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   1 /*
   2  * security/tomoyo/tomoyo.c
   3  *
   4  * LSM hooks for TOMOYO Linux.
   5  *
   6  * Copyright (C) 2005-2009  NTT DATA CORPORATION
   7  *
   8  * Version: 2.2.0   2009/04/01
   9  *
  10  */
  11
  12 #include <linux/security.h>
  13 #include "common.h"
  14
  15 static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
  16 {
  17         new->security = NULL;
  18         return 0;
  19 }
  20
  21 static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
  22                                gfp_t gfp)
  23 {
  24         struct tomoyo_domain_info *domain = old->security;
  25         new->security = domain;
  26         if (domain)
  27                 atomic_inc(&domain->users);
  28         return 0;
  29 }
  30
  31 static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
  32 {
  33         tomoyo_cred_prepare(new, old, 0);
  34 }
  35
  36 static void tomoyo_cred_free(struct cred *cred)
  37 {
  38         struct tomoyo_domain_info *domain = cred->security;
  39         if (domain)
  40                 atomic_dec(&domain->users);
  41 }
  42
  43 static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
  44 {
  45         int rc;
  46
  47         rc = cap_bprm_set_creds(bprm);
  48         if (rc)
  49                 return rc;
  50
  51         /*
  52          * Do only if this function is called for the first time of an execve
  53          * operation.
  54          */
  55         if (bprm->cred_prepared)
  56                 return 0;
  57         /*
  58          * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
  59          * for the first time.
  60          */
  61         if (!tomoyo_policy_loaded)
  62                 tomoyo_load_policy(bprm->filename);
  63         /*
  64          * Release reference to "struct tomoyo_domain_info" stored inside
  65          * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
  66          * stored inside "bprm->cred->security" will be acquired later inside
  67          * tomoyo_find_next_domain().
  68          */
  69         atomic_dec(&((struct tomoyo_domain_info *)
  70                      bprm->cred->security)->users);
  71         /*
  72          * Tell tomoyo_bprm_check_security() is called for the first time of an
  73          * execve operation.
  74          */
  75         bprm->cred->security = NULL;
  76         return 0;
  77 }
  78
  79 static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
  80 {
  81         struct tomoyo_domain_info *domain = bprm->cred->security;
  82
  83         /*
  84          * Execute permission is checked against pathname passed to do_execve()
  85          * using current domain.
  86          */
  87         if (!domain) {
  88                 const int idx = tomoyo_read_lock();
  89                 const int err = tomoyo_find_next_domain(bprm);
  90                 tomoyo_read_unlock(idx);
  91                 return err;
  92         }
  93         /*
  94          * Read permission is checked against interpreters using next domain.
  95          * '1' is the result of open_to_namei_flags(O_RDONLY).
  96          */
  97         return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
  98 }
  99
 100 static int tomoyo_path_truncate(struct path *path, loff_t length,
 101                                 unsigned int time_attrs)
 102 {
 103         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_TRUNCATE, path);
 104 }
 105
 106 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
 107 {
 108         struct path path = { parent->mnt, dentry };
 109         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_UNLINK, &path);
 110 }
 111
 112 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 113                              int mode)
 114 {
 115         struct path path = { parent->mnt, dentry };
 116         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_MKDIR, &path);
 117 }
 118
 119 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 120 {
 121         struct path path = { parent->mnt, dentry };
 122         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_RMDIR, &path);
 123 }
 124
 125 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 126                                const char *old_name)
 127 {
 128         struct path path = { parent->mnt, dentry };
 129         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_SYMLINK, &path);
 130 }
 131
 132 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 133                              int mode, unsigned int dev)
 134 {
 135         struct path path = { parent->mnt, dentry };
 136         int type = TOMOYO_TYPE_CREATE;
 137
 138         switch (mode & S_IFMT) {
 139         case S_IFCHR:
 140                 type = TOMOYO_TYPE_MKCHAR;
 141                 break;
 142         case S_IFBLK:
 143                 type = TOMOYO_TYPE_MKBLOCK;
 144                 break;
 145         case S_IFIFO:
 146                 type = TOMOYO_TYPE_MKFIFO;
 147                 break;
 148         case S_IFSOCK:
 149                 type = TOMOYO_TYPE_MKSOCK;
 150                 break;
 151         }
 152         return tomoyo_path_perm(tomoyo_domain(), type, &path);
 153 }
 154
 155 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 156                             struct dentry *new_dentry)
 157 {
 158         struct path path1 = { new_dir->mnt, old_dentry };
 159         struct path path2 = { new_dir->mnt, new_dentry };
 160         return tomoyo_path2_perm(tomoyo_domain(), TOMOYO_TYPE_LINK, &path1,
