoyo_self_operations = {
 124        .write = tomoyo_write_self,
 125        .read  = tomoyo_read_self,
 126};
 127
 128/**
 129 * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface.
 130 *
 131 * @inode: Pointer to "struct inode".
 132 * @file:  Pointer to "struct file".
 133 *
 134 * Returns 0 on success, negative value otherwise.
 135 */
 136static int tomoyo_open(struct inode *inode, struct file *file)
 137{
 138        const int key = ((u8 *) file->f_path.dentry->d_inode->i_private)
 139                - ((u8 *) NULL);
 140        return tomoyo_open_control(key, file);
 141}
 142
 143/**
 144 * tomoyo_release - close() for /sys/kernel/security/tomoyo/ interface.
 145 *
 146 * @inode: Pointer to "struct inode".
 147 * @file:  Pointer to "struct file".
 148 *
 149 * Returns 0 on success, negative value otherwise.
 150 */
 151static int tomoyo_release(struct inode *inode, struct file *file)
 152{
 153        return tomoyo_close_control(file->private_data);
 154}
 155
 156/**
 157 * tomoyo_poll - poll() for /sys/kernel/security/tomoyo/ interface.
 158 *
 159 * @file: Pointer to "struct file".
 160 * @wait: Pointer to "poll_table". Maybe NULL.
 161 *
 162 * Returns POLLIN | POLLRDNORM | POLLOUT | POLLWRNORM if ready to read/write,
 163 * POLLOUT | POLLWRNORM otherwise.
 164 */
 165static unsigned int tomoyo_poll(struct file *file, poll_table *wait)
 166{
 167        return tomoyo_poll_control(file, wait);
 168}
 169
 170/**
 171 * tomoyo_read - read() for /sys/kernel/security/tomoyo/ interface.
 172 *
 173 * @file:  Pointer to "struct file".
 174 * @buf:   Pointer to buffer.
 175 * @count: Size of @buf.
 176 * @ppos:  Unused.
 177 *
 178 * Returns bytes read on success, negative value otherwise.
 179 */
 180static ssize_t tomoyo_read(struct file *file, char __user *buf, size_t count,
 181                           loff_t *ppos)
 182{
 183        return tomoyo_read_control(file->private_data, buf, count);
 184}
 185
 186/**
 187 * tomoyo_write - write() for /sys/kernel/security/tomoyo/ interface.
 188 *
 189 * @file:  Pointer to "struct file".
 190 * @buf:   Pointer to buffer.
 191 * @count: Size of @buf.
 192 * @ppos:  Unused.
 193 *
 194 * Returns @count on success, negative value otherwise.
 195 */
 196static ssize_t tomoyo_write(struct file *file, const char __user *buf,
 197                            size_t count, loff_t *ppos)
 198{
 199        return tomoyo_write_control(file->private_data, buf, count);
 200}
 201
 202/*
 203 * tomoyo_operations is a "struct file_operations" which is used for handling
 204 * /sys/kernel/security/tomoyo/ interface.
 205 *
 206 * Some files under /sys/kernel/security/tomoyo/ directory accept open(O_RDWR).
 207 * See tomoyo_io_buffer for internals.
 208 */
 209static const struct file_operations tomoyo_operations = {
 210        .open    = tomoyo_open,
 211        .release = tomoyo_release,
 212        .poll    = tomoyo_poll,
 213        .read    = tomoyo_read,
 214        .write   = tomoyo_write,
 215        .llseek  = noop_llseek,
 216};
 217
 218/**
 219 * tomoyo_create_entry - Create interface files under /sys/kernel/security/tomoyo/ directory.
 220 *
 221 * @name:   The name of the interface file.
 222 * @mode:   The permission of the interface file.
 223 * @parent: The parent directory.
 224 * @key:    Type of interface.
 225 *
 226 * Returns nothing.
 227 */
 228static void __init tomoyo_create_entry(const char *name, const umode_t mode,
 229                                       struct dentry *parent, const u8 key)
 230{
 231        securityfs_create_file(name, mode, parent, ((u8 *) NULL) + key,
 232                               &tomoyo_operations);
 233}
 234
 235/**
 236 * tomoyo_initerface_init - Initialize /sys/kernel/security/tomoyo/ interface.
 237 *
 238 * Returns 0.
 239 */
 240static int __init tomoyo_initerface_init(void)
 241{
 242        struct dentry *tomoyo_dir;
 243
 244        /* Don't create securityfs entries unless registered. */
 245        if (current_cred()->security != &tomoyo_kernel_domain)
 246                return 0;
 247
 248        tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
 249        tomoyo_create_entry("query",            0600, tomoyo_dir,
 250                            TOMOYO_QUERY);
 251        tomoyo_create_entry("domain_policy",    0600, tomoyo_dir,
 252                            TOMOYO_DOMAINPOLICY);
 253        tomoyo_create_entry("exception_policy", 0600, tomoyo_dir,
 254                            TOMOYO_EXCEPTIONPOLICY);
 255        tomoyo_create_entry("audit",            0400, tomoyo_dir,
 256                            TOMOYO_AUDIT);
 257        tomoyo_create_entry(".process_status",  0600, tomoyo_dir,
 258                            TOMOYO_PROCESS_STATUS);
 259        tomoyo_create_entry("stat",             0644, tomoyo_dir,
 260                            TOMOYO_STAT);
 261        tomoyo_create_entry("profile",          0600, tomoyo_dir,
 262                            TOMOYO_PROFILE);
 263        tomoyo_create_entry("manager",          0600, tomoyo_dir,
 264                            TOMOYO_MANAGER);
 265        tomoyo_create_entry("version",          0400, tomoyo_dir,
 266                            TOMOYO_VERSION);
 267        securityfs_create_file("self_domain", 0666, tomoyo_dir, NULL,
 268                               &tomoyo_self_operations);
 269        tomoyo_load_builtin_policy();
 270        return 0;
 271}
 272
 273fs_initcall(tomoyo_initerface_init);
 274
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