security/tomoyo/tomoyo.c

   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_check_1path_perm(tomoyo_domain(),
 104                                        TOMOYO_TYPE_TRUNCATE_ACL,
 105                                        path);
 106 }
 107
 108 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
 109 {
 110         struct path path = { parent->mnt, dentry };
 111         return tomoyo_check_1path_perm(tomoyo_domain(),
 112                                        TOMOYO_TYPE_UNLINK_ACL,
 113                                        &path);
 114 }
 115
 116 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 117                              int mode)
 118 {
 119         struct path path = { parent->mnt, dentry };
 120         return tomoyo_check_1path_perm(tomoyo_domain(),
 121                                        TOMOYO_TYPE_MKDIR_ACL,
 122                                        &path);
 123 }
 124
 125 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 126 {
 127         struct path path = { parent->mnt, dentry };
 128         return tomoyo_check_1path_perm(tomoyo_domain(),
 129                                        TOMOYO_TYPE_RMDIR_ACL,
 130                                        &path);
 131 }
 132
 133 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 134                                const char *old_name)
 135 {
 136         struct path path = { parent->mnt, dentry };
 137         return tomoyo_check_1path_perm(tomoyo_domain(),
 138                                        TOMOYO_TYPE_SYMLINK_ACL,
 139                                        &path);
 140 }
 141
 142 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 143                              int mode, unsigned int dev)
 144 {
 145         struct path path = { parent->mnt, dentry };
 146         int type = TOMOYO_TYPE_CREATE_ACL;
 147
 148         switch (mode & S_IFMT) {
 149         case S_IFCHR:
 150                 type = TOMOYO_TYPE_MKCHAR_ACL;
 151                 break;
 152         case S_IFBLK:
 153                 type = TOMOYO_TYPE_MKBLOCK_ACL;
 154                 break;
 155         case S_IFIFO:
 156                 type = TOMOYO_TYPE_MKFIFO_ACL;
 157                 break;
 158         case S_IFSOCK:
 159                 type = TOMOYO_TYPE_MKSOCK_ACL;
 160                 break;
 161         }
 162         return tomoyo_check_1path_perm(tomoyo_domain(),
 163                                        type, &path);
 164 }
 165
 166 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 167                             struct dentry *new_dentry)
 168 {
 169         struct path path1 = { new_dir->mnt, old_dentry };
 170         struct path path2 = { new_dir->mnt, new_dentry };
 171         return tomoyo_check_2path_perm(tomoyo_domain(),
 172                                        TOMOYO_TYPE_LINK_ACL,
 173                                        &path1, &path2);
 174 }
 175
 176 static int tomoyo_path_rename(struct path *old_parent,
 177                               struct dentry *old_dentry,
 178                               struct path *new_parent,
 179                               struct dentry *new_dentry)
 180 {
 181         struct path path1 = { old_parent->mnt, old_dentry };
 182         struct path path2 = { new_parent->mnt, new_dentry };
 183         return tomoyo_check_2path_perm(tomoyo_domain(),
 184                                        TOMOYO_TYPE_RENAME_ACL,
 185                                        &path1, &path2);
 186 }
 187
 188 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 189                              unsigned long arg)
 190 {
 191         if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
 192                 return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
 193         return 0;
 194 }
 195
 196 static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
 197 {
 198         int flags = f->f_flags;
 199
 200         if ((flags + 1) & O_ACCMODE)
 201                 flags++;
 202         flags |= f->f_flags & (O_APPEND | O_TRUNC);
 203         /* Don't check read permission here if called from do_execve(). */
 204         if (current->in_execve)
 205                 return 0;
 206         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 207 }
 208
 209 static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
 210                              unsigned long arg)
 211 {
 212         return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_IOCTL_ACL,
 213                                        &file->f_path);
 214 }
 215
 216 static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
 217                              mode_t mode)
 218 {
 219         struct path path = { mnt, dentry };
 220         return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_CHMOD_ACL,
 221                                        &path);
 222 }
 223
 224 static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
 225 {
 226         int error = 0;
 227         if (uid != (uid_t) -1)
 228                 error = tomoyo_check_1path_perm(tomoyo_domain(),
 229                                                 TOMOYO_TYPE_CHOWN_ACL, path);
 230         if (!error && gid != (gid_t) -1)
 231                 error = tomoyo_check_1path_perm(tomoyo_domain(),
 232                                                 TOMOYO_TYPE_CHGRP_ACL, path);
 233         return error;
 234 }
 235
 236 static int tomoyo_path_chroot(struct path *path)
 237 {
 238         return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_CHROOT_ACL,
 239                                        path);
 240 }
 241
 242 static int tomoyo_sb_mount(char *dev_name, struct path *path,
 243                            char *type, unsigned long flags, void *data)
 244 {
 245         return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_MOUNT_ACL,
 246                                        path);
 247 }
 248
 249 static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
 250 {
 251         struct path path = { mnt, mnt->mnt_root };
 252         return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_UMOUNT_ACL,
 253                                        &path);
 254 }
 255
 256 static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
 257 {
 258         return tomoyo_check_2path_perm(tomoyo_domain(),
 259                                        TOMOYO_TYPE_PIVOT_ROOT_ACL,
 260                                        new_path, old_path);
 261 }
 262
 263 /*
 264  * tomoyo_security_ops is a "struct security_operations" which is used for
 265  * registering TOMOYO.
 266  */
 267 static struct security_operations tomoyo_security_ops = {
 268         .name                = "tomoyo",
 269         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 270         .cred_prepare        = tomoyo_cred_prepare,
 271         .cred_transfer       = tomoyo_cred_transfer,
 272         .cred_free           = tomoyo_cred_free,
 273         .bprm_set_creds      = tomoyo_bprm_set_creds,
 274         .bprm_check_security = tomoyo_bprm_check_security,
 275         .file_fcntl          = tomoyo_file_fcntl,
 276         .dentry_open         = tomoyo_dentry_open,
 277         .path_truncate       = tomoyo_path_truncate,
 278         .path_unlink         = tomoyo_path_unlink,
 279         .path_mkdir          = tomoyo_path_mkdir,
 280         .path_rmdir          = tomoyo_path_rmdir,
 281         .path_symlink        = tomoyo_path_symlink,
 282         .path_mknod          = tomoyo_path_mknod,
 283         .path_link           = tomoyo_path_link,
 284         .path_rename         = tomoyo_path_rename,
 285         .file_ioctl          = tomoyo_file_ioctl,
 286         .path_chmod          = tomoyo_path_chmod,
 287         .path_chown          = tomoyo_path_chown,
 288         .path_chroot         = tomoyo_path_chroot,
 289         .sb_mount            = tomoyo_sb_mount,
 290         .sb_umount           = tomoyo_sb_umount,
 291         .sb_pivotroot        = tomoyo_sb_pivotroot,
 292 };
 293
 294 /* Lock for GC. */
 295 struct srcu_struct tomoyo_ss;
 296
 297 static int __init tomoyo_init(void)
 298 {
 299         struct cred *cred = (struct cred *) current_cred();
 300
 301         if (!security_module_enable(&tomoyo_security_ops))
 302                 return 0;
 303         /* register ourselves with the security framework */
 304         if (register_security(&tomoyo_security_ops) ||
 305             init_srcu_struct(&tomoyo_ss))
 306                 panic("Failure registering TOMOYO Linux");
 307         printk(KERN_INFO "TOMOYO Linux initialized\n");
 308         cred->security = &tomoyo_kernel_domain;
 309         tomoyo_realpath_init();
 310         return 0;
 311 }
 312
 313 security_initcall(tomoyo_init);