 161                                  &path2);
 162 }
 163
 164 static int tomoyo_path_rename(struct path *old_parent,
 165                               struct dentry *old_dentry,
 166                               struct path *new_parent,
 167                               struct dentry *new_dentry)
 168 {
 169         struct path path1 = { old_parent->mnt, old_dentry };
 170         struct path path2 = { new_parent->mnt, new_dentry };
 171         return tomoyo_path2_perm(tomoyo_domain(), TOMOYO_TYPE_RENAME, &path1,
 172                                  &path2);
 173 }
 174
 175 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 176                              unsigned long arg)
 177 {
 178         if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
 179                 return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
 180         return 0;
 181 }
 182
 183 static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
 184 {
 185         int flags = f->f_flags;
 186
 187         if ((flags + 1) & O_ACCMODE)
 188                 flags++;
 189         flags |= f->f_flags & (O_APPEND | O_TRUNC);
 190         /* Don't check read permission here if called from do_execve(). */
 191         if (current->in_execve)
 192                 return 0;
 193         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 194 }
 195
 196 static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
 197                              unsigned long arg)
 198 {
 199         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_IOCTL,
 200                                 &file->f_path);
 201 }
 202
 203 static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
 204                              mode_t mode)
 205 {
 206         struct path path = { mnt, dentry };
 207         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_CHMOD, &path);
 208 }
 209
 210 static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
 211 {
 212         int error = 0;
 213         if (uid != (uid_t) -1)
 214                 error = tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_CHOWN,
 215                                          path);
 216         if (!error && gid != (gid_t) -1)
 217                 error = tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_CHGRP,
 218                                          path);
 219         return error;
 220 }
 221
 222 static int tomoyo_path_chroot(struct path *path)
 223 {
 224         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_CHROOT, path);
 225 }
 226
 227 static int tomoyo_sb_mount(char *dev_name, struct path *path,
 228                            char *type, unsigned long flags, void *data)
 229 {
 230         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_MOUNT, path);
 231 }
 232
 233 static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
 234 {
 235         struct path path = { mnt, mnt->mnt_root };
 236         return tomoyo_path_perm(tomoyo_domain(), TOMOYO_TYPE_UMOUNT, &path);
 237 }
 238
 239 static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
 240 {
 241         return tomoyo_path2_perm(tomoyo_domain(), TOMOYO_TYPE_PIVOT_ROOT,
 242                                  new_path, old_path);
 243 }
 244
 245 /*
 246  * tomoyo_security_ops is a "struct security_operations" which is used for
 247  * registering TOMOYO.
 248  */
 249 static struct security_operations tomoyo_security_ops = {
 250         .name                = "tomoyo",
 251         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 252         .cred_prepare        = tomoyo_cred_prepare,
 253         .cred_transfer       = tomoyo_cred_transfer,
 254         .cred_free           = tomoyo_cred_free,
 255         .bprm_set_creds      = tomoyo_bprm_set_creds,
 256         .bprm_check_security = tomoyo_bprm_check_security,
 257         .file_fcntl          = tomoyo_file_fcntl,
 258         .dentry_open         = tomoyo_dentry_open,
 259         .path_truncate       = tomoyo_path_truncate,
 260         .path_unlink         = tomoyo_path_unlink,
 261         .path_mkdir          = tomoyo_path_mkdir,
 262         .path_rmdir          = tomoyo_path_rmdir,
 263         .path_symlink        = tomoyo_path_symlink,
 264         .path_mknod          = tomoyo_path_mknod,
 265         .path_link           = tomoyo_path_link,
 266         .path_rename         = tomoyo_path_rename,
 267         .file_ioctl          = tomoyo_file_ioctl,
 268         .path_chmod          = tomoyo_path_chmod,
 269         .path_chown          = tomoyo_path_chown,
 270         .path_chroot         = tomoyo_path_chroot,
 271         .sb_mount            = tomoyo_sb_mount,
 272         .sb_umount           = tomoyo_sb_umount,
 273         .sb_pivotroot        = tomoyo_sb_pivotroot,
 274 };
 275
 276 /* Lock for GC. */
 277 struct srcu_struct tomoyo_ss;
 278
 279 static int __init tomoyo_init(void)
 280 {
 281         struct cred *cred = (struct cred *) current_cred();
 282
 283         if (!security_module_enable(&tomoyo_security_ops))
 284                 return 0;
 285         /* register ourselves with the security framework */
 286         if (register_security(&tomoyo_security_ops) ||
 287             init_srcu_struct(&tomoyo_ss))
 288                 panic("Failure registering TOMOYO Linux");
 289         printk(KERN_INFO "TOMOYO Linux initialized\n");
 290         cred->security = &tomoyo_kernel_domain;
 291         tomoyo_realpath_init();
 292         return 0;
 293 }
 294
 295 security_initcall(tomoyo_init